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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.31 02-June-2012
5    -------------------------
6    
7    1.  Fixing a wrong JIT test case and some compiler warnings.
8    
9    2.  Removed a bashism from the RunTest script.
10    
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
14    
15    4.  Partial matching support is added to the JIT compiler.
16    
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
19    
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
23    
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
26    
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
29    
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
32    
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
35    
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
39    
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
42    
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
44    
45    9.  (*MARK) control verb is now supported by the JIT compiler.
46    
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
49    
50    11. Add PCRE_INFO_MAXLOOKBEHIND.
51    
52    12. Applied a (slightly modified) user-supplied patch that improves performance
53        when the heap is used for recursion (compiled with --disable-stack-for-
54        recursion). Instead of malloc and free for each heap frame each time a
55        logical recursion happens, frames are retained on a chain and re-used where
56        possible. This sometimes gives as much as 30% improvement.
57    
58    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
59        call.
60    
61    14. As documented, (*COMMIT) is now confined to within a positive assertion.
62    
63    15. It is now possible to link pcretest with libedit as an alternative to
64        libreadline.
65    
66    16. (*COMMIT) control verb is now supported by the JIT compiler.
67    
68    17. The Unicode data tables have been updated to Unicode 6.1.0.
69    
70    18. Added --file-list option to pcregrep.
71    
72    19. Added binary file support to pcregrep, including the -a, --binary-files,
73        -I, and --text options.
74    
75    20. The madvise function is renamed for posix_madvise for QNX compatibility
76        reasons. Fixed by Giuseppe D'Angelo.
77    
78    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
79    
80    22. Changed the option for creating symbolic links for 16-bit man pages from
81        -s to -sf so that re-installing does not cause issues.
82    
83    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
84    
85    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
86        matches in certain environments (the workspace was not being correctly
87        retained). Also added to pcre_dfa_exec() a simple plausibility check on
88        some of the workspace data at the beginning of a restart.
89    
90    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
91        was not doing so when it should - probably a typo introduced by SVN 528
92        (change 8.10/14).
93    
94    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
95        \w+ when the character tables indicated that \x{c4} was a word character.
96        There were several related cases, all because the tests for doing a table
97        lookup were testing for characters less than 127 instead of 255.
98    
99    27. If a pattern contains capturing parentheses that are not used in a match,
100        their slots in the ovector are set to -1. For those that are higher than
101        any matched groups, this happens at the end of processing. In the case when
102        there were back references that the ovector was too small to contain
103        (causing temporary malloc'd memory to be used during matching), and the
104        highest capturing number was not used, memory off the end of the ovector
105        was incorrectly being set to -1. (It was using the size of the temporary
106        memory instead of the true size.)
107    
108    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
109        ovector size, it uses memory at the end of the block that it has got.
110    
111    29. Check for an overlong MARK name and give an error at compile time. The
112        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
113    
114    30. JIT compiler update.
115    
116    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
117        Rill for the patch.
118    
119    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
120    
121    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
122    
123    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
124        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
125        was enabled.
126    
127    35. Improve JIT code generation for greedy plus quantifier.
128    
129    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
130        1 to "aa" instead of to an empty string. The bug affected repeated groups
131        that could potentially match an empty string.
132    
133    37. Optimizing single character iterators in JIT.
134    
135    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
136        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
137        codepoints that are too big for the mode are faulted, and in a UTF mode,
138        disallowed codepoints are also faulted.
139    
140    39. If PCRE was compiled with UTF support, in three places in the DFA
141        matcher there was code that should only have been obeyed in UTF mode, but
142        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
143        processing when bytes with values greater than 127 were present. In 16-bit
144        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
145        both cases the values are those that cannot be the first data item in a UTF
146        character. The three items that might have provoked this were recursions,
147        possessively repeated groups, and atomic groups.
148    
149    
150    Version 8.30 04-February-2012
151    -----------------------------
152    
153    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
154        name is defined in ctype.h.
155    
156    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
157        only in quite long subpatterns.
158    
159    3.  Removed the function pcre_info(), which has been obsolete and deprecated
160        since it was replaced by pcre_fullinfo() in February 2000.
161    
162    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
163        match a (*MARK), and the match failed at the start of the subject, a
164        reference to memory before the start of the subject could occur. This bug
165        was introduced by fix 17 of release 8.21.
