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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.32
5    ------------
6    
7    1.  Improved JIT compiler optimizations for first character search and single
8        character iterators.
9    
10    2.  Supporting IBM XL C compilers for PPC architectures in the JIT compiler.
11        Patch by Daniel Richard G.
12    
13    3.  Single character iterator optimizations in the JIT compiler.
14    
15    4.  Improved JIT compiler optimizations for character ranges.
16    
17    5.  Rename the "leave" variable names to "quit" to improve WinCE compatibility.
18        Reported by Giuseppe D'Angelo.
19    
20    6.  The PCRE_STARTLINE bit, indicating that a match can occur only at the start
21        of a line, was being set incorrectly in cases where .* appeared inside
22        atomic brackets at the start of a pattern, or where there was a subsequent
23        *PRUNE or *SKIP.
24    
25    7.  Improved instruction cache flush for POWER/PowerPC.
26        Patch by Daniel Richard G.
27    
28    8.  Fixed a number of issues in pcregrep, making it more compatible with GNU
29        grep:
30    
31        (a) There is now no limit to the number of patterns to be matched.
32    
33        (b) An error is given if a pattern is too long.
34    
35        (c) Multiple uses of --exclude, --exclude-dir, --include, and --include-dir
36            are now supported.
37    
38        (d) --exclude-from and --include-from (multiple use) have been added.
39    
40        (e) Exclusions and inclusions now apply to all files and directories, not
41            just to those obtained from scanning a directory recursively.
42    
43        (f) Multiple uses of -f and --file-list are now supported.
44    
45        (g) In a Windows environment, the default for -d has been changed from
46            "read" (the GNU grep default) to "skip", because otherwise the presence
47            of a directory in the file list provokes an error.
48    
49        (h) The documentation has been revised and clarified in places.
50    
51    9.  Improve the matching speed of capturing brackets.
52    
53    10. Changed the meaning of \X in the interpreters so that it now matches a
54        Unicode extended grapheme cluster.
55    
56    
57    
58    Version 8.31 06-July-2012
59    -------------------------
60    
61    1.  Fixing a wrong JIT test case and some compiler warnings.
62    
63    2.  Removed a bashism from the RunTest script.
64    
65    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
66        to unsigned type, result still unsigned" that was given by an MS compiler
67        on encountering the code "-sizeof(xxx)".
68    
69    4.  Partial matching support is added to the JIT compiler.
70    
71    5.  Fixed several bugs concerned with partial matching of items that consist
72        of more than one character:
73    
74        (a) /^(..)\1/ did not partially match "aba" because checking references was
75            done on an "all or nothing" basis. This also applied to repeated
76            references.
77    
78        (b) \R did not give a hard partial match if \r was found at the end of the
79            subject.
80    
81        (c) \X did not give a hard partial match after matching one or more
82            characters at the end of the subject.
83    
84        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
85            a partial match for the string "\r".
86    
87        (e) When newline was set to CRLF, the metacharacter "." did not recognize
88            a partial match for a CR character at the end of the subject string.
89    
90    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
91        running pcretest, the text "(JIT)" added to the output whenever JIT is
92        actually used to run the match.
93    
94    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
95        or /S+[+] with a digit between 1 and 7.
96    
97    8.  OP_NOT now supports any UTF character not just single-byte ones.
98    
99    9.  (*MARK) control verb is now supported by the JIT compiler.
100    
101    10. The command "./RunTest list" lists the available tests without actually
102        running any of them. (Because I keep forgetting what they all are.)
103    
104    11. Add PCRE_INFO_MAXLOOKBEHIND.
105    
106    12. Applied a (slightly modified) user-supplied patch that improves performance
107        when the heap is used for recursion (compiled with --disable-stack-for-
108        recursion). Instead of malloc and free for each heap frame each time a
109        logical recursion happens, frames are retained on a chain and re-used where
110        possible. This sometimes gives as much as 30% improvement.
111    
112    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
113        call.
114    
115    14. As documented, (*COMMIT) is now confined to within a positive assertion.
116    
117    15. It is now possible to link pcretest with libedit as an alternative to
118        libreadline.
119    
120    16. (*COMMIT) control verb is now supported by the JIT compiler.
121    
122    17. The Unicode data tables have been updated to Unicode 6.1.0.
123    
124    18. Added --file-list option to pcregrep.
125    
126    19. Added binary file support to pcregrep, including the -a, --binary-files,
127        -I, and --text options.
