1"""Unit tests for the positional only argument syntax specified in PEP 570."""
2
3import dis
4import pickle
5import unittest
6
7from test.support import check_syntax_error
8
9
10def global_pos_only_f(a, b, /):
11    return a, b
12
13def global_pos_only_and_normal(a, /, b):
14    return a, b
15
16def global_pos_only_defaults(a=1, /, b=2):
17    return a, b
18
19def global_inner_has_pos_only():
20    def f(x: int, /): ...
21    return f
22
23
24class PositionalOnlyTestCase(unittest.TestCase):
25
26    def assertRaisesSyntaxError(self, codestr, regex="invalid syntax"):
27        with self.assertRaisesRegex(SyntaxError, regex):
28            compile(codestr + "\n", "<test>", "single")
29
30    def test_invalid_syntax_errors(self):
31        check_syntax_error(self, "def f(a, b = 5, /, c): pass", "non-default argument follows default argument")
32        check_syntax_error(self, "def f(a = 5, b, /, c): pass", "non-default argument follows default argument")
33        check_syntax_error(self, "def f(a = 5, b=1, /, c, *, d=2): pass", "non-default argument follows default argument")
34        check_syntax_error(self, "def f(a = 5, b, /): pass", "non-default argument follows default argument")
35        check_syntax_error(self, "def f(*args, /): pass")
36        check_syntax_error(self, "def f(*args, a, /): pass")
37        check_syntax_error(self, "def f(**kwargs, /): pass")
38        check_syntax_error(self, "def f(/, a = 1): pass")
39        check_syntax_error(self, "def f(/, a): pass")
40        check_syntax_error(self, "def f(/): pass")
41        check_syntax_error(self, "def f(*, a, /): pass")
42        check_syntax_error(self, "def f(*, /, a): pass")
43        check_syntax_error(self, "def f(a, /, a): pass", "duplicate argument 'a' in function definition")
44        check_syntax_error(self, "def f(a, /, *, a): pass", "duplicate argument 'a' in function definition")
45        check_syntax_error(self, "def f(a, b/2, c): pass")
46        check_syntax_error(self, "def f(a, /, c, /): pass")
47        check_syntax_error(self, "def f(a, /, c, /, d): pass")
48        check_syntax_error(self, "def f(a, /, c, /, d, *, e): pass")
49        check_syntax_error(self, "def f(a, *, c, /, d, e): pass")
50
51    def test_invalid_syntax_errors_async(self):
52        check_syntax_error(self, "async def f(a, b = 5, /, c): pass", "non-default argument follows default argument")
53        check_syntax_error(self, "async def f(a = 5, b, /, c): pass", "non-default argument follows default argument")
54        check_syntax_error(self, "async def f(a = 5, b=1, /, c, d=2): pass", "non-default argument follows default argument")
55        check_syntax_error(self, "async def f(a = 5, b, /): pass", "non-default argument follows default argument")
56        check_syntax_error(self, "async def f(*args, /): pass")
57        check_syntax_error(self, "async def f(*args, a, /): pass")
58        check_syntax_error(self, "async def f(**kwargs, /): pass")
59        check_syntax_error(self, "async def f(/, a = 1): pass")
60        check_syntax_error(self, "async def f(/, a): pass")
61        check_syntax_error(self, "async def f(/): pass")
62        check_syntax_error(self, "async def f(*, a, /): pass")
63        check_syntax_error(self, "async def f(*, /, a): pass")
64        check_syntax_error(self, "async def f(a, /, a): pass", "duplicate argument 'a' in function definition")
65        check_syntax_error(self, "async def f(a, /, *, a): pass", "duplicate argument 'a' in function definition")
66        check_syntax_error(self, "async def f(a, b/2, c): pass")
67        check_syntax_error(self, "async def f(a, /, c, /): pass")
68        check_syntax_error(self, "async def f(a, /, c, /, d): pass")
69        check_syntax_error(self, "async def f(a, /, c, /, d, *, e): pass")
