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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 so that it now matches a Unicode extended
54        grapheme cluster.
55    
56    11. Patch by Daniel Richard G to the autoconf files to add a macro for sorting
57        out POSIX threads when JIT support is configured.
58    
59    12. Added support for PCRE_STUDY_EXTRA_NEEDED.
60    
61    
62    
63    Version 8.31 06-July-2012
64    -------------------------
65    
66    1.  Fixing a wrong JIT test case and some compiler warnings.
67    
68    2.  Removed a bashism from the RunTest script.
69    
70    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
71        to unsigned type, result still unsigned" that was given by an MS compiler
72        on encountering the code "-sizeof(xxx)".
73    
74    4.  Partial matching support is added to the JIT compiler.
75    
76    5.  Fixed several bugs concerned with partial matching of items that consist
77        of more than one character:
78    
79        (a) /^(..)\1/ did not partially match "aba" because checking references was
80            done on an "all or nothing" basis. This also applied to repeated
81            references.
82    
83        (b) \R did not give a hard partial match if \r was found at the end of the
84            subject.
85    
86        (c) \X did not give a hard partial match after matching one or more
87            characters at the end of the subject.
88    
89        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
90            a partial match for the string "\r".
91    
92        (e) When newline was set to CRLF, the metacharacter "." did not recognize
93            a partial match for a CR character at the end of the subject string.
94    
95    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
96        running pcretest, the text "(JIT)" added to the output whenever JIT is
97        actually used to run the match.
98    
99    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
100        or /S+[+] with a digit between 1 and 7.
101    
102    8.  OP_NOT now supports any UTF character not just single-byte ones.
103    
104    9.  (*MARK) control verb is now supported by the JIT compiler.
105    
106    10. The command "./RunTest list" lists the available tests without actually
107        running any of them. (Because I keep forgetting what they all are.)
108    
109    11. Add PCRE_INFO_MAXLOOKBEHIND.
110    
111    12. Applied a (slightly modified) user-supplied patch that improves performance
112        when the heap is used for recursion (compiled with --disable-stack-for-
113        recursion). Instead of malloc and free for each heap frame each time a
114        logical recursion happens, frames are retained on a chain and re-used where
115        possible. This sometimes gives as much as 30% improvement.
116    
117    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
118        call.
119    
120    14. As documented, (*COMMIT) is now confined to within a positive assertion.
121    
122    15. It is now possible to link pcretest with libedit as an alternative to
123        libreadline.
124    
125    16. (*COMMIT) control verb is now supported by the JIT compiler.
126    
127    17. The Unicode data tables have been updated to Unicode 6.1.0.
128    
129    18. Added --file-list option to pcregrep.
130    
131    19. Added binary file support to pcregrep, including the -a, --binary-files,
132        -I, and --text options.
133    
134    20. The madvise function is renamed for posix_madvise for QNX compatibility
135        reasons. Fixed by Giuseppe D'Angelo.
136    
137    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
138    
139    22. Changed the option for creating symbolic links for 16-bit man pages from
140        -s to -sf so that re-installing does not cause issues.
141    
142    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
143    
144    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
145        matches in certain environments (the workspace was not being correctly
146        retained). Also added to pcre_dfa_exec() a simple plausibility check on
147        some of the workspace data at the beginning of a restart.
148    
149    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
150        was not doing so when it should - probably a typo introduced by SVN 528
151        (change 8.10/14).
152    
153    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
154        \w+ when the character tables indicated that \x{c4} was a word character.
155        There were several related cases, all because the tests for doing a table
156        lookup were testing for characters less than 127 instead of 255.
157    
158    27. If a pattern contains capturing parentheses that are not used in a match,
159        their slots in the ovector are set to -1. For those that are higher than
160        any matched groups, this happens at the end of processing. In the case when
161        there were back references that the ovector was too small to contain
162        (causing temporary malloc'd memory to be used during matching), and the
163        highest capturing number was not used, memory off the end of the ovector
164        was incorrectly being set to -1. (It was using the size of the temporary
165        memory instead of the true size.)
