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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.31
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    
100    Version 8.30 04-February-2012
101    -----------------------------
102    
103    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
104        name is defined in ctype.h.
105    
106    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
107        only in quite long subpatterns.
108    
109    3.  Removed the function pcre_info(), which has been obsolete and deprecated
110        since it was replaced by pcre_fullinfo() in February 2000.
111    
112    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
113        match a (*MARK), and the match failed at the start of the subject, a
114        reference to memory before the start of the subject could occur. This bug
115        was introduced by fix 17 of release 8.21.
116    
117    5.  A reference to an unset group with zero minimum repetition was giving
118        totally wrong answers (in non-JavaScript-compatibility mode). For example,
119        /(another)?(\1?)test/ matched against "hello world test". This bug was
120        introduced in release 8.13.
121    
122    6.  Add support for 16-bit character strings (a large amount of work involving
123        many changes and refactorings).
124    
125    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
126        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
127        from a file.
128    
129    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
130        rounding is not applied in this particular case).
131    
132    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
133        if they appear, or are escaped, in patterns.
134    
135    10. Get rid of a number of -Wunused-but-set-variable warnings.
136    
137    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
138        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
139        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
140        also returns the mark "x". This bug applied to capturing parentheses,
141        non-capturing parentheses, and atomic parentheses. It also applied to some
142        assertions.
143    
144    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
145        information out of configure.ac instead of relying on pcre.h.generic, which
146        is not stored in the repository.
147    
148    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
149        -lreadline.
150    
151    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
152    
153    15. Applied Graycode's patch to put the top-level frame on the stack rather
154        than the heap when not using the stack for recursion. This gives a
155        performance improvement in many cases when recursion is not deep.
156    
157    16. Experimental code added to "pcretest -C" to output the stack frame size.
158    
159    
160    Version 8.21 12-Dec-2011
161    ------------------------
162    
163    1.  Updating the JIT compiler.
164    
165    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
166        are added as well.
167    
168    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
169        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
170        calling _pcre_jit_exec. Some extra comments are added.
171    
172    4.  (*MARK) settings inside atomic groups that do not contain any capturing
173        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
174        was introduced by change 18 for 8.20.
175    
176    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
177        ECMA-262 standard.
178    
179    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
180        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
181        This bug was probably introduced by change 9 of 8.13.
182    
183    7.  While fixing 6 above, I noticed that a number of other items were being
184        incorrectly rejected as "not fixed length". This arose partly because newer
185        opcodes had not been added to the fixed-length checking code. I have (a)
186        corrected the bug and added tests for these items, and (b) arranged for an
187        error to occur if an unknown opcode is encountered while checking for fixed
188        length instead of just assuming "not fixed length". The items that were
189        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
190        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
191        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
192    
193    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
194        being incorrectly compiled and would have given unpredicatble results.
195    
196    9.  A possessively repeated subpattern with minimum repeat count greater than
197        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
198        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
199        the first (A) could occur when it should not.
200    
201    10. Add a cast and remove a redundant test from the code.
202    
203    11. JIT should use pcre_malloc/pcre_free for allocation.
204    
205    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
206        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
207        is anything other than /usr, -L is still shown).
208    
209    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
210    
211    14. Perl does not support \N without a following name in a [] class; PCRE now
212        also gives an error.
213    
214    15. If a forward reference was repeated with an upper limit of around 2000,
215        it caused the error "internal error: overran compiling workspace". The
216        maximum number of forward references (including repeats) was limited by the
217        internal workspace, and dependent on the LINK_SIZE. The code has been
218        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
219        the default depends on LINK_SIZE. There is a new upper limit (for safety)
220        of around 200,000 forward references. While doing this, I also speeded up
221        the filling in of repeated forward references.
222    
223    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
224        incorrectly expecting the subject to contain another "a" after the start.
225    
226    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
227        in the match, the SKIP should be ignored. This was not happening; instead
228        the SKIP was being treated as NOMATCH. For patterns such as
229        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
230        tested.
231    
232    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
233        now much more compatible with Perl, in particular in cases where the result
234        is a non-match for a non-anchored pattern. For example, if
235        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
236        "m", where previously it did not return a name. A side effect of this
237        change is that for partial matches, the last encountered mark name is
238        returned, as for non matches. A number of tests that were previously not
239        Perl-compatible have been moved into the Perl-compatible test files. The
240        refactoring has had the pleasing side effect of removing one argument from
241        the match() function, thus reducing its stack requirements.
242    
243    19. If the /S+ option was used in pcretest to study a pattern using JIT,
244        subsequent uses of /S (without +) incorrectly behaved like /S+.