70        check_syntax_error(self, "async def f(a, *, c, /, d, e): pass")
71
72    def test_optional_positional_only_args(self):
73        def f(a, b=10, /, c=100):
74            return a + b + c
75
76        self.assertEqual(f(1, 2, 3), 6)
77        self.assertEqual(f(1, 2, c=3), 6)
78        with self.assertRaisesRegex(TypeError, r"f\(\) got some positional-only arguments passed as keyword arguments: 'b'"):
79            f(1, b=2, c=3)
80
81        self.assertEqual(f(1, 2), 103)
82        with self.assertRaisesRegex(TypeError, r"f\(\) got some positional-only arguments passed as keyword arguments: 'b'"):
83            f(1, b=2)
84        self.assertEqual(f(1, c=2), 13)
85
86        def f(a=1, b=10, /, c=100):
87            return a + b + c
88
89        self.assertEqual(f(1, 2, 3), 6)
90        self.assertEqual(f(1, 2, c=3), 6)
91        with self.assertRaisesRegex(TypeError, r"f\(\) got some positional-only arguments passed as keyword arguments: 'b'"):
92            f(1, b=2, c=3)
93
94        self.assertEqual(f(1, 2), 103)
95        with self.assertRaisesRegex(TypeError, r"f\(\) got some positional-only arguments passed as keyword arguments: 'b'"):
96            f(1, b=2)
97        self.assertEqual(f(1, c=2), 13)
98
99    def test_syntax_for_many_positional_only(self):
100        # more than 255 positional only arguments, should compile ok
101        fundef = "def f(%s, /):\n  pass\n" % ', '.join('i%d' % i for i in range(300))
102        compile(fundef, "<test>", "single")
103
104    def test_pos_only_definition(self):
105        def f(a, b, c, /, d, e=1, *, f, g=2):
106            pass
107
108        self.assertEqual(5, f.__code__.co_argcount)  # 3 posonly + 2 "standard args"
109        self.assertEqual(3, f.__code__.co_posonlyargcount)
110        self.assertEqual((1,), f.__defaults__)
111
112        def f(a, b, c=1, /, d=2, e=3, *, f, g=4):
113            pass
114
115        self.assertEqual(5, f.__code__.co_argcount)  # 3 posonly + 2 "standard args"
116        self.assertEqual(3, f.__code__.co_posonlyargcount)
117        self.assertEqual((1, 2, 3), f.__defaults__)
118
119    def test_pos_only_call_via_unpacking(self):
120        def f(a, b, /):
121            return a + b
122
123        self.assertEqual(f(*[1, 2]), 3)
124
125    def test_use_positional_as_keyword(self):
126        def f(a, /):
127            pass
128        expected = r"f\(\) got some positional-only arguments passed as keyword arguments: 'a'"
129        with self.assertRaisesRegex(TypeError, expected):
130            f(a=1)
131
132        def f(a, /, b):
133            pass
134        expected = r"f\(\) got some positional-only arguments passed as keyword arguments: 'a'"
135        with self.assertRaisesRegex(TypeError, expected):
136            f(a=1, b=2)
137
138        def f(a, b, /):
139            pass
140        expected = r"f\(\) got some positional-only arguments passed as keyword arguments: 'a, b'"
141        with self.assertRaisesRegex(TypeError, expected):
142            f(a=1, b=2)
143
144    def test_positional_only_and_arg_invalid_calls(self):
145        def f(a, b, /, c):
146            pass
147        with self.assertRaisesRegex(TypeError, r"f\(\) missing 1 required positional argument: 'c'"):
148            f(1, 2)
149        with self.assertRaisesRegex(TypeError, r"f\(\) missing 2 required positional arguments: 'b' and 'c'"):
150            f(1)
151        with self.assertRaisesRegex(TypeError, r"f\(\) missing 3 required positional arguments: 'a', 'b', and 'c'"):
152            f()
153        with self.assertRaisesRegex(TypeError, r"f\(\) takes 3 positional arguments but 4 were given"):
154            f(1, 2, 3, 4)
155
156    def test_positional_only_and_optional_arg_invalid_calls(self):
157        def f(a, b, /, c=3):
158            pass
159        f(1, 2)  # does not raise