128    
129    20. The madvise function is renamed for posix_madvise for QNX compatibility
130        reasons. Fixed by Giuseppe D'Angelo.
131    
132    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
133    
134    22. Changed the option for creating symbolic links for 16-bit man pages from
135        -s to -sf so that re-installing does not cause issues.
136    
137    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
138    
139    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
140        matches in certain environments (the workspace was not being correctly
141        retained). Also added to pcre_dfa_exec() a simple plausibility check on
142        some of the workspace data at the beginning of a restart.
143    
144    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
145        was not doing so when it should - probably a typo introduced by SVN 528
146        (change 8.10/14).
147    
148    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
149        \w+ when the character tables indicated that \x{c4} was a word character.
150        There were several related cases, all because the tests for doing a table
151        lookup were testing for characters less than 127 instead of 255.
152    
153    27. If a pattern contains capturing parentheses that are not used in a match,
154        their slots in the ovector are set to -1. For those that are higher than
155        any matched groups, this happens at the end of processing. In the case when
156        there were back references that the ovector was too small to contain
157        (causing temporary malloc'd memory to be used during matching), and the
158        highest capturing number was not used, memory off the end of the ovector
159        was incorrectly being set to -1. (It was using the size of the temporary
160        memory instead of the true size.)
161    
162    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
163        ovector size, it uses memory at the end of the block that it has got.
164    
165    29. Check for an overlong MARK name and give an error at compile time. The
166        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
167    
168    30. JIT compiler update.
169    
170    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
171        Rill for the patch.
172    
173    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
174    
175    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
176    
177    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
178        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
179        was enabled.
180    
181    35. Improve JIT code generation for greedy plus quantifier.
182    
183    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
184        1 to "aa" instead of to an empty string. The bug affected repeated groups
185        that could potentially match an empty string.
186    
187    37. Optimizing single character iterators in JIT.
188    
189    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
190        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
191        codepoints that are too big for the mode are faulted, and in a UTF mode,
192        disallowed codepoints are also faulted.
193    
194    39. If PCRE was compiled with UTF support, in three places in the DFA
195        matcher there was code that should only have been obeyed in UTF mode, but
196        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
197        processing when bytes with values greater than 127 were present. In 16-bit
198        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
199        both cases the values are those that cannot be the first data item in a UTF
200        character. The three items that might have provoked this were recursions,
201        possessively repeated groups, and atomic groups.
202    
203    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
204        and pcregrep, because some OS require shared objects to be explicitly
205        passed to ld, causing the link step to fail if they are not.
206    
207    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
208        mode, patterns that started with \h* or \R* might be incorrectly matched.
209    
210    
211    Version 8.30 04-February-2012
212    -----------------------------
213    
214    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
215        name is defined in ctype.h.
216    
217    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
218        only in quite long subpatterns.
219    
220    3.  Removed the function pcre_info(), which has been obsolete and deprecated
221        since it was replaced by pcre_fullinfo() in February 2000.
222    
223    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
224        match a (*MARK), and the match failed at the start of the subject, a
225        reference to memory before the start of the subject could occur. This bug
226        was introduced by fix 17 of release 8.21.
227    
228    5.  A reference to an unset group with zero minimum repetition was giving
229        totally wrong answers (in non-JavaScript-compatibility mode). For example,
230        /(another)?(\1?)test/ matched against "hello world test". This bug was
231        introduced in release 8.13.
232    
233    6.  Add support for 16-bit character strings (a large amount of work involving
234        many changes and refactorings).
235    
236    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
237        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
238        from a file.
239    
240    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
241        rounding is not applied in this particular case).
242    
243    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
244        if they appear, or are escaped, in patterns.
245    
246    10. Get rid of a number of -Wunused-but-set-variable warnings.
247    
248    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
249        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
250        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
251        also returns the mark "x". This bug applied to capturing parentheses,
252        non-capturing parentheses, and atomic parentheses. It also applied to some
253        assertions.
254    
255    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
256        information out of configure.ac instead of relying on pcre.h.generic, which
257        is not stored in the repository.
258    
259    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
260        -lreadline.
261    
262    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
263    
264    15. Applied Graycode's patch to put the top-level frame on the stack rather
265        than the heap when not using the stack for recursion. This gives a
266        performance improvement in many cases when recursion is not deep.
267    
268    16. Experimental code added to "pcretest -C" to output the stack frame size.
269    
270    
271    Version 8.21 12-Dec-2011
272    ------------------------
273    
274    1.  Updating the JIT compiler.
275    
276    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
277        are added as well.