245    
246    21. Retrieve executable code size support for the JIT compiler and fixing
247        some warnings.
248    
249    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
250        not work when the shorter character appeared right at the end of the
251        subject string.
252    
253    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
254        systems.
255    
256    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
257        output it when the /M option is used in pcretest.
258    
259    25. The CheckMan script was not being included in the distribution. Also, added
260        an explicit "perl" to run Perl scripts from the PrepareRelease script
261        because this is reportedly needed in Windows.
262    
263    26. If study data was being save in a file and studying had not found a set of
264        "starts with" bytes for the pattern, the data written to the file (though
265        never used) was taken from uninitialized memory and so caused valgrind to
266        complain.
267    
268    27. Updated RunTest.bat as provided by Sheri Pierce.
269    
270    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
271    
272    29. Computation of memory usage for the table of capturing group names was
273        giving an unnecessarily large value.
274    
275    
276    Version 8.20 21-Oct-2011
277    ------------------------
278    
279    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
280        a POSIX class. After further experiments with Perl, which convinced me that
281        Perl has bugs and confusions, a closing square bracket is no longer allowed
282        in a POSIX name. This bug also affected patterns with classes that started
283        with full stops.
284    
285    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
286        captured substring, but while checking the failing first alternative,
287        substring 1 is temporarily captured. If the output vector supplied to
288        pcre_exec() was not big enough for this capture, the yield of the function
289        was still zero ("insufficient space for captured substrings"). This cannot
290        be totally fixed without adding another stack variable, which seems a lot
291        of expense for a edge case. However, I have improved the situation in cases
292        such as /(a)(b)x|abc/ matched against "abc", where the return code
293        indicates that fewer than the maximum number of slots in the ovector have
294        been set.
295    
296    3.  Related to (2) above: when there are more back references in a pattern than
297        slots in the output vector, pcre_exec() uses temporary memory during
298        matching, and copies in the captures as far as possible afterwards. It was
299        using the entire output vector, but this conflicts with the specification
300        that only 2/3 is used for passing back captured substrings. Now it uses
301        only the first 2/3, for compatibility. This is, of course, another edge
302        case.
303    
304    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
305        main code base, and can be used by building with --enable-jit. When this is
306        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
307        runtime --no-jit option is given.
308    
309    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
310        ovector, the return from the function was zero, implying that there were
311        other matches that did not fit. The correct "exactly full" value is now
312        returned.
313    
314    6.  If a subpattern that was called recursively or as a subroutine contained
315        (*PRUNE) or any other control that caused it to give a non-standard return,
316        invalid errors such as "Error -26 (nested recursion at the same subject
317        position)" or even infinite loops could occur.
318    
319    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
320        computing the minimum length on reaching *ACCEPT, and so ended up with the
321        wrong value of 1 rather than 0. Further investigation indicates that
322        computing a minimum subject length in the presence of *ACCEPT is difficult
323        (think back references, subroutine calls), and so I have changed the code
324        so that no minimum is registered for a pattern that contains *ACCEPT.
325    
326    8.  If (*THEN) was present in the first (true) branch of a conditional group,
327        it was not handled as intended. [But see 16 below.]
328    
329    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
330        Sheri Pierce.
331    
332    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
333        the first byte in a match must be "a".
334    
335    11. Change 17 for 8.13 increased the recursion depth for patterns like
336        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
337        pattern contains any instances of (*THEN). If it does not, the old
338        optimizations are restored. It would be nice to do this on a per-group
339        basis, but at the moment that is not feasible.
340    
341    12. In some environments, the output of pcretest -C is CRLF terminated. This
342        broke RunTest's code that checks for the link size. A single white space
343        character after the value is now allowed for.
344    
345    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
346        For "fr", it uses the Windows-specific input and output files.
347    
348    14. If (*THEN) appeared in a group that was called recursively or as a
349        subroutine, it did not work as intended. [But see next item.]
350    
351    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
352        pattern fragments (but not containing any | characters). If A and B are
353        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
354        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
355        D. In other words, Perl considers parentheses that do not contain any |
356        characters to be part of a surrounding alternative, whereas PCRE was
357        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
358        differently. PCRE now behaves in the same way as Perl, except in the case
359        of subroutine/recursion calls such as (?1) which have in any case always
360        been different (but PCRE had them first :-).
361    
362    16. Related to 15 above: Perl does not treat the | in a conditional group as
363        creating alternatives. Such a group is treated in the same way as an
364        ordinary group without any | characters when processing (*THEN). PCRE has
365        been changed to match Perl's behaviour.
