11.5.4 (2021-05-06)
2==================
3This release fixes another compilation failure when building regex. This time,
4the fix is for when the `pattern` feature is enabled, which only works on
5nightly Rust. CI has been updated to test this case.
6
7* [BUG #772](https://github.com/rust-lang/regex/pull/772):
8  Fix build when `pattern` feature is enabled.
9
10
111.5.3 (2021-05-01)
12==================
13This releases fixes a bug when building regex with only the `unicode-perl`
14feature. It turns out that while CI was building this configuration, it wasn't
15actually failing the overall build on a failed compilation.
16
17* [BUG #769](https://github.com/rust-lang/regex/issues/769):
18  Fix build in `regex-syntax` when only the `unicode-perl` feature is enabled.
19
20
211.5.2 (2021-05-01)
22==================
23This release fixes a performance bug when Unicode word boundaries are used.
24Namely, for certain regexes on certain inputs, it's possible for the lazy DFA
25to stop searching (causing a fallback to a slower engine) when it doesn't
26actually need to.
27
28[PR #768](https://github.com/rust-lang/regex/pull/768) fixes the bug, which was
29originally reported in
30[ripgrep#1860](https://github.com/BurntSushi/ripgrep/issues/1860).
31
32
331.5.1 (2021-04-30)
34==================
35This is a patch release that fixes a compilation error when the `perf-literal`
36feature is not enabled.
37
38
391.5.0 (2021-04-30)
40==================
41This release primarily updates to Rust 2018 (finally) and bumps the MSRV to
42Rust 1.41 (from Rust 1.28). Rust 1.41 was chosen because it's still reasonably
43old, and is what's in Debian stable at the time of writing.
44
45This release also drops this crate's own bespoke substring search algorithms
46in favor of a new
47[`memmem` implementation provided by the `memchr` crate](https://docs.rs/memchr/2.4.0/memchr/memmem/index.html).
48This will change the performance profile of some regexes, sometimes getting a
49little worse, and hopefully more frequently, getting a lot better. Please
50report any serious performance regressions if you find them.
51
52
531.4.6 (2021-04-22)
54==================
55This is a small patch release that fixes the compiler's size check on how much
56heap memory a regex uses. Previously, the compiler did not account for the
57heap usage of Unicode character classes. Now it does. It's possible that this
58may make some regexes fail to compile that previously did compile. If that
59happens, please file an issue.
60
61* [BUG OSS-fuzz#33579](https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=33579):
62  Some regexes can use more heap memory than one would expect.
63
64
651.4.5 (2021-03-14)
66==================
67This is a small patch release that fixes a regression in the size of a `Regex`
68in the 1.4.4 release. Prior to 1.4.4, a `Regex` was 552 bytes. In the 1.4.4
69release, it was 856 bytes due to internal changes. In this release, a `Regex`
70is now 16 bytes. In general, the size of a `Regex` was never something that was
71on my radar, but this increased size in the 1.4.4 release seems to have crossed
72a threshold and resulted in stack overflows in some programs.
73
74* [BUG #750](https://github.com/rust-lang/regex/pull/750):
75  Fixes stack overflows seemingly caused by a large `Regex` size by decreasing
76  its size.
77
78
791.4.4 (2021-03-11)
80==================
81This is a small patch release that contains some bug fixes. Notably, it also
82drops the `thread_local` (and `lazy_static`, via transitivity) dependencies.
83
84Bug fixes:
85
86* [BUG #362](https://github.com/rust-lang/regex/pull/362):
87  Memory leaks caused by an internal caching strategy should now be fixed.
88* [BUG #576](https://github.com/rust-lang/regex/pull/576):
89  All regex types now implement `UnwindSafe` and `RefUnwindSafe`.
90* [BUG #728](https://github.com/rust-lang/regex/pull/749):
91  Add missing `Replacer` impls for `Vec<u8>`, `String`, `Cow`, etc.
92
93
941.4.3 (2021-01-08)
95==================
96This is a small patch release that adds some missing standard trait
97implementations for some types in the public API.
98
99Bug fixes:
100
101* [BUG #734](https://github.com/rust-lang/regex/pull/734):
102  Add `FusedIterator` and `ExactSizeIterator` impls to iterator types.
103* [BUG #735](https://github.com/rust-lang/regex/pull/735):
104  Add missing `Debug` impls to public API types.
105
106
1071.4.2 (2020-11-01)
108==================
109This is a small bug fix release that bans `\P{any}`. We previously banned empty
110classes like `[^\w\W]`, but missed the `\P{any}` case. In the future, we hope
111to permit empty classes.
112
113* [BUG #722](https://github.com/rust-lang/regex/issues/722):
114  Ban `\P{any}` to avoid a panic in the regex compiler. Found by OSS-Fuzz.
115
116
1171.4.1 (2020-10-13)
118==================
119This is a small bug fix release that makes `\p{cf}` work. Previously, it would
120report "property not found" even though `cf` is a valid abbreviation for the
121`Format` general category.
122
123* [BUG #719](https://github.com/rust-lang/regex/issues/719):
124  Fixes bug that prevented `\p{cf}` from working.
125
126
1271.4.0 (2020-10-11)
128==================
129This releases has a few minor documentation fixes as well as some very minor
130API additions. The MSRV remains at Rust 1.28 for now, but this is intended to
131increase to at least Rust 1.41.1 soon.