278    
279    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
280        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
281        calling _pcre_jit_exec. Some extra comments are added.
282    
283    4.  (*MARK) settings inside atomic groups that do not contain any capturing
284        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
285        was introduced by change 18 for 8.20.
286    
287    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
288        ECMA-262 standard.
289    
290    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
291        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
292        This bug was probably introduced by change 9 of 8.13.
293    
294    7.  While fixing 6 above, I noticed that a number of other items were being
295        incorrectly rejected as "not fixed length". This arose partly because newer
296        opcodes had not been added to the fixed-length checking code. I have (a)
297        corrected the bug and added tests for these items, and (b) arranged for an
298        error to occur if an unknown opcode is encountered while checking for fixed
299        length instead of just assuming "not fixed length". The items that were
300        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
301        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
302        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
303    
304    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
305        being incorrectly compiled and would have given unpredicatble results.
306    
307    9.  A possessively repeated subpattern with minimum repeat count greater than
308        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
309        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
310        the first (A) could occur when it should not.
311    
312    10. Add a cast and remove a redundant test from the code.
313    
314    11. JIT should use pcre_malloc/pcre_free for allocation.
315    
316    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
317        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
318        is anything other than /usr, -L is still shown).
319    
320    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
321    
322    14. Perl does not support \N without a following name in a [] class; PCRE now
323        also gives an error.
324    
325    15. If a forward reference was repeated with an upper limit of around 2000,
326        it caused the error "internal error: overran compiling workspace". The
327        maximum number of forward references (including repeats) was limited by the
328        internal workspace, and dependent on the LINK_SIZE. The code has been
329        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
330        the default depends on LINK_SIZE. There is a new upper limit (for safety)
331        of around 200,000 forward references. While doing this, I also speeded up
332        the filling in of repeated forward references.
333    
334    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
335        incorrectly expecting the subject to contain another "a" after the start.
336    
337    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
338        in the match, the SKIP should be ignored. This was not happening; instead
339        the SKIP was being treated as NOMATCH. For patterns such as
340        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
341        tested.
342    
343    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
344        now much more compatible with Perl, in particular in cases where the result
345        is a non-match for a non-anchored pattern. For example, if
346        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
347        "m", where previously it did not return a name. A side effect of this
348        change is that for partial matches, the last encountered mark name is
349        returned, as for non matches. A number of tests that were previously not
350        Perl-compatible have been moved into the Perl-compatible test files. The
351        refactoring has had the pleasing side effect of removing one argument from
352        the match() function, thus reducing its stack requirements.
353    
354    19. If the /S+ option was used in pcretest to study a pattern using JIT,
355        subsequent uses of /S (without +) incorrectly behaved like /S+.
356    
357    21. Retrieve executable code size support for the JIT compiler and fixing
358        some warnings.
359    
360    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
361        not work when the shorter character appeared right at the end of the
362        subject string.
363    
364    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
365        systems.
366    
367    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
368        output it when the /M option is used in pcretest.
369    
370    25. The CheckMan script was not being included in the distribution. Also, added
371        an explicit "perl" to run Perl scripts from the PrepareRelease script
372        because this is reportedly needed in Windows.
373    
374    26. If study data was being save in a file and studying had not found a set of
375        "starts with" bytes for the pattern, the data written to the file (though
376        never used) was taken from uninitialized memory and so caused valgrind to
377        complain.
378    
379    27. Updated RunTest.bat as provided by Sheri Pierce.
380    
381    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
382    
383    29. Computation of memory usage for the table of capturing group names was
384        giving an unnecessarily large value.
385    
386    
387    Version 8.20 21-Oct-2011
388    ------------------------
389    
390    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
391        a POSIX class. After further experiments with Perl, which convinced me that
392        Perl has bugs and confusions, a closing square bracket is no longer allowed
393        in a POSIX name. This bug also affected patterns with classes that started
394        with full stops.
395    
396    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
397        captured substring, but while checking the failing first alternative,
398        substring 1 is temporarily captured. If the output vector supplied to
399        pcre_exec() was not big enough for this capture, the yield of the function
400        was still zero ("insufficient space for captured substrings"). This cannot
401        be totally fixed without adding another stack variable, which seems a lot
402        of expense for a edge case. However, I have improved the situation in cases
403        such as /(a)(b)x|abc/ matched against "abc", where the return code
404        indicates that fewer than the maximum number of slots in the ovector have
405        been set.