160        with self.assertRaisesRegex(TypeError, r"f\(\) missing 1 required positional argument: 'b'"):
161            f(1)
162        with self.assertRaisesRegex(TypeError, r"f\(\) missing 2 required positional arguments: 'a' and 'b'"):
163            f()
164        with self.assertRaisesRegex(TypeError, r"f\(\) takes from 2 to 3 positional arguments but 4 were given"):
165            f(1, 2, 3, 4)
166
167    def test_positional_only_and_kwonlyargs_invalid_calls(self):
168        def f(a, b, /, c, *, d, e):
169            pass
170        f(1, 2, 3, d=1, e=2)  # does not raise
171        with self.assertRaisesRegex(TypeError, r"missing 1 required keyword-only argument: 'd'"):
172            f(1, 2, 3, e=2)
173        with self.assertRaisesRegex(TypeError, r"missing 2 required keyword-only arguments: 'd' and 'e'"):
174            f(1, 2, 3)
175        with self.assertRaisesRegex(TypeError, r"f\(\) missing 1 required positional argument: 'c'"):
176            f(1, 2)
177        with self.assertRaisesRegex(TypeError, r"f\(\) missing 2 required positional arguments: 'b' and 'c'"):
178            f(1)
179        with self.assertRaisesRegex(TypeError, r" missing 3 required positional arguments: 'a', 'b', and 'c'"):
180            f()
181        with self.assertRaisesRegex(TypeError, r"f\(\) takes 3 positional arguments but 6 positional arguments "
182                                               r"\(and 2 keyword-only arguments\) were given"):
183            f(1, 2, 3, 4, 5, 6, d=7, e=8)
184        with self.assertRaisesRegex(TypeError, r"f\(\) got an unexpected keyword argument 'f'"):
185            f(1, 2, 3, d=1, e=4, f=56)
186
187    def test_positional_only_invalid_calls(self):
188        def f(a, b, /):
189            pass
190        f(1, 2)  # does not raise
191        with self.assertRaisesRegex(TypeError, r"f\(\) missing 1 required positional argument: 'b'"):
192            f(1)
193        with self.assertRaisesRegex(TypeError, r"f\(\) missing 2 required positional arguments: 'a' and 'b'"):
194            f()
195        with self.assertRaisesRegex(TypeError, r"f\(\) takes 2 positional arguments but 3 were given"):
196            f(1, 2, 3)
197
198    def test_positional_only_with_optional_invalid_calls(self):
199        def f(a, b=2, /):
200            pass
201        f(1)  # does not raise
202        with self.assertRaisesRegex(TypeError, r"f\(\) missing 1 required positional argument: 'a'"):
203            f()
204
205        with self.assertRaisesRegex(TypeError, r"f\(\) takes from 1 to 2 positional arguments but 3 were given"):
206            f(1, 2, 3)
207
208    def test_no_standard_args_usage(self):
209        def f(a, b, /, *, c):
210            pass
211
212        f(1, 2, c=3)
213        with self.assertRaises(TypeError):
214            f(1, b=2, c=3)
215
216    def test_change_default_pos_only(self):
217        def f(a, b=2, /, c=3):
218            return a + b + c
219
220        self.assertEqual((2,3), f.__defaults__)
221        f.__defaults__ = (1, 2, 3)
222        self.assertEqual(f(1, 2, 3), 6)
223
224    def test_lambdas(self):
225        x = lambda a, /, b: a + b
226        self.assertEqual(x(1,2), 3)
227        self.assertEqual(x(1,b=2), 3)
228
229        x = lambda a, /, b=2: a + b
230        self.assertEqual(x(1), 3)
231
232        x = lambda a, b, /: a + b
233        self.assertEqual(x(1, 2), 3)
234
235        x = lambda a, b, /, : a + b
236        self.assertEqual(x(1, 2), 3)
237
238    def test_invalid_syntax_lambda(self):
239        check_syntax_error(self, "lambda a, b = 5, /, c: None", "non-default argument follows default argument")
240        check_syntax_error(self, "lambda a = 5, b, /, c: None", "non-default argument follows default argument")
241        check_syntax_error(self, "lambda a = 5, b, /: None", "non-default argument follows default argument")