132
133This release also adds support for OSS-Fuzz. Kudos to
134[@DavidKorczynski](https://github.com/DavidKorczynski)
135for doing the heavy lifting for that!
136
137New features:
138
139* [FEATURE #649](https://github.com/rust-lang/regex/issues/649):
140  Support `[`, `]` and `.` in capture group names.
141* [FEATURE #687](https://github.com/rust-lang/regex/issues/687):
142  Add `is_empty` predicate to `RegexSet`.
143* [FEATURE #689](https://github.com/rust-lang/regex/issues/689):
144  Implement `Clone` for `SubCaptureMatches`.
145* [FEATURE #715](https://github.com/rust-lang/regex/issues/715):
146  Add `empty` constructor to `RegexSet` for convenience.
147
148Bug fixes:
149
150* [BUG #694](https://github.com/rust-lang/regex/issues/694):
151  Fix doc example for `Replacer::replace_append`.
152* [BUG #698](https://github.com/rust-lang/regex/issues/698):
153  Clarify docs for `s` flag when using a `bytes::Regex`.
154* [BUG #711](https://github.com/rust-lang/regex/issues/711):
155  Clarify `is_match` docs to indicate that it can match anywhere in string.
156
157
1581.3.9 (2020-05-28)
159==================
160This release fixes a MSRV (Minimum Support Rust Version) regression in the
1611.3.8 release. Namely, while 1.3.8 compiles on Rust 1.28, it actually does not
162compile on other Rust versions, such as Rust 1.39.
163
164Bug fixes:
165
166* [BUG #685](https://github.com/rust-lang/regex/issues/685):
167  Remove use of `doc_comment` crate, which cannot be used before Rust 1.43.
168
169
1701.3.8 (2020-05-28)
171==================
172This release contains a couple of important bug fixes driven
173by better support for empty-subexpressions in regexes. For
174example, regexes like `b|` are now allowed. Major thanks to
175[@sliquister](https://github.com/sliquister) for implementing support for this
176in [#677](https://github.com/rust-lang/regex/pull/677).
177
178Bug fixes:
179
180* [BUG #523](https://github.com/rust-lang/regex/pull/523):
181  Add note to documentation that spaces can be escaped in `x` mode.
182* [BUG #524](https://github.com/rust-lang/regex/issues/524):
183  Add support for empty sub-expressions, including empty alternations.
184* [BUG #659](https://github.com/rust-lang/regex/issues/659):
185  Fix match bug caused by an empty sub-expression miscompilation.
186
187
1881.3.7 (2020-04-17)
189==================
190This release contains a small bug fix that fixes how `regex` forwards crate
191features to `regex-syntax`. In particular, this will reduce recompilations in
192some cases.
193
194Bug fixes:
195
196* [BUG #665](https://github.com/rust-lang/regex/pull/665):
197  Fix feature forwarding to `regex-syntax`.
198
199
2001.3.6 (2020-03-24)
201==================
202This release contains a sizable (~30%) performance improvement when compiling
203some kinds of large regular expressions.
204
205Performance improvements:
206
207* [PERF #657](https://github.com/rust-lang/regex/pull/657):
208  Improvement performance of compiling large regular expressions.
209
210
2111.3.5 (2020-03-12)
212==================
213This release updates this crate to Unicode 13.
214
215New features:
216
217* [FEATURE #653](https://github.com/rust-lang/regex/pull/653):
218  Update `regex-syntax` to Unicode 13.
219
220
2211.3.4 (2020-01-30)
222==================
223This is a small bug fix release that fixes a bug related to the scoping of
224flags in a regex. Namely, before this fix, a regex like `((?i)a)b)` would
225match `aB` despite the fact that `b` should not be matched case insensitively.
226
227Bug fixes:
228
229* [BUG #640](https://github.com/rust-lang/regex/issues/640):
230  Fix bug related to the scoping of flags in a regex.
231
232
2331.3.3 (2020-01-09)
234==================
235This is a small maintenance release that upgrades the dependency on
236`thread_local` from `0.3` to `1.0`. The minimum supported Rust version remains
237at Rust 1.28.
238
239
2401.3.2 (2020-01-09)
241==================
242This is a small maintenance release with some house cleaning and bug fixes.
243
244New features:
245
246* [FEATURE #631](https://github.com/rust-lang/regex/issues/631):
247  Add a `Match::range` method an a `From<Match> for Range` impl.
248
249Bug fixes:
250
251* [BUG #521](https://github.com/rust-lang/regex/issues/521):
252  Corrects `/-/.splitn("a", 2)` to return `["a"]` instead of `["a", ""]`.
253* [BUG #594](https://github.com/rust-lang/regex/pull/594):
254  Improve error reporting when writing `\p\`.
255* [BUG #627](https://github.com/rust-lang/regex/issues/627):
256  Corrects `/-/.split("a-")` to return `["a", ""]` instead of `["a"]`.
257* [BUG #633](https://github.com/rust-lang/regex/pull/633):
258  Squash deprecation warnings for the `std::error::Error::description` method.
259
260
2611.3.1 (2019-09-04)
262==================
263This is a maintenance release with no changes in order to try to work-around
264a [docs.rs/Cargo issue](https://github.com/rust-lang/docs.rs/issues/400).
265
266
2671.3.0 (2019-09-03)
268==================
269This release adds a plethora of new crate features that permit users of regex
270to shrink its size considerably, in exchange for giving up either functionality
271(such as Unicode support) or runtime performance. When all such features are
272disabled, the dependency tree for `regex` shrinks to exactly 1 crate
273(`regex-syntax`). More information about the new crate features can be
274[found in the docs](https://docs.rs/regex/*/#crate-features).