406    
407    3.  Related to (2) above: when there are more back references in a pattern than
408        slots in the output vector, pcre_exec() uses temporary memory during
409        matching, and copies in the captures as far as possible afterwards. It was
410        using the entire output vector, but this conflicts with the specification
411        that only 2/3 is used for passing back captured substrings. Now it uses
412        only the first 2/3, for compatibility. This is, of course, another edge
413        case.
414    
415    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
416        main code base, and can be used by building with --enable-jit. When this is
417        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
418        runtime --no-jit option is given.
419    
420    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
421        ovector, the return from the function was zero, implying that there were
422        other matches that did not fit. The correct "exactly full" value is now
423        returned.
424    
425    6.  If a subpattern that was called recursively or as a subroutine contained
426        (*PRUNE) or any other control that caused it to give a non-standard return,
427        invalid errors such as "Error -26 (nested recursion at the same subject
428        position)" or even infinite loops could occur.
429    
430    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
431        computing the minimum length on reaching *ACCEPT, and so ended up with the
432        wrong value of 1 rather than 0. Further investigation indicates that
433        computing a minimum subject length in the presence of *ACCEPT is difficult
434        (think back references, subroutine calls), and so I have changed the code
435        so that no minimum is registered for a pattern that contains *ACCEPT.
436    
437    8.  If (*THEN) was present in the first (true) branch of a conditional group,
438        it was not handled as intended. [But see 16 below.]
439    
440    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
441        Sheri Pierce.
442    
443    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
444        the first byte in a match must be "a".
445    
446    11. Change 17 for 8.13 increased the recursion depth for patterns like
447        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
448        pattern contains any instances of (*THEN). If it does not, the old
449        optimizations are restored. It would be nice to do this on a per-group
450        basis, but at the moment that is not feasible.
451    
452    12. In some environments, the output of pcretest -C is CRLF terminated. This
453        broke RunTest's code that checks for the link size. A single white space
454        character after the value is now allowed for.
455    
456    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
457        For "fr", it uses the Windows-specific input and output files.
458    
459    14. If (*THEN) appeared in a group that was called recursively or as a
460        subroutine, it did not work as intended. [But see next item.]
461    
462    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
463        pattern fragments (but not containing any | characters). If A and B are
464        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
465        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
466        D. In other words, Perl considers parentheses that do not contain any |
467        characters to be part of a surrounding alternative, whereas PCRE was
468        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
469        differently. PCRE now behaves in the same way as Perl, except in the case
470        of subroutine/recursion calls such as (?1) which have in any case always
471        been different (but PCRE had them first :-).
472    
473    16. Related to 15 above: Perl does not treat the | in a conditional group as
474        creating alternatives. Such a group is treated in the same way as an
475        ordinary group without any | characters when processing (*THEN). PCRE has
476        been changed to match Perl's behaviour.
477    
478    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
479        RunGrepTest script failed.
480    
481    18. Change 22 for version 13 caused atomic groups to use more stack. This is
482        inevitable for groups that contain captures, but it can lead to a lot of
483        stack use in large patterns. The old behaviour has been restored for atomic
484        groups that do not contain any capturing parentheses.
485    
486    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
487        suppress the check for a minimum subject length at run time. (If it was
488        given to pcre_exec() or pcre_dfa_exec() it did work.)
489    
490    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
491        fail to work when decoding hex characters in data strings in EBCDIC
492        environments.
493    
494    21. It appears that in at least one Mac OS environment, the isxdigit() function
495        is implemented as a macro that evaluates to its argument more than once,
496        contravening the C 90 Standard (I haven't checked a later standard). There
497        was an instance in pcretest which caused it to go wrong when processing
498        \x{...} escapes in subject strings. The has been rewritten to avoid using
499        things like p++ in the argument of isxdigit().
500    
501    
502    Version 8.13 16-Aug-2011
503  ------------------------  ------------------------
504    
505  1.  The Unicode data tables have been updated to Unicode 6.0.0.  1.  The Unicode data tables have been updated to Unicode 6.0.0.
# Line 20  Version 8.13 30-Apr-2011 Line 518  Version 8.13 30-Apr-2011
518      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
519      2-byte code at the end of the subject (it thought there wasn't enough data      2-byte code at the end of the subject (it thought there wasn't enough data
520      left).      left).
