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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    
95    Version 8.30 04-February-2012
96    -----------------------------
97    
98    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
99        name is defined in ctype.h.
100    
101    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
102        only in quite long subpatterns.
103    
104    3.  Removed the function pcre_info(), which has been obsolete and deprecated
105        since it was replaced by pcre_fullinfo() in February 2000.
106    
107    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
108        match a (*MARK), and the match failed at the start of the subject, a
109        reference to memory before the start of the subject could occur. This bug
110        was introduced by fix 17 of release 8.21.
111    
112    5.  A reference to an unset group with zero minimum repetition was giving
113        totally wrong answers (in non-JavaScript-compatibility mode). For example,
114        /(another)?(\1?)test/ matched against "hello world test". This bug was
115        introduced in release 8.13.
116    
117    6.  Add support for 16-bit character strings (a large amount of work involving
118        many changes and refactorings).
119    
120    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
121        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
122        from a file.
123    
124    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
125        rounding is not applied in this particular case).
126    
127    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
128        if they appear, or are escaped, in patterns.
129    
130    10. Get rid of a number of -Wunused-but-set-variable warnings.
131    
132    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
133        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
134        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
135        also returns the mark "x". This bug applied to capturing parentheses,
136        non-capturing parentheses, and atomic parentheses. It also applied to some
137        assertions.
138    
139    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
140        information out of configure.ac instead of relying on pcre.h.generic, which
141        is not stored in the repository.
142    
143    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
144        -lreadline.
145    
146    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
147    
148    15. Applied Graycode's patch to put the top-level frame on the stack rather
149        than the heap when not using the stack for recursion. This gives a
150        performance improvement in many cases when recursion is not deep.
151    
152    16. Experimental code added to "pcretest -C" to output the stack frame size.
153    
154    
155    Version 8.21 12-Dec-2011
156    ------------------------
157    
158    1.  Updating the JIT compiler.
159    
160    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
161        are added as well.
162    
163    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
164        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
165        calling _pcre_jit_exec. Some extra comments are added.
166    
167    4.  (*MARK) settings inside atomic groups that do not contain any capturing
168        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
169        was introduced by change 18 for 8.20.
170    
171    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
172        ECMA-262 standard.
173    
174    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
175        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
176        This bug was probably introduced by change 9 of 8.13.
177    
178    7.  While fixing 6 above, I noticed that a number of other items were being
179        incorrectly rejected as "not fixed length". This arose partly because newer
180        opcodes had not been added to the fixed-length checking code. I have (a)
181        corrected the bug and added tests for these items, and (b) arranged for an
182        error to occur if an unknown opcode is encountered while checking for fixed
183        length instead of just assuming "not fixed length". The items that were
184        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
185        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
186        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
187    
188    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
189        being incorrectly compiled and would have given unpredicatble results.
190    
191    9.  A possessively repeated subpattern with minimum repeat count greater than
192        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
193        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
194        the first (A) could occur when it should not.
195    
196    10. Add a cast and remove a redundant test from the code.
197    
198    11. JIT should use pcre_malloc/pcre_free for allocation.
199    
200    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
201        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
202        is anything other than /usr, -L is still shown).
203    
204    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
205    
206    14. Perl does not support \N without a following name in a [] class; PCRE now
207        also gives an error.
208    
209    15. If a forward reference was repeated with an upper limit of around 2000,
210        it caused the error "internal error: overran compiling workspace". The
211        maximum number of forward references (including repeats) was limited by the
212        internal workspace, and dependent on the LINK_SIZE. The code has been
213        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
214        the default depends on LINK_SIZE. There is a new upper limit (for safety)
215        of around 200,000 forward references. While doing this, I also speeded up
216        the filling in of repeated forward references.
217    
218    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
219        incorrectly expecting the subject to contain another "a" after the start.
220    
221    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
222        in the match, the SKIP should be ignored. This was not happening; instead
223        the SKIP was being treated as NOMATCH. For patterns such as
224        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
225        tested.
226    
227    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
228        now much more compatible with Perl, in particular in cases where the result
229        is a non-match for a non-anchored pattern. For example, if
230        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
231        "m", where previously it did not return a name. A side effect of this
232        change is that for partial matches, the last encountered mark name is
233        returned, as for non matches. A number of tests that were previously not
234        Perl-compatible have been moved into the Perl-compatible test files. The
235        refactoring has had the pleasing side effect of removing one argument from
236        the match() function, thus reducing its stack requirements.
237    
238    19. If the /S+ option was used in pcretest to study a pattern using JIT,
239        subsequent uses of /S (without +) incorrectly behaved like /S+.