275
276Note that while this is a new minor version release, the minimum supported
277Rust version for this crate remains at `1.28.0`.
278
279New features:
280
281* [FEATURE #474](https://github.com/rust-lang/regex/issues/474):
282  The `use_std` feature has been deprecated in favor of the `std` feature.
283  The `use_std` feature will be removed in regex 2. Until then, `use_std` will
284  remain as an alias for the `std` feature.
285* [FEATURE #583](https://github.com/rust-lang/regex/issues/583):
286  Add a substantial number of crate features shrinking `regex`.
287
288
2891.2.1 (2019-08-03)
290==================
291This release does a bit of house cleaning. Namely:
292
293* This repository is now using rustfmt.
294* License headers have been removed from all files, in following suit with the
295  Rust project.
296* Teddy has been removed from the `regex` crate, and is now part of the
297  `aho-corasick` crate.
298  [See `aho-corasick`'s new `packed` sub-module for details](https://docs.rs/aho-corasick/0.7.6/aho_corasick/packed/index.html).
299* The `utf8-ranges` crate has been deprecated, with its functionality moving
300  into the
301  [`utf8` sub-module of `regex-syntax`](https://docs.rs/regex-syntax/0.6.11/regex_syntax/utf8/index.html).
302* The `ucd-util` dependency has been dropped, in favor of implementing what
303  little we need inside of `regex-syntax` itself.
304
305In general, this is part of an ongoing (long term) effort to make optimizations
306in the regex engine easier to reason about. The current code is too convoluted
307and thus it is very easy to introduce new bugs. This simplification effort is
308the primary motivation behind re-working the `aho-corasick` crate to not only
309bundle algorithms like Teddy, but to also provide regex-like match semantics
310automatically.
311
312Moving forward, the plan is to join up with the `bstr` and `regex-automata`
313crates, with the former providing more sophisticated substring search
314algorithms (thereby deleting existing code in `regex`) and the latter providing
315ahead-of-time compiled DFAs for cases where they are inexpensive to compute.
316
317
3181.2.0 (2019-07-20)
319==================
320This release updates regex's minimum supported Rust version to 1.28, which was
321release almost 1 year ago. This release also updates regex's Unicode data
322tables to 12.1.0.
323
324
3251.1.9 (2019-07-06)
326==================
327This release contains a bug fix that caused regex's tests to fail, due to a
328dependency on an unreleased behavior in regex-syntax.
329
330* [BUG #593](https://github.com/rust-lang/regex/issues/593):
331  Move an integration-style test on error messages into regex-syntax.
332
333
3341.1.8 (2019-07-04)
335==================
336This release contains a few small internal refactorings. One of which fixes
337an instance of undefined behavior in a part of the SIMD code.
338
339Bug fixes:
340
341* [BUG #545](https://github.com/rust-lang/regex/issues/545):
342  Improves error messages when a repetition operator is used without a number.
343* [BUG #588](https://github.com/rust-lang/regex/issues/588):
344  Removes use of a repr(Rust) union used for type punning in the Teddy matcher.
345* [BUG #591](https://github.com/rust-lang/regex/issues/591):
346  Update docs for running benchmarks and improve failure modes.
347
348
3491.1.7 (2019-06-09)
350==================
351This release fixes up a few warnings as a result of recent deprecations.
352
353
3541.1.6 (2019-04-16)
355==================
356This release fixes a regression introduced by a bug fix (for
357[BUG #557](https://github.com/rust-lang/regex/issues/557)) which could cause
358the regex engine to enter an infinite loop. This bug was originally
359[reported against ripgrep](https://github.com/BurntSushi/ripgrep/issues/1247).
360
361
3621.1.5 (2019-04-01)
363==================
364This release fixes a bug in regex's dependency specification where it requires
365a newer version of regex-syntax, but this wasn't communicated correctly in the
366Cargo.toml. This would have been caught by a minimal version check, but this
367check was disabled because the `rand` crate itself advertises incorrect
368dependency specifications.
369
370Bug fixes:
371
372* [BUG #570](https://github.com/rust-lang/regex/pull/570):
373  Fix regex-syntax minimal version.
374
375
3761.1.4 (2019-03-31)
377==================
378This release fixes a backwards compatibility regression where Regex was no
379longer UnwindSafe. This was caused by the upgrade to aho-corasick 0.7, whose
380AhoCorasick type was itself not UnwindSafe. This has been fixed in aho-corasick
3810.7.4, which we now require.
382
383Bug fixes:
384
385* [BUG #568](https://github.com/rust-lang/regex/pull/568):
386  Fix an API regression where Regex was no longer UnwindSafe.
387
388
3891.1.3 (2019-03-30)
390==================
391This releases fixes a few bugs and adds a performance improvement when a regex
392is a simple alternation of literals.
393
394Performance improvements:
395
396* [OPT #566](https://github.com/rust-lang/regex/pull/566):
397  Upgrades `aho-corasick` to 0.7 and uses it for `foo|bar|...|quux` regexes.
398
399Bug fixes:
400
401* [BUG #527](https://github.com/rust-lang/regex/issues/527):
402  Fix a bug where the parser would panic on patterns like `((?x))`.
403* [BUG #555](https://github.com/rust-lang/regex/issues/555):
404  Fix a bug where the parser would panic on patterns like `(?m){1,1}`.
405* [BUG #557](https://github.com/rust-lang/regex/issues/557):
406  Fix a bug where captures could lead to an incorrect match.
407
408
4091.1.2 (2019-02-27)
410==================
411This release fixes a bug found in the fix introduced in 1.1.1.