242        check_syntax_error(self, "lambda *args, /: None")
243        check_syntax_error(self, "lambda *args, a, /: None")
244        check_syntax_error(self, "lambda **kwargs, /: None")
245        check_syntax_error(self, "lambda /, a = 1: None")
246        check_syntax_error(self, "lambda /, a: None")
247        check_syntax_error(self, "lambda /: None")
248        check_syntax_error(self, "lambda *, a, /: None")
249        check_syntax_error(self, "lambda *, /, a: None")
250        check_syntax_error(self, "lambda a, /, a: None", "duplicate argument 'a' in function definition")
251        check_syntax_error(self, "lambda a, /, *, a: None", "duplicate argument 'a' in function definition")
252        check_syntax_error(self, "lambda a, /, b, /: None")
253        check_syntax_error(self, "lambda a, /, b, /, c: None")
254        check_syntax_error(self, "lambda a, /, b, /, c, *, d: None")
255        check_syntax_error(self, "lambda a, *, b, /, c: None")
256
257    def test_posonly_methods(self):
258        class Example:
259            def f(self, a, b, /):
260                return a, b
261
262        self.assertEqual(Example().f(1, 2), (1, 2))
263        self.assertEqual(Example.f(Example(), 1, 2), (1, 2))
264        self.assertRaises(TypeError, Example.f, 1, 2)
265        expected = r"f\(\) got some positional-only arguments passed as keyword arguments: 'b'"
266        with self.assertRaisesRegex(TypeError, expected):
267            Example().f(1, b=2)
268
269    def test_mangling(self):
270        class X:
271            def f(self, *, __a=42):
272                return __a
273        self.assertEqual(X().f(), 42)
274
275    def test_module_function(self):
276        with self.assertRaisesRegex(TypeError, r"f\(\) missing 2 required positional arguments: 'a' and 'b'"):
277            global_pos_only_f()
278
279
280    def test_closures(self):
281        def f(x,y):
282            def g(x2,/,y2):
283                return x + y + x2 + y2
284            return g
285
286        self.assertEqual(f(1,2)(3,4), 10)
287        with self.assertRaisesRegex(TypeError, r"g\(\) missing 1 required positional argument: 'y2'"):
288            f(1,2)(3)
289        with self.assertRaisesRegex(TypeError, r"g\(\) takes 2 positional arguments but 3 were given"):
290            f(1,2)(3,4,5)
291
292        def f(x,/,y):
293            def g(x2,y2):
294                return x + y + x2 + y2
295            return g
296
297        self.assertEqual(f(1,2)(3,4), 10)
298
299        def f(x,/,y):
300            def g(x2,/,y2):
301                return x + y + x2 + y2
302            return g
303
304        self.assertEqual(f(1,2)(3,4), 10)
305        with self.assertRaisesRegex(TypeError, r"g\(\) missing 1 required positional argument: 'y2'"):
306            f(1,2)(3)
307        with self.assertRaisesRegex(TypeError, r"g\(\) takes 2 positional arguments but 3 were given"):
308            f(1,2)(3,4,5)
309
310    def test_same_keyword_as_positional_with_kwargs(self):
311        def f(something,/,**kwargs):
312            return (something, kwargs)
313
314        self.assertEqual(f(42, something=42), (42, {'something': 42}))
315
316        with self.assertRaisesRegex(TypeError, r"f\(\) missing 1 required positional argument: 'something'"):
317            f(something=42)
318
319        self.assertEqual(f(42), (42, {}))
320
321    def test_mangling(self):
322        class X:
323            def f(self, __a=42, /):
324                return __a
325
326            def f2(self, __a=42, /, __b=43):
327                return (__a, __b)
328
329            def f3(self, __a=42, /, __b=43, *, __c=44):
330                return (__a, __b, __c)
331
332        self.assertEqual(X().f(), 42)
333        self.assertEqual(X().f2(), (42, 43))
334        self.assertEqual(X().f3(), (42, 43, 44))