366    
367    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
368        RunGrepTest script failed.
369    
370    18. Change 22 for version 13 caused atomic groups to use more stack. This is
371        inevitable for groups that contain captures, but it can lead to a lot of
372        stack use in large patterns. The old behaviour has been restored for atomic
373        groups that do not contain any capturing parentheses.
374    
375    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
376        suppress the check for a minimum subject length at run time. (If it was
377        given to pcre_exec() or pcre_dfa_exec() it did work.)
378    
379    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
380        fail to work when decoding hex characters in data strings in EBCDIC
381        environments.
382    
383    21. It appears that in at least one Mac OS environment, the isxdigit() function
384        is implemented as a macro that evaluates to its argument more than once,
385        contravening the C 90 Standard (I haven't checked a later standard). There
386        was an instance in pcretest which caused it to go wrong when processing
387        \x{...} escapes in subject strings. The has been rewritten to avoid using
388        things like p++ in the argument of isxdigit().
389    
390    
391    Version 8.13 16-Aug-2011
392  ------------------------  ------------------------
393    
394  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 407  Version 8.13 30-Apr-2011
407      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
408      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
409      left).      left).
410    
411  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
412      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
413      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
414      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
415    
416  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
417      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
418      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
419      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
420      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
421    
422  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
423      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
424      failure, the offset and reason code are output.      failure, the offset and reason code are output.
425    
426  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
427      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
428      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
429      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
430      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
431      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
432      has been changed.      has been changed.
433    
434  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
435      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
436      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
437      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,
438      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
439      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
440      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
441      (?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.
442    
443  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
444      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
445      using pcre_exec().      using pcre_exec().
446    
447  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
448      discovered and fixed:      discovered and fixed:
449    
450      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
451      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
452      ((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.
453      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
454      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
455    
456  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
457      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
458      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
459    
460  13. Be more explicit in pcre_study() instead of relying on "default" for  13. Be more explicit in pcre_study() instead of relying on "default" for
461      opcodes that mean there is no starting character; this means that when new      opcodes that mean there is no starting character; this means that when new
462      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
463      pick them up.      pick them up.
464    
465  14. The -s option of pcretest has been documented for ages as being an old  14. The -s option of pcretest has been documented for ages as being an old
466      synonym of -m (show memory usage). I have changed it to mean "force study      synonym of -m (show memory usage). I have changed it to mean "force study
467      for every regex", that is, assume /S for every regex. This is similar to -i      for every regex", that is, assume /S for every regex. This is similar to -i
468      and -d etc. It's slightly incompatible, but I'm hoping nobody is still      and -d etc. It's slightly incompatible, but I'm hoping nobody is still
469      using it. It makes it easier to run collection of tests with study enabled,      using it. It makes it easier to run collections of tests with and without
470      and thereby test pcre_study() more easily.      study enabled, and thereby test pcre_study() more easily. All the standard
471        tests are now run with and without -s (but some patterns can be marked as
472        "never study" - see 20 below).
473    
474  15. When (*ACCEPT) was used in a subpattern that was called recursively, the  15. When (*ACCEPT) was used in a subpattern that was called recursively, the
475      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
476      correctly.      correctly.
477    
478  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
479      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
480      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
481      match.      match.
482    
483    17. There was optimizing code for the last branch of non-capturing parentheses,
484        and also for the obeyed branch of a conditional subexpression, which used
485        tail recursion to cut down on stack usage. Unfortunately, now that there is
486        the possibility of (*THEN) occurring in these branches, tail recursion is
487        no longer possible because the return has to be checked for (*THEN). These
488        two optimizations have therefore been removed. [But see 8.20/11 above.]
489    
490    18. If a pattern containing \R was studied, it was assumed that \R always
491        matched two bytes, thus causing the minimum subject length to be
492        incorrectly computed because \R can also match just one byte.
493    
494    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
495        was incorrectly computed.
496    
497    20. If /S is present twice on a test pattern in pcretest input, it now
498        *disables* studying, thereby overriding the use of -s on the command line
499        (see 14 above). This is necessary for one or two tests to keep the output
500        identical in both cases.
501    
502    21. When (*ACCEPT) was used in an assertion that matched an empty string and
503        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
504    
505    22. When an atomic group that contained a capturing parenthesis was
506        successfully matched, but the branch in which it appeared failed, the
507        capturing was not being forgotten if a higher numbered group was later
508        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
509        group 1 to "a", when in fact it should be unset. This applied to multi-
510        branched capturing and non-capturing groups, repeated or not, and also to
511        positive assertions (capturing in negative assertions does not happen
512        in PCRE) and also to nested atomic groups.
