1 /*-------------------------------------------------------------------------
2 *
3 * parse_coerce.c
4 * handle type coercions/conversions for parser
5 *
6 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/parser/parse_coerce.c
12 *
13 *-------------------------------------------------------------------------
14 */
15 #include "postgres.h"
16
17 #include "catalog/pg_cast.h"
18 #include "catalog/pg_class.h"
19 #include "catalog/pg_inherits.h"
20 #include "catalog/pg_proc.h"
21 #include "catalog/pg_type.h"
22 #include "nodes/makefuncs.h"
23 #include "nodes/nodeFuncs.h"
24 #include "parser/parse_coerce.h"
25 #include "parser/parse_relation.h"
26 #include "parser/parse_type.h"
27 #include "utils/builtins.h"
28 #include "utils/datum.h" /* needed for datumIsEqual() */
29 #include "utils/fmgroids.h"
30 #include "utils/lsyscache.h"
31 #include "utils/syscache.h"
32 #include "utils/typcache.h"
33
34
35 static Node *coerce_type_typmod(Node *node,
36 Oid targetTypeId, int32 targetTypMod,
37 CoercionContext ccontext, CoercionForm cformat,
38 int location,
39 bool hideInputCoercion);
40 static void hide_coercion_node(Node *node);
41 static Node *build_coercion_expression(Node *node,
42 CoercionPathType pathtype,
43 Oid funcId,
44 Oid targetTypeId, int32 targetTypMod,
45 CoercionContext ccontext, CoercionForm cformat,
46 int location);
47 static Node *coerce_record_to_complex(ParseState *pstate, Node *node,
48 Oid targetTypeId,
49 CoercionContext ccontext,
50 CoercionForm cformat,
51 int location);
52 static bool is_complex_array(Oid typid);
53 static bool typeIsOfTypedTable(Oid reltypeId, Oid reloftypeId);
54
55
56 /*
57 * coerce_to_target_type()
58 * Convert an expression to a target type and typmod.
59 *
60 * This is the general-purpose entry point for arbitrary type coercion
61 * operations. Direct use of the component operations can_coerce_type,
62 * coerce_type, and coerce_type_typmod should be restricted to special
63 * cases (eg, when the conversion is expected to succeed).
64 *
65 * Returns the possibly-transformed expression tree, or NULL if the type
66 * conversion is not possible. (We do this, rather than ereport'ing directly,
67 * so that callers can generate custom error messages indicating context.)
68 *
69 * pstate - parse state (can be NULL, see coerce_type)
70 * expr - input expression tree (already transformed by transformExpr)
71 * exprtype - result type of expr
72 * targettype - desired result type
73 * targettypmod - desired result typmod
74 * ccontext, cformat - context indicators to control coercions
75 * location - parse location of the coercion request, or -1 if unknown/implicit
76 */
77 Node *
coerce_to_target_type(ParseState * pstate,Node * expr,Oid exprtype,Oid targettype,int32 targettypmod,CoercionContext ccontext,CoercionForm cformat,int location)78 coerce_to_target_type(ParseState *pstate, Node *expr, Oid exprtype,
79 Oid targettype, int32 targettypmod,
80 CoercionContext ccontext,
81 CoercionForm cformat,
82 int location)
83 {
84 Node *result;
85 Node *origexpr;
86
87 if (!can_coerce_type(1, &exprtype, &targettype, ccontext))
88 return NULL;
89
90 /*
91 * If the input has a CollateExpr at the top, strip it off, perform the
92 * coercion, and put a new one back on. This is annoying since it
93 * duplicates logic in coerce_type, but if we don't do this then it's too
94 * hard to tell whether coerce_type actually changed anything, and we
95 * *must* know that to avoid possibly calling hide_coercion_node on
96 * something that wasn't generated by coerce_type. Note that if there are
97 * multiple stacked CollateExprs, we just discard all but the topmost.
98 * Also, if the target type isn't collatable, we discard the CollateExpr.
99 */
100 origexpr = expr;
101 while (expr && IsA(expr, CollateExpr))
102 expr = (Node *) ((CollateExpr *) expr)->arg;
103
104 result = coerce_type(pstate, expr, exprtype,
105 targettype, targettypmod,
106 ccontext, cformat, location);
107
108 /*
109 * If the target is a fixed-length type, it may need a length coercion as
110 * well as a type coercion. If we find ourselves adding both, force the
111 * inner coercion node to implicit display form.
112 */
113 result = coerce_type_typmod(result,
114 targettype, targettypmod,
115 ccontext, cformat, location,
116 (result != expr && !IsA(result, Const)));
117
118 if (expr != origexpr && type_is_collatable(targettype))
119 {
120 /* Reinstall top CollateExpr */
121 CollateExpr *coll = (CollateExpr *) origexpr;
122 CollateExpr *newcoll = makeNode(CollateExpr);
123
124 newcoll->arg = (Expr *) result;
125 newcoll->collOid = coll->collOid;
126 newcoll->location = coll->location;
127 result = (Node *) newcoll;
128 }
129
130 return result;
131 }
132
133
134 /*
135 * coerce_type()
136 * Convert an expression to a different type.
137 *
138 * The caller should already have determined that the coercion is possible;
139 * see can_coerce_type.
140 *
141 * Normally, no coercion to a typmod (length) is performed here. The caller
142 * must call coerce_type_typmod as well, if a typmod constraint is wanted.
143 * (But if the target type is a domain, it may internally contain a
144 * typmod constraint, which will be applied inside coerce_to_domain.)
145 * In some cases pg_cast specifies a type coercion function that also
146 * applies length conversion, and in those cases only, the result will
147 * already be properly coerced to the specified typmod.
148 *
149 * pstate is only used in the case that we are able to resolve the type of
150 * a previously UNKNOWN Param. It is okay to pass pstate = NULL if the
151 * caller does not want type information updated for Params.
152 *
153 * Note: this function must not modify the given expression tree, only add
154 * decoration on top of it. See transformSetOperationTree, for example.
155 */
156 Node *
coerce_type(ParseState * pstate,Node * node,Oid inputTypeId,Oid targetTypeId,int32 targetTypeMod,CoercionContext ccontext,CoercionForm cformat,int location)157 coerce_type(ParseState *pstate, Node *node,
158 Oid inputTypeId, Oid targetTypeId, int32 targetTypeMod,
159 CoercionContext ccontext, CoercionForm cformat, int location)
160 {
161 Node *result;
162 CoercionPathType pathtype;
163 Oid funcId;
164
165 if (targetTypeId == inputTypeId ||
166 node == NULL)
167 {
168 /* no conversion needed */
169 return node;
170 }
171 if (targetTypeId == ANYOID ||
172 targetTypeId == ANYELEMENTOID ||
173 targetTypeId == ANYNONARRAYOID ||
174 targetTypeId == ANYCOMPATIBLEOID ||
175 targetTypeId == ANYCOMPATIBLENONARRAYOID)
176 {
177 /*
178 * Assume can_coerce_type verified that implicit coercion is okay.
179 *
180 * Note: by returning the unmodified node here, we are saying that
181 * it's OK to treat an UNKNOWN constant as a valid input for a
182 * function accepting one of these pseudotypes. This should be all
183 * right, since an UNKNOWN value is still a perfectly valid Datum.
184 *
185 * NB: we do NOT want a RelabelType here: the exposed type of the
186 * function argument must be its actual type, not the polymorphic
187 * pseudotype.
188 */
189 return node;
190 }
191 if (targetTypeId == ANYARRAYOID ||
192 targetTypeId == ANYENUMOID ||
193 targetTypeId == ANYRANGEOID ||
194 targetTypeId == ANYMULTIRANGEOID ||
195 targetTypeId == ANYCOMPATIBLEARRAYOID ||
196 targetTypeId == ANYCOMPATIBLERANGEOID ||
197 targetTypeId == ANYCOMPATIBLEMULTIRANGEOID)
198 {
199 /*
200 * Assume can_coerce_type verified that implicit coercion is okay.
201 *
202 * These cases are unlike the ones above because the exposed type of
203 * the argument must be an actual array, enum, range, or multirange
204 * type. In particular the argument must *not* be an UNKNOWN
205 * constant. If it is, we just fall through; below, we'll call the
206 * pseudotype's input function, which will produce an error. Also, if
207 * what we have is a domain over array, enum, range, or multirange, we
208 * have to relabel it to its base type.
209 *
210 * Note: currently, we can't actually see a domain-over-enum here,
211 * since the other functions in this file will not match such a
212 * parameter to ANYENUM. But that should get changed eventually.
213 */
214 if (inputTypeId != UNKNOWNOID)
215 {
216 Oid baseTypeId = getBaseType(inputTypeId);
217
218 if (baseTypeId != inputTypeId)
219 {
220 RelabelType *r = makeRelabelType((Expr *) node,
221 baseTypeId, -1,
222 InvalidOid,
223 cformat);
224
225 r->location = location;
226 return (Node *) r;
227 }
228 /* Not a domain type, so return it as-is */
229 return node;
230 }
231 }
232 if (inputTypeId == UNKNOWNOID && IsA(node, Const))
233 {
234 /*
235 * Input is a string constant with previously undetermined type. Apply
236 * the target type's typinput function to it to produce a constant of
237 * the target type.
238 *
239 * NOTE: this case cannot be folded together with the other
240 * constant-input case, since the typinput function does not
241 * necessarily behave the same as a type conversion function. For
242 * example, int4's typinput function will reject "1.2", whereas
243 * float-to-int type conversion will round to integer.
244 *
245 * XXX if the typinput function is not immutable, we really ought to
246 * postpone evaluation of the function call until runtime. But there
247 * is no way to represent a typinput function call as an expression
248 * tree, because C-string values are not Datums. (XXX This *is*
249 * possible as of 7.3, do we want to do it?)
250 */
251 Const *con = (Const *) node;
252 Const *newcon = makeNode(Const);
253 Oid baseTypeId;
254 int32 baseTypeMod;
255 int32 inputTypeMod;
256 Type baseType;
257 ParseCallbackState pcbstate;
258
259 /*
260 * If the target type is a domain, we want to call its base type's
261 * input routine, not domain_in(). This is to avoid premature failure
262 * when the domain applies a typmod: existing input routines follow
263 * implicit-coercion semantics for length checks, which is not always
264 * what we want here. The needed check will be applied properly
265 * inside coerce_to_domain().
266 */
267 baseTypeMod = targetTypeMod;
268 baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
269
270 /*
271 * For most types we pass typmod -1 to the input routine, because
272 * existing input routines follow implicit-coercion semantics for
273 * length checks, which is not always what we want here. Any length
274 * constraint will be applied later by our caller. An exception
275 * however is the INTERVAL type, for which we *must* pass the typmod
276 * or it won't be able to obey the bizarre SQL-spec input rules. (Ugly
277 * as sin, but so is this part of the spec...)
278 */
279 if (baseTypeId == INTERVALOID)
280 inputTypeMod = baseTypeMod;
281 else
282 inputTypeMod = -1;
283
284 baseType = typeidType(baseTypeId);
285
286 newcon->consttype = baseTypeId;
287 newcon->consttypmod = inputTypeMod;
288 newcon->constcollid = typeTypeCollation(baseType);
289 newcon->constlen = typeLen(baseType);
290 newcon->constbyval = typeByVal(baseType);
291 newcon->constisnull = con->constisnull;
292
293 /*
294 * We use the original literal's location regardless of the position
295 * of the coercion. This is a change from pre-9.2 behavior, meant to
296 * simplify life for pg_stat_statements.
297 */
298 newcon->location = con->location;
299
300 /*
301 * Set up to point at the constant's text if the input routine throws
302 * an error.
303 */
304 setup_parser_errposition_callback(&pcbstate, pstate, con->location);
305
306 /*
307 * We assume here that UNKNOWN's internal representation is the same
308 * as CSTRING.
309 */
310 if (!con->constisnull)
311 newcon->constvalue = stringTypeDatum(baseType,
312 DatumGetCString(con->constvalue),
313 inputTypeMod);
314 else
315 newcon->constvalue = stringTypeDatum(baseType,
316 NULL,
317 inputTypeMod);
318
319 /*
320 * If it's a varlena value, force it to be in non-expanded
321 * (non-toasted) format; this avoids any possible dependency on
322 * external values and improves consistency of representation.
323 */
324 if (!con->constisnull && newcon->constlen == -1)
325 newcon->constvalue =
326 PointerGetDatum(PG_DETOAST_DATUM(newcon->constvalue));
327
328 #ifdef RANDOMIZE_ALLOCATED_MEMORY
329
330 /*
331 * For pass-by-reference data types, repeat the conversion to see if
332 * the input function leaves any uninitialized bytes in the result. We
333 * can only detect that reliably if RANDOMIZE_ALLOCATED_MEMORY is
334 * enabled, so we don't bother testing otherwise. The reason we don't
335 * want any instability in the input function is that comparison of
336 * Const nodes relies on bytewise comparison of the datums, so if the
337 * input function leaves garbage then subexpressions that should be
338 * identical may not get recognized as such. See pgsql-hackers
339 * discussion of 2008-04-04.
340 */
341 if (!con->constisnull && !newcon->constbyval)
342 {
343 Datum val2;
344
345 val2 = stringTypeDatum(baseType,
346 DatumGetCString(con->constvalue),
347 inputTypeMod);
348 if (newcon->constlen == -1)
349 val2 = PointerGetDatum(PG_DETOAST_DATUM(val2));
350 if (!datumIsEqual(newcon->constvalue, val2, false, newcon->constlen))
351 elog(WARNING, "type %s has unstable input conversion for \"%s\"",
352 typeTypeName(baseType), DatumGetCString(con->constvalue));
353 }
354 #endif
355
356 cancel_parser_errposition_callback(&pcbstate);
357
358 result = (Node *) newcon;
359
360 /* If target is a domain, apply constraints. */
361 if (baseTypeId != targetTypeId)
362 result = coerce_to_domain(result,
363 baseTypeId, baseTypeMod,
364 targetTypeId,
365 ccontext, cformat, location,
366 false);
367
368 ReleaseSysCache(baseType);
369
370 return result;
371 }
372 if (IsA(node, Param) &&
373 pstate != NULL && pstate->p_coerce_param_hook != NULL)
374 {
375 /*
376 * Allow the CoerceParamHook to decide what happens. It can return a
377 * transformed node (very possibly the same Param node), or return
378 * NULL to indicate we should proceed with normal coercion.
379 */
380 result = pstate->p_coerce_param_hook(pstate,
381 (Param *) node,
382 targetTypeId,
383 targetTypeMod,
384 location);
385 if (result)
386 return result;
387 }
388 if (IsA(node, CollateExpr))
389 {
390 /*
391 * If we have a COLLATE clause, we have to push the coercion
392 * underneath the COLLATE; or discard the COLLATE if the target type
393 * isn't collatable. This is really ugly, but there is little choice
394 * because the above hacks on Consts and Params wouldn't happen
395 * otherwise. This kluge has consequences in coerce_to_target_type.
396 */
397 CollateExpr *coll = (CollateExpr *) node;
398
399 result = coerce_type(pstate, (Node *) coll->arg,
400 inputTypeId, targetTypeId, targetTypeMod,
401 ccontext, cformat, location);
402 if (type_is_collatable(targetTypeId))
403 {
404 CollateExpr *newcoll = makeNode(CollateExpr);
405
406 newcoll->arg = (Expr *) result;
407 newcoll->collOid = coll->collOid;
408 newcoll->location = coll->location;
409 result = (Node *) newcoll;
410 }
411 return result;
412 }
413 pathtype = find_coercion_pathway(targetTypeId, inputTypeId, ccontext,
414 &funcId);
415 if (pathtype != COERCION_PATH_NONE)
416 {
417 if (pathtype != COERCION_PATH_RELABELTYPE)
418 {
419 /*
420 * Generate an expression tree representing run-time application
421 * of the conversion function. If we are dealing with a domain
422 * target type, the conversion function will yield the base type,
423 * and we need to extract the correct typmod to use from the
424 * domain's typtypmod.
425 */
426 Oid baseTypeId;
427 int32 baseTypeMod;
428
429 baseTypeMod = targetTypeMod;
430 baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
431
432 result = build_coercion_expression(node, pathtype, funcId,
433 baseTypeId, baseTypeMod,
434 ccontext, cformat, location);
435
436 /*
437 * If domain, coerce to the domain type and relabel with domain
438 * type ID, hiding the previous coercion node.