240    
241    21. Retrieve executable code size support for the JIT compiler and fixing
242        some warnings.
243    
244    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
245        not work when the shorter character appeared right at the end of the
246        subject string.
247    
248    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
249        systems.
250    
251    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
252        output it when the /M option is used in pcretest.
253    
254    25. The CheckMan script was not being included in the distribution. Also, added
255        an explicit "perl" to run Perl scripts from the PrepareRelease script
256        because this is reportedly needed in Windows.
257    
258    26. If study data was being save in a file and studying had not found a set of
259        "starts with" bytes for the pattern, the data written to the file (though
260        never used) was taken from uninitialized memory and so caused valgrind to
261        complain.
262    
263    27. Updated RunTest.bat as provided by Sheri Pierce.
264    
265    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
266    
267    29. Computation of memory usage for the table of capturing group names was
268        giving an unnecessarily large value.
269    
270    
271    Version 8.20 21-Oct-2011
272    ------------------------
273    
274    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
275        a POSIX class. After further experiments with Perl, which convinced me that
276        Perl has bugs and confusions, a closing square bracket is no longer allowed
277        in a POSIX name. This bug also affected patterns with classes that started
278        with full stops.
279    
280    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
281        captured substring, but while checking the failing first alternative,
282        substring 1 is temporarily captured. If the output vector supplied to
283        pcre_exec() was not big enough for this capture, the yield of the function
284        was still zero ("insufficient space for captured substrings"). This cannot
285        be totally fixed without adding another stack variable, which seems a lot
286        of expense for a edge case. However, I have improved the situation in cases
287        such as /(a)(b)x|abc/ matched against "abc", where the return code
288        indicates that fewer than the maximum number of slots in the ovector have
289        been set.
290    
291    3.  Related to (2) above: when there are more back references in a pattern than
292        slots in the output vector, pcre_exec() uses temporary memory during
293        matching, and copies in the captures as far as possible afterwards. It was
294        using the entire output vector, but this conflicts with the specification
295        that only 2/3 is used for passing back captured substrings. Now it uses
296        only the first 2/3, for compatibility. This is, of course, another edge
297        case.
298    
299    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
300        main code base, and can be used by building with --enable-jit. When this is
301        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
302        runtime --no-jit option is given.
303    
304    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
305        ovector, the return from the function was zero, implying that there were
306        other matches that did not fit. The correct "exactly full" value is now
307        returned.
308    
309    6.  If a subpattern that was called recursively or as a subroutine contained
310        (*PRUNE) or any other control that caused it to give a non-standard return,
311        invalid errors such as "Error -26 (nested recursion at the same subject
312        position)" or even infinite loops could occur.
313    
314    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
315        computing the minimum length on reaching *ACCEPT, and so ended up with the
316        wrong value of 1 rather than 0. Further investigation indicates that
317        computing a minimum subject length in the presence of *ACCEPT is difficult
318        (think back references, subroutine calls), and so I have changed the code
319        so that no minimum is registered for a pattern that contains *ACCEPT.
320    
321    8.  If (*THEN) was present in the first (true) branch of a conditional group,
322        it was not handled as intended. [But see 16 below.]
323    
324    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
325        Sheri Pierce.
326    
327    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
328        the first byte in a match must be "a".
329    
330    11. Change 17 for 8.13 increased the recursion depth for patterns like
331        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
332        pattern contains any instances of (*THEN). If it does not, the old
333        optimizations are restored. It would be nice to do this on a per-group
334        basis, but at the moment that is not feasible.
335    
336    12. In some environments, the output of pcretest -C is CRLF terminated. This
337        broke RunTest's code that checks for the link size. A single white space
338        character after the value is now allowed for.
339    
340    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
341        For "fr", it uses the Windows-specific input and output files.
342    
343    14. If (*THEN) appeared in a group that was called recursively or as a
344        subroutine, it did not work as intended. [But see next item.]
345    
346    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
347        pattern fragments (but not containing any | characters). If A and B are
348        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
349        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
350        D. In other words, Perl considers parentheses that do not contain any |
351        characters to be part of a surrounding alternative, whereas PCRE was
352        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
353        differently. PCRE now behaves in the same way as Perl, except in the case
354        of subroutine/recursion calls such as (?1) which have in any case always
355        been different (but PCRE had them first :-).
356    
357    16. Related to 15 above: Perl does not treat the | in a conditional group as
358        creating alternatives. Such a group is treated in the same way as an
359        ordinary group without any | characters when processing (*THEN). PCRE has
360        been changed to match Perl's behaviour.