513    
514    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
515        subject after a captured substring, to make it easier to tell which of a
516        number of identical substrings has been captured.
517    
518    24. The way atomic groups are processed by pcre_exec() has been changed so that
519        if they are repeated, backtracking one repetition now resets captured
520        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
521        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
522        "aaa". Previously, it would have been "a". As part of this code
523        refactoring, the way recursive calls are handled has also been changed.
524    
525    25. If an assertion condition captured any substrings, they were not passed
526        back unless some other capturing happened later. For example, if
527        (?(?=(a))a) was matched against "a", no capturing was returned.
528    
529    26. When studying a pattern that contained subroutine calls or assertions,
530        the code for finding the minimum length of a possible match was handling
531        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
532        group 1 called group 2 while simultaneously a separate group 2 called group
533        1). A stack overflow occurred in this case. I have fixed this by limiting
534        the recursion depth to 10.
535    
536    27. Updated RunTest.bat in the distribution to the version supplied by Tom
537        Fortmann. This supports explicit test numbers on the command line, and has
538        argument validation and error reporting.
539    
540    28. An instance of \X with an unlimited repeat could fail if at any point the
541        first character it looked at was a mark character.
542    
543    29. Some minor code refactoring concerning Unicode properties and scripts
544        should reduce the stack requirement of match() slightly.
545    
546    30. Added the '=' option to pcretest to check the setting of unused capturing
547        slots at the end of the pattern, which are documented as being -1, but are
548        not included in the return count.
549    
550    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
551        compiled something random. Now it gives a compile-time error (as does
552        Perl).
553    
554    32. A *MARK encountered during the processing of a positive assertion is now
555        recorded and passed back (compatible with Perl).
556    
557    33. If --only-matching or --colour was set on a pcregrep call whose pattern
558        had alternative anchored branches, the search for a second match in a line
559        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
560        matched the line "0102" twice. The same bug affected patterns that started
561        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
562        twice.
563    
564    34. Previously, PCRE did not allow quantification of assertions. However, Perl
565        does, and because of capturing effects, quantifying parenthesized
566        assertions may at times be useful. Quantifiers are now allowed for
567        parenthesized assertions.
568    
569    35. A minor code tidy in pcre_compile() when checking options for \R usage.
570    
571    36. \g was being checked for fancy things in a character class, when it should
572        just be a literal "g".
573    
574    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
575        appearance of a nested POSIX class supersedes an apparent external class.
576        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
577        unescaped square brackets may also appear as part of class names. For
578        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
579        more like Perl. (But see 8.20/1 above.)
580    
581    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
582        was because it thought it was \N{name}, which is not supported).
583    
584    39. Add minix to OS list not supporting the -S option in pcretest.
585    
586    40. PCRE tries to detect cases of infinite recursion at compile time, but it
587        cannot analyze patterns in sufficient detail to catch mutual recursions
588        such as ((?1))((?2)). There is now a runtime test that gives an error if a
589        subgroup is called recursively as a subpattern for a second time at the
590        same position in the subject string. In previous releases this might have
591        been caught by the recursion limit, or it might have run out of stack.
592    
593    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
594        happen only once. PCRE was, however incorrectly giving a compile time error
595        "recursive call could loop indefinitely" because it cannot analyze the
596        pattern in sufficient detail. The compile time test no longer happens when
597        PCRE is compiling a conditional subpattern, but actual runaway loops are
598        now caught at runtime (see 40 above).
599    
600    42. It seems that Perl allows any characters other than a closing parenthesis
601        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
602        has been changed to be the same.
603    
604    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
605        as not to get warnings when autogen.sh is called. Also changed
606        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
607    
608    44. To help people who use pcregrep to scan files containing exceedingly long
609        lines, the following changes have been made:
610    
611        (a) The default value of the buffer size parameter has been increased from
612            8K to 20K. (The actual buffer used is three times this size.)
613    
614        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
615            PCRE is built.
616    
617        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
618            to be set at run time.
619    
620        (d) Numerical values in pcregrep options can be followed by K or M, for
621            example --buffer-size=50K.
622    
623        (e) If a line being scanned overflows pcregrep's buffer, an error is now
624            given and the return code is set to 2.
625    
626    45. Add a pointer to the latest mark to the callout data block.
627    
628    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
629        partial match of an empty string instead of no match. This was specific to
630        the use of ".".
631    
632    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
633        complete match instead of a partial match. This bug was dependent on both
634        the PCRE_UTF8 and PCRE_DOTALL options being set.
635    
636    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
637        starting byte set, because \b was not being ignored.
638    
639    
640  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
641  ------------------------  ------------------------

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