439 */
440 if (targetTypeId != baseTypeId)
441 result = coerce_to_domain(result, baseTypeId, baseTypeMod,
442 targetTypeId,
443 ccontext, cformat, location,
444 true);
445 }
446 else
447 {
448 /*
449 * We don't need to do a physical conversion, but we do need to
450 * attach a RelabelType node so that the expression will be seen
451 * to have the intended type when inspected by higher-level code.
452 *
453 * Also, domains may have value restrictions beyond the base type
454 * that must be accounted for. If the destination is a domain
455 * then we won't need a RelabelType node.
456 */
457 result = coerce_to_domain(node, InvalidOid, -1, targetTypeId,
458 ccontext, cformat, location,
459 false);
460 if (result == node)
461 {
462 /*
463 * XXX could we label result with exprTypmod(node) instead of
464 * default -1 typmod, to save a possible length-coercion
465 * later? Would work if both types have same interpretation of
466 * typmod, which is likely but not certain.
467 */
468 RelabelType *r = makeRelabelType((Expr *) result,
469 targetTypeId, -1,
470 InvalidOid,
471 cformat);
472
473 r->location = location;
474 result = (Node *) r;
475 }
476 }
477 return result;
478 }
479 if (inputTypeId == RECORDOID &&
480 ISCOMPLEX(targetTypeId))
481 {
482 /* Coerce a RECORD to a specific complex type */
483 return coerce_record_to_complex(pstate, node, targetTypeId,
484 ccontext, cformat, location);
485 }
486 if (targetTypeId == RECORDOID &&
487 ISCOMPLEX(inputTypeId))
488 {
489 /* Coerce a specific complex type to RECORD */
490 /* NB: we do NOT want a RelabelType here */
491 return node;
492 }
493 #ifdef NOT_USED
494 if (inputTypeId == RECORDARRAYOID &&
495 is_complex_array(targetTypeId))
496 {
497 /* Coerce record[] to a specific complex array type */
498 /* not implemented yet ... */
499 }
500 #endif
501 if (targetTypeId == RECORDARRAYOID &&
502 is_complex_array(inputTypeId))
503 {
504 /* Coerce a specific complex array type to record[] */
505 /* NB: we do NOT want a RelabelType here */
506 return node;
507 }
508 if (typeInheritsFrom(inputTypeId, targetTypeId)
509 || typeIsOfTypedTable(inputTypeId, targetTypeId))
510 {
511 /*
512 * Input class type is a subclass of target, so generate an
513 * appropriate runtime conversion (removing unneeded columns and
514 * possibly rearranging the ones that are wanted).
515 *
516 * We will also get here when the input is a domain over a subclass of
517 * the target type. To keep life simple for the executor, we define
518 * ConvertRowtypeExpr as only working between regular composite types;
519 * therefore, in such cases insert a RelabelType to smash the input
520 * expression down to its base type.
521 */
522 Oid baseTypeId = getBaseType(inputTypeId);
523 ConvertRowtypeExpr *r = makeNode(ConvertRowtypeExpr);
524
525 if (baseTypeId != inputTypeId)
526 {
527 RelabelType *rt = makeRelabelType((Expr *) node,
528 baseTypeId, -1,
529 InvalidOid,
530 COERCE_IMPLICIT_CAST);
531
532 rt->location = location;
533 node = (Node *) rt;
534 }
535 r->arg = (Expr *) node;
536 r->resulttype = targetTypeId;
537 r->convertformat = cformat;
538 r->location = location;
539 return (Node *) r;
540 }
541 /* If we get here, caller blew it */
542 elog(ERROR, "failed to find conversion function from %s to %s",
543 format_type_be(inputTypeId), format_type_be(targetTypeId));
544 return NULL; /* keep compiler quiet */
545 }
546
547
548 /*
549 * can_coerce_type()
550 * Can input_typeids be coerced to target_typeids?
551 *
552 * We must be told the context (CAST construct, assignment, implicit coercion)
553 * as this determines the set of available casts.
554 */
555 bool
can_coerce_type(int nargs,const Oid * input_typeids,const Oid * target_typeids,CoercionContext ccontext)556 can_coerce_type(int nargs, const Oid *input_typeids, const Oid *target_typeids,
557 CoercionContext ccontext)
558 {
559 bool have_generics = false;
560 int i;
561
562 /* run through argument list... */
563 for (i = 0; i < nargs; i++)
564 {
565 Oid inputTypeId = input_typeids[i];
566 Oid targetTypeId = target_typeids[i];
567 CoercionPathType pathtype;
568 Oid funcId;
569
570 /* no problem if same type */
571 if (inputTypeId == targetTypeId)
572 continue;
573
574 /* accept if target is ANY */
575 if (targetTypeId == ANYOID)
576 continue;
577
578 /* accept if target is polymorphic, for now */
579 if (IsPolymorphicType(targetTypeId))
580 {
581 have_generics = true; /* do more checking later */
582 continue;
583 }
584
585 /*
586 * If input is an untyped string constant, assume we can convert it to
587 * anything.
588 */
589 if (inputTypeId == UNKNOWNOID)
590 continue;
591
592 /*
593 * If pg_cast shows that we can coerce, accept. This test now covers
594 * both binary-compatible and coercion-function cases.
595 */
596 pathtype = find_coercion_pathway(targetTypeId, inputTypeId, ccontext,
597 &funcId);
598 if (pathtype != COERCION_PATH_NONE)
599 continue;
600
601 /*
602 * If input is RECORD and target is a composite type, assume we can
603 * coerce (may need tighter checking here)
604 */
605 if (inputTypeId == RECORDOID &&
606 ISCOMPLEX(targetTypeId))
607 continue;
608
609 /*
610 * If input is a composite type and target is RECORD, accept
611 */
612 if (targetTypeId == RECORDOID &&
613 ISCOMPLEX(inputTypeId))
614 continue;
615
616 #ifdef NOT_USED /* not implemented yet */
617
618 /*
619 * If input is record[] and target is a composite array type, assume
620 * we can coerce (may need tighter checking here)
621 */
622 if (inputTypeId == RECORDARRAYOID &&
623 is_complex_array(targetTypeId))
624 continue;
625 #endif
626
627 /*
628 * If input is a composite array type and target is record[], accept
629 */
630 if (targetTypeId == RECORDARRAYOID &&
631 is_complex_array(inputTypeId))
632 continue;
633
634 /*
635 * If input is a class type that inherits from target, accept
636 */
637 if (typeInheritsFrom(inputTypeId, targetTypeId)
638 || typeIsOfTypedTable(inputTypeId, targetTypeId))
639 continue;
640
641 /*
642 * Else, cannot coerce at this argument position
643 */
644 return false;
645 }
646
647 /* If we found any generic argument types, cross-check them */
648 if (have_generics)
649 {
650 if (!check_generic_type_consistency(input_typeids, target_typeids,
651 nargs))
652 return false;
653 }
654
655 return true;
656 }
657
658
659 /*
660 * Create an expression tree to represent coercion to a domain type.
661 *
662 * 'arg': input expression
663 * 'baseTypeId': base type of domain, if known (pass InvalidOid if caller
664 * has not bothered to look this up)
665 * 'baseTypeMod': base type typmod of domain, if known (pass -1 if caller
666 * has not bothered to look this up)
667 * 'typeId': target type to coerce to
668 * 'ccontext': context indicator to control coercions
669 * 'cformat': coercion display format
670 * 'location': coercion request location
671 * 'hideInputCoercion': if true, hide the input coercion under this one.
672 *
673 * If the target type isn't a domain, the given 'arg' is returned as-is.
674 */
675 Node *
coerce_to_domain(Node * arg,Oid baseTypeId,int32 baseTypeMod,Oid typeId,CoercionContext ccontext,CoercionForm cformat,int location,bool hideInputCoercion)676 coerce_to_domain(Node *arg, Oid baseTypeId, int32 baseTypeMod, Oid typeId,
677 CoercionContext ccontext, CoercionForm cformat, int location,
678 bool hideInputCoercion)
679 {
680 CoerceToDomain *result;
681
682 /* Get the base type if it hasn't been supplied */
683 if (baseTypeId == InvalidOid)
684 baseTypeId = getBaseTypeAndTypmod(typeId, &baseTypeMod);
685
686 /* If it isn't a domain, return the node as it was passed in */
687 if (baseTypeId == typeId)
688 return arg;
689
690 /* Suppress display of nested coercion steps */
691 if (hideInputCoercion)
692 hide_coercion_node(arg);
693
694 /*
695 * If the domain applies a typmod to its base type, build the appropriate
696 * coercion step. Mark it implicit for display purposes, because we don't
697 * want it shown separately by ruleutils.c; but the isExplicit flag passed
698 * to the conversion function depends on the manner in which the domain
699 * coercion is invoked, so that the semantics of implicit and explicit
700 * coercion differ. (Is that really the behavior we want?)
701 *
702 * NOTE: because we apply this as part of the fixed expression structure,
703 * ALTER DOMAIN cannot alter the typtypmod. But it's unclear that that
704 * would be safe to do anyway, without lots of knowledge about what the
705 * base type thinks the typmod means.
706 */
707 arg = coerce_type_typmod(arg, baseTypeId, baseTypeMod,
708 ccontext, COERCE_IMPLICIT_CAST, location,
709 false);
710
711 /*
712 * Now build the domain coercion node. This represents run-time checking
713 * of any constraints currently attached to the domain. This also ensures
714 * that the expression is properly labeled as to result type.
715 */
716 result = makeNode(CoerceToDomain);
717 result->arg = (Expr *) arg;
718 result->resulttype = typeId;
719 result->resulttypmod = -1; /* currently, always -1 for domains */
720 /* resultcollid will be set by parse_collate.c */
721 result->coercionformat = cformat;
722 result->location = location;
723
724 return (Node *) result;
725 }
726
727
728 /*
729 * coerce_type_typmod()
730 * Force a value to a particular typmod, if meaningful and possible.
731 *
732 * This is applied to values that are going to be stored in a relation
733 * (where we have an atttypmod for the column) as well as values being
734 * explicitly CASTed (where the typmod comes from the target type spec).
735 *
736 * The caller must have already ensured that the value is of the correct
737 * type, typically by applying coerce_type.
738 *
739 * ccontext may affect semantics, depending on whether the length coercion
740 * function pays attention to the isExplicit flag it's passed.
741 *
742 * cformat determines the display properties of the generated node (if any).
743 *
744 * If hideInputCoercion is true *and* we generate a node, the input node is
745 * forced to IMPLICIT display form, so that only the typmod coercion node will
746 * be visible when displaying the expression.
747 *
748 * NOTE: this does not need to work on domain types, because any typmod
749 * coercion for a domain is considered to be part of the type coercion
750 * needed to produce the domain value in the first place. So, no getBaseType.
751 */
752 static Node *
coerce_type_typmod(Node * node,Oid targetTypeId,int32 targetTypMod,CoercionContext ccontext,CoercionForm cformat,int location,bool hideInputCoercion)753 coerce_type_typmod(Node *node, Oid targetTypeId, int32 targetTypMod,
754 CoercionContext ccontext, CoercionForm cformat,
755 int location,
756 bool hideInputCoercion)
757 {
758 CoercionPathType pathtype;
759 Oid funcId;
760
761 /* Skip coercion if already done */
762 if (targetTypMod == exprTypmod(node))
763 return node;
764
765 /* Suppress display of nested coercion steps */
766 if (hideInputCoercion)
767 hide_coercion_node(node);
768
769 pathtype = find_typmod_coercion_function(targetTypeId, &funcId);
770
771 if (pathtype != COERCION_PATH_NONE)
772 {
773 node = build_coercion_expression(node, pathtype, funcId,
774 targetTypeId, targetTypMod,
775 ccontext, cformat, location);
776 }
777 else
778 {
779 /*
780 * We don't need to perform any actual coercion step, but we should
781 * apply a RelabelType to ensure that the expression exposes the
782 * intended typmod.
783 */
784 node = applyRelabelType(node, targetTypeId, targetTypMod,
785 exprCollation(node),
786 cformat, location, false);
787 }
788
789 return node;
790 }
791
792 /*
793 * Mark a coercion node as IMPLICIT so it will never be displayed by
794 * ruleutils.c. We use this when we generate a nest of coercion nodes
795 * to implement what is logically one conversion; the inner nodes are
796 * forced to IMPLICIT_CAST format. This does not change their semantics,
797 * only display behavior.
798 *
799 * It is caller error to call this on something that doesn't have a
800 * CoercionForm field.
801 */
802 static void
hide_coercion_node(Node * node)803 hide_coercion_node(Node *node)
804 {
805 if (IsA(node, FuncExpr))
806 ((FuncExpr *) node)->funcformat = COERCE_IMPLICIT_CAST;
807 else if (IsA(node, RelabelType))
808 ((RelabelType *) node)->relabelformat = COERCE_IMPLICIT_CAST;
809 else if (IsA(node, CoerceViaIO))
810 ((CoerceViaIO *) node)->coerceformat = COERCE_IMPLICIT_CAST;
811 else if (IsA(node, ArrayCoerceExpr))
812 ((ArrayCoerceExpr *) node)->coerceformat = COERCE_IMPLICIT_CAST;
813 else if (IsA(node, ConvertRowtypeExpr))
814 ((ConvertRowtypeExpr *) node)->convertformat = COERCE_IMPLICIT_CAST;
815 else if (IsA(node, RowExpr))
816 ((RowExpr *) node)->row_format = COERCE_IMPLICIT_CAST;
817 else if (IsA(node, CoerceToDomain))
818 ((CoerceToDomain *) node)->coercionformat = COERCE_IMPLICIT_CAST;
819 else
820 elog(ERROR, "unsupported node type: %d", (int) nodeTag(node));
821 }
822
823 /*
824 * build_coercion_expression()
825 * Construct an expression tree for applying a pg_cast entry.
826 *
827 * This is used for both type-coercion and length-coercion operations,
828 * since there is no difference in terms of the calling convention.
829 */
830 static Node *
build_coercion_expression(Node * node,CoercionPathType pathtype,Oid funcId,Oid targetTypeId,int32 targetTypMod,CoercionContext ccontext,CoercionForm cformat,int location)831 build_coercion_expression(Node *node,
832 CoercionPathType pathtype,
833 Oid funcId,
834 Oid targetTypeId, int32 targetTypMod,
835 CoercionContext ccontext, CoercionForm cformat,
836 int location)
837 {
838 int nargs = 0;
839
840 if (OidIsValid(funcId))
841 {
842 HeapTuple tp;
843 Form_pg_proc procstruct;
844
845 tp = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcId));
846 if (!HeapTupleIsValid(tp))
847 elog(ERROR, "cache lookup failed for function %u", funcId);
848 procstruct = (Form_pg_proc) GETSTRUCT(tp);
849
850 /*
851 * These Asserts essentially check that function is a legal coercion
852 * function. We can't make the seemingly obvious tests on prorettype
853 * and proargtypes[0], even in the COERCION_PATH_FUNC case, because of
854 * various binary-compatibility cases.