166    
167    5.  A reference to an unset group with zero minimum repetition was giving
168        totally wrong answers (in non-JavaScript-compatibility mode). For example,
169        /(another)?(\1?)test/ matched against "hello world test". This bug was
170        introduced in release 8.13.
171    
172    6.  Add support for 16-bit character strings (a large amount of work involving
173        many changes and refactorings).
174    
175    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
176        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
177        from a file.
178    
179    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
180        rounding is not applied in this particular case).
181    
182    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
183        if they appear, or are escaped, in patterns.
184    
185    10. Get rid of a number of -Wunused-but-set-variable warnings.
186    
187    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
188        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
189        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
190        also returns the mark "x". This bug applied to capturing parentheses,
191        non-capturing parentheses, and atomic parentheses. It also applied to some
192        assertions.
193    
194    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
195        information out of configure.ac instead of relying on pcre.h.generic, which
196        is not stored in the repository.
197    
198    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
199        -lreadline.
200    
201    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
202    
203    15. Applied Graycode's patch to put the top-level frame on the stack rather
204        than the heap when not using the stack for recursion. This gives a
205        performance improvement in many cases when recursion is not deep.
206    
207    16. Experimental code added to "pcretest -C" to output the stack frame size.
208    
209    
210    Version 8.21 12-Dec-2011
211    ------------------------
212    
213    1.  Updating the JIT compiler.
214    
215    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
216        are added as well.
217    
218    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
219        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
220        calling _pcre_jit_exec. Some extra comments are added.
221    
222    4.  (*MARK) settings inside atomic groups that do not contain any capturing
223        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
224        was introduced by change 18 for 8.20.
225    
226    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
227        ECMA-262 standard.
228    
229    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
230        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
231        This bug was probably introduced by change 9 of 8.13.
232    
233    7.  While fixing 6 above, I noticed that a number of other items were being
234        incorrectly rejected as "not fixed length". This arose partly because newer
235        opcodes had not been added to the fixed-length checking code. I have (a)
236        corrected the bug and added tests for these items, and (b) arranged for an
237        error to occur if an unknown opcode is encountered while checking for fixed
238        length instead of just assuming "not fixed length". The items that were
239        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
240        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
241        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
242    
243    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
244        being incorrectly compiled and would have given unpredicatble results.
245    
246    9.  A possessively repeated subpattern with minimum repeat count greater than
247        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
248        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
249        the first (A) could occur when it should not.
250    
251    10. Add a cast and remove a redundant test from the code.
252    
253    11. JIT should use pcre_malloc/pcre_free for allocation.
254    
255    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
256        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
257        is anything other than /usr, -L is still shown).
258    
259    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
260    
261    14. Perl does not support \N without a following name in a [] class; PCRE now
262        also gives an error.
263    
264    15. If a forward reference was repeated with an upper limit of around 2000,
265        it caused the error "internal error: overran compiling workspace". The
266        maximum number of forward references (including repeats) was limited by the
267        internal workspace, and dependent on the LINK_SIZE. The code has been
268        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
269        the default depends on LINK_SIZE. There is a new upper limit (for safety)
270        of around 200,000 forward references. While doing this, I also speeded up
271        the filling in of repeated forward references.
272    
273    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
274        incorrectly expecting the subject to contain another "a" after the start.
275    
276    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
277        in the match, the SKIP should be ignored. This was not happening; instead
278        the SKIP was being treated as NOMATCH. For patterns such as
279        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
280        tested.
281    
282    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
283        now much more compatible with Perl, in particular in cases where the result
284        is a non-match for a non-anchored pattern. For example, if
285        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
286        "m", where previously it did not return a name. A side effect of this
287        change is that for partial matches, the last encountered mark name is
288        returned, as for non matches. A number of tests that were previously not
289        Perl-compatible have been moved into the Perl-compatible test files. The
290        refactoring has had the pleasing side effect of removing one argument from
291        the match() function, thus reducing its stack requirements.
292    
293    19. If the /S+ option was used in pcretest to study a pattern using JIT,
294        subsequent uses of /S (without +) incorrectly behaved like /S+.
295    
296    21. Retrieve executable code size support for the JIT compiler and fixing
297        some warnings.
298    
299    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
300        not work when the shorter character appeared right at the end of the
301        subject string.
302    
303    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
304        systems.
305    
306    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
307        output it when the /M option is used in pcretest.