335
336    def test_too_many_arguments(self):
337        # more than 255 positional-only arguments, should compile ok
338        fundef = "def f(%s, /):\n  pass\n" % ', '.join('i%d' % i for i in range(300))
339        compile(fundef, "<test>", "single")
340
341    def test_serialization(self):
342        pickled_posonly = pickle.dumps(global_pos_only_f)
343        pickled_optional = pickle.dumps(global_pos_only_and_normal)
344        pickled_defaults = pickle.dumps(global_pos_only_defaults)
345
346        unpickled_posonly = pickle.loads(pickled_posonly)
347        unpickled_optional = pickle.loads(pickled_optional)
348        unpickled_defaults = pickle.loads(pickled_defaults)
349
350        self.assertEqual(unpickled_posonly(1,2), (1,2))
351        expected = r"global_pos_only_f\(\) got some positional-only arguments "\
352                   r"passed as keyword arguments: 'a, b'"
353        with self.assertRaisesRegex(TypeError, expected):
354            unpickled_posonly(a=1,b=2)
355
356        self.assertEqual(unpickled_optional(1,2), (1,2))
357        expected = r"global_pos_only_and_normal\(\) got some positional-only arguments "\
358                   r"passed as keyword arguments: 'a'"
359        with self.assertRaisesRegex(TypeError, expected):
360            unpickled_optional(a=1,b=2)
361
362        self.assertEqual(unpickled_defaults(), (1,2))
363        expected = r"global_pos_only_defaults\(\) got some positional-only arguments "\
364                   r"passed as keyword arguments: 'a'"
365        with self.assertRaisesRegex(TypeError, expected):
366            unpickled_defaults(a=1,b=2)
367
368    def test_async(self):
369
370        async def f(a=1, /, b=2):
371            return a, b
372
373        with self.assertRaisesRegex(TypeError, r"f\(\) got some positional-only arguments passed as keyword arguments: 'a'"):
374            f(a=1, b=2)
375
376        def _check_call(*args, **kwargs):
377            try:
378                coro = f(*args, **kwargs)
379                coro.send(None)
380            except StopIteration as e:
381                result = e.value
382            self.assertEqual(result, (1, 2))
383
384        _check_call(1, 2)
385        _check_call(1, b=2)
386        _check_call(1)
387        _check_call()
388
389    def test_generator(self):
390
391        def f(a=1, /, b=2):
392            yield a, b
393
394        with self.assertRaisesRegex(TypeError, r"f\(\) got some positional-only arguments passed as keyword arguments: 'a'"):
395            f(a=1, b=2)
396
397        gen = f(1, 2)
398        self.assertEqual(next(gen), (1, 2))
399        gen = f(1, b=2)
400        self.assertEqual(next(gen), (1, 2))
401        gen = f(1)
402        self.assertEqual(next(gen), (1, 2))
403        gen = f()
404        self.assertEqual(next(gen), (1, 2))
405
406    def test_super(self):
407
408        sentinel = object()
409
410        class A:
411            def method(self):
412                return sentinel
413
414        class C(A):
415            def method(self, /):
416                return super().method()
417
418        self.assertEqual(C().method(), sentinel)
419
420    def test_annotations(self):
421        assert global_inner_has_pos_only().__annotations__ == {'x': int}
422
423    def test_annotations_constant_fold(self):
424        def g():
425            def f(x: not (int is int), /): ...
426
427        # without constant folding we end up with
428        # COMPARE_OP(is), UNARY_NOT
429        # with constant folding we should expect a COMPARE_OP(is not)
430        codes = [(i.opname, i.argval) for i in dis.get_instructions(g)]
431        self.assertNotIn(('UNARY_NOT', None), codes)
432        self.assertIn(('COMPARE_OP', 'is not'), codes)
433
434
435if __name__ == "__main__":
436    unittest.main()
437