855 */
856 /* Assert(targetTypeId == procstruct->prorettype); */
857 Assert(!procstruct->proretset);
858 Assert(procstruct->prokind == PROKIND_FUNCTION);
859 nargs = procstruct->pronargs;
860 Assert(nargs >= 1 && nargs <= 3);
861 /* Assert(procstruct->proargtypes.values[0] == exprType(node)); */
862 Assert(nargs < 2 || procstruct->proargtypes.values[1] == INT4OID);
863 Assert(nargs < 3 || procstruct->proargtypes.values[2] == BOOLOID);
864
865 ReleaseSysCache(tp);
866 }
867
868 if (pathtype == COERCION_PATH_FUNC)
869 {
870 /* We build an ordinary FuncExpr with special arguments */
871 FuncExpr *fexpr;
872 List *args;
873 Const *cons;
874
875 Assert(OidIsValid(funcId));
876
877 args = list_make1(node);
878
879 if (nargs >= 2)
880 {
881 /* Pass target typmod as an int4 constant */
882 cons = makeConst(INT4OID,
883 -1,
884 InvalidOid,
885 sizeof(int32),
886 Int32GetDatum(targetTypMod),
887 false,
888 true);
889
890 args = lappend(args, cons);
891 }
892
893 if (nargs == 3)
894 {
895 /* Pass it a boolean isExplicit parameter, too */
896 cons = makeConst(BOOLOID,
897 -1,
898 InvalidOid,
899 sizeof(bool),
900 BoolGetDatum(ccontext == COERCION_EXPLICIT),
901 false,
902 true);
903
904 args = lappend(args, cons);
905 }
906
907 fexpr = makeFuncExpr(funcId, targetTypeId, args,
908 InvalidOid, InvalidOid, cformat);
909 fexpr->location = location;
910 return (Node *) fexpr;
911 }
912 else if (pathtype == COERCION_PATH_ARRAYCOERCE)
913 {
914 /* We need to build an ArrayCoerceExpr */
915 ArrayCoerceExpr *acoerce = makeNode(ArrayCoerceExpr);
916 CaseTestExpr *ctest = makeNode(CaseTestExpr);
917 Oid sourceBaseTypeId;
918 int32 sourceBaseTypeMod;
919 Oid targetElementType;
920 Node *elemexpr;
921
922 /*
923 * Look through any domain over the source array type. Note we don't
924 * expect that the target type is a domain; it must be a plain array.
925 * (To get to a domain target type, we'll do coerce_to_domain later.)
926 */
927 sourceBaseTypeMod = exprTypmod(node);
928 sourceBaseTypeId = getBaseTypeAndTypmod(exprType(node),
929 &sourceBaseTypeMod);
930
931 /*
932 * Set up a CaseTestExpr representing one element of the source array.
933 * This is an abuse of CaseTestExpr, but it's OK as long as there
934 * can't be any CaseExpr or ArrayCoerceExpr within the completed
935 * elemexpr.
936 */
937 ctest->typeId = get_element_type(sourceBaseTypeId);
938 Assert(OidIsValid(ctest->typeId));
939 ctest->typeMod = sourceBaseTypeMod;
940 ctest->collation = InvalidOid; /* Assume coercions don't care */
941
942 /* And coerce it to the target element type */
943 targetElementType = get_element_type(targetTypeId);
944 Assert(OidIsValid(targetElementType));
945
946 elemexpr = coerce_to_target_type(NULL,
947 (Node *) ctest,
948 ctest->typeId,
949 targetElementType,
950 targetTypMod,
951 ccontext,
952 cformat,
953 location);
954 if (elemexpr == NULL) /* shouldn't happen */
955 elog(ERROR, "failed to coerce array element type as expected");
956
957 acoerce->arg = (Expr *) node;
958 acoerce->elemexpr = (Expr *) elemexpr;
959 acoerce->resulttype = targetTypeId;
960
961 /*
962 * Label the output as having a particular element typmod only if we
963 * ended up with a per-element expression that is labeled that way.
964 */
965 acoerce->resulttypmod = exprTypmod(elemexpr);
966 /* resultcollid will be set by parse_collate.c */
967 acoerce->coerceformat = cformat;
968 acoerce->location = location;
969
970 return (Node *) acoerce;
971 }
972 else if (pathtype == COERCION_PATH_COERCEVIAIO)
973 {
974 /* We need to build a CoerceViaIO node */
975 CoerceViaIO *iocoerce = makeNode(CoerceViaIO);
976
977 Assert(!OidIsValid(funcId));
978
979 iocoerce->arg = (Expr *) node;
980 iocoerce->resulttype = targetTypeId;
981 /* resultcollid will be set by parse_collate.c */
982 iocoerce->coerceformat = cformat;
983 iocoerce->location = location;
984
985 return (Node *) iocoerce;
986 }
987 else
988 {
989 elog(ERROR, "unsupported pathtype %d in build_coercion_expression",
990 (int) pathtype);
991 return NULL; /* keep compiler quiet */
992 }
993 }
994
995
996 /*
997 * coerce_record_to_complex
998 * Coerce a RECORD to a specific composite type.
999 *
1000 * Currently we only support this for inputs that are RowExprs or whole-row
1001 * Vars.
1002 */
1003 static Node *
coerce_record_to_complex(ParseState * pstate,Node * node,Oid targetTypeId,CoercionContext ccontext,CoercionForm cformat,int location)1004 coerce_record_to_complex(ParseState *pstate, Node *node,
1005 Oid targetTypeId,
1006 CoercionContext ccontext,
1007 CoercionForm cformat,
1008 int location)
1009 {
1010 RowExpr *rowexpr;
1011 Oid baseTypeId;
1012 int32 baseTypeMod = -1;
1013 TupleDesc tupdesc;
1014 List *args = NIL;
1015 List *newargs;
1016 int i;
1017 int ucolno;
1018 ListCell *arg;
1019
1020 if (node && IsA(node, RowExpr))
1021 {
1022 /*
1023 * Since the RowExpr must be of type RECORD, we needn't worry about it
1024 * containing any dropped columns.
1025 */
1026 args = ((RowExpr *) node)->args;
1027 }
1028 else if (node && IsA(node, Var) &&
1029 ((Var *) node)->varattno == InvalidAttrNumber)
1030 {
1031 int rtindex = ((Var *) node)->varno;
1032 int sublevels_up = ((Var *) node)->varlevelsup;
1033 int vlocation = ((Var *) node)->location;
1034 ParseNamespaceItem *nsitem;
1035
1036 nsitem = GetNSItemByRangeTablePosn(pstate, rtindex, sublevels_up);
1037 args = expandNSItemVars(nsitem, sublevels_up, vlocation, NULL);
1038 }
1039 else
1040 ereport(ERROR,
1041 (errcode(ERRCODE_CANNOT_COERCE),
1042 errmsg("cannot cast type %s to %s",
1043 format_type_be(RECORDOID),
1044 format_type_be(targetTypeId)),
1045 parser_coercion_errposition(pstate, location, node)));
1046
1047 /*
1048 * Look up the composite type, accounting for possibility that what we are
1049 * given is a domain over composite.
1050 */
1051 baseTypeId = getBaseTypeAndTypmod(targetTypeId, &baseTypeMod);
1052 tupdesc = lookup_rowtype_tupdesc(baseTypeId, baseTypeMod);
1053
1054 /* Process the fields */
1055 newargs = NIL;
1056 ucolno = 1;
1057 arg = list_head(args);
1058 for (i = 0; i < tupdesc->natts; i++)
1059 {
1060 Node *expr;
1061 Node *cexpr;
1062 Oid exprtype;
1063 Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
1064
1065 /* Fill in NULLs for dropped columns in rowtype */
1066 if (attr->attisdropped)
1067 {
1068 /*
1069 * can't use atttypid here, but it doesn't really matter what type
1070 * the Const claims to be.
1071 */
1072 newargs = lappend(newargs,
1073 makeNullConst(INT4OID, -1, InvalidOid));
1074 continue;
1075 }
1076
1077 if (arg == NULL)
1078 ereport(ERROR,
1079 (errcode(ERRCODE_CANNOT_COERCE),
1080 errmsg("cannot cast type %s to %s",
1081 format_type_be(RECORDOID),
1082 format_type_be(targetTypeId)),
1083 errdetail("Input has too few columns."),
1084 parser_coercion_errposition(pstate, location, node)));
1085 expr = (Node *) lfirst(arg);
1086 exprtype = exprType(expr);
1087
1088 cexpr = coerce_to_target_type(pstate,
1089 expr, exprtype,
1090 attr->atttypid,
1091 attr->atttypmod,
1092 ccontext,
1093 COERCE_IMPLICIT_CAST,
1094 -1);
1095 if (cexpr == NULL)
1096 ereport(ERROR,
1097 (errcode(ERRCODE_CANNOT_COERCE),
1098 errmsg("cannot cast type %s to %s",
1099 format_type_be(RECORDOID),
1100 format_type_be(targetTypeId)),
1101 errdetail("Cannot cast type %s to %s in column %d.",
1102 format_type_be(exprtype),
1103 format_type_be(attr->atttypid),
1104 ucolno),
1105 parser_coercion_errposition(pstate, location, expr)));
1106 newargs = lappend(newargs, cexpr);
1107 ucolno++;
1108 arg = lnext(args, arg);
1109 }
1110 if (arg != NULL)
1111 ereport(ERROR,
1112 (errcode(ERRCODE_CANNOT_COERCE),
1113 errmsg("cannot cast type %s to %s",
1114 format_type_be(RECORDOID),
1115 format_type_be(targetTypeId)),
1116 errdetail("Input has too many columns."),
1117 parser_coercion_errposition(pstate, location, node)));
1118
1119 ReleaseTupleDesc(tupdesc);
1120
1121 rowexpr = makeNode(RowExpr);
1122 rowexpr->args = newargs;
1123 rowexpr->row_typeid = baseTypeId;
1124 rowexpr->row_format = cformat;
1125 rowexpr->colnames = NIL; /* not needed for named target type */
1126 rowexpr->location = location;
1127
1128 /* If target is a domain, apply constraints */
1129 if (baseTypeId != targetTypeId)
1130 {
1131 rowexpr->row_format = COERCE_IMPLICIT_CAST;
1132 return coerce_to_domain((Node *) rowexpr,
1133 baseTypeId, baseTypeMod,
1134 targetTypeId,
1135 ccontext, cformat, location,
1136 false);
1137 }
1138
1139 return (Node *) rowexpr;
1140 }
1141
1142 /*
1143 * coerce_to_boolean()
1144 * Coerce an argument of a construct that requires boolean input
1145 * (AND, OR, NOT, etc). Also check that input is not a set.
1146 *
1147 * Returns the possibly-transformed node tree.
1148 *
1149 * As with coerce_type, pstate may be NULL if no special unknown-Param
1150 * processing is wanted.
1151 */
1152 Node *
coerce_to_boolean(ParseState * pstate,Node * node,const char * constructName)1153 coerce_to_boolean(ParseState *pstate, Node *node,
1154 const char *constructName)
1155 {
1156 Oid inputTypeId = exprType(node);
1157
1158 if (inputTypeId != BOOLOID)
1159 {
1160 Node *newnode;
1161
1162 newnode = coerce_to_target_type(pstate, node, inputTypeId,
1163 BOOLOID, -1,
1164 COERCION_ASSIGNMENT,
1165 COERCE_IMPLICIT_CAST,
1166 -1);
1167 if (newnode == NULL)
1168 ereport(ERROR,
1169 (errcode(ERRCODE_DATATYPE_MISMATCH),
1170 /* translator: first %s is name of a SQL construct, eg WHERE */
1171 errmsg("argument of %s must be type %s, not type %s",
1172 constructName, "boolean",
1173 format_type_be(inputTypeId)),
1174 parser_errposition(pstate, exprLocation(node))));
1175 node = newnode;
1176 }
1177
1178 if (expression_returns_set(node))
1179 ereport(ERROR,
1180 (errcode(ERRCODE_DATATYPE_MISMATCH),
1181 /* translator: %s is name of a SQL construct, eg WHERE */
1182 errmsg("argument of %s must not return a set",
1183 constructName),
1184 parser_errposition(pstate, exprLocation(node))));
1185
1186 return node;
1187 }
1188
1189 /*
1190 * coerce_to_specific_type_typmod()
1191 * Coerce an argument of a construct that requires a specific data type,
1192 * with a specific typmod. Also check that input is not a set.
1193 *
1194 * Returns the possibly-transformed node tree.
1195 *
1196 * As with coerce_type, pstate may be NULL if no special unknown-Param
1197 * processing is wanted.
1198 */
1199 Node *
coerce_to_specific_type_typmod(ParseState * pstate,Node * node,Oid targetTypeId,int32 targetTypmod,const char * constructName)1200 coerce_to_specific_type_typmod(ParseState *pstate, Node *node,
1201 Oid targetTypeId, int32 targetTypmod,
1202 const char *constructName)
1203 {
1204 Oid inputTypeId = exprType(node);
1205
1206 if (inputTypeId != targetTypeId)
1207 {
1208 Node *newnode;
1209
1210 newnode = coerce_to_target_type(pstate, node, inputTypeId,
1211 targetTypeId, targetTypmod,
1212 COERCION_ASSIGNMENT,
1213 COERCE_IMPLICIT_CAST,
1214 -1);
1215 if (newnode == NULL)
1216 ereport(ERROR,
1217 (errcode(ERRCODE_DATATYPE_MISMATCH),
1218 /* translator: first %s is name of a SQL construct, eg LIMIT */
1219 errmsg("argument of %s must be type %s, not type %s",
1220 constructName,
1221 format_type_be(targetTypeId),
1222 format_type_be(inputTypeId)),
1223 parser_errposition(pstate, exprLocation(node))));
1224 node = newnode;
1225 }
1226
1227 if (expression_returns_set(node))
1228 ereport(ERROR,
1229 (errcode(ERRCODE_DATATYPE_MISMATCH),
1230 /* translator: %s is name of a SQL construct, eg LIMIT */
1231 errmsg("argument of %s must not return a set",
1232 constructName),
1233 parser_errposition(pstate, exprLocation(node))));
1234
1235 return node;
1236 }
1237
1238 /*
1239 * coerce_to_specific_type()
1240 * Coerce an argument of a construct that requires a specific data type.
1241 * Also check that input is not a set.
1242 *
1243 * Returns the possibly-transformed node tree.
1244 *
1245 * As with coerce_type, pstate may be NULL if no special unknown-Param
1246 * processing is wanted.
1247 */
1248 Node *
coerce_to_specific_type(ParseState * pstate,Node * node,Oid targetTypeId,const char * constructName)1249 coerce_to_specific_type(ParseState *pstate, Node *node,
1250 Oid targetTypeId,
1251 const char *constructName)
1252 {
1253 return coerce_to_specific_type_typmod(pstate, node,
1254 targetTypeId, -1,
1255 constructName);
1256 }
1257
1258 /*
1259 * parser_coercion_errposition - report coercion error location, if possible
1260 *
1261 * We prefer to point at the coercion request (CAST, ::, etc) if possible;
1262 * but there may be no such location in the case of an implicit coercion.
1263 * In that case point at the input expression.
1264 *
1265 * XXX possibly this is more generally useful than coercion errors;
1266 * if so, should rename and place with parser_errposition.
1267 */
1268 int
parser_coercion_errposition(ParseState * pstate,int coerce_location,Node * input_expr)1269 parser_coercion_errposition(ParseState *pstate,
1270 int coerce_location,
1271 Node *input_expr)
1272 {
1273 if (coerce_location >= 0)
1274 return parser_errposition(pstate, coerce_location);
1275 else
1276 return parser_errposition(pstate, exprLocation(input_expr));
1277 }
1278
1279
1280 /*
1281 * select_common_type()
1282 * Determine the common supertype of a list of input expressions.
1283 * This is used for determining the output type of CASE, UNION,
1284 * and similar constructs.
1285 *
1286 * 'exprs' is a *nonempty* list of expressions. Note that earlier items
1287 * in the list will be preferred if there is doubt.
1288 * 'context' is a phrase to use in the error message if we fail to select
1289 * a usable type. Pass NULL to have the routine return InvalidOid
1290 * rather than throwing an error on failure.
1291 * 'which_expr': if not NULL, receives a pointer to the particular input
1292 * expression from which the result type was taken.
1293 */
1294 Oid
select_common_type(ParseState * pstate,List * exprs,const char * context,Node ** which_expr)1295 select_common_type(ParseState *pstate, List *exprs, const char *context,
1296 Node **which_expr)
1297 {
1298 Node *pexpr;
1299 Oid ptype;
1300 TYPCATEGORY pcategory;
1301 bool pispreferred;
1302 ListCell *lc;
1303
1304 Assert(exprs != NIL);
1305 pexpr = (Node *) linitial(exprs);
1306 lc = list_second_cell(exprs);
1307 ptype = exprType(pexpr);
1308
1309 /*
1310 * If all input types are valid and exactly the same, just pick that type.
1311 * This is the only way that we will resolve the result as being a domain
1312 * type; otherwise domains are smashed to their base types for comparison.