308    
309    25. The CheckMan script was not being included in the distribution. Also, added
310        an explicit "perl" to run Perl scripts from the PrepareRelease script
311        because this is reportedly needed in Windows.
312    
313    26. If study data was being save in a file and studying had not found a set of
314        "starts with" bytes for the pattern, the data written to the file (though
315        never used) was taken from uninitialized memory and so caused valgrind to
316        complain.
317    
318    27. Updated RunTest.bat as provided by Sheri Pierce.
319    
320    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
321    
322    29. Computation of memory usage for the table of capturing group names was
323        giving an unnecessarily large value.
324    
325    
326    Version 8.20 21-Oct-2011
327    ------------------------
328    
329    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
330        a POSIX class. After further experiments with Perl, which convinced me that
331        Perl has bugs and confusions, a closing square bracket is no longer allowed
332        in a POSIX name. This bug also affected patterns with classes that started
333        with full stops.
334    
335    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
336        captured substring, but while checking the failing first alternative,
337        substring 1 is temporarily captured. If the output vector supplied to
338        pcre_exec() was not big enough for this capture, the yield of the function
339        was still zero ("insufficient space for captured substrings"). This cannot
340        be totally fixed without adding another stack variable, which seems a lot
341        of expense for a edge case. However, I have improved the situation in cases
342        such as /(a)(b)x|abc/ matched against "abc", where the return code
343        indicates that fewer than the maximum number of slots in the ovector have
344        been set.
345    
346    3.  Related to (2) above: when there are more back references in a pattern than
347        slots in the output vector, pcre_exec() uses temporary memory during
348        matching, and copies in the captures as far as possible afterwards. It was
349        using the entire output vector, but this conflicts with the specification
350        that only 2/3 is used for passing back captured substrings. Now it uses
351        only the first 2/3, for compatibility. This is, of course, another edge
352        case.
353    
354    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
355        main code base, and can be used by building with --enable-jit. When this is
356        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
357        runtime --no-jit option is given.
358    
359    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
360        ovector, the return from the function was zero, implying that there were
361        other matches that did not fit. The correct "exactly full" value is now
362        returned.
363    
364    6.  If a subpattern that was called recursively or as a subroutine contained
365        (*PRUNE) or any other control that caused it to give a non-standard return,
366        invalid errors such as "Error -26 (nested recursion at the same subject
367        position)" or even infinite loops could occur.
368    
369    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
370        computing the minimum length on reaching *ACCEPT, and so ended up with the
371        wrong value of 1 rather than 0. Further investigation indicates that
372        computing a minimum subject length in the presence of *ACCEPT is difficult
373        (think back references, subroutine calls), and so I have changed the code
374        so that no minimum is registered for a pattern that contains *ACCEPT.
375    
376    8.  If (*THEN) was present in the first (true) branch of a conditional group,
377        it was not handled as intended. [But see 16 below.]
378    
379    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
380        Sheri Pierce.
381    
382    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
383        the first byte in a match must be "a".
384    
385    11. Change 17 for 8.13 increased the recursion depth for patterns like
386        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
387        pattern contains any instances of (*THEN). If it does not, the old
388        optimizations are restored. It would be nice to do this on a per-group
389        basis, but at the moment that is not feasible.
390    
391    12. In some environments, the output of pcretest -C is CRLF terminated. This
392        broke RunTest's code that checks for the link size. A single white space
393        character after the value is now allowed for.
394    
395    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
396        For "fr", it uses the Windows-specific input and output files.
397    
398    14. If (*THEN) appeared in a group that was called recursively or as a
399        subroutine, it did not work as intended. [But see next item.]
400    
401    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
402        pattern fragments (but not containing any | characters). If A and B are
403        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
404        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
405        D. In other words, Perl considers parentheses that do not contain any |
406        characters to be part of a surrounding alternative, whereas PCRE was
407        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
408        differently. PCRE now behaves in the same way as Perl, except in the case
409        of subroutine/recursion calls such as (?1) which have in any case always
410        been different (but PCRE had them first :-).
411    
412    16. Related to 15 above: Perl does not treat the | in a conditional group as
413        creating alternatives. Such a group is treated in the same way as an
414        ordinary group without any | characters when processing (*THEN). PCRE has
415        been changed to match Perl's behaviour.