412
413Bug fixes:
414
415* [BUG edf45e6f](https://github.com/rust-lang/regex/commit/edf45e6f):
416  Fix bug introduced in reverse suffix literal matcher in the 1.1.1 release.
417
418
4191.1.1 (2019-02-27)
420==================
421This is a small release with one fix for a bug caused by literal optimizations.
422
423Bug fixes:
424
425* [BUG 661bf53d](https://github.com/rust-lang/regex/commit/661bf53d):
426  Fixes a bug in the reverse suffix literal optimization. This was originally
427  reported
428  [against ripgrep](https://github.com/BurntSushi/ripgrep/issues/1203).
429
430
4311.1.0 (2018-11-30)
432==================
433This is a small release with a couple small enhancements. This release also
434increases the minimal supported Rust version (MSRV) to 1.24.1 (from 1.20.0). In
435accordance with this crate's MSRV policy, this release bumps the minor version
436number.
437
438Performance improvements:
439
440* [OPT #511](https://github.com/rust-lang/regex/pull/511),
441  [OPT #540](https://github.com/rust-lang/regex/pull/540):
442  Improve lazy DFA construction for large regex sets.
443
444New features:
445
446* [FEATURE #538](https://github.com/rust-lang/regex/pull/538):
447  Add Emoji and "break" Unicode properties. See [UNICODE.md](UNICODE.md).
448
449Bug fixes:
450
451* [BUG #530](https://github.com/rust-lang/regex/pull/530):
452  Add Unicode license (for data tables).
453* Various typo/doc fixups.
454
455
4561.0.6 (2018-11-06)
457==================
458This is a small release.
459
460Performance improvements:
461
462* [OPT #513](https://github.com/rust-lang/regex/pull/513):
463  Improve performance of compiling large Unicode classes by 8-10%.
464
465Bug fixes:
466
467* [BUG #533](https://github.com/rust-lang/regex/issues/533):
468  Fix definition of `[[:blank:]]` class that regressed in `regex-syntax 0.5`.
469
470
4711.0.5 (2018-09-06)
472==================
473This is a small release with an API enhancement.
474
475New features:
476
477* [FEATURE #509](https://github.com/rust-lang/regex/pull/509):
478  Generalize impls of the `Replacer` trait.
479
480
4811.0.4 (2018-08-25)
482==================
483This is a small release that bumps the quickcheck dependency.
484
485
4861.0.3 (2018-08-24)
487==================
488This is a small bug fix release.
489
490Bug fixes:
491
492* [BUG #504](https://github.com/rust-lang/regex/pull/504):
493  Fix for Cargo's "minimal version" support.
494* [BUG 1e39165f](https://github.com/rust-lang/regex/commit/1e39165f):
495  Fix doc examples for byte regexes.
496
497
4981.0.2 (2018-07-18)
499==================
500This release exposes some new lower level APIs on `Regex` that permit
501amortizing allocation and controlling the location at which a search is
502performed in a more granular way. Most users of the regex crate will not
503need or want to use these APIs.
504
505New features:
506
507* [FEATURE #493](https://github.com/rust-lang/regex/pull/493):
508  Add a few lower level APIs for amortizing allocation and more fine grained
509  searching.
510
511Bug fixes:
512
513* [BUG 3981d2ad](https://github.com/rust-lang/regex/commit/3981d2ad):
514  Correct outdated documentation on `RegexBuilder::dot_matches_new_line`.
515* [BUG 7ebe4ae0](https://github.com/rust-lang/regex/commit/7ebe4ae0):
516  Correct outdated documentation on `Parser::allow_invalid_utf8` in the
517  `regex-syntax` crate.
518* [BUG 24c7770b](https://github.com/rust-lang/regex/commit/24c7770b):
519  Fix a bug in the HIR printer where it wouldn't correctly escape meta
520  characters in character classes.
521
522
5231.0.1 (2018-06-19)
524==================
525This release upgrades regex's Unicode tables to Unicode 11, and enables SIMD
526optimizations automatically on Rust stable (1.27 or newer).
527
528New features:
529
530* [FEATURE #486](https://github.com/rust-lang/regex/pull/486):
531  Implement `size_hint` on `RegexSet` match iterators.
532* [FEATURE #488](https://github.com/rust-lang/regex/pull/488):
533  Update Unicode tables for Unicode 11.
534* [FEATURE #490](https://github.com/rust-lang/regex/pull/490):
535  SIMD optimizations are now enabled automatically in Rust stable, for versions
536  1.27 and up. No compilation flags or features need to be set. CPU support
537  SIMD is detected automatically at runtime.
538
539Bug fixes:
540
541* [BUG #482](https://github.com/rust-lang/regex/pull/482):
542  Present a better compilation error when the `use_std` feature isn't used.
543
544
5451.0.0 (2018-05-01)
546==================
547This release marks the 1.0 release of regex.
548
549While this release includes some breaking changes, most users of older versions
550of the regex library should be able to migrate to 1.0 by simply bumping the
551version number. The important changes are as follows:
552
553* We adopt Rust 1.20 as the new minimum supported version of Rust for regex.