1313 */
1314 if (ptype != UNKNOWNOID)
1315 {
1316 for_each_cell(lc, exprs, lc)
1317 {
1318 Node *nexpr = (Node *) lfirst(lc);
1319 Oid ntype = exprType(nexpr);
1320
1321 if (ntype != ptype)
1322 break;
1323 }
1324 if (lc == NULL) /* got to the end of the list? */
1325 {
1326 if (which_expr)
1327 *which_expr = pexpr;
1328 return ptype;
1329 }
1330 }
1331
1332 /*
1333 * Nope, so set up for the full algorithm. Note that at this point, lc
1334 * points to the first list item with type different from pexpr's; we need
1335 * not re-examine any items the previous loop advanced over.
1336 */
1337 ptype = getBaseType(ptype);
1338 get_type_category_preferred(ptype, &pcategory, &pispreferred);
1339
1340 for_each_cell(lc, exprs, lc)
1341 {
1342 Node *nexpr = (Node *) lfirst(lc);
1343 Oid ntype = getBaseType(exprType(nexpr));
1344
1345 /* move on to next one if no new information... */
1346 if (ntype != UNKNOWNOID && ntype != ptype)
1347 {
1348 TYPCATEGORY ncategory;
1349 bool nispreferred;
1350
1351 get_type_category_preferred(ntype, &ncategory, &nispreferred);
1352 if (ptype == UNKNOWNOID)
1353 {
1354 /* so far, only unknowns so take anything... */
1355 pexpr = nexpr;
1356 ptype = ntype;
1357 pcategory = ncategory;
1358 pispreferred = nispreferred;
1359 }
1360 else if (ncategory != pcategory)
1361 {
1362 /*
1363 * both types in different categories? then not much hope...
1364 */
1365 if (context == NULL)
1366 return InvalidOid;
1367 ereport(ERROR,
1368 (errcode(ERRCODE_DATATYPE_MISMATCH),
1369 /*------
1370 translator: first %s is name of a SQL construct, eg CASE */
1371 errmsg("%s types %s and %s cannot be matched",
1372 context,
1373 format_type_be(ptype),
1374 format_type_be(ntype)),
1375 parser_errposition(pstate, exprLocation(nexpr))));
1376 }
1377 else if (!pispreferred &&
1378 can_coerce_type(1, &ptype, &ntype, COERCION_IMPLICIT) &&
1379 !can_coerce_type(1, &ntype, &ptype, COERCION_IMPLICIT))
1380 {
1381 /*
1382 * take new type if can coerce to it implicitly but not the
1383 * other way; but if we have a preferred type, stay on it.
1384 */
1385 pexpr = nexpr;
1386 ptype = ntype;
1387 pcategory = ncategory;
1388 pispreferred = nispreferred;
1389 }
1390 }
1391 }
1392
1393 /*
1394 * If all the inputs were UNKNOWN type --- ie, unknown-type literals ---
1395 * then resolve as type TEXT. This situation comes up with constructs
1396 * like SELECT (CASE WHEN foo THEN 'bar' ELSE 'baz' END); SELECT 'foo'
1397 * UNION SELECT 'bar'; It might seem desirable to leave the construct's
1398 * output type as UNKNOWN, but that really doesn't work, because we'd
1399 * probably end up needing a runtime coercion from UNKNOWN to something
1400 * else, and we usually won't have it. We need to coerce the unknown
1401 * literals while they are still literals, so a decision has to be made
1402 * now.
1403 */
1404 if (ptype == UNKNOWNOID)
1405 ptype = TEXTOID;
1406
1407 if (which_expr)
1408 *which_expr = pexpr;
1409 return ptype;
1410 }
1411
1412 /*
1413 * select_common_type_from_oids()
1414 * Determine the common supertype of an array of type OIDs.
1415 *
1416 * This is the same logic as select_common_type(), but working from
1417 * an array of type OIDs not a list of expressions. As in that function,
1418 * earlier entries in the array have some preference over later ones.
1419 * On failure, return InvalidOid if noerror is true, else throw an error.
1420 *
1421 * Note: neither caller will pass any UNKNOWNOID entries, so the tests
1422 * for that in this function are dead code. However, they don't cost much,
1423 * and it seems better to keep this logic as close to select_common_type()
1424 * as possible.
1425 */
1426 static Oid
select_common_type_from_oids(int nargs,const Oid * typeids,bool noerror)1427 select_common_type_from_oids(int nargs, const Oid *typeids, bool noerror)
1428 {
1429 Oid ptype;
1430 TYPCATEGORY pcategory;
1431 bool pispreferred;
1432 int i = 1;
1433
1434 Assert(nargs > 0);
1435 ptype = typeids[0];
1436
1437 /* If all input types are valid and exactly the same, pick that type. */
1438 if (ptype != UNKNOWNOID)
1439 {
1440 for (; i < nargs; i++)
1441 {
1442 if (typeids[i] != ptype)
1443 break;
1444 }
1445 if (i == nargs)
1446 return ptype;
1447 }
1448
1449 /*
1450 * Nope, so set up for the full algorithm. Note that at this point, we
1451 * can skip array entries before "i"; they are all equal to ptype.
1452 */
1453 ptype = getBaseType(ptype);
1454 get_type_category_preferred(ptype, &pcategory, &pispreferred);
1455
1456 for (; i < nargs; i++)
1457 {
1458 Oid ntype = getBaseType(typeids[i]);
1459
1460 /* move on to next one if no new information... */
1461 if (ntype != UNKNOWNOID && ntype != ptype)
1462 {
1463 TYPCATEGORY ncategory;
1464 bool nispreferred;
1465
1466 get_type_category_preferred(ntype, &ncategory, &nispreferred);
1467 if (ptype == UNKNOWNOID)
1468 {
1469 /* so far, only unknowns so take anything... */
1470 ptype = ntype;
1471 pcategory = ncategory;
1472 pispreferred = nispreferred;
1473 }
1474 else if (ncategory != pcategory)
1475 {
1476 /*
1477 * both types in different categories? then not much hope...
1478 */
1479 if (noerror)
1480 return InvalidOid;
1481 ereport(ERROR,
1482 (errcode(ERRCODE_DATATYPE_MISMATCH),
1483 errmsg("argument types %s and %s cannot be matched",
1484 format_type_be(ptype),
1485 format_type_be(ntype))));
1486 }
1487 else if (!pispreferred &&
1488 can_coerce_type(1, &ptype, &ntype, COERCION_IMPLICIT) &&
1489 !can_coerce_type(1, &ntype, &ptype, COERCION_IMPLICIT))
1490 {
1491 /*
1492 * take new type if can coerce to it implicitly but not the
1493 * other way; but if we have a preferred type, stay on it.
1494 */
1495 ptype = ntype;
1496 pcategory = ncategory;
1497 pispreferred = nispreferred;
1498 }
1499 }
1500 }
1501
1502 /* Like select_common_type(), choose TEXT if all inputs were UNKNOWN */
1503 if (ptype == UNKNOWNOID)
1504 ptype = TEXTOID;
1505
1506 return ptype;
1507 }
1508
1509 /*
1510 * coerce_to_common_type()
1511 * Coerce an expression to the given type.
1512 *
1513 * This is used following select_common_type() to coerce the individual
1514 * expressions to the desired type. 'context' is a phrase to use in the
1515 * error message if we fail to coerce.
1516 *
1517 * As with coerce_type, pstate may be NULL if no special unknown-Param
1518 * processing is wanted.
1519 */
1520 Node *
coerce_to_common_type(ParseState * pstate,Node * node,Oid targetTypeId,const char * context)1521 coerce_to_common_type(ParseState *pstate, Node *node,
1522 Oid targetTypeId, const char *context)
1523 {
1524 Oid inputTypeId = exprType(node);
1525
1526 if (inputTypeId == targetTypeId)
1527 return node; /* no work */
1528 if (can_coerce_type(1, &inputTypeId, &targetTypeId, COERCION_IMPLICIT))
1529 node = coerce_type(pstate, node, inputTypeId, targetTypeId, -1,
1530 COERCION_IMPLICIT, COERCE_IMPLICIT_CAST, -1);
1531 else
1532 ereport(ERROR,
1533 (errcode(ERRCODE_CANNOT_COERCE),
1534 /* translator: first %s is name of a SQL construct, eg CASE */
1535 errmsg("%s could not convert type %s to %s",
1536 context,
1537 format_type_be(inputTypeId),
1538 format_type_be(targetTypeId)),
1539 parser_errposition(pstate, exprLocation(node))));
1540 return node;
1541 }
1542
1543 /*
1544 * select_common_typmod()
1545 * Determine the common typmod of a list of input expressions.
1546 *
1547 * common_type is the selected common type of the expressions, typically
1548 * computed using select_common_type().
1549 */
1550 int32
select_common_typmod(ParseState * pstate,List * exprs,Oid common_type)1551 select_common_typmod(ParseState *pstate, List *exprs, Oid common_type)
1552 {
1553 ListCell *lc;
1554 bool first = true;
1555 int32 result = -1;
1556
1557 foreach(lc, exprs)
1558 {
1559 Node *expr = (Node *) lfirst(lc);
1560
1561 /* Types must match */
1562 if (exprType(expr) != common_type)
1563 return -1;
1564 else if (first)
1565 {
1566 result = exprTypmod(expr);
1567 first = false;
1568 }
1569 else
1570 {
1571 /* As soon as we see a non-matching typmod, fall back to -1 */
1572 if (result != exprTypmod(expr))
1573 return -1;
1574 }
1575 }
1576
1577 return result;
1578 }
1579
1580 /*
1581 * check_generic_type_consistency()
1582 * Are the actual arguments potentially compatible with a
1583 * polymorphic function?
1584 *
1585 * The argument consistency rules are:
1586 *
1587 * 1) All arguments declared ANYELEMENT must have the same datatype.
1588 * 2) All arguments declared ANYARRAY must have the same datatype,
1589 * which must be a varlena array type.
1590 * 3) All arguments declared ANYRANGE must be the same range type.
1591 * Similarly, all arguments declared ANYMULTIRANGE must be the same
1592 * multirange type; and if both of these appear, the ANYRANGE type
1593 * must be the element type of the ANYMULTIRANGE type.
1594 * 4) If there are arguments of more than one of these polymorphic types,
1595 * the array element type and/or range subtype must be the same as each
1596 * other and the same as the ANYELEMENT type.
1597 * 5) ANYENUM is treated the same as ANYELEMENT except that if it is used
1598 * (alone or in combination with plain ANYELEMENT), we add the extra
1599 * condition that the ANYELEMENT type must be an enum.
1600 * 6) ANYNONARRAY is treated the same as ANYELEMENT except that if it is used,
1601 * we add the extra condition that the ANYELEMENT type must not be an array.
1602 * (This is a no-op if used in combination with ANYARRAY or ANYENUM, but
1603 * is an extra restriction if not.)
1604 * 7) All arguments declared ANYCOMPATIBLE must be implicitly castable
1605 * to a common supertype (chosen as per select_common_type's rules).
1606 * ANYCOMPATIBLENONARRAY works like ANYCOMPATIBLE but also requires the
1607 * common supertype to not be an array. If there are ANYCOMPATIBLEARRAY
1608 * or ANYCOMPATIBLERANGE or ANYCOMPATIBLEMULTIRANGE arguments, their element
1609 * types or subtypes are included while making the choice of common supertype.
1610 * 8) The resolved type of ANYCOMPATIBLEARRAY arguments will be the array
1611 * type over the common supertype (which might not be the same array type
1612 * as any of the original arrays).
1613 * 9) All ANYCOMPATIBLERANGE arguments must be the exact same range type
1614 * (after domain flattening), since we have no preference rule that would
1615 * let us choose one over another. Furthermore, that range's subtype
1616 * must exactly match the common supertype chosen by rule 7.
1617 * 10) All ANYCOMPATIBLEMULTIRANGE arguments must be the exact same multirange
1618 * type (after domain flattening), since we have no preference rule that
1619 * would let us choose one over another. Furthermore, if ANYCOMPATIBLERANGE
1620 * also appears, that range type must be the multirange's element type;
1621 * otherwise, the multirange's range's subtype must exactly match the
1622 * common supertype chosen by rule 7.
1623 *
1624 * Domains over arrays match ANYARRAY, and are immediately flattened to their
1625 * base type. (Thus, for example, we will consider it a match if one ANYARRAY
1626 * argument is a domain over int4[] while another one is just int4[].) Also
1627 * notice that such a domain does *not* match ANYNONARRAY. The same goes
1628 * for ANYCOMPATIBLEARRAY and ANYCOMPATIBLENONARRAY.
1629 *
1630 * Similarly, domains over ranges match ANYRANGE or ANYCOMPATIBLERANGE,
1631 * and are immediately flattened to their base type. Likewise, domains
1632 * over multiranges match ANYMULTIRANGE or ANYCOMPATIBLEMULTIRANGE and are
1633 * immediately flattened to their base type.
1634 *
1635 * Note that domains aren't currently considered to match ANYENUM,
1636 * even if their base type would match.
1637 *
1638 * If we have UNKNOWN input (ie, an untyped literal) for any polymorphic
1639 * argument, assume it is okay.
1640 *
1641 * We do not ereport here, but just return false if a rule is violated.
1642 */
1643 bool
check_generic_type_consistency(const Oid * actual_arg_types,const Oid * declared_arg_types,int nargs)1644 check_generic_type_consistency(const Oid *actual_arg_types,
1645 const Oid *declared_arg_types,
1646 int nargs)
1647 {
1648 Oid elem_typeid = InvalidOid;
1649 Oid array_typeid = InvalidOid;
1650 Oid range_typeid = InvalidOid;
1651 Oid multirange_typeid = InvalidOid;
1652 Oid anycompatible_range_typeid = InvalidOid;
1653 Oid anycompatible_range_typelem = InvalidOid;
1654 Oid anycompatible_multirange_typeid = InvalidOid;
1655 Oid anycompatible_multirange_typelem = InvalidOid;
1656 Oid range_typelem = InvalidOid;
1657 bool have_anynonarray = false;
1658 bool have_anyenum = false;
1659 bool have_anycompatible_nonarray = false;
1660 int n_anycompatible_args = 0;
1661 Oid anycompatible_actual_types[FUNC_MAX_ARGS];
1662
1663 /*
1664 * Loop through the arguments to see if we have any that are polymorphic.
1665 * If so, require the actual types to be consistent.