521    
522  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
523      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
524      as the output vector has at least 2 elements. The offset of the start of      as the output vector has at least 2 elements. The offset of the start of
525      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
526    
527  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
528      now returned is for the first byte of the failing character, instead of the      now returned is for the first byte of the failing character, instead of the
529      last byte inspected. This is an incompatible change, but I hope it is small      last byte inspected. This is an incompatible change, but I hope it is small
530      enough not to be a problem. It makes the returned offset consistent with      enough not to be a problem. It makes the returned offset consistent with
531      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
532    
533  7.  pcretest now gives a text phrase as well as the error number when  7.  pcretest now gives a text phrase as well as the error number when
534      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
535      failure, the offset and reason code are output.      failure, the offset and reason code are output.
536    
537  8.  When \R was used with a maximizing quantifier it failed to skip backwards  8.  When \R was used with a maximizing quantifier it failed to skip backwards
538      over a \r\n pair if the subsequent match failed. Instead, it just skipped      over a \r\n pair if the subsequent match failed. Instead, it just skipped
539      back over a single character (\n). This seems wrong (because it treated the      back over a single character (\n). This seems wrong (because it treated the
540      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
541      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
542      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
543      has been changed.      has been changed.
544    
545  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
546      of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile      of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
547      time (the PCRE_DOTALL option was changed this way some time ago: version      time (the PCRE_DOTALL option was changed this way some time ago: version
548      7.7 change 16). This has made it possible to abolish the OP_OPT op code,      7.7 change 16). This has made it possible to abolish the OP_OPT op code,
549      which was always a bit of a fudge. It also means that there is one less      which was always a bit of a fudge. It also means that there is one less
550      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
551      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
552      (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.      (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
553    
554    10. More internal refactoring has drastically reduced the number of recursive
555        calls to match() for possessively repeated groups such as (abc)++ when
556        using pcre_exec().
557    
558    11. While implementing 10, a number of bugs in the handling of groups were
559        discovered and fixed:
560    
561        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
562        (a|)*(?1) gave a compile-time internal error.
563        ((a|)+)+  did not notice that the outer group could match an empty string.
564        (^a|^)+   was not marked as anchored.
565        (.*a|.*)+ was not marked as matching at start or after a newline.
566    
567    12. Yet more internal refactoring has removed another argument from the match()
568        function. Special calls to this function are now indicated by setting a
569        value in a variable in the "match data" data block.
570    
571    13. Be more explicit in pcre_study() instead of relying on "default" for
572        opcodes that mean there is no starting character; this means that when new
573        ones are added and accidentally left out of pcre_study(), testing should
574        pick them up.
575    
576    14. The -s option of pcretest has been documented for ages as being an old
577        synonym of -m (show memory usage). I have changed it to mean "force study
578        for every regex", that is, assume /S for every regex. This is similar to -i
579        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
580        using it. It makes it easier to run collections of tests with and without
581        study enabled, and thereby test pcre_study() more easily. All the standard
582        tests are now run with and without -s (but some patterns can be marked as
583        "never study" - see 20 below).
584    
585    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
586        restoration of the capturing data to the outer values was not happening
587        correctly.
588    
589    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
590        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
591        pattern had matched an empty string, and so incorrectly returned a no
592        match.
593    
594    17. There was optimizing code for the last branch of non-capturing parentheses,
595        and also for the obeyed branch of a conditional subexpression, which used
596        tail recursion to cut down on stack usage. Unfortunately, now that there is
597        the possibility of (*THEN) occurring in these branches, tail recursion is
598        no longer possible because the return has to be checked for (*THEN). These
599        two optimizations have therefore been removed. [But see 8.20/11 above.]
600    
601    18. If a pattern containing \R was studied, it was assumed that \R always
602        matched two bytes, thus causing the minimum subject length to be
603        incorrectly computed because \R can also match just one byte.
604    
605    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
606        was incorrectly computed.
607    
608    20. If /S is present twice on a test pattern in pcretest input, it now
609        *disables* studying, thereby overriding the use of -s on the command line
610        (see 14 above). This is necessary for one or two tests to keep the output
611        identical in both cases.
612    
613    21. When (*ACCEPT) was used in an assertion that matched an empty string and
614        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
615    
616    22. When an atomic group that contained a capturing parenthesis was
617        successfully matched, but the branch in which it appeared failed, the
618        capturing was not being forgotten if a higher numbered group was later
619        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
620        group 1 to "a", when in fact it should be unset. This applied to multi-
621        branched capturing and non-capturing groups, repeated or not, and also to
622        positive assertions (capturing in negative assertions does not happen
623        in PCRE) and also to nested atomic groups.
624    
625    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
626        subject after a captured substring, to make it easier to tell which of a
627        number of identical substrings has been captured.