361    
362    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
363        RunGrepTest script failed.
364    
365    18. Change 22 for version 13 caused atomic groups to use more stack. This is
366        inevitable for groups that contain captures, but it can lead to a lot of
367        stack use in large patterns. The old behaviour has been restored for atomic
368        groups that do not contain any capturing parentheses.
369    
370    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
371        suppress the check for a minimum subject length at run time. (If it was
372        given to pcre_exec() or pcre_dfa_exec() it did work.)
373    
374    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
375        fail to work when decoding hex characters in data strings in EBCDIC
376        environments.
377    
378    21. It appears that in at least one Mac OS environment, the isxdigit() function
379        is implemented as a macro that evaluates to its argument more than once,
380        contravening the C 90 Standard (I haven't checked a later standard). There
381        was an instance in pcretest which caused it to go wrong when processing
382        \x{...} escapes in subject strings. The has been rewritten to avoid using
383        things like p++ in the argument of isxdigit().
384    
385    
386    Version 8.13 16-Aug-2011
387  ------------------------  ------------------------
388    
389  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 402  Version 8.13 30-Apr-2011
402      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
403      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
404      left).      left).
405    
406  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
407      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
408      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
409      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
410    
411  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
412      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
413      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
414      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
415      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
416    
417  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
418      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
419      failure, the offset and reason code are output.      failure, the offset and reason code are output.
420    
421  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
422      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
423      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
424      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
425      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
426      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
427      has been changed.      has been changed.
428    
429  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
430      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
431      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
432      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,
433      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
434      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
435      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
436      (?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.
437    
438  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
439      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
440      using pcre_exec().      using pcre_exec().
441    
442  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
443      discovered and fixed:      discovered and fixed:
444    
445      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
446      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
447      ((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.
448      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
449      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
450    
451  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
452      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
453      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
454    
455  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
456      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
457      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
458      pick them up.      pick them up.
459    
460  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
461      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
462      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
463      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
464      using it. It makes it easier to run collections of tests with and without      using it. It makes it easier to run collections of tests with and without
465      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
466      tests are now run with and without -s (but some patterns can be marked as      tests are now run with and without -s (but some patterns can be marked as
467      "never study" - see 20 below).      "never study" - see 20 below).
468    
469  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
470      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
471      correctly.      correctly.
472    
473  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
474      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
475      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
476      match.      match.
477    
478  17. There was optimizing code for the last branch of non-capturing parentheses,  17. There was optimizing code for the last branch of non-capturing parentheses,
479      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
480      tail recursion to cut down on stack usage. Unfortunately, not that there is      tail recursion to cut down on stack usage. Unfortunately, now that there is
481      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
482      no longer possible because the return has to be checked for (*THEN). These      no longer possible because the return has to be checked for (*THEN). These
483      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
484    
485  18. If a pattern containing \R was studied, it was assumed that \R always  18. If a pattern containing \R was studied, it was assumed that \R always
486      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
487      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
488    
489  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
490      was incorrectly computed.      was incorrectly computed.
491    
492  20. If /S is present twice on a test pattern in pcretest input, it *disables*  20. If /S is present twice on a test pattern in pcretest input, it now
493      studying, thereby overriding the use of -s on the command line. This is      *disables* studying, thereby overriding the use of -s on the command line
494      necessary for one or two tests to keep the output identical in both cases.      (see 14 above). This is necessary for one or two tests to keep the output
495        identical in both cases.
496    
497  21. When (*ACCEPT) was used in an assertion that matched an empty string and  21. When (*ACCEPT) was used in an assertion that matched an empty string and
498      PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.      PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
499    
500  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
501      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
502      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
503      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
504      group 1 to "a", when in fact it should be unset. This applied to multi-      group 1 to "a", when in fact it should be unset. This applied to multi-
505      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
506      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
507      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
508    
509  23. Add the ++ qualifier feature to pcretest, to show the remainder of the  23. Add the ++ qualifier feature to pcretest, to show the remainder of the
510      subject after a captured substring (to make it easier to tell which of a      subject after a captured substring, to make it easier to tell which of a
511      number of identical substrings has been captured).      number of identical substrings has been captured.
512    
513  24. The way atomic groups are processed by pcre_exec() has been changed so that  24. The way atomic groups are processed by pcre_exec() has been changed so that
514      if they are repeated, backtracking one repetition now resets captured      if they are repeated, backtracking one repetition now resets captured
515      values correctly. For example, if ((?>(a+)b)+aabab) is matched against      values correctly. For example, if ((?>(a+)b)+aabab) is matched against
516      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
517      "aaa". Previously, it would have been "a". As part of this code      "aaa". Previously, it would have been "a". As part of this code
518      refactoring, the way recursive calls are handled has also been changed.      refactoring, the way recursive calls are handled has also been changed.