1666 */
1667 Assert(nargs <= FUNC_MAX_ARGS);
1668 for (int j = 0; j < nargs; j++)
1669 {
1670 Oid decl_type = declared_arg_types[j];
1671 Oid actual_type = actual_arg_types[j];
1672
1673 if (decl_type == ANYELEMENTOID ||
1674 decl_type == ANYNONARRAYOID ||
1675 decl_type == ANYENUMOID)
1676 {
1677 if (decl_type == ANYNONARRAYOID)
1678 have_anynonarray = true;
1679 else if (decl_type == ANYENUMOID)
1680 have_anyenum = true;
1681 if (actual_type == UNKNOWNOID)
1682 continue;
1683 if (OidIsValid(elem_typeid) && actual_type != elem_typeid)
1684 return false;
1685 elem_typeid = actual_type;
1686 }
1687 else if (decl_type == ANYARRAYOID)
1688 {
1689 if (actual_type == UNKNOWNOID)
1690 continue;
1691 actual_type = getBaseType(actual_type); /* flatten domains */
1692 if (OidIsValid(array_typeid) && actual_type != array_typeid)
1693 return false;
1694 array_typeid = actual_type;
1695 }
1696 else if (decl_type == ANYRANGEOID)
1697 {
1698 if (actual_type == UNKNOWNOID)
1699 continue;
1700 actual_type = getBaseType(actual_type); /* flatten domains */
1701 if (OidIsValid(range_typeid) && actual_type != range_typeid)
1702 return false;
1703 range_typeid = actual_type;
1704 }
1705 else if (decl_type == ANYMULTIRANGEOID)
1706 {
1707 if (actual_type == UNKNOWNOID)
1708 continue;
1709 actual_type = getBaseType(actual_type); /* flatten domains */
1710 if (OidIsValid(multirange_typeid) && actual_type != multirange_typeid)
1711 return false;
1712 multirange_typeid = actual_type;
1713 }
1714 else if (decl_type == ANYCOMPATIBLEOID ||
1715 decl_type == ANYCOMPATIBLENONARRAYOID)
1716 {
1717 if (decl_type == ANYCOMPATIBLENONARRAYOID)
1718 have_anycompatible_nonarray = true;
1719 if (actual_type == UNKNOWNOID)
1720 continue;
1721 /* collect the actual types of non-unknown COMPATIBLE args */
1722 anycompatible_actual_types[n_anycompatible_args++] = actual_type;
1723 }
1724 else if (decl_type == ANYCOMPATIBLEARRAYOID)
1725 {
1726 Oid elem_type;
1727
1728 if (actual_type == UNKNOWNOID)
1729 continue;
1730 actual_type = getBaseType(actual_type); /* flatten domains */
1731 elem_type = get_element_type(actual_type);
1732 if (!OidIsValid(elem_type))
1733 return false; /* not an array */
1734 /* collect the element type for common-supertype choice */
1735 anycompatible_actual_types[n_anycompatible_args++] = elem_type;
1736 }
1737 else if (decl_type == ANYCOMPATIBLERANGEOID)
1738 {
1739 if (actual_type == UNKNOWNOID)
1740 continue;
1741 actual_type = getBaseType(actual_type); /* flatten domains */
1742 if (OidIsValid(anycompatible_range_typeid))
1743 {
1744 /* All ANYCOMPATIBLERANGE arguments must be the same type */
1745 if (anycompatible_range_typeid != actual_type)
1746 return false;
1747 }
1748 else
1749 {
1750 anycompatible_range_typeid = actual_type;
1751 anycompatible_range_typelem = get_range_subtype(actual_type);
1752 if (!OidIsValid(anycompatible_range_typelem))
1753 return false; /* not a range type */
1754 /* collect the subtype for common-supertype choice */
1755 anycompatible_actual_types[n_anycompatible_args++] = anycompatible_range_typelem;
1756 }
1757 }
1758 else if (decl_type == ANYCOMPATIBLEMULTIRANGEOID)
1759 {
1760 if (actual_type == UNKNOWNOID)
1761 continue;
1762 actual_type = getBaseType(actual_type); /* flatten domains */
1763 if (OidIsValid(anycompatible_multirange_typeid))
1764 {
1765 /* All ANYCOMPATIBLEMULTIRANGE arguments must be the same type */
1766 if (anycompatible_multirange_typeid != actual_type)
1767 return false;
1768 }
1769 else
1770 {
1771 anycompatible_multirange_typeid = actual_type;
1772 anycompatible_multirange_typelem = get_multirange_range(actual_type);
1773 if (!OidIsValid(anycompatible_multirange_typelem))
1774 return false; /* not a multirange type */
1775 /* we'll consider the subtype below */
1776 }
1777 }
1778 }
1779
1780 /* Get the element type based on the array type, if we have one */
1781 if (OidIsValid(array_typeid))
1782 {
1783 if (array_typeid == ANYARRAYOID)
1784 {
1785 /*
1786 * Special case for matching ANYARRAY input to an ANYARRAY
1787 * argument: allow it for now. enforce_generic_type_consistency()
1788 * might complain later, depending on the presence of other
1789 * polymorphic arguments or results, but it will deliver a less
1790 * surprising error message than "function does not exist".
1791 *
1792 * (If you think to change this, note that can_coerce_type will
1793 * consider such a situation as a match, so that we might not even
1794 * get here.)
1795 */
1796 }
1797 else
1798 {
1799 Oid array_typelem;
1800
1801 array_typelem = get_element_type(array_typeid);
1802 if (!OidIsValid(array_typelem))
1803 return false; /* should be an array, but isn't */
1804
1805 if (!OidIsValid(elem_typeid))
1806 {
1807 /*
1808 * if we don't have an element type yet, use the one we just
1809 * got
1810 */
1811 elem_typeid = array_typelem;
1812 }
1813 else if (array_typelem != elem_typeid)
1814 {
1815 /* otherwise, they better match */
1816 return false;
1817 }
1818 }
1819 }
1820
1821 /* Deduce range type from multirange type, or check that they agree */
1822 if (OidIsValid(multirange_typeid))
1823 {
1824 Oid multirange_typelem;
1825
1826 multirange_typelem = get_multirange_range(multirange_typeid);
1827 if (!OidIsValid(multirange_typelem))
1828 return false; /* should be a multirange, but isn't */
1829
1830 if (!OidIsValid(range_typeid))
1831 {
1832 /* If we don't have a range type yet, use the one we just got */
1833 range_typeid = multirange_typelem;
1834 range_typelem = get_range_subtype(multirange_typelem);
1835 if (!OidIsValid(range_typelem))
1836 return false; /* should be a range, but isn't */
1837 }
1838 else if (multirange_typelem != range_typeid)
1839 {
1840 /* otherwise, they better match */
1841 return false;
1842 }
1843 }
1844
1845 /* Get the element type based on the range type, if we have one */
1846 if (OidIsValid(range_typeid))
1847 {
1848 range_typelem = get_range_subtype(range_typeid);
1849 if (!OidIsValid(range_typelem))
1850 return false; /* should be a range, but isn't */
1851
1852 if (!OidIsValid(elem_typeid))
1853 {
1854 /*
1855 * If we don't have an element type yet, use the one we just got
1856 */
1857 elem_typeid = range_typelem;
1858 }
1859 else if (range_typelem != elem_typeid)
1860 {
1861 /* otherwise, they better match */
1862 return false;
1863 }
1864 }
1865
1866 if (have_anynonarray)
1867 {
1868 /* require the element type to not be an array or domain over array */
1869 if (type_is_array_domain(elem_typeid))
1870 return false;
1871 }
1872
1873 if (have_anyenum)
1874 {
1875 /* require the element type to be an enum */
1876 if (!type_is_enum(elem_typeid))
1877 return false;
1878 }
1879
1880 /* Deduce range type from multirange type, or check that they agree */
1881 if (OidIsValid(anycompatible_multirange_typeid))
1882 {
1883 if (OidIsValid(anycompatible_range_typeid))
1884 {
1885 if (anycompatible_multirange_typelem !=
1886 anycompatible_range_typeid)
1887 return false;
1888 }
1889 else
1890 {
1891 anycompatible_range_typeid = anycompatible_multirange_typelem;
1892 anycompatible_range_typelem = get_range_subtype(anycompatible_range_typeid);
1893 if (!OidIsValid(anycompatible_range_typelem))
1894 return false; /* not a range type */
1895 /* collect the subtype for common-supertype choice */
1896 anycompatible_actual_types[n_anycompatible_args++] =
1897 anycompatible_range_typelem;
1898 }
1899 }
1900
1901 /* Check matching of ANYCOMPATIBLE-family arguments, if any */
1902 if (n_anycompatible_args > 0)
1903 {
1904 Oid anycompatible_typeid;
1905
1906 anycompatible_typeid =
1907 select_common_type_from_oids(n_anycompatible_args,
1908 anycompatible_actual_types,
1909 true);
1910
1911 if (!OidIsValid(anycompatible_typeid))
1912 return false; /* there's no common supertype */
1913
1914 if (have_anycompatible_nonarray)
1915 {
1916 /*
1917 * require the anycompatible type to not be an array or domain
1918 * over array
1919 */
1920 if (type_is_array_domain(anycompatible_typeid))
1921 return false;
1922 }
1923
1924 /*
1925 * The anycompatible type must exactly match the range element type,
1926 * if we were able to identify one. This checks compatibility for
1927 * anycompatiblemultirange too since that also sets
1928 * anycompatible_range_typelem above.
1929 */
1930 if (OidIsValid(anycompatible_range_typelem) &&
1931 anycompatible_range_typelem != anycompatible_typeid)
1932 return false;
1933 }
1934
1935 /* Looks valid */
1936 return true;
1937 }
1938
1939 /*
1940 * enforce_generic_type_consistency()
1941 * Make sure a polymorphic function is legally callable, and
1942 * deduce actual argument and result types.
1943 *
1944 * If any polymorphic pseudotype is used in a function's arguments or
1945 * return type, we make sure the actual data types are consistent with
1946 * each other. The argument consistency rules are shown above for
1947 * check_generic_type_consistency().
1948 *
1949 * If we have UNKNOWN input (ie, an untyped literal) for any polymorphic
1950 * argument, we attempt to deduce the actual type it should have. If
1951 * successful, we alter that position of declared_arg_types[] so that
1952 * make_fn_arguments will coerce the literal to the right thing.
1953 *
1954 * If we have polymorphic arguments of the ANYCOMPATIBLE family,
1955 * we similarly alter declared_arg_types[] entries to show the resolved
1956 * common supertype, so that make_fn_arguments will coerce the actual
1957 * arguments to the proper type.
1958 *
1959 * Rules are applied to the function's return type (possibly altering it)
1960 * if it is declared as a polymorphic type and there is at least one
1961 * polymorphic argument type:
1962 *
1963 * 1) If return type is ANYELEMENT, and any argument is ANYELEMENT, use the
1964 * argument's actual type as the function's return type.
1965 * 2) If return type is ANYARRAY, and any argument is ANYARRAY, use the
1966 * argument's actual type as the function's return type.
1967 * 3) Similarly, if return type is ANYRANGE or ANYMULTIRANGE, and any
1968 * argument is ANYRANGE or ANYMULTIRANGE, use that argument's actual type
1969 * (or the corresponding range or multirange type) as the function's return
1970 * type.
1971 * 4) Otherwise, if return type is ANYELEMENT or ANYARRAY, and there is
1972 * at least one ANYELEMENT, ANYARRAY, ANYRANGE, or ANYMULTIRANGE input,
1973 * deduce the return type from those inputs, or throw error if we can't.
1974 * 5) Otherwise, if return type is ANYRANGE or ANYMULTIRANGE, throw error.
1975 * (We have no way to select a specific range type if the arguments don't
1976 * include ANYRANGE or ANYMULTIRANGE.)
1977 * 6) ANYENUM is treated the same as ANYELEMENT except that if it is used
1978 * (alone or in combination with plain ANYELEMENT), we add the extra
1979 * condition that the ANYELEMENT type must be an enum.
1980 * 7) ANYNONARRAY is treated the same as ANYELEMENT except that if it is used,
1981 * we add the extra condition that the ANYELEMENT type must not be an array.
1982 * (This is a no-op if used in combination with ANYARRAY or ANYENUM, but
1983 * is an extra restriction if not.)
1984 * 8) ANYCOMPATIBLE, ANYCOMPATIBLEARRAY, and ANYCOMPATIBLENONARRAY are handled
1985 * by resolving the common supertype of those arguments (or their element
1986 * types, for array inputs), and then coercing all those arguments to the
1987 * common supertype, or the array type over the common supertype for
1988 * ANYCOMPATIBLEARRAY.
1989 * 9) For ANYCOMPATIBLERANGE and ANYCOMPATIBLEMULTIRANGE, there must be at
1990 * least one non-UNKNOWN input matching those arguments, and all such
1991 * inputs must be the same range type (or its multirange type, as
1992 * appropriate), since we cannot deduce a range type from non-range types.
1993 * Furthermore, the range type's subtype is included while choosing the
1994 * common supertype for ANYCOMPATIBLE et al, and it must exactly match
1995 * that common supertype.
1996 *
1997 * Domains over arrays or ranges match ANYARRAY or ANYRANGE arguments,
1998 * respectively, and are immediately flattened to their base type. (In
1999 * particular, if the return type is also ANYARRAY or ANYRANGE, we'll set
2000 * it to the base type not the domain type.) The same is true for
2001 * ANYMULTIRANGE, ANYCOMPATIBLEARRAY, ANYCOMPATIBLERANGE, and
2002 * ANYCOMPATIBLEMULTIRANGE.
2003 *
2004 * When allow_poly is false, we are not expecting any of the actual_arg_types
2005 * to be polymorphic, and we should not return a polymorphic result type
2006 * either. When allow_poly is true, it is okay to have polymorphic "actual"
2007 * arg types, and we can return a matching polymorphic type as the result.
2008 * (This case is currently used only to check compatibility of an aggregate's
2009 * declaration with the underlying transfn.)
2010 *
2011 * A special case is that we could see ANYARRAY as an actual_arg_type even
2012 * when allow_poly is false (this is possible only because pg_statistic has
2013 * columns shown as anyarray in the catalogs). We allow this to match a
2014 * declared ANYARRAY argument, but only if there is no other polymorphic
2015 * argument that we would need to match it with, and no need to determine
2016 * the element type to infer the result type. Note this means that functions
2017 * taking ANYARRAY had better behave sanely if applied to the pg_statistic
2018 * columns; they can't just assume that successive inputs are of the same
2019 * actual element type. There is no similar logic for ANYCOMPATIBLEARRAY;
2020 * there isn't a need for it since there are no catalog columns of that type,
2021 * so we won't see it as input. We could consider matching an actual ANYARRAY
2022 * input to an ANYCOMPATIBLEARRAY argument, but at present that seems useless
2023 * as well, since there's no value in using ANYCOMPATIBLEARRAY unless there's
2024 * at least one other ANYCOMPATIBLE-family argument or result.
2025 *
2026 * Also, if there are no arguments declared to be of polymorphic types,
2027 * we'll return the rettype unmodified even if it's polymorphic. This should
2028 * never occur for user-declared functions, because CREATE FUNCTION prevents
2029 * it. But it does happen for some built-in functions, such as array_in().
2030 */
2031 Oid
enforce_generic_type_consistency(const Oid * actual_arg_types,Oid * declared_arg_types,int nargs,Oid rettype,bool allow_poly)2032 enforce_generic_type_consistency(const Oid *actual_arg_types,
2033 Oid *declared_arg_types,
2034 int nargs,
2035 Oid rettype,
2036 bool allow_poly)
2037 {
2038 bool have_poly_anycompatible = false;
2039 bool have_poly_unknowns = false;
2040 Oid elem_typeid = InvalidOid;
2041 Oid array_typeid = InvalidOid;
2042 Oid range_typeid = InvalidOid;
2043 Oid multirange_typeid = InvalidOid;
2044 Oid anycompatible_typeid = InvalidOid;
2045 Oid anycompatible_array_typeid = InvalidOid;
2046 Oid anycompatible_range_typeid = InvalidOid;
2047 Oid anycompatible_range_typelem = InvalidOid;
2048 Oid anycompatible_multirange_typeid = InvalidOid;
2049 Oid anycompatible_multirange_typelem = InvalidOid;
2050 bool have_anynonarray = (rettype == ANYNONARRAYOID);
2051 bool have_anyenum = (rettype == ANYENUMOID);
2052 bool have_anymultirange = (rettype == ANYMULTIRANGEOID);
2053 bool have_anycompatible_nonarray = (rettype == ANYCOMPATIBLENONARRAYOID);
2054 bool have_anycompatible_array = (rettype == ANYCOMPATIBLEARRAYOID);
2055 bool have_anycompatible_range = (rettype == ANYCOMPATIBLERANGEOID);
2056 bool have_anycompatible_multirange = (rettype == ANYCOMPATIBLEMULTIRANGEOID);
2057 int n_poly_args = 0; /* this counts all family-1 arguments */
2058 int n_anycompatible_args = 0; /* this counts only non-unknowns */
2059 Oid anycompatible_actual_types[FUNC_MAX_ARGS];
2060
2061 /*
2062 * Loop through the arguments to see if we have any that are polymorphic.
2063 * If so, require the actual types to be consistent.