166    
167    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
168        ovector size, it uses memory at the end of the block that it has got.
169    
170    29. Check for an overlong MARK name and give an error at compile time. The
171        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
172    
173    30. JIT compiler update.
174    
175    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
176        Rill for the patch.
177    
178    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
179    
180    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
181    
182    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
183        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
184        was enabled.
185    
186    35. Improve JIT code generation for greedy plus quantifier.
187    
188    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
189        1 to "aa" instead of to an empty string. The bug affected repeated groups
190        that could potentially match an empty string.
191    
192    37. Optimizing single character iterators in JIT.
193    
194    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
195        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
196        codepoints that are too big for the mode are faulted, and in a UTF mode,
197        disallowed codepoints are also faulted.
198    
199    39. If PCRE was compiled with UTF support, in three places in the DFA
200        matcher there was code that should only have been obeyed in UTF mode, but
201        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
202        processing when bytes with values greater than 127 were present. In 16-bit
203        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
204        both cases the values are those that cannot be the first data item in a UTF
205        character. The three items that might have provoked this were recursions,
206        possessively repeated groups, and atomic groups.
207    
208    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
209        and pcregrep, because some OS require shared objects to be explicitly
210        passed to ld, causing the link step to fail if they are not.
211    
212    41. There were two incorrect #ifdefs in pcre_study.c, meaning that, in 16-bit
213        mode, patterns that started with \h* or \R* might be incorrectly matched.
214    
215    
216    Version 8.30 04-February-2012
217    -----------------------------
218    
219    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
220        name is defined in ctype.h.
221    
222    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
223        only in quite long subpatterns.
224    
225    3.  Removed the function pcre_info(), which has been obsolete and deprecated
226        since it was replaced by pcre_fullinfo() in February 2000.
227    
228    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
229        match a (*MARK), and the match failed at the start of the subject, a
230        reference to memory before the start of the subject could occur. This bug
231        was introduced by fix 17 of release 8.21.
232    
233    5.  A reference to an unset group with zero minimum repetition was giving
234        totally wrong answers (in non-JavaScript-compatibility mode). For example,
235        /(another)?(\1?)test/ matched against "hello world test". This bug was
236        introduced in release 8.13.
237    
238    6.  Add support for 16-bit character strings (a large amount of work involving
239        many changes and refactorings).
240    
241    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
242        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
243        from a file.
244    
245    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
246        rounding is not applied in this particular case).
247    
248    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
249        if they appear, or are escaped, in patterns.
250    
251    10. Get rid of a number of -Wunused-but-set-variable warnings.
252    
253    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
254        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
255        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
256        also returns the mark "x". This bug applied to capturing parentheses,
257        non-capturing parentheses, and atomic parentheses. It also applied to some
258        assertions.
259    
260    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
261        information out of configure.ac instead of relying on pcre.h.generic, which
262        is not stored in the repository.
263    
264    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
265        -lreadline.
266    
267    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
268    
269    15. Applied Graycode's patch to put the top-level frame on the stack rather
270        than the heap when not using the stack for recursion. This gives a
271        performance improvement in many cases when recursion is not deep.
272    
273    16. Experimental code added to "pcretest -C" to output the stack frame size.
274    
275    
276    Version 8.21 12-Dec-2011
277    ------------------------
278    
279    1.  Updating the JIT compiler.
280    
281    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
282        are added as well.
283    
284    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
285        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
286        calling _pcre_jit_exec. Some extra comments are added.
287    
288    4.  (*MARK) settings inside atomic groups that do not contain any capturing
289        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
290        was introduced by change 18 for 8.20.