554  We also tentativley adopt a policy that permits bumping the minimum supported
555  version of Rust in minor version releases of regex, but no patch releases.
556  That is, with respect to semver, we do not strictly consider bumping the
557  minimum version of Rust to be a breaking change, but adopt a conservative
558  stance as a compromise.
559* Octal syntax in regular expressions has been disabled by default. This
560  permits better error messages that inform users that backreferences aren't
561  available. Octal syntax can be re-enabled via the corresponding option on
562  `RegexBuilder`.
563* `(?-u:\B)` is no longer allowed in Unicode regexes since it can match at
564  invalid UTF-8 code unit boundaries. `(?-u:\b)` is still allowed in Unicode
565  regexes.
566* The `From<regex_syntax::Error>` impl has been removed. This formally removes
567  the public dependency on `regex-syntax`.
568* A new feature, `use_std`, has been added and enabled by default. Disabling
569  the feature will result in a compilation error. In the future, this may
570  permit us to support `no_std` environments (w/ `alloc`) in a backwards
571  compatible way.
572
573For more information and discussion, please see
574[1.0 release tracking issue](https://github.com/rust-lang/regex/issues/457).
575
576
5770.2.11 (2018-05-01)
578===================
579This release primarily contains bug fixes. Some of them resolve bugs where
580the parser could panic.
581
582New features:
583
584* [FEATURE #459](https://github.com/rust-lang/regex/pull/459):
585  Include C++'s standard regex library and Boost's regex library in the
586  benchmark harness. We now include D/libphobos, C++/std, C++/boost, Oniguruma,
587  PCRE1, PCRE2, RE2 and Tcl in the harness.
588
589Bug fixes:
590
591* [BUG #445](https://github.com/rust-lang/regex/issues/445):
592  Clarify order of indices returned by RegexSet match iterator.
593* [BUG #461](https://github.com/rust-lang/regex/issues/461):
594  Improve error messages for invalid regexes like `[\d-a]`.
595* [BUG #464](https://github.com/rust-lang/regex/issues/464):
596  Fix a bug in the error message pretty printer that could cause a panic when
597  a regex contained a literal `\n` character.
598* [BUG #465](https://github.com/rust-lang/regex/issues/465):
599  Fix a panic in the parser that was caused by applying a repetition operator
600  to `(?flags)`.
601* [BUG #466](https://github.com/rust-lang/regex/issues/466):
602  Fix a bug where `\pC` was not recognized as an alias for `\p{Other}`.
603* [BUG #470](https://github.com/rust-lang/regex/pull/470):
604  Fix a bug where literal searches did more work than necessary for anchored
605  regexes.
606
607
6080.2.10 (2018-03-16)
609===================
610This release primarily updates the regex crate to changes made in `std::arch`
611on nightly Rust.
612
613New features:
614
615* [FEATURE #458](https://github.com/rust-lang/regex/pull/458):
616  The `Hir` type in `regex-syntax` now has a printer.
617
618
6190.2.9 (2018-03-12)
620==================
621This release introduces a new nightly only feature, `unstable`, which enables
622SIMD optimizations for certain types of regexes. No additional compile time
623options are necessary, and the regex crate will automatically choose the
624best CPU features at run time. As a result, the `simd` (nightly only) crate
625dependency has been dropped.
626
627New features:
628
629* [FEATURE #456](https://github.com/rust-lang/regex/pull/456):
630  The regex crate now includes AVX2 optimizations in addition to the extant
631  SSSE3 optimization.
632
633Bug fixes:
634
635* [BUG #455](https://github.com/rust-lang/regex/pull/455):
636  Fix a bug where `(?x)[ / - ]` failed to parse.
637
638
6390.2.8 (2018-03-12)
640==================
641Bug gixes:
642
643* [BUG #454](https://github.com/rust-lang/regex/pull/454):
644  Fix a bug in the nest limit checker being too aggressive.
645
646
6470.2.7 (2018-03-07)
648==================
649This release includes a ground-up rewrite of the regex-syntax crate, which has
650been in development for over a year.
651
652New features:
653
654* Error messages for invalid regexes have been greatly improved. You get these
655  automatically; you don't need to do anything. In addition to better
656  formatting, error messages will now explicitly call out the use of look
657  around. When regex 1.0 is released, this will happen for backreferences as
658  well.
659* Full support for intersection, difference and symmetric difference of
660  character classes. These can be used via the `&&`, `--` and `~~` binary
661  operators within classes.
662* A Unicode Level 1 conformat implementation of `\p{..}` character classes.
663  Things like `\p{scx:Hira}`, `\p{age:3.2}` or `\p{Changes_When_Casefolded}`
664  now work. All property name and value aliases are supported, and properties
665  are selected via loose matching. e.g., `\p{Greek}` is the same as
666  `\p{G r E e K}`.
667* A new `UNICODE.md` document has been added to this repository that
668  exhaustively documents support for UTS#18.
669* Empty sub-expressions are now permitted in most places. That is, `()+` is
670  now a valid regex.
671* Almost everything in regex-syntax now uses constant stack space, even when
672  performing anaylsis that requires structural induction. This reduces the risk
673  of a user provided regular expression causing a stack overflow.
674* [FEATURE #174](https://github.com/rust-lang/regex/issues/174):
675  The `Ast` type in `regex-syntax` now contains span information.
676* [FEATURE #424](https://github.com/rust-lang/regex/issues/424):
677  Support `\u`, `\u{...}`, `\U` and `\U{...}` syntax for specifying code points
678  in a regular expression.