2064 */
2065 Assert(nargs <= FUNC_MAX_ARGS);
2066 for (int j = 0; j < nargs; j++)
2067 {
2068 Oid decl_type = declared_arg_types[j];
2069 Oid actual_type = actual_arg_types[j];
2070
2071 if (decl_type == ANYELEMENTOID ||
2072 decl_type == ANYNONARRAYOID ||
2073 decl_type == ANYENUMOID)
2074 {
2075 n_poly_args++;
2076 if (decl_type == ANYNONARRAYOID)
2077 have_anynonarray = true;
2078 else if (decl_type == ANYENUMOID)
2079 have_anyenum = true;
2080 if (actual_type == UNKNOWNOID)
2081 {
2082 have_poly_unknowns = true;
2083 continue;
2084 }
2085 if (allow_poly && decl_type == actual_type)
2086 continue; /* no new information here */
2087 if (OidIsValid(elem_typeid) && actual_type != elem_typeid)
2088 ereport(ERROR,
2089 (errcode(ERRCODE_DATATYPE_MISMATCH),
2090 errmsg("arguments declared \"%s\" are not all alike", "anyelement"),
2091 errdetail("%s versus %s",
2092 format_type_be(elem_typeid),
2093 format_type_be(actual_type))));
2094 elem_typeid = actual_type;
2095 }
2096 else if (decl_type == ANYARRAYOID)
2097 {
2098 n_poly_args++;
2099 if (actual_type == UNKNOWNOID)
2100 {
2101 have_poly_unknowns = true;
2102 continue;
2103 }
2104 if (allow_poly && decl_type == actual_type)
2105 continue; /* no new information here */
2106 actual_type = getBaseType(actual_type); /* flatten domains */
2107 if (OidIsValid(array_typeid) && actual_type != array_typeid)
2108 ereport(ERROR,
2109 (errcode(ERRCODE_DATATYPE_MISMATCH),
2110 errmsg("arguments declared \"%s\" are not all alike", "anyarray"),
2111 errdetail("%s versus %s",
2112 format_type_be(array_typeid),
2113 format_type_be(actual_type))));
2114 array_typeid = actual_type;
2115 }
2116 else if (decl_type == ANYRANGEOID)
2117 {
2118 n_poly_args++;
2119 if (actual_type == UNKNOWNOID)
2120 {
2121 have_poly_unknowns = true;
2122 continue;
2123 }
2124 if (allow_poly && decl_type == actual_type)
2125 continue; /* no new information here */
2126 actual_type = getBaseType(actual_type); /* flatten domains */
2127 if (OidIsValid(range_typeid) && actual_type != range_typeid)
2128 ereport(ERROR,
2129 (errcode(ERRCODE_DATATYPE_MISMATCH),
2130 errmsg("arguments declared \"%s\" are not all alike", "anyrange"),
2131 errdetail("%s versus %s",
2132 format_type_be(range_typeid),
2133 format_type_be(actual_type))));
2134 range_typeid = actual_type;
2135 }
2136 else if (decl_type == ANYMULTIRANGEOID)
2137 {
2138 n_poly_args++;
2139 have_anymultirange = true;
2140 if (actual_type == UNKNOWNOID)
2141 {
2142 have_poly_unknowns = true;
2143 continue;
2144 }
2145 if (allow_poly && decl_type == actual_type)
2146 continue; /* no new information here */
2147 actual_type = getBaseType(actual_type); /* flatten domains */
2148 if (OidIsValid(multirange_typeid) && actual_type != multirange_typeid)
2149 ereport(ERROR,
2150 (errcode(ERRCODE_DATATYPE_MISMATCH),
2151 errmsg("arguments declared \"%s\" are not all alike", "anymultirange"),
2152 errdetail("%s versus %s",
2153 format_type_be(multirange_typeid),
2154 format_type_be(actual_type))));
2155 multirange_typeid = actual_type;
2156 }
2157 else if (decl_type == ANYCOMPATIBLEOID ||
2158 decl_type == ANYCOMPATIBLENONARRAYOID)
2159 {
2160 have_poly_anycompatible = true;
2161 if (decl_type == ANYCOMPATIBLENONARRAYOID)
2162 have_anycompatible_nonarray = true;
2163 if (actual_type == UNKNOWNOID)
2164 continue;
2165 if (allow_poly && decl_type == actual_type)
2166 continue; /* no new information here */
2167 /* collect the actual types of non-unknown COMPATIBLE args */
2168 anycompatible_actual_types[n_anycompatible_args++] = actual_type;
2169 }
2170 else if (decl_type == ANYCOMPATIBLEARRAYOID)
2171 {
2172 Oid anycompatible_elem_type;
2173
2174 have_poly_anycompatible = true;
2175 have_anycompatible_array = true;
2176 if (actual_type == UNKNOWNOID)
2177 continue;
2178 if (allow_poly && decl_type == actual_type)
2179 continue; /* no new information here */
2180 actual_type = getBaseType(actual_type); /* flatten domains */
2181 anycompatible_elem_type = get_element_type(actual_type);
2182 if (!OidIsValid(anycompatible_elem_type))
2183 ereport(ERROR,
2184 (errcode(ERRCODE_DATATYPE_MISMATCH),
2185 errmsg("argument declared %s is not an array but type %s",
2186 "anycompatiblearray",
2187 format_type_be(actual_type))));
2188 /* collect the element type for common-supertype choice */
2189 anycompatible_actual_types[n_anycompatible_args++] = anycompatible_elem_type;
2190 }
2191 else if (decl_type == ANYCOMPATIBLERANGEOID)
2192 {
2193 have_poly_anycompatible = true;
2194 have_anycompatible_range = true;
2195 if (actual_type == UNKNOWNOID)
2196 continue;
2197 if (allow_poly && decl_type == actual_type)
2198 continue; /* no new information here */
2199 actual_type = getBaseType(actual_type); /* flatten domains */
2200 if (OidIsValid(anycompatible_range_typeid))
2201 {
2202 /* All ANYCOMPATIBLERANGE arguments must be the same type */
2203 if (anycompatible_range_typeid != actual_type)
2204 ereport(ERROR,
2205 (errcode(ERRCODE_DATATYPE_MISMATCH),
2206 errmsg("arguments declared \"%s\" are not all alike", "anycompatiblerange"),
2207 errdetail("%s versus %s",
2208 format_type_be(anycompatible_range_typeid),
2209 format_type_be(actual_type))));
2210 }
2211 else
2212 {
2213 anycompatible_range_typeid = actual_type;
2214 anycompatible_range_typelem = get_range_subtype(actual_type);
2215 if (!OidIsValid(anycompatible_range_typelem))
2216 ereport(ERROR,
2217 (errcode(ERRCODE_DATATYPE_MISMATCH),
2218 errmsg("argument declared %s is not a range type but type %s",
2219 "anycompatiblerange",
2220 format_type_be(actual_type))));
2221 /* collect the subtype for common-supertype choice */
2222 anycompatible_actual_types[n_anycompatible_args++] = anycompatible_range_typelem;
2223 }
2224 }
2225 else if (decl_type == ANYCOMPATIBLEMULTIRANGEOID)
2226 {
2227 have_poly_anycompatible = true;
2228 have_anycompatible_multirange = true;
2229 if (actual_type == UNKNOWNOID)
2230 continue;
2231 if (allow_poly && decl_type == actual_type)
2232 continue; /* no new information here */
2233 actual_type = getBaseType(actual_type); /* flatten domains */
2234 if (OidIsValid(anycompatible_multirange_typeid))
2235 {
2236 /* All ANYCOMPATIBLEMULTIRANGE arguments must be the same type */
2237 if (anycompatible_multirange_typeid != actual_type)
2238 ereport(ERROR,
2239 (errcode(ERRCODE_DATATYPE_MISMATCH),
2240 errmsg("arguments declared \"%s\" are not all alike", "anycompatiblemultirange"),
2241 errdetail("%s versus %s",
2242 format_type_be(anycompatible_multirange_typeid),
2243 format_type_be(actual_type))));
2244 }
2245 else
2246 {
2247 anycompatible_multirange_typeid = actual_type;
2248 anycompatible_multirange_typelem = get_multirange_range(actual_type);
2249 if (!OidIsValid(anycompatible_multirange_typelem))
2250 ereport(ERROR,
2251 (errcode(ERRCODE_DATATYPE_MISMATCH),
2252 errmsg("argument declared %s is not a multirange type but type %s",
2253 "anycompatiblemultirange",
2254 format_type_be(actual_type))));
2255 /* we'll consider the subtype below */
2256 }
2257 }
2258 }
2259
2260 /*
2261 * Fast Track: if none of the arguments are polymorphic, return the
2262 * unmodified rettype. Not our job to resolve it if it's polymorphic.
2263 */
2264 if (n_poly_args == 0 && !have_poly_anycompatible)
2265 return rettype;
2266
2267 /* Check matching of family-1 polymorphic arguments, if any */
2268 if (n_poly_args)
2269 {
2270 /* Get the element type based on the array type, if we have one */
2271 if (OidIsValid(array_typeid))
2272 {
2273 Oid array_typelem;
2274
2275 if (array_typeid == ANYARRAYOID)
2276 {
2277 /*
2278 * Special case for matching ANYARRAY input to an ANYARRAY
2279 * argument: allow it iff no other arguments are family-1
2280 * polymorphics (otherwise we couldn't be sure whether the
2281 * array element type matches up) and the result type doesn't
2282 * require us to infer a specific element type.
2283 */
2284 if (n_poly_args != 1 ||
2285 (rettype != ANYARRAYOID &&
2286 IsPolymorphicTypeFamily1(rettype)))
2287 ereport(ERROR,
2288 (errcode(ERRCODE_DATATYPE_MISMATCH),
2289 errmsg("cannot determine element type of \"anyarray\" argument")));
2290 array_typelem = ANYELEMENTOID;
2291 }
2292 else
2293 {
2294 array_typelem = get_element_type(array_typeid);
2295 if (!OidIsValid(array_typelem))
2296 ereport(ERROR,
2297 (errcode(ERRCODE_DATATYPE_MISMATCH),
2298 errmsg("argument declared %s is not an array but type %s",
2299 "anyarray", format_type_be(array_typeid))));
2300 }
2301
2302 if (!OidIsValid(elem_typeid))
2303 {
2304 /*
2305 * if we don't have an element type yet, use the one we just
2306 * got
2307 */
2308 elem_typeid = array_typelem;
2309 }
2310 else if (array_typelem != elem_typeid)
2311 {
2312 /* otherwise, they better match */
2313 ereport(ERROR,
2314 (errcode(ERRCODE_DATATYPE_MISMATCH),
2315 errmsg("argument declared %s is not consistent with argument declared %s",
2316 "anyarray", "anyelement"),
2317 errdetail("%s versus %s",
2318 format_type_be(array_typeid),
2319 format_type_be(elem_typeid))));
2320 }
2321 }
2322
2323 /* Deduce range type from multirange type, or vice versa */
2324 if (OidIsValid(multirange_typeid))
2325 {
2326 Oid multirange_typelem;
2327
2328 multirange_typelem = get_multirange_range(multirange_typeid);
2329 if (!OidIsValid(multirange_typelem))
2330 ereport(ERROR,
2331 (errcode(ERRCODE_DATATYPE_MISMATCH),
2332 errmsg("argument declared %s is not a multirange type but type %s",
2333 "anymultirange",
2334 format_type_be(multirange_typeid))));
2335
2336 if (!OidIsValid(range_typeid))
2337 {
2338 /* if we don't have a range type yet, use the one we just got */
2339 range_typeid = multirange_typelem;
2340 }
2341 else if (multirange_typelem != range_typeid)
2342 {
2343 /* otherwise, they better match */
2344 ereport(ERROR,
2345 (errcode(ERRCODE_DATATYPE_MISMATCH),
2346 errmsg("argument declared %s is not consistent with argument declared %s",
2347 "anymultirange", "anyrange"),
2348 errdetail("%s versus %s",
2349 format_type_be(multirange_typeid),
2350 format_type_be(range_typeid))));
2351 }
2352 }
2353 else if (have_anymultirange && OidIsValid(range_typeid))
2354 {
2355 multirange_typeid = get_range_multirange(range_typeid);
2356 /* We'll complain below if that didn't work */
2357 }
2358
2359 /* Get the element type based on the range type, if we have one */
2360 if (OidIsValid(range_typeid))
2361 {
2362 Oid range_typelem;
2363
2364 range_typelem = get_range_subtype(range_typeid);
2365 if (!OidIsValid(range_typelem))
2366 ereport(ERROR,
2367 (errcode(ERRCODE_DATATYPE_MISMATCH),
2368 errmsg("argument declared %s is not a range type but type %s",
2369 "anyrange",
2370 format_type_be(range_typeid))));
2371
2372 if (!OidIsValid(elem_typeid))
2373 {
2374 /*
2375 * if we don't have an element type yet, use the one we just
2376 * got
2377 */
2378 elem_typeid = range_typelem;
2379 }
2380 else if (range_typelem != elem_typeid)
2381 {
2382 /* otherwise, they better match */
2383 ereport(ERROR,
2384 (errcode(ERRCODE_DATATYPE_MISMATCH),
2385 errmsg("argument declared %s is not consistent with argument declared %s",
2386 "anyrange", "anyelement"),
2387 errdetail("%s versus %s",
2388 format_type_be(range_typeid),
2389 format_type_be(elem_typeid))));
2390 }
2391 }
2392
2393 if (!OidIsValid(elem_typeid))
2394 {
2395 if (allow_poly)
2396 {
2397 elem_typeid = ANYELEMENTOID;
2398 array_typeid = ANYARRAYOID;
2399 range_typeid = ANYRANGEOID;
2400 multirange_typeid = ANYMULTIRANGEOID;
2401 }
2402 else
2403 {
2404 /*
2405 * Only way to get here is if all the family-1 polymorphic
2406 * arguments have UNKNOWN inputs.