291    
292    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
293        ECMA-262 standard.
294    
295    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
296        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
297        This bug was probably introduced by change 9 of 8.13.
298    
299    7.  While fixing 6 above, I noticed that a number of other items were being
300        incorrectly rejected as "not fixed length". This arose partly because newer
301        opcodes had not been added to the fixed-length checking code. I have (a)
302        corrected the bug and added tests for these items, and (b) arranged for an
303        error to occur if an unknown opcode is encountered while checking for fixed
304        length instead of just assuming "not fixed length". The items that were
305        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
306        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
307        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
308    
309    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
310        being incorrectly compiled and would have given unpredicatble results.
311    
312    9.  A possessively repeated subpattern with minimum repeat count greater than
313        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
314        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
315        the first (A) could occur when it should not.
316    
317    10. Add a cast and remove a redundant test from the code.
318    
319    11. JIT should use pcre_malloc/pcre_free for allocation.
320    
321    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
322        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
323        is anything other than /usr, -L is still shown).
324    
325    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
326    
327    14. Perl does not support \N without a following name in a [] class; PCRE now
328        also gives an error.
329    
330    15. If a forward reference was repeated with an upper limit of around 2000,
331        it caused the error "internal error: overran compiling workspace". The
332        maximum number of forward references (including repeats) was limited by the
333        internal workspace, and dependent on the LINK_SIZE. The code has been
334        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
335        the default depends on LINK_SIZE. There is a new upper limit (for safety)
336        of around 200,000 forward references. While doing this, I also speeded up
337        the filling in of repeated forward references.
338    
339    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
340        incorrectly expecting the subject to contain another "a" after the start.
341    
342    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
343        in the match, the SKIP should be ignored. This was not happening; instead
344        the SKIP was being treated as NOMATCH. For patterns such as
345        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
346        tested.
347    
348    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
349        now much more compatible with Perl, in particular in cases where the result
350        is a non-match for a non-anchored pattern. For example, if
351        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
352        "m", where previously it did not return a name. A side effect of this
353        change is that for partial matches, the last encountered mark name is
354        returned, as for non matches. A number of tests that were previously not
355        Perl-compatible have been moved into the Perl-compatible test files. The
356        refactoring has had the pleasing side effect of removing one argument from
357        the match() function, thus reducing its stack requirements.
358    
359    19. If the /S+ option was used in pcretest to study a pattern using JIT,
360        subsequent uses of /S (without +) incorrectly behaved like /S+.
361    
362    21. Retrieve executable code size support for the JIT compiler and fixing
363        some warnings.
364    
365    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
366        not work when the shorter character appeared right at the end of the
367        subject string.
368    
369    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
370        systems.
371    
372    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
373        output it when the /M option is used in pcretest.
374    
375    25. The CheckMan script was not being included in the distribution. Also, added
376        an explicit "perl" to run Perl scripts from the PrepareRelease script
377        because this is reportedly needed in Windows.
378    
379    26. If study data was being save in a file and studying had not found a set of
380        "starts with" bytes for the pattern, the data written to the file (though
381        never used) was taken from uninitialized memory and so caused valgrind to
382        complain.
383    
384    27. Updated RunTest.bat as provided by Sheri Pierce.
385    
386    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
387    
388    29. Computation of memory usage for the table of capturing group names was
389        giving an unnecessarily large value.
390    
391    
392    Version 8.20 21-Oct-2011
393    ------------------------
394    
395    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
396        a POSIX class. After further experiments with Perl, which convinced me that
397        Perl has bugs and confusions, a closing square bracket is no longer allowed
398        in a POSIX name. This bug also affected patterns with classes that started
399        with full stops.
400    
401    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
402        captured substring, but while checking the failing first alternative,
403        substring 1 is temporarily captured. If the output vector supplied to
404        pcre_exec() was not big enough for this capture, the yield of the function
405        was still zero ("insufficient space for captured substrings"). This cannot
406        be totally fixed without adding another stack variable, which seems a lot
407        of expense for a edge case. However, I have improved the situation in cases
408        such as /(a)(b)x|abc/ matched against "abc", where the return code
409        indicates that fewer than the maximum number of slots in the ovector have
410        been set.