679* [FEATURE #449](https://github.com/rust-lang/regex/pull/449):
680  Add a `Replace::by_ref` adapter for use of a replacer without consuming it.
681
682Bug fixes:
683
684* [BUG #446](https://github.com/rust-lang/regex/issues/446):
685  We re-enable the Boyer-Moore literal matcher.
686
687
6880.2.6 (2018-02-08)
689==================
690Bug fixes:
691
692* [BUG #446](https://github.com/rust-lang/regex/issues/446):
693  Fixes a bug in the new Boyer-Moore searcher that results in a match failure.
694  We fix this bug by temporarily disabling Boyer-Moore.
695
696
6970.2.5 (2017-12-30)
698==================
699Bug fixes:
700
701* [BUG #437](https://github.com/rust-lang/regex/issues/437):
702  Fixes a bug in the new Boyer-Moore searcher that results in a panic.
703
704
7050.2.4 (2017-12-30)
706==================
707New features:
708
709* [FEATURE #348](https://github.com/rust-lang/regex/pull/348):
710  Improve performance for capture searches on anchored regex.
711  (Contributed by @ethanpailes. Nice work!)
712* [FEATURE #419](https://github.com/rust-lang/regex/pull/419):
713  Expand literal searching to include Tuned Boyer-Moore in some cases.
714  (Contributed by @ethanpailes. Nice work!)
715
716Bug fixes:
717
718* [BUG](https://github.com/rust-lang/regex/pull/436):
719  The regex compiler plugin has been removed.
720* [BUG](https://github.com/rust-lang/regex/pull/436):
721  `simd` has been bumped to `0.2.1`, which fixes a Rust nightly build error.
722* [BUG](https://github.com/rust-lang/regex/pull/436):
723  Bring the benchmark harness up to date.
724
725
7260.2.3 (2017-11-30)
727==================
728New features:
729
730* [FEATURE #374](https://github.com/rust-lang/regex/pull/374):
731  Add `impl From<Match> for &str`.
732* [FEATURE #380](https://github.com/rust-lang/regex/pull/380):
733  Derive `Clone` and `PartialEq` on `Error`.
734* [FEATURE #400](https://github.com/rust-lang/regex/pull/400):
735  Update to Unicode 10.
736
737Bug fixes:
738
739* [BUG #375](https://github.com/rust-lang/regex/issues/375):
740  Fix a bug that prevented the bounded backtracker from terminating.
741* [BUG #393](https://github.com/rust-lang/regex/issues/393),
742  [BUG #394](https://github.com/rust-lang/regex/issues/394):
743  Fix bug with `replace` methods for empty matches.
744
745
7460.2.2 (2017-05-21)
747==================
748New features:
749
750* [FEATURE #341](https://github.com/rust-lang/regex/issues/341):
751  Support nested character classes and intersection operation.
752  For example, `[\p{Greek}&&\pL]` matches greek letters and
753  `[[0-9]&&[^4]]` matches every decimal digit except `4`.
754  (Much thanks to @robinst, who contributed this awesome feature.)
755
756Bug fixes:
757
758* [BUG #321](https://github.com/rust-lang/regex/issues/321):
759  Fix bug in literal extraction and UTF-8 decoding.
760* [BUG #326](https://github.com/rust-lang/regex/issues/326):
761  Add documentation tip about the `(?x)` flag.
762* [BUG #333](https://github.com/rust-lang/regex/issues/333):
763  Show additional replacement example using curly braces.
764* [BUG #334](https://github.com/rust-lang/regex/issues/334):
765  Fix bug when resolving captures after a match.
766* [BUG #338](https://github.com/rust-lang/regex/issues/338):
767  Add example that uses `Captures::get` to API documentation.
768* [BUG #353](https://github.com/rust-lang/regex/issues/353):
769  Fix RegexSet bug that caused match failure in some cases.
770* [BUG #354](https://github.com/rust-lang/regex/pull/354):
771  Fix panic in parser when `(?x)` is used.
772* [BUG #358](https://github.com/rust-lang/regex/issues/358):
773  Fix literal optimization bug with RegexSet.
774* [BUG #359](https://github.com/rust-lang/regex/issues/359):
775  Fix example code in README.
776* [BUG #365](https://github.com/rust-lang/regex/pull/365):
777  Fix bug in `rure_captures_len` in the C binding.
778* [BUG #367](https://github.com/rust-lang/regex/issues/367):
779  Fix byte class bug that caused a panic.
780
781
7820.2.1
783=====
784One major bug with `replace_all` has been fixed along with a couple of other
785touchups.
786
787* [BUG #312](https://github.com/rust-lang/regex/issues/312):
788  Fix documentation for `NoExpand` to reference correct lifetime parameter.
789* [BUG #314](https://github.com/rust-lang/regex/issues/314):
790  Fix a bug with `replace_all` when replacing a match with the empty string.
791* [BUG #316](https://github.com/rust-lang/regex/issues/316):
792  Note a missing breaking change from the `0.2.0` CHANGELOG entry.
793  (`RegexBuilder::compile` was renamed to `RegexBuilder::build`.)
794* [BUG #324](https://github.com/rust-lang/regex/issues/324):
795  Compiling `regex` should only require one version of `memchr` crate.
796
797
7980.2.0
799=====
800This is a new major release of the regex crate, and is an implementation of the
801[regex 1.0 RFC](https://github.com/rust-lang/rfcs/blob/master/text/1620-regex-1.0.md).