416    
417    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
418        RunGrepTest script failed.
419    
420    18. Change 22 for version 13 caused atomic groups to use more stack. This is
421        inevitable for groups that contain captures, but it can lead to a lot of
422        stack use in large patterns. The old behaviour has been restored for atomic
423        groups that do not contain any capturing parentheses.
424    
425    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
426        suppress the check for a minimum subject length at run time. (If it was
427        given to pcre_exec() or pcre_dfa_exec() it did work.)
428    
429    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
430        fail to work when decoding hex characters in data strings in EBCDIC
431        environments.
432    
433    21. It appears that in at least one Mac OS environment, the isxdigit() function
434        is implemented as a macro that evaluates to its argument more than once,
435        contravening the C 90 Standard (I haven't checked a later standard). There
436        was an instance in pcretest which caused it to go wrong when processing
437        \x{...} escapes in subject strings. The has been rewritten to avoid using
438        things like p++ in the argument of isxdigit().
439    
440    
441    Version 8.13 16-Aug-2011
442  ------------------------  ------------------------
443    
444  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 457  Version 8.13 30-Apr-2011
457      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
458      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
459      left).      left).
460    
461  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
462      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
463      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
464      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
465    
466  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
467      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
468      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
469      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
470      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
471    
472  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
473      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
474      failure, the offset and reason code are output.      failure, the offset and reason code are output.
475    
476  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
477      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
478      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
479      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
480      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
481      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
482      has been changed.      has been changed.
483    
484  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
485      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
486      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
487      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,
488      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
489      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
490      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
491      (?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.
492    
493  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
494      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
495      using pcre_exec().      using pcre_exec().
496    
497  11. While implementing 10, a number of bugs in the handling of groups were  11. While implementing 10, a number of bugs in the handling of groups were
498      discovered and fixed:      discovered and fixed:
499    
500      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
501      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
502      ((a|)+)+  did not notice that the outer group could match an empty string.      ((a|)+)+  did not notice that the outer group could match an empty string.
503      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
504      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
505    
506  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
507      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
508      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
509    
510    13. Be more explicit in pcre_study() instead of relying on "default" for
511        opcodes that mean there is no starting character; this means that when new
512        ones are added and accidentally left out of pcre_study(), testing should
513        pick them up.
514    
515    14. The -s option of pcretest has been documented for ages as being an old
516        synonym of -m (show memory usage). I have changed it to mean "force study
517        for every regex", that is, assume /S for every regex. This is similar to -i
518        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
519        using it. It makes it easier to run collections of tests with and without
520        study enabled, and thereby test pcre_study() more easily. All the standard
521        tests are now run with and without -s (but some patterns can be marked as
522        "never study" - see 20 below).
523    
524    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
525        restoration of the capturing data to the outer values was not happening
526        correctly.
527    
528    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
529        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
530        pattern had matched an empty string, and so incorrectly returned a no
531        match.
532    
533    17. There was optimizing code for the last branch of non-capturing parentheses,
534        and also for the obeyed branch of a conditional subexpression, which used
535        tail recursion to cut down on stack usage. Unfortunately, now that there is
536        the possibility of (*THEN) occurring in these branches, tail recursion is
537        no longer possible because the return has to be checked for (*THEN). These
538        two optimizations have therefore been removed. [But see 8.20/11 above.]
539    
540    18. If a pattern containing \R was studied, it was assumed that \R always
541        matched two bytes, thus causing the minimum subject length to be
542        incorrectly computed because \R can also match just one byte.
543    
544    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
545        was incorrectly computed.
546    
547    20. If /S is present twice on a test pattern in pcretest input, it now
548        *disables* studying, thereby overriding the use of -s on the command line
549        (see 14 above). This is necessary for one or two tests to keep the output
550        identical in both cases.
551    
552    21. When (*ACCEPT) was used in an assertion that matched an empty string and
553        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
554    
555    22. When an atomic group that contained a capturing parenthesis was
556        successfully matched, but the branch in which it appeared failed, the
557        capturing was not being forgotten if a higher numbered group was later
558        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
559        group 1 to "a", when in fact it should be unset. This applied to multi-
560        branched capturing and non-capturing groups, repeated or not, and also to
561        positive assertions (capturing in negative assertions does not happen
562        in PCRE) and also to nested atomic groups.
563    
564    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
565        subject after a captured substring, to make it easier to tell which of a
566        number of identical substrings has been captured.