411    
412    3.  Related to (2) above: when there are more back references in a pattern than
413        slots in the output vector, pcre_exec() uses temporary memory during
414        matching, and copies in the captures as far as possible afterwards. It was
415        using the entire output vector, but this conflicts with the specification
416        that only 2/3 is used for passing back captured substrings. Now it uses
417        only the first 2/3, for compatibility. This is, of course, another edge
418        case.
419    
420    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
421        main code base, and can be used by building with --enable-jit. When this is
422        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
423        runtime --no-jit option is given.
424    
425    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
426        ovector, the return from the function was zero, implying that there were
427        other matches that did not fit. The correct "exactly full" value is now
428        returned.
429    
430    6.  If a subpattern that was called recursively or as a subroutine contained
431        (*PRUNE) or any other control that caused it to give a non-standard return,
432        invalid errors such as "Error -26 (nested recursion at the same subject
433        position)" or even infinite loops could occur.
434    
435    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
436        computing the minimum length on reaching *ACCEPT, and so ended up with the
437        wrong value of 1 rather than 0. Further investigation indicates that
438        computing a minimum subject length in the presence of *ACCEPT is difficult
439        (think back references, subroutine calls), and so I have changed the code
440        so that no minimum is registered for a pattern that contains *ACCEPT.
441    
442    8.  If (*THEN) was present in the first (true) branch of a conditional group,
443        it was not handled as intended. [But see 16 below.]
444    
445    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
446        Sheri Pierce.
447    
448    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
449        the first byte in a match must be "a".
450    
451    11. Change 17 for 8.13 increased the recursion depth for patterns like
452        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
453        pattern contains any instances of (*THEN). If it does not, the old
454        optimizations are restored. It would be nice to do this on a per-group
455        basis, but at the moment that is not feasible.
456    
457    12. In some environments, the output of pcretest -C is CRLF terminated. This
458        broke RunTest's code that checks for the link size. A single white space
459        character after the value is now allowed for.
460    
461    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
462        For "fr", it uses the Windows-specific input and output files.
463    
464    14. If (*THEN) appeared in a group that was called recursively or as a
465        subroutine, it did not work as intended. [But see next item.]
466    
467    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
468        pattern fragments (but not containing any | characters). If A and B are
469        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
470        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
471        D. In other words, Perl considers parentheses that do not contain any |
472        characters to be part of a surrounding alternative, whereas PCRE was
473        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
474        differently. PCRE now behaves in the same way as Perl, except in the case
475        of subroutine/recursion calls such as (?1) which have in any case always
476        been different (but PCRE had them first :-).
477    
478    16. Related to 15 above: Perl does not treat the | in a conditional group as
479        creating alternatives. Such a group is treated in the same way as an
480        ordinary group without any | characters when processing (*THEN). PCRE has
481        been changed to match Perl's behaviour.
482    
483    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
484        RunGrepTest script failed.
485    
486    18. Change 22 for version 13 caused atomic groups to use more stack. This is
487        inevitable for groups that contain captures, but it can lead to a lot of
488        stack use in large patterns. The old behaviour has been restored for atomic
489        groups that do not contain any capturing parentheses.
490    
491    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
492        suppress the check for a minimum subject length at run time. (If it was
493        given to pcre_exec() or pcre_dfa_exec() it did work.)
494    
495    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
496        fail to work when decoding hex characters in data strings in EBCDIC
497        environments.
498    
499    21. It appears that in at least one Mac OS environment, the isxdigit() function
500        is implemented as a macro that evaluates to its argument more than once,
501        contravening the C 90 Standard (I haven't checked a later standard). There
502        was an instance in pcretest which caused it to go wrong when processing
503        \x{...} escapes in subject strings. The has been rewritten to avoid using
504        things like p++ in the argument of isxdigit().
505    
506    
507    Version 8.13 16-Aug-2011
508  ------------------------  ------------------------
509    
510  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 523  Version 8.13 30-Apr-2011
523      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
524      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
525      left).      left).