802We are releasing a `0.2` first, and if there are no major problems, we will
803release a `1.0` shortly. For `0.2`, the minimum *supported* Rust version is
8041.12.
805
806There are a number of **breaking changes** in `0.2`. They are split into two
807types. The first type correspond to breaking changes in regular expression
808syntax. The second type correspond to breaking changes in the API.
809
810Breaking changes for regex syntax:
811
812* POSIX character classes now require double bracketing. Previously, the regex
813  `[:upper:]` would parse as the `upper` POSIX character class. Now it parses
814  as the character class containing the characters `:upper:`. The fix to this
815  change is to use `[[:upper:]]` instead. Note that variants like
816  `[[:upper:][:blank:]]` continue to work.
817* The character `[` must always be escaped inside a character class.
818* The characters `&`, `-` and `~` must be escaped if any one of them are
819  repeated consecutively. For example, `[&]`, `[\&]`, `[\&\&]`, `[&-&]` are all
820  equivalent while `[&&]` is illegal. (The motivation for this and the prior
821  change is to provide a backwards compatible path for adding character class
822  set notation.)
823* A `bytes::Regex` now has Unicode mode enabled by default (like the main
824  `Regex` type). This means regexes compiled with `bytes::Regex::new` that
825  don't have the Unicode flag set should add `(?-u)` to recover the original
826  behavior.
827
828Breaking changes for the regex API:
829
830* `find` and `find_iter` now **return `Match` values instead of
831  `(usize, usize)`.** `Match` values have `start` and `end` methods, which
832  return the match offsets. `Match` values also have an `as_str` method,
833  which returns the text of the match itself.
834* The `Captures` type now only provides a single iterator over all capturing
835  matches, which should replace uses of `iter` and `iter_pos`. Uses of
836  `iter_named` should use the `capture_names` method on `Regex`.
837* The `at` method on the `Captures` type has been renamed to `get`, and it
838  now returns a `Match`. Similarly, the `name` method on `Captures` now returns
839  a `Match`.
840* The `replace` methods now return `Cow` values. The `Cow::Borrowed` variant
841  is returned when no replacements are made.
842* The `Replacer` trait has been completely overhauled. This should only
843  impact clients that implement this trait explicitly. Standard uses of
844  the `replace` methods should continue to work unchanged. If you implement
845  the `Replacer` trait, please consult the new documentation.
846* The `quote` free function has been renamed to `escape`.
847* The `Regex::with_size_limit` method has been removed. It is replaced by
848  `RegexBuilder::size_limit`.
849* The `RegexBuilder` type has switched from owned `self` method receivers to
850  `&mut self` method receivers. Most uses will continue to work unchanged, but
851  some code may require naming an intermediate variable to hold the builder.
852* The `compile` method on `RegexBuilder` has been renamed to `build`.
853* The free `is_match` function has been removed. It is replaced by compiling
854  a `Regex` and calling its `is_match` method.
855* The `PartialEq` and `Eq` impls on `Regex` have been dropped. If you relied
856  on these impls, the fix is to define a wrapper type around `Regex`, impl
857  `Deref` on it and provide the necessary impls.
858* The `is_empty` method on `Captures` has been removed. This always returns
859  `false`, so its use is superfluous.
860* The `Syntax` variant of the `Error` type now contains a string instead of
861  a `regex_syntax::Error`. If you were examining syntax errors more closely,
862  you'll need to explicitly use the `regex_syntax` crate to re-parse the regex.
863* The `InvalidSet` variant of the `Error` type has been removed since it is
864  no longer used.
865* Most of the iterator types have been renamed to match conventions. If you
866  were using these iterator types explicitly, please consult the documentation
867  for its new name. For example, `RegexSplits` has been renamed to `Split`.
868
869A number of bugs have been fixed:
870
871* [BUG #151](https://github.com/rust-lang/regex/issues/151):
872  The `Replacer` trait has been changed to permit the caller to control
873  allocation.
874* [BUG #165](https://github.com/rust-lang/regex/issues/165):
875  Remove the free `is_match` function.
876* [BUG #166](https://github.com/rust-lang/regex/issues/166):
877  Expose more knobs (available in `0.1`) and remove `with_size_limit`.
878* [BUG #168](https://github.com/rust-lang/regex/issues/168):
879  Iterators produced by `Captures` now have the correct lifetime parameters.
880* [BUG #175](https://github.com/rust-lang/regex/issues/175):
881  Fix a corner case in the parsing of POSIX character classes.
882* [BUG #178](https://github.com/rust-lang/regex/issues/178):
883  Drop the `PartialEq` and `Eq` impls on `Regex`.
884* [BUG #179](https://github.com/rust-lang/regex/issues/179):
885  Remove `is_empty` from `Captures` since it always returns false.
886* [BUG #276](https://github.com/rust-lang/regex/issues/276):
887  Position of named capture can now be retrieved from a `Captures`.
888* [BUG #296](https://github.com/rust-lang/regex/issues/296):
889  Remove winapi/kernel32-sys dependency on UNIX.
890* [BUG #307](https://github.com/rust-lang/regex/issues/307):
891  Fix error on emscripten.
892
893
8940.1.80
895======
896* [PR #292](https://github.com/rust-lang/regex/pull/292):
897  Fixes bug #291, which was introduced by PR #290.
898
8990.1.79
900======
901* Require regex-syntax 0.3.8.