2407 */
2408 ereport(ERROR,
2409 (errcode(ERRCODE_DATATYPE_MISMATCH),
2410 errmsg("could not determine polymorphic type because input has type %s",
2411 "unknown")));
2412 }
2413 }
2414
2415 if (have_anynonarray && elem_typeid != ANYELEMENTOID)
2416 {
2417 /*
2418 * require the element type to not be an array or domain over
2419 * array
2420 */
2421 if (type_is_array_domain(elem_typeid))
2422 ereport(ERROR,
2423 (errcode(ERRCODE_DATATYPE_MISMATCH),
2424 errmsg("type matched to anynonarray is an array type: %s",
2425 format_type_be(elem_typeid))));
2426 }
2427
2428 if (have_anyenum && elem_typeid != ANYELEMENTOID)
2429 {
2430 /* require the element type to be an enum */
2431 if (!type_is_enum(elem_typeid))
2432 ereport(ERROR,
2433 (errcode(ERRCODE_DATATYPE_MISMATCH),
2434 errmsg("type matched to anyenum is not an enum type: %s",
2435 format_type_be(elem_typeid))));
2436 }
2437 }
2438
2439 /* Check matching of family-2 polymorphic arguments, if any */
2440 if (have_poly_anycompatible)
2441 {
2442 /* Deduce range type from multirange type, or vice versa */
2443 if (OidIsValid(anycompatible_multirange_typeid))
2444 {
2445 if (OidIsValid(anycompatible_range_typeid))
2446 {
2447 if (anycompatible_multirange_typelem !=
2448 anycompatible_range_typeid)
2449 ereport(ERROR,
2450 (errcode(ERRCODE_DATATYPE_MISMATCH),
2451 errmsg("argument declared %s is not consistent with argument declared %s",
2452 "anycompatiblemultirange",
2453 "anycompatiblerange"),
2454 errdetail("%s versus %s",
2455 format_type_be(anycompatible_multirange_typeid),
2456 format_type_be(anycompatible_range_typeid))));
2457 }
2458 else
2459 {
2460 anycompatible_range_typeid = anycompatible_multirange_typelem;
2461 anycompatible_range_typelem = get_range_subtype(anycompatible_range_typeid);
2462 if (!OidIsValid(anycompatible_range_typelem))
2463 ereport(ERROR,
2464 (errcode(ERRCODE_DATATYPE_MISMATCH),
2465 errmsg("argument declared %s is not a multirange type but type %s",
2466 "anycompatiblemultirange",
2467 format_type_be(anycompatible_multirange_typeid))));
2468 /* this enables element type matching check below */
2469 have_anycompatible_range = true;
2470 /* collect the subtype for common-supertype choice */
2471 anycompatible_actual_types[n_anycompatible_args++] =
2472 anycompatible_range_typelem;
2473 }
2474 }
2475 else if (have_anycompatible_multirange &&
2476 OidIsValid(anycompatible_range_typeid))
2477 {
2478 anycompatible_multirange_typeid = get_range_multirange(anycompatible_range_typeid);
2479 /* We'll complain below if that didn't work */
2480 }
2481
2482 if (n_anycompatible_args > 0)
2483 {
2484 anycompatible_typeid =
2485 select_common_type_from_oids(n_anycompatible_args,
2486 anycompatible_actual_types,
2487 false);
2488
2489 if (have_anycompatible_array)
2490 {
2491 anycompatible_array_typeid = get_array_type(anycompatible_typeid);
2492 if (!OidIsValid(anycompatible_array_typeid))
2493 ereport(ERROR,
2494 (errcode(ERRCODE_UNDEFINED_OBJECT),
2495 errmsg("could not find array type for data type %s",
2496 format_type_be(anycompatible_typeid))));
2497 }
2498
2499 if (have_anycompatible_range)
2500 {
2501 /* we can't infer a range type from the others */
2502 if (!OidIsValid(anycompatible_range_typeid))
2503 ereport(ERROR,
2504 (errcode(ERRCODE_DATATYPE_MISMATCH),
2505 errmsg("could not determine polymorphic type %s because input has type %s",
2506 "anycompatiblerange", "unknown")));
2507
2508 /*
2509 * the anycompatible type must exactly match the range element
2510 * type
2511 */
2512 if (anycompatible_range_typelem != anycompatible_typeid)
2513 ereport(ERROR,
2514 (errcode(ERRCODE_DATATYPE_MISMATCH),
2515 errmsg("anycompatiblerange type %s does not match anycompatible type %s",
2516 format_type_be(anycompatible_range_typeid),
2517 format_type_be(anycompatible_typeid))));
2518 }
2519
2520 if (have_anycompatible_multirange)
2521 {
2522 /* we can't infer a multirange type from the others */
2523 if (!OidIsValid(anycompatible_multirange_typeid))
2524 ereport(ERROR,
2525 (errcode(ERRCODE_DATATYPE_MISMATCH),
2526 errmsg("could not determine polymorphic type %s because input has type %s",
2527 "anycompatiblemultirange", "unknown")));
2528
2529 /*
2530 * the anycompatible type must exactly match the multirange
2531 * element type
2532 */
2533 if (anycompatible_range_typelem != anycompatible_typeid)
2534 ereport(ERROR,
2535 (errcode(ERRCODE_DATATYPE_MISMATCH),
2536 errmsg("anycompatiblemultirange type %s does not match anycompatible type %s",
2537 format_type_be(anycompatible_multirange_typeid),
2538 format_type_be(anycompatible_typeid))));
2539 }
2540
2541 if (have_anycompatible_nonarray)
2542 {
2543 /*
2544 * require the element type to not be an array or domain over
2545 * array
2546 */
2547 if (type_is_array_domain(anycompatible_typeid))
2548 ereport(ERROR,
2549 (errcode(ERRCODE_DATATYPE_MISMATCH),
2550 errmsg("type matched to anycompatiblenonarray is an array type: %s",
2551 format_type_be(anycompatible_typeid))));
2552 }
2553 }
2554 else
2555 {
2556 if (allow_poly)
2557 {
2558 anycompatible_typeid = ANYCOMPATIBLEOID;
2559 anycompatible_array_typeid = ANYCOMPATIBLEARRAYOID;
2560 anycompatible_range_typeid = ANYCOMPATIBLERANGEOID;
2561 anycompatible_multirange_typeid = ANYCOMPATIBLEMULTIRANGEOID;
2562 }
2563 else
2564 {
2565 /*
2566 * Only way to get here is if all the family-2 polymorphic
2567 * arguments have UNKNOWN inputs. Resolve to TEXT as
2568 * select_common_type() would do. That doesn't license us to
2569 * use TEXTRANGE or TEXTMULTIRANGE, though.
2570 */
2571 anycompatible_typeid = TEXTOID;
2572 anycompatible_array_typeid = TEXTARRAYOID;
2573 if (have_anycompatible_range)
2574 ereport(ERROR,
2575 (errcode(ERRCODE_DATATYPE_MISMATCH),
2576 errmsg("could not determine polymorphic type %s because input has type %s",
2577 "anycompatiblerange", "unknown")));
2578 if (have_anycompatible_multirange)
2579 ereport(ERROR,
2580 (errcode(ERRCODE_DATATYPE_MISMATCH),
2581 errmsg("could not determine polymorphic type %s because input has type %s",
2582 "anycompatiblemultirange", "unknown")));
2583 }
2584 }
2585
2586 /* replace family-2 polymorphic types by selected types */
2587 for (int j = 0; j < nargs; j++)
2588 {
2589 Oid decl_type = declared_arg_types[j];
2590
2591 if (decl_type == ANYCOMPATIBLEOID ||
2592 decl_type == ANYCOMPATIBLENONARRAYOID)
2593 declared_arg_types[j] = anycompatible_typeid;
2594 else if (decl_type == ANYCOMPATIBLEARRAYOID)
2595 declared_arg_types[j] = anycompatible_array_typeid;
2596 else if (decl_type == ANYCOMPATIBLERANGEOID)
2597 declared_arg_types[j] = anycompatible_range_typeid;
2598 else if (decl_type == ANYCOMPATIBLEMULTIRANGEOID)
2599 declared_arg_types[j] = anycompatible_multirange_typeid;
2600 }
2601 }
2602
2603 /*
2604 * If we had any UNKNOWN inputs for family-1 polymorphic arguments,
2605 * re-scan to assign correct types to them.
2606 *
2607 * Note: we don't have to consider unknown inputs that were matched to
2608 * family-2 polymorphic arguments, because we forcibly updated their
2609 * declared_arg_types[] positions just above.
2610 */
2611 if (have_poly_unknowns)
2612 {
2613 for (int j = 0; j < nargs; j++)
2614 {
2615 Oid decl_type = declared_arg_types[j];
2616 Oid actual_type = actual_arg_types[j];
2617
2618 if (actual_type != UNKNOWNOID)
2619 continue;
2620
2621 if (decl_type == ANYELEMENTOID ||
2622 decl_type == ANYNONARRAYOID ||
2623 decl_type == ANYENUMOID)
2624 declared_arg_types[j] = elem_typeid;
2625 else if (decl_type == ANYARRAYOID)
2626 {
2627 if (!OidIsValid(array_typeid))
2628 {
2629 array_typeid = get_array_type(elem_typeid);
2630 if (!OidIsValid(array_typeid))
2631 ereport(ERROR,
2632 (errcode(ERRCODE_UNDEFINED_OBJECT),
2633 errmsg("could not find array type for data type %s",
2634 format_type_be(elem_typeid))));
2635 }
2636 declared_arg_types[j] = array_typeid;
2637 }
2638 else if (decl_type == ANYRANGEOID)
2639 {
2640 if (!OidIsValid(range_typeid))
2641 {
2642 /* we can't infer a range type from the others */
2643 ereport(ERROR,
2644 (errcode(ERRCODE_DATATYPE_MISMATCH),
2645 errmsg("could not determine polymorphic type %s because input has type %s",
2646 "anyrange", "unknown")));
2647 }
2648 declared_arg_types[j] = range_typeid;
2649 }
2650 else if (decl_type == ANYMULTIRANGEOID)
2651 {
2652 if (!OidIsValid(multirange_typeid))
2653 {
2654 /* we can't infer a multirange type from the others */
2655 ereport(ERROR,
2656 (errcode(ERRCODE_DATATYPE_MISMATCH),
2657 errmsg("could not determine polymorphic type %s because input has type %s",
2658 "anymultirange", "unknown")));
2659 }
2660 declared_arg_types[j] = multirange_typeid;
2661 }
2662 }
2663 }
2664
2665 /* if we return ANYELEMENT use the appropriate argument type */
2666 if (rettype == ANYELEMENTOID ||
2667 rettype == ANYNONARRAYOID ||
2668 rettype == ANYENUMOID)
2669 return elem_typeid;
2670
2671 /* if we return ANYARRAY use the appropriate argument type */
2672 if (rettype == ANYARRAYOID)
2673 {
2674 if (!OidIsValid(array_typeid))
2675 {
2676 array_typeid = get_array_type(elem_typeid);
2677 if (!OidIsValid(array_typeid))
2678 ereport(ERROR,
2679 (errcode(ERRCODE_UNDEFINED_OBJECT),
2680 errmsg("could not find array type for data type %s",
2681 format_type_be(elem_typeid))));
2682 }
2683 return array_typeid;
2684 }
2685
2686 /* if we return ANYRANGE use the appropriate argument type */
2687 if (rettype == ANYRANGEOID)
2688 {
2689 /* this error is unreachable if the function signature is valid: */
2690 if (!OidIsValid(range_typeid))
2691 ereport(ERROR,
2692 (errcode(ERRCODE_DATATYPE_MISMATCH),
2693 errmsg_internal("could not determine polymorphic type %s because input has type %s",
2694 "anyrange", "unknown")));
2695 return range_typeid;
2696 }
2697
2698 /* if we return ANYMULTIRANGE use the appropriate argument type */
2699 if (rettype == ANYMULTIRANGEOID)
2700 {
2701 /* this error is unreachable if the function signature is valid: */
2702 if (!OidIsValid(multirange_typeid))
2703 ereport(ERROR,
2704 (errcode(ERRCODE_DATATYPE_MISMATCH),
2705 errmsg_internal("could not determine polymorphic type %s because input has type %s",
2706 "anymultirange", "unknown")));
2707 return multirange_typeid;
2708 }
2709
2710 /* if we return ANYCOMPATIBLE use the appropriate type */
2711 if (rettype == ANYCOMPATIBLEOID ||
2712 rettype == ANYCOMPATIBLENONARRAYOID)
2713 {
2714 /* this error is unreachable if the function signature is valid: */
2715 if (!OidIsValid(anycompatible_typeid))
2716 ereport(ERROR,
2717 (errcode(ERRCODE_DATATYPE_MISMATCH),
2718 errmsg_internal("could not identify anycompatible type")));
2719 return anycompatible_typeid;
2720 }
2721
2722 /* if we return ANYCOMPATIBLEARRAY use the appropriate type */
2723 if (rettype == ANYCOMPATIBLEARRAYOID)
2724 {
2725 /* this error is unreachable if the function signature is valid: */
2726 if (!OidIsValid(anycompatible_array_typeid))
2727 ereport(ERROR,
2728 (errcode(ERRCODE_DATATYPE_MISMATCH),
2729 errmsg_internal("could not identify anycompatiblearray type")));
2730 return anycompatible_array_typeid;
2731 }
2732
2733 /* if we return ANYCOMPATIBLERANGE use the appropriate argument type */
2734 if (rettype == ANYCOMPATIBLERANGEOID)
2735 {
2736 /* this error is unreachable if the function signature is valid: */
2737 if (!OidIsValid(anycompatible_range_typeid))
2738 ereport(ERROR,
2739 (errcode(ERRCODE_DATATYPE_MISMATCH),
2740 errmsg_internal("could not identify anycompatiblerange type")));
2741 return anycompatible_range_typeid;
2742 }
2743
2744 /* if we return ANYCOMPATIBLEMULTIRANGE use the appropriate argument type */
2745 if (rettype == ANYCOMPATIBLEMULTIRANGEOID)
2746 {
2747 /* this error is unreachable if the function signature is valid: */
2748 if (!OidIsValid(anycompatible_multirange_typeid))
2749 ereport(ERROR,
2750 (errcode(ERRCODE_DATATYPE_MISMATCH),
2751 errmsg_internal("could not identify anycompatiblemultirange type")));
2752 return anycompatible_multirange_typeid;
2753 }
2754
2755 /* we don't return a generic type; send back the original return type */
2756 return rettype;
2757 }
2758
2759 /*
2760 * check_valid_polymorphic_signature()
2761 * Is a proposed function signature valid per polymorphism rules?
2762 *
2763 * Returns NULL if the signature is valid (either ret_type is not polymorphic,
2764 * or it can be deduced from the given declared argument types). Otherwise,
2765 * returns a palloc'd, already translated errdetail string saying why not.
2766 */
2767 char *
check_valid_polymorphic_signature(Oid ret_type,const Oid * declared_arg_types,int nargs)2768 check_valid_polymorphic_signature(Oid ret_type,
2769 const Oid *declared_arg_types,
2770 int nargs)
2771 {
2772 if (ret_type == ANYRANGEOID || ret_type == ANYMULTIRANGEOID)
2773 {
2774 /*
2775 * ANYRANGE and ANYMULTIRANGE require an ANYRANGE or ANYMULTIRANGE
2776 * input, else we can't tell which of several range types with the
2777 * same element type to use.
2778 */
2779 for (int i = 0; i < nargs; i++)
2780 {
2781 if (declared_arg_types[i] == ANYRANGEOID ||
2782 declared_arg_types[i] == ANYMULTIRANGEOID)
2783 return NULL; /* OK */
2784 }
2785 return psprintf(_("A result of type %s requires at least one input of type anyrange or anymultirange."),
2786 format_type_be(ret_type));
2787 }
2788 else if (ret_type == ANYCOMPATIBLERANGEOID || ret_type == ANYCOMPATIBLEMULTIRANGEOID)
2789 {
2790 /*
2791 * ANYCOMPATIBLERANGE and ANYCOMPATIBLEMULTIRANGE require an
2792 * ANYCOMPATIBLERANGE or ANYCOMPATIBLEMULTIRANGE input, else we can't
2793 * tell which of several range types with the same element type to
2794 * use.
2795 */
2796 for (int i = 0; i < nargs; i++)
2797 {
2798 if (declared_arg_types[i] == ANYCOMPATIBLERANGEOID ||
2799 declared_arg_types[i] == ANYCOMPATIBLEMULTIRANGEOID)
2800 return NULL; /* OK */
2801 }
2802 return psprintf(_("A result of type %s requires at least one input of type anycompatiblerange or anycompatiblemultirange."),
2803 format_type_be(ret_type));
2804 }
2805 else if (IsPolymorphicTypeFamily1(ret_type))
2806 {
2807 /* Otherwise, any family-1 type can be deduced from any other */
2808 for (int i = 0; i < nargs; i++)
2809 {
2810 if (IsPolymorphicTypeFamily1(declared_arg_types[i]))
2811 return NULL; /* OK */
2812 }
2813 /* Keep this list in sync with IsPolymorphicTypeFamily1! */
2814 return psprintf(_("A result of type %s requires at least one input of type anyelement, anyarray, anynonarray, anyenum, anyrange, or anymultirange."),
2815 format_type_be(ret_type));
2816 }
2817 else if (IsPolymorphicTypeFamily2(ret_type))
2818 {
2819 /* Otherwise, any family-2 type can be deduced from any other */
2820 for (int i = 0; i < nargs; i++)
2821 {
2822 if (IsPolymorphicTypeFamily2(declared_arg_types[i]))
2823 return NULL; /* OK */
2824 }
2825 /* Keep this list in sync with IsPolymorphicTypeFamily2! */
2826 return psprintf(_("A result of type %s requires at least one input of type anycompatible, anycompatiblearray, anycompatiblenonarray, anycompatiblerange, or anycompatiblemultirange."),
2827 format_type_be(ret_type));
2828 }
2829 else
2830 return NULL; /* OK, ret_type is not polymorphic */
2831 }
2832
2833 /*
2834 * check_valid_internal_signature()
2835 * Is a proposed function signature valid per INTERNAL safety rules?
2836 *
2837 * Returns NULL if OK, or a suitable error message if ret_type is INTERNAL but
2838 * none of the declared arg types are. (It's unsafe to create such a function
2839 * since it would allow invocation of INTERNAL-consuming functions directly
2840 * from SQL.) It's overkill to return the error detail message, since there
2841 * is only one possibility, but we do it like this to keep the API similar to
2842 * check_valid_polymorphic_signature().
2843 */
2844 char *
check_valid_internal_signature(Oid ret_type,const Oid * declared_arg_types,int nargs)2845 check_valid_internal_signature(Oid ret_type,
2846 const Oid *declared_arg_types,
2847 int nargs)
2848 {
2849 if (ret_type == INTERNALOID)
2850 {
2851 for (int i = 0; i < nargs; i++)
2852 {
2853 if (declared_arg_types[i] == ret_type)
2854 return NULL; /* OK */
2855 }
2856 return pstrdup(_("A result of type internal requires at least one input of type internal."));
2857 }
2858 else
2859 return NULL; /* OK, ret_type is not INTERNAL */
2860 }
2861
2862
2863 /* TypeCategory()
2864 * Assign a category to the specified type OID.
2865 *
2866 * NB: this must not return TYPCATEGORY_INVALID.