526    
527  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
528      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
529      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
530      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
531    
532  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
533      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
534      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
535      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
536      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
537    
538  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
539      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
540      failure, the offset and reason code are output.      failure, the offset and reason code are output.
541    
542  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
543      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
544      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
545      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
546      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
547      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
548      has been changed.      has been changed.
549    
550  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
551      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
552      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
553      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,
554      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
555      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
556      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
557      (?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.
558    
559    10. More internal refactoring has drastically reduced the number of recursive
560        calls to match() for possessively repeated groups such as (abc)++ when
561        using pcre_exec().
562    
563    11. While implementing 10, a number of bugs in the handling of groups were
564        discovered and fixed:
565    
566        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
567        (a|)*(?1) gave a compile-time internal error.
568        ((a|)+)+  did not notice that the outer group could match an empty string.
569        (^a|^)+   was not marked as anchored.
570        (.*a|.*)+ was not marked as matching at start or after a newline.
571    
572    12. Yet more internal refactoring has removed another argument from the match()
573        function. Special calls to this function are now indicated by setting a
574        value in a variable in the "match data" data block.
575    
576    13. Be more explicit in pcre_study() instead of relying on "default" for
577        opcodes that mean there is no starting character; this means that when new
578        ones are added and accidentally left out of pcre_study(), testing should
579        pick them up.
580    
581    14. The -s option of pcretest has been documented for ages as being an old
582        synonym of -m (show memory usage). I have changed it to mean "force study
583        for every regex", that is, assume /S for every regex. This is similar to -i
584        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
585        using it. It makes it easier to run collections of tests with and without
586        study enabled, and thereby test pcre_study() more easily. All the standard
587        tests are now run with and without -s (but some patterns can be marked as
588        "never study" - see 20 below).
589    
590    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
591        restoration of the capturing data to the outer values was not happening
592        correctly.
593    
594    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
595        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
596        pattern had matched an empty string, and so incorrectly returned a no
597        match.
598    
599    17. There was optimizing code for the last branch of non-capturing parentheses,
600        and also for the obeyed branch of a conditional subexpression, which used
601        tail recursion to cut down on stack usage. Unfortunately, now that there is
602        the possibility of (*THEN) occurring in these branches, tail recursion is
603        no longer possible because the return has to be checked for (*THEN). These
604        two optimizations have therefore been removed. [But see 8.20/11 above.]
605    
606    18. If a pattern containing \R was studied, it was assumed that \R always
607        matched two bytes, thus causing the minimum subject length to be
608        incorrectly computed because \R can also match just one byte.
609    
610    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
611        was incorrectly computed.
612    
613    20. If /S is present twice on a test pattern in pcretest input, it now
614        *disables* studying, thereby overriding the use of -s on the command line
615        (see 14 above). This is necessary for one or two tests to keep the output
616        identical in both cases.
617    
618    21. When (*ACCEPT) was used in an assertion that matched an empty string and
619        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
620    
621    22. When an atomic group that contained a capturing parenthesis was
622        successfully matched, but the branch in which it appeared failed, the
623        capturing was not being forgotten if a higher numbered group was later
624        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
625        group 1 to "a", when in fact it should be unset. This applied to multi-
626        branched capturing and non-capturing groups, repeated or not, and also to
627        positive assertions (capturing in negative assertions does not happen
628        in PCRE) and also to nested atomic groups.
629    
630    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
631        subject after a captured substring, to make it easier to tell which of a
632        number of identical substrings has been captured.
633    
634    24. The way atomic groups are processed by pcre_exec() has been changed so that
635        if they are repeated, backtracking one repetition now resets captured
636        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
637        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
638        "aaa". Previously, it would have been "a". As part of this code
639        refactoring, the way recursive calls are handled has also been changed.
640    
641    25. If an assertion condition captured any substrings, they were not passed
642        back unless some other capturing happened later. For example, if
643        (?(?=(a))a) was matched against "a", no capturing was returned.