902
9030.1.78
904======
905* [PR #290](https://github.com/rust-lang/regex/pull/290):
906  Fixes bug #289, which caused some regexes with a certain combination
907  of literals to match incorrectly.
908
9090.1.77
910======
911* [PR #281](https://github.com/rust-lang/regex/pull/281):
912  Fixes bug #280 by disabling all literal optimizations when a pattern
913  is partially anchored.
914
9150.1.76
916======
917* Tweak criteria for using the Teddy literal matcher.
918
9190.1.75
920======
921* [PR #275](https://github.com/rust-lang/regex/pull/275):
922  Improves match verification performance in the Teddy SIMD searcher.
923* [PR #278](https://github.com/rust-lang/regex/pull/278):
924  Replaces slow substring loop in the Teddy SIMD searcher with Aho-Corasick.
925* Implemented DoubleEndedIterator on regex set match iterators.
926
9270.1.74
928======
929* Release regex-syntax 0.3.5 with a minor bug fix.
930* Fix bug #272.
931* Fix bug #277.
932* [PR #270](https://github.com/rust-lang/regex/pull/270):
933  Fixes bugs #264, #268 and an unreported where the DFA cache size could be
934  drastically under estimated in some cases (leading to high unexpected memory
935  usage).
936
9370.1.73
938======
939* Release `regex-syntax 0.3.4`.
940* Bump `regex-syntax` dependency version for `regex` to `0.3.4`.
941
9420.1.72
943======
944* [PR #262](https://github.com/rust-lang/regex/pull/262):
945  Fixes a number of small bugs caught by fuzz testing (AFL).
946
9470.1.71
948======
949* [PR #236](https://github.com/rust-lang/regex/pull/236):
950  Fix a bug in how suffix literals were extracted, which could lead
951  to invalid match behavior in some cases.
952
9530.1.70
954======
955* [PR #231](https://github.com/rust-lang/regex/pull/231):
956  Add SIMD accelerated multiple pattern search.
957* [PR #228](https://github.com/rust-lang/regex/pull/228):
958  Reintroduce the reverse suffix literal optimization.
959* [PR #226](https://github.com/rust-lang/regex/pull/226):
960  Implements NFA state compression in the lazy DFA.
961* [PR #223](https://github.com/rust-lang/regex/pull/223):
962  A fully anchored RegexSet can now short-circuit.
963
9640.1.69
965======
966* [PR #216](https://github.com/rust-lang/regex/pull/216):
967  Tweak the threshold for running backtracking.
968* [PR #217](https://github.com/rust-lang/regex/pull/217):
969  Add upper limit (from the DFA) to capture search (for the NFA).
970* [PR #218](https://github.com/rust-lang/regex/pull/218):
971  Add rure, a C API.
972
9730.1.68
974======
975* [PR #210](https://github.com/rust-lang/regex/pull/210):
976  Fixed a performance bug in `bytes::Regex::replace` where `extend` was used
977  instead of `extend_from_slice`.
978* [PR #211](https://github.com/rust-lang/regex/pull/211):
979  Fixed a bug in the handling of word boundaries in the DFA.
980* [PR #213](https://github.com/rust-lang/pull/213):
981  Added RE2 and Tcl to the benchmark harness. Also added a CLI utility from
982  running regexes using any of the following regex engines: PCRE1, PCRE2,
983  Oniguruma, RE2, Tcl and of course Rust's own regexes.
984
9850.1.67
986======
987* [PR #201](https://github.com/rust-lang/regex/pull/201):
988  Fix undefined behavior in the `regex!` compiler plugin macro.
989* [PR #205](https://github.com/rust-lang/regex/pull/205):
990  More improvements to DFA performance. Competitive with RE2. See PR for
991  benchmarks.
992* [PR #209](https://github.com/rust-lang/regex/pull/209):
993  Release 0.1.66 was semver incompatible since it required a newer version
994  of Rust than previous releases. This PR fixes that. (And `0.1.66` was
995  yanked.)
996
9970.1.66
998======
999* Speculative support for Unicode word boundaries was added to the DFA. This
1000  should remove the last common case that disqualified use of the DFA.
1001* An optimization that scanned for suffix literals and then matched the regular
1002  expression in reverse was removed because it had worst case quadratic time
1003  complexity. It was replaced with a more limited optimization where, given any
1004  regex of the form `re$`, it will be matched in reverse from the end of the
1005  haystack.
1006* [PR #202](https://github.com/rust-lang/regex/pull/202):
1007  The inner loop of the DFA was heavily optimized to improve cache locality
1008  and reduce the overall number of instructions run on each iteration. This
1009  represents the first use of `unsafe` in `regex` (to elide bounds checks).
1010* [PR #200](https://github.com/rust-lang/regex/pull/200):
1011  Use of the `mempool` crate (which used thread local storage) was replaced
1012  with a faster version of a similar API in @Amanieu's `thread_local` crate.
1013  It should reduce contention when using a regex from multiple threads
1014  simultaneously.
1015* PCRE2 JIT benchmarks were added. A benchmark comparison can be found
1016  [here](https://gist.github.com/anonymous/14683c01993e91689f7206a18675901b).
1017  (Includes a comparison with PCRE1's JIT and Oniguruma.)
1018* A bug where word boundaries weren't being matched correctly in the DFA was
1019  fixed. This only affected use of `bytes::Regex`.
1020* [#160](https://github.com/rust-lang/regex/issues/160):
1021  `Captures` now has a `Debug` impl.
1022