567    
568    24. The way atomic groups are processed by pcre_exec() has been changed so that
569        if they are repeated, backtracking one repetition now resets captured
570        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
571        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
572        "aaa". Previously, it would have been "a". As part of this code
573        refactoring, the way recursive calls are handled has also been changed.
574    
575    25. If an assertion condition captured any substrings, they were not passed
576        back unless some other capturing happened later. For example, if
577        (?(?=(a))a) was matched against "a", no capturing was returned.
578    
579    26. When studying a pattern that contained subroutine calls or assertions,
580        the code for finding the minimum length of a possible match was handling
581        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
582        group 1 called group 2 while simultaneously a separate group 2 called group
583        1). A stack overflow occurred in this case. I have fixed this by limiting
584        the recursion depth to 10.
585    
586    27. Updated RunTest.bat in the distribution to the version supplied by Tom
587        Fortmann. This supports explicit test numbers on the command line, and has
588        argument validation and error reporting.
589    
590    28. An instance of \X with an unlimited repeat could fail if at any point the
591        first character it looked at was a mark character.
592    
593    29. Some minor code refactoring concerning Unicode properties and scripts
594        should reduce the stack requirement of match() slightly.
595    
596    30. Added the '=' option to pcretest to check the setting of unused capturing
597        slots at the end of the pattern, which are documented as being -1, but are
598        not included in the return count.
599    
600    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
601        compiled something random. Now it gives a compile-time error (as does
602        Perl).
603    
604    32. A *MARK encountered during the processing of a positive assertion is now
605        recorded and passed back (compatible with Perl).
606    
607    33. If --only-matching or --colour was set on a pcregrep call whose pattern
608        had alternative anchored branches, the search for a second match in a line
609        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
610        matched the line "0102" twice. The same bug affected patterns that started
611        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
612        twice.
613    
614    34. Previously, PCRE did not allow quantification of assertions. However, Perl
615        does, and because of capturing effects, quantifying parenthesized
616        assertions may at times be useful. Quantifiers are now allowed for
617        parenthesized assertions.
618    
619    35. A minor code tidy in pcre_compile() when checking options for \R usage.
620    
621    36. \g was being checked for fancy things in a character class, when it should
622        just be a literal "g".
623    
624    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
625        appearance of a nested POSIX class supersedes an apparent external class.
626        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
627        unescaped square brackets may also appear as part of class names. For
628        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
629        more like Perl. (But see 8.20/1 above.)
630    
631    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
632        was because it thought it was \N{name}, which is not supported).
633    
634    39. Add minix to OS list not supporting the -S option in pcretest.
635    
636    40. PCRE tries to detect cases of infinite recursion at compile time, but it
637        cannot analyze patterns in sufficient detail to catch mutual recursions
638        such as ((?1))((?2)). There is now a runtime test that gives an error if a
639        subgroup is called recursively as a subpattern for a second time at the
640        same position in the subject string. In previous releases this might have
641        been caught by the recursion limit, or it might have run out of stack.
642    
643    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
644        happen only once. PCRE was, however incorrectly giving a compile time error
645        "recursive call could loop indefinitely" because it cannot analyze the
646        pattern in sufficient detail. The compile time test no longer happens when
647        PCRE is compiling a conditional subpattern, but actual runaway loops are
648        now caught at runtime (see 40 above).
649    
650    42. It seems that Perl allows any characters other than a closing parenthesis
651        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
652        has been changed to be the same.
653    
654    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
655        as not to get warnings when autogen.sh is called. Also changed
656        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
657    
658    44. To help people who use pcregrep to scan files containing exceedingly long
659        lines, the following changes have been made:
660    
661        (a) The default value of the buffer size parameter has been increased from
662            8K to 20K. (The actual buffer used is three times this size.)
663    
664        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
665            PCRE is built.
666    
667        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
668            to be set at run time.
669    
670        (d) Numerical values in pcregrep options can be followed by K or M, for
671            example --buffer-size=50K.
672    
673        (e) If a line being scanned overflows pcregrep's buffer, an error is now
674            given and the return code is set to 2.
675    
676    45. Add a pointer to the latest mark to the callout data block.
677    
678    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
679        partial match of an empty string instead of no match. This was specific to
680        the use of ".".
681    
682    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
683        complete match instead of a partial match. This bug was dependent on both
684        the PCRE_UTF8 and PCRE_DOTALL options being set.
685    
686    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
687        starting byte set, because \b was not being ignored.
688    
689    
690  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

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