2867 */
2868 TYPCATEGORY
TypeCategory(Oid type)2869 TypeCategory(Oid type)
2870 {
2871 char typcategory;
2872 bool typispreferred;
2873
2874 get_type_category_preferred(type, &typcategory, &typispreferred);
2875 Assert(typcategory != TYPCATEGORY_INVALID);
2876 return (TYPCATEGORY) typcategory;
2877 }
2878
2879
2880 /* IsPreferredType()
2881 * Check if this type is a preferred type for the given category.
2882 *
2883 * If category is TYPCATEGORY_INVALID, then we'll return true for preferred
2884 * types of any category; otherwise, only for preferred types of that
2885 * category.
2886 */
2887 bool
IsPreferredType(TYPCATEGORY category,Oid type)2888 IsPreferredType(TYPCATEGORY category, Oid type)
2889 {
2890 char typcategory;
2891 bool typispreferred;
2892
2893 get_type_category_preferred(type, &typcategory, &typispreferred);
2894 if (category == typcategory || category == TYPCATEGORY_INVALID)
2895 return typispreferred;
2896 else
2897 return false;
2898 }
2899
2900
2901 /* IsBinaryCoercible()
2902 * Check if srctype is binary-coercible to targettype.
2903 *
2904 * This notion allows us to cheat and directly exchange values without
2905 * going through the trouble of calling a conversion function. Note that
2906 * in general, this should only be an implementation shortcut. Before 7.4,
2907 * this was also used as a heuristic for resolving overloaded functions and
2908 * operators, but that's basically a bad idea.
2909 *
2910 * As of 7.3, binary coercibility isn't hardwired into the code anymore.
2911 * We consider two types binary-coercible if there is an implicitly
2912 * invokable, no-function-needed pg_cast entry. Also, a domain is always
2913 * binary-coercible to its base type, though *not* vice versa (in the other
2914 * direction, one must apply domain constraint checks before accepting the
2915 * value as legitimate). We also need to special-case various polymorphic
2916 * types.
2917 *
2918 * This function replaces IsBinaryCompatible(), which was an inherently
2919 * symmetric test. Since the pg_cast entries aren't necessarily symmetric,
2920 * the order of the operands is now significant.
2921 */
2922 bool
IsBinaryCoercible(Oid srctype,Oid targettype)2923 IsBinaryCoercible(Oid srctype, Oid targettype)
2924 {
2925 HeapTuple tuple;
2926 Form_pg_cast castForm;
2927 bool result;
2928
2929 /* Fast path if same type */
2930 if (srctype == targettype)
2931 return true;
2932
2933 /* Anything is coercible to ANY or ANYELEMENT or ANYCOMPATIBLE */
2934 if (targettype == ANYOID || targettype == ANYELEMENTOID ||
2935 targettype == ANYCOMPATIBLEOID)
2936 return true;
2937
2938 /* If srctype is a domain, reduce to its base type */
2939 if (OidIsValid(srctype))
2940 srctype = getBaseType(srctype);
2941
2942 /* Somewhat-fast path for domain -> base type case */
2943 if (srctype == targettype)
2944 return true;
2945
2946 /* Also accept any array type as coercible to ANY[COMPATIBLE]ARRAY */
2947 if (targettype == ANYARRAYOID || targettype == ANYCOMPATIBLEARRAYOID)
2948 if (type_is_array(srctype))
2949 return true;
2950
2951 /* Also accept any non-array type as coercible to ANY[COMPATIBLE]NONARRAY */
2952 if (targettype == ANYNONARRAYOID || targettype == ANYCOMPATIBLENONARRAYOID)
2953 if (!type_is_array(srctype))
2954 return true;
2955
2956 /* Also accept any enum type as coercible to ANYENUM */
2957 if (targettype == ANYENUMOID)
2958 if (type_is_enum(srctype))
2959 return true;
2960
2961 /* Also accept any range type as coercible to ANY[COMPATIBLE]RANGE */
2962 if (targettype == ANYRANGEOID || targettype == ANYCOMPATIBLERANGEOID)
2963 if (type_is_range(srctype))
2964 return true;
2965
2966 /* Also, any multirange type is coercible to ANY[COMPATIBLE]MULTIRANGE */
2967 if (targettype == ANYMULTIRANGEOID || targettype == ANYCOMPATIBLEMULTIRANGEOID)
2968 if (type_is_multirange(srctype))
2969 return true;
2970
2971 /* Also accept any composite type as coercible to RECORD */
2972 if (targettype == RECORDOID)
2973 if (ISCOMPLEX(srctype))
2974 return true;
2975
2976 /* Also accept any composite array type as coercible to RECORD[] */
2977 if (targettype == RECORDARRAYOID)
2978 if (is_complex_array(srctype))
2979 return true;
2980
2981 /* Else look in pg_cast */
2982 tuple = SearchSysCache2(CASTSOURCETARGET,
2983 ObjectIdGetDatum(srctype),
2984 ObjectIdGetDatum(targettype));
2985 if (!HeapTupleIsValid(tuple))
2986 return false; /* no cast */
2987 castForm = (Form_pg_cast) GETSTRUCT(tuple);
2988
2989 result = (castForm->castmethod == COERCION_METHOD_BINARY &&
2990 castForm->castcontext == COERCION_CODE_IMPLICIT);
2991
2992 ReleaseSysCache(tuple);
2993
2994 return result;
2995 }
2996
2997
2998 /*
2999 * find_coercion_pathway
3000 * Look for a coercion pathway between two types.
3001 *
3002 * Currently, this deals only with scalar-type cases; it does not consider
3003 * polymorphic types nor casts between composite types. (Perhaps fold
3004 * those in someday?)
3005 *
3006 * ccontext determines the set of available casts.
3007 *
3008 * The possible result codes are:
3009 * COERCION_PATH_NONE: failed to find any coercion pathway
3010 * *funcid is set to InvalidOid
3011 * COERCION_PATH_FUNC: apply the coercion function returned in *funcid
3012 * COERCION_PATH_RELABELTYPE: binary-compatible cast, no function needed
3013 * *funcid is set to InvalidOid
3014 * COERCION_PATH_ARRAYCOERCE: need an ArrayCoerceExpr node
3015 * *funcid is set to InvalidOid
3016 * COERCION_PATH_COERCEVIAIO: need a CoerceViaIO node
3017 * *funcid is set to InvalidOid
3018 *
3019 * Note: COERCION_PATH_RELABELTYPE does not necessarily mean that no work is
3020 * needed to do the coercion; if the target is a domain then we may need to
3021 * apply domain constraint checking. If you want to check for a zero-effort
3022 * conversion then use IsBinaryCoercible().
3023 */
3024 CoercionPathType
find_coercion_pathway(Oid targetTypeId,Oid sourceTypeId,CoercionContext ccontext,Oid * funcid)3025 find_coercion_pathway(Oid targetTypeId, Oid sourceTypeId,
3026 CoercionContext ccontext,
3027 Oid *funcid)
3028 {
3029 CoercionPathType result = COERCION_PATH_NONE;
3030 HeapTuple tuple;
3031
3032 *funcid = InvalidOid;
3033
3034 /* Perhaps the types are domains; if so, look at their base types */
3035 if (OidIsValid(sourceTypeId))
3036 sourceTypeId = getBaseType(sourceTypeId);
3037 if (OidIsValid(targetTypeId))
3038 targetTypeId = getBaseType(targetTypeId);
3039
3040 /* Domains are always coercible to and from their base type */
3041 if (sourceTypeId == targetTypeId)
3042 return COERCION_PATH_RELABELTYPE;
3043
3044 /* Look in pg_cast */
3045 tuple = SearchSysCache2(CASTSOURCETARGET,
3046 ObjectIdGetDatum(sourceTypeId),
3047 ObjectIdGetDatum(targetTypeId));
3048
3049 if (HeapTupleIsValid(tuple))
3050 {
3051 Form_pg_cast castForm = (Form_pg_cast) GETSTRUCT(tuple);
3052 CoercionContext castcontext;
3053
3054 /* convert char value for castcontext to CoercionContext enum */
3055 switch (castForm->castcontext)
3056 {
3057 case COERCION_CODE_IMPLICIT:
3058 castcontext = COERCION_IMPLICIT;
3059 break;
3060 case COERCION_CODE_ASSIGNMENT:
3061 castcontext = COERCION_ASSIGNMENT;
3062 break;
3063 case COERCION_CODE_EXPLICIT:
3064 castcontext = COERCION_EXPLICIT;
3065 break;
3066 default:
3067 elog(ERROR, "unrecognized castcontext: %d",
3068 (int) castForm->castcontext);
3069 castcontext = 0; /* keep compiler quiet */
3070 break;
3071 }
3072
3073 /* Rely on ordering of enum for correct behavior here */
3074 if (ccontext >= castcontext)
3075 {
3076 switch (castForm->castmethod)
3077 {
3078 case COERCION_METHOD_FUNCTION:
3079 result = COERCION_PATH_FUNC;
3080 *funcid = castForm->castfunc;
3081 break;
3082 case COERCION_METHOD_INOUT:
3083 result = COERCION_PATH_COERCEVIAIO;
3084 break;
3085 case COERCION_METHOD_BINARY:
3086 result = COERCION_PATH_RELABELTYPE;
3087 break;
3088 default:
3089 elog(ERROR, "unrecognized castmethod: %d",
3090 (int) castForm->castmethod);
3091 break;
3092 }
3093 }
3094
3095 ReleaseSysCache(tuple);
3096 }
3097 else
3098 {
3099 /*
3100 * If there's no pg_cast entry, perhaps we are dealing with a pair of
3101 * array types. If so, and if their element types have a conversion
3102 * pathway, report that we can coerce with an ArrayCoerceExpr.
3103 *
3104 * Hack: disallow coercions to oidvector and int2vector, which
3105 * otherwise tend to capture coercions that should go to "real" array
3106 * types. We want those types to be considered "real" arrays for many
3107 * purposes, but not this one. (Also, ArrayCoerceExpr isn't
3108 * guaranteed to produce an output that meets the restrictions of
3109 * these datatypes, such as being 1-dimensional.)
3110 */
3111 if (targetTypeId != OIDVECTOROID && targetTypeId != INT2VECTOROID)
3112 {
3113 Oid targetElem;
3114 Oid sourceElem;
3115
3116 if ((targetElem = get_element_type(targetTypeId)) != InvalidOid &&
3117 (sourceElem = get_element_type(sourceTypeId)) != InvalidOid)
3118 {
3119 CoercionPathType elempathtype;
3120 Oid elemfuncid;
3121
3122 elempathtype = find_coercion_pathway(targetElem,
3123 sourceElem,
3124 ccontext,
3125 &elemfuncid);
3126 if (elempathtype != COERCION_PATH_NONE)
3127 {
3128 result = COERCION_PATH_ARRAYCOERCE;
3129 }
3130 }
3131 }
3132
3133 /*
3134 * If we still haven't found a possibility, consider automatic casting
3135 * using I/O functions. We allow assignment casts to string types and
3136 * explicit casts from string types to be handled this way. (The
3137 * CoerceViaIO mechanism is a lot more general than that, but this is
3138 * all we want to allow in the absence of a pg_cast entry.) It would
3139 * probably be better to insist on explicit casts in both directions,
3140 * but this is a compromise to preserve something of the pre-8.3
3141 * behavior that many types had implicit (yipes!) casts to text.
3142 */
3143 if (result == COERCION_PATH_NONE)
3144 {
3145 if (ccontext >= COERCION_ASSIGNMENT &&
3146 TypeCategory(targetTypeId) == TYPCATEGORY_STRING)
3147 result = COERCION_PATH_COERCEVIAIO;
3148 else if (ccontext >= COERCION_EXPLICIT &&
3149 TypeCategory(sourceTypeId) == TYPCATEGORY_STRING)
3150 result = COERCION_PATH_COERCEVIAIO;
3151 }
3152 }
3153
3154 /*
3155 * When parsing PL/pgSQL assignments, allow an I/O cast to be used
3156 * whenever no normal coercion is available.
3157 */
3158 if (result == COERCION_PATH_NONE &&
3159 ccontext == COERCION_PLPGSQL)
3160 result = COERCION_PATH_COERCEVIAIO;
3161
3162 return result;
3163 }
3164
3165
3166 /*
3167 * find_typmod_coercion_function -- does the given type need length coercion?
3168 *
3169 * If the target type possesses a pg_cast function from itself to itself,
3170 * it must need length coercion.
3171 *
3172 * "bpchar" (ie, char(N)) and "numeric" are examples of such types.
3173 *
3174 * If the given type is a varlena array type, we do not look for a coercion
3175 * function associated directly with the array type, but instead look for
3176 * one associated with the element type. An ArrayCoerceExpr node must be
3177 * used to apply such a function. (Note: currently, it's pointless to
3178 * return the funcid in this case, because it'll just get looked up again
3179 * in the recursive construction of the ArrayCoerceExpr's elemexpr.)
3180 *
3181 * We use the same result enum as find_coercion_pathway, but the only possible
3182 * result codes are:
3183 * COERCION_PATH_NONE: no length coercion needed
3184 * COERCION_PATH_FUNC: apply the function returned in *funcid
3185 * COERCION_PATH_ARRAYCOERCE: apply the function using ArrayCoerceExpr
3186 */
3187 CoercionPathType
find_typmod_coercion_function(Oid typeId,Oid * funcid)3188 find_typmod_coercion_function(Oid typeId,
3189 Oid *funcid)
3190 {
3191 CoercionPathType result;
3192 Type targetType;
3193 Form_pg_type typeForm;
3194 HeapTuple tuple;
3195
3196 *funcid = InvalidOid;
3197 result = COERCION_PATH_FUNC;
3198
3199 targetType = typeidType(typeId);
3200 typeForm = (Form_pg_type) GETSTRUCT(targetType);
3201
3202 /* Check for a "true" array type */
3203 if (IsTrueArrayType(typeForm))
3204 {
3205 /* Yes, switch our attention to the element type */
3206 typeId = typeForm->typelem;
3207 result = COERCION_PATH_ARRAYCOERCE;
3208 }
3209 ReleaseSysCache(targetType);
3210
3211 /* Look in pg_cast */
3212 tuple = SearchSysCache2(CASTSOURCETARGET,
3213 ObjectIdGetDatum(typeId),
3214 ObjectIdGetDatum(typeId));
3215
3216 if (HeapTupleIsValid(tuple))
3217 {
3218 Form_pg_cast castForm = (Form_pg_cast) GETSTRUCT(tuple);
3219
3220 *funcid = castForm->castfunc;
3221 ReleaseSysCache(tuple);
3222 }
3223
3224 if (!OidIsValid(*funcid))
3225 result = COERCION_PATH_NONE;
3226
3227 return result;
3228 }
3229
3230 /*
3231 * is_complex_array
3232 * Is this type an array of composite?
3233 *
3234 * Note: this will not return true for record[]; check for RECORDARRAYOID
3235 * separately if needed.
3236 */
3237 static bool
is_complex_array(Oid typid)3238 is_complex_array(Oid typid)
3239 {
3240 Oid elemtype = get_element_type(typid);
3241
3242 return (OidIsValid(elemtype) && ISCOMPLEX(elemtype));
3243 }
3244
3245
3246 /*
3247 * Check whether reltypeId is the row type of a typed table of type
3248 * reloftypeId, or is a domain over such a row type. (This is conceptually
3249 * similar to the subtype relationship checked by typeInheritsFrom().)
3250 */
3251 static bool
typeIsOfTypedTable(Oid reltypeId,Oid reloftypeId)3252 typeIsOfTypedTable(Oid reltypeId, Oid reloftypeId)
3253 {
3254 Oid relid = typeOrDomainTypeRelid(reltypeId);
3255 bool result = false;
3256
3257 if (relid)
3258 {
3259 HeapTuple tp;
3260 Form_pg_class reltup;
3261
3262 tp = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
3263 if (!HeapTupleIsValid(tp))
3264 elog(ERROR, "cache lookup failed for relation %u", relid);
3265
3266 reltup = (Form_pg_class) GETSTRUCT(tp);
3267 if (reltup->reloftype == reloftypeId)
3268 result = true;
3269
3270 ReleaseSysCache(tp);
3271 }
3272
3273 return result;
3274 }
3275