628    
629    24. The way atomic groups are processed by pcre_exec() has been changed so that
630        if they are repeated, backtracking one repetition now resets captured
631        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
632        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
633        "aaa". Previously, it would have been "a". As part of this code
634        refactoring, the way recursive calls are handled has also been changed.
635    
636    25. If an assertion condition captured any substrings, they were not passed
637        back unless some other capturing happened later. For example, if
638        (?(?=(a))a) was matched against "a", no capturing was returned.
639    
640    26. When studying a pattern that contained subroutine calls or assertions,
641        the code for finding the minimum length of a possible match was handling
642        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
643        group 1 called group 2 while simultaneously a separate group 2 called group
644        1). A stack overflow occurred in this case. I have fixed this by limiting
645        the recursion depth to 10.
646    
647    27. Updated RunTest.bat in the distribution to the version supplied by Tom
648        Fortmann. This supports explicit test numbers on the command line, and has
649        argument validation and error reporting.
650    
651    28. An instance of \X with an unlimited repeat could fail if at any point the
652        first character it looked at was a mark character.
653    
654    29. Some minor code refactoring concerning Unicode properties and scripts
655        should reduce the stack requirement of match() slightly.
656    
657    30. Added the '=' option to pcretest to check the setting of unused capturing
658        slots at the end of the pattern, which are documented as being -1, but are
659        not included in the return count.
660    
661    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
662        compiled something random. Now it gives a compile-time error (as does
663        Perl).
664    
665    32. A *MARK encountered during the processing of a positive assertion is now
666        recorded and passed back (compatible with Perl).
667    
668    33. If --only-matching or --colour was set on a pcregrep call whose pattern
669        had alternative anchored branches, the search for a second match in a line
670        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
671        matched the line "0102" twice. The same bug affected patterns that started
672        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
673        twice.
674    
675    34. Previously, PCRE did not allow quantification of assertions. However, Perl
676        does, and because of capturing effects, quantifying parenthesized
677        assertions may at times be useful. Quantifiers are now allowed for
678        parenthesized assertions.
679    
680    35. A minor code tidy in pcre_compile() when checking options for \R usage.
681    
682    36. \g was being checked for fancy things in a character class, when it should
683        just be a literal "g".
684    
685    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
686        appearance of a nested POSIX class supersedes an apparent external class.
687        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
688        unescaped square brackets may also appear as part of class names. For
689        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
690        more like Perl. (But see 8.20/1 above.)
691    
692    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
693        was because it thought it was \N{name}, which is not supported).
694    
695    39. Add minix to OS list not supporting the -S option in pcretest.
696    
697    40. PCRE tries to detect cases of infinite recursion at compile time, but it
698        cannot analyze patterns in sufficient detail to catch mutual recursions
699        such as ((?1))((?2)). There is now a runtime test that gives an error if a
700        subgroup is called recursively as a subpattern for a second time at the
701        same position in the subject string. In previous releases this might have
702        been caught by the recursion limit, or it might have run out of stack.
703    
704    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
705        happen only once. PCRE was, however incorrectly giving a compile time error
706        "recursive call could loop indefinitely" because it cannot analyze the
707        pattern in sufficient detail. The compile time test no longer happens when
708        PCRE is compiling a conditional subpattern, but actual runaway loops are
709        now caught at runtime (see 40 above).
710    
711    42. It seems that Perl allows any characters other than a closing parenthesis
712        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
713        has been changed to be the same.
714    
715    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
716        as not to get warnings when autogen.sh is called. Also changed
717        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
718    
719    44. To help people who use pcregrep to scan files containing exceedingly long
720        lines, the following changes have been made:
721    
722        (a) The default value of the buffer size parameter has been increased from
723            8K to 20K. (The actual buffer used is three times this size.)
724    
725        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
726            PCRE is built.
727    
728        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
729            to be set at run time.
730    
731        (d) Numerical values in pcregrep options can be followed by K or M, for
732            example --buffer-size=50K.
733    
734        (e) If a line being scanned overflows pcregrep's buffer, an error is now
735            given and the return code is set to 2.
736    
737    45. Add a pointer to the latest mark to the callout data block.
738    
739    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
740        partial match of an empty string instead of no match. This was specific to
741        the use of ".".
742    
743    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
744        complete match instead of a partial match. This bug was dependent on both
745        the PCRE_UTF8 and PCRE_DOTALL options being set.
746    
747    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
748        starting byte set, because \b was not being ignored.
749    
750    
751  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
752  ------------------------  ------------------------

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