644    
645    26. When studying a pattern that contained subroutine calls or assertions,
646        the code for finding the minimum length of a possible match was handling
647        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
648        group 1 called group 2 while simultaneously a separate group 2 called group
649        1). A stack overflow occurred in this case. I have fixed this by limiting
650        the recursion depth to 10.
651    
652    27. Updated RunTest.bat in the distribution to the version supplied by Tom
653        Fortmann. This supports explicit test numbers on the command line, and has
654        argument validation and error reporting.
655    
656    28. An instance of \X with an unlimited repeat could fail if at any point the
657        first character it looked at was a mark character.
658    
659    29. Some minor code refactoring concerning Unicode properties and scripts
660        should reduce the stack requirement of match() slightly.
661    
662    30. Added the '=' option to pcretest to check the setting of unused capturing
663        slots at the end of the pattern, which are documented as being -1, but are
664        not included in the return count.
665    
666    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
667        compiled something random. Now it gives a compile-time error (as does
668        Perl).
669    
670    32. A *MARK encountered during the processing of a positive assertion is now
671        recorded and passed back (compatible with Perl).
672    
673    33. If --only-matching or --colour was set on a pcregrep call whose pattern
674        had alternative anchored branches, the search for a second match in a line
675        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
676        matched the line "0102" twice. The same bug affected patterns that started
677        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
678        twice.
679    
680    34. Previously, PCRE did not allow quantification of assertions. However, Perl
681        does, and because of capturing effects, quantifying parenthesized
682        assertions may at times be useful. Quantifiers are now allowed for
683        parenthesized assertions.
684    
685    35. A minor code tidy in pcre_compile() when checking options for \R usage.
686    
687    36. \g was being checked for fancy things in a character class, when it should
688        just be a literal "g".
689    
690    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
691        appearance of a nested POSIX class supersedes an apparent external class.
692        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
693        unescaped square brackets may also appear as part of class names. For
694        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
695        more like Perl. (But see 8.20/1 above.)
696    
697    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
698        was because it thought it was \N{name}, which is not supported).
699    
700    39. Add minix to OS list not supporting the -S option in pcretest.
701    
702    40. PCRE tries to detect cases of infinite recursion at compile time, but it
703        cannot analyze patterns in sufficient detail to catch mutual recursions
704        such as ((?1))((?2)). There is now a runtime test that gives an error if a
705        subgroup is called recursively as a subpattern for a second time at the
706        same position in the subject string. In previous releases this might have
707        been caught by the recursion limit, or it might have run out of stack.
708    
709    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
710        happen only once. PCRE was, however incorrectly giving a compile time error
711        "recursive call could loop indefinitely" because it cannot analyze the
712        pattern in sufficient detail. The compile time test no longer happens when
713        PCRE is compiling a conditional subpattern, but actual runaway loops are
714        now caught at runtime (see 40 above).
715    
716    42. It seems that Perl allows any characters other than a closing parenthesis
717        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
718        has been changed to be the same.
719    
720    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
721        as not to get warnings when autogen.sh is called. Also changed
722        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
723    
724    44. To help people who use pcregrep to scan files containing exceedingly long
725        lines, the following changes have been made:
726    
727        (a) The default value of the buffer size parameter has been increased from
728            8K to 20K. (The actual buffer used is three times this size.)
729    
730        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
731            PCRE is built.
732    
733        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
734            to be set at run time.
735    
736        (d) Numerical values in pcregrep options can be followed by K or M, for
737            example --buffer-size=50K.
738    
739        (e) If a line being scanned overflows pcregrep's buffer, an error is now
740            given and the return code is set to 2.
741    
742    45. Add a pointer to the latest mark to the callout data block.
743    
744    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
745        partial match of an empty string instead of no match. This was specific to
746        the use of ".".
747    
748    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
749        complete match instead of a partial match. This bug was dependent on both
750        the PCRE_UTF8 and PCRE_DOTALL options being set.
751    
752    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
753        starting byte set, because \b was not being ignored.
754    
755    
756  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
757  ------------------------  ------------------------

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