519    
520  24. If an assertion condition captured any substrings, they were not passed  25. If an assertion condition captured any substrings, they were not passed
521      back unless some other capturing happened later. For example, if      back unless some other capturing happened later. For example, if
522      (?(?=(a))a) was matched against "a", no capturing was returned.      (?(?=(a))a) was matched against "a", no capturing was returned.
523    
524  25. When studying a pattern that contained subroutine calls or assertions,  26. When studying a pattern that contained subroutine calls or assertions,
525      the code for finding the minimum length of a possible match was handling      the code for finding the minimum length of a possible match was handling
526      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
527      group 1 called group 2 while simultaneously a separate group 2 called group      group 1 called group 2 while simultaneously a separate group 2 called group
528      1). A stack overflow occurred in this case. I have fixed this by limiting      1). A stack overflow occurred in this case. I have fixed this by limiting
529      the recursion depth to 10.      the recursion depth to 10.
530    
531  26. Updated RunTest.bat in the distribution to the version supplied by Tom  27. Updated RunTest.bat in the distribution to the version supplied by Tom
532      Fortmann. This supports explicit test numbers on the command line, and has      Fortmann. This supports explicit test numbers on the command line, and has
533      argument validation and error reporting.      argument validation and error reporting.
534    
535  27. An instance of \X with an unlimited repeat could fail if at any point the  28. An instance of \X with an unlimited repeat could fail if at any point the
536      first character it looked at was a mark character.      first character it looked at was a mark character.
537    
538  28. Some minor code refactoring concerning Unicode properties and scripts  29. Some minor code refactoring concerning Unicode properties and scripts
539      should reduce the stack requirement of match() slightly.      should reduce the stack requirement of match() slightly.
540    
541  29. Added the '=' option to pcretest to check the setting of unused capturing  30. Added the '=' option to pcretest to check the setting of unused capturing
542      slots at the end of the pattern, which are documented as being -1, but are      slots at the end of the pattern, which are documented as being -1, but are
543      not included in the return count.      not included in the return count.
544    
545  30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE  31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
546      compiled something random. Now it gives a compile-time error (as does      compiled something random. Now it gives a compile-time error (as does
547      Perl).      Perl).
548    
549  31. A *MARK encountered during the processing of a positive assertion is now  32. A *MARK encountered during the processing of a positive assertion is now
550      recorded and passed back (compatible with Perl).      recorded and passed back (compatible with Perl).
551    
552    33. If --only-matching or --colour was set on a pcregrep call whose pattern
553        had alternative anchored branches, the search for a second match in a line
554        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
555        matched the line "0102" twice. The same bug affected patterns that started
556        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
557        twice.
558    
559    34. Previously, PCRE did not allow quantification of assertions. However, Perl
560        does, and because of capturing effects, quantifying parenthesized
561        assertions may at times be useful. Quantifiers are now allowed for
562        parenthesized assertions.
563    
564    35. A minor code tidy in pcre_compile() when checking options for \R usage.
565    
566    36. \g was being checked for fancy things in a character class, when it should
567        just be a literal "g".
568    
569    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
570        appearance of a nested POSIX class supersedes an apparent external class.
571        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
572        unescaped square brackets may also appear as part of class names. For
573        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
574        more like Perl. (But see 8.20/1 above.)
575    
576    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
577        was because it thought it was \N{name}, which is not supported).
578    
579    39. Add minix to OS list not supporting the -S option in pcretest.
580    
581    40. PCRE tries to detect cases of infinite recursion at compile time, but it
582        cannot analyze patterns in sufficient detail to catch mutual recursions
583        such as ((?1))((?2)). There is now a runtime test that gives an error if a
584        subgroup is called recursively as a subpattern for a second time at the
585        same position in the subject string. In previous releases this might have
586        been caught by the recursion limit, or it might have run out of stack.
587    
588    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
589        happen only once. PCRE was, however incorrectly giving a compile time error
590        "recursive call could loop indefinitely" because it cannot analyze the
591        pattern in sufficient detail. The compile time test no longer happens when
592        PCRE is compiling a conditional subpattern, but actual runaway loops are
593        now caught at runtime (see 40 above).
594    
595    42. It seems that Perl allows any characters other than a closing parenthesis
596        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
597        has been changed to be the same.
598    
599    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
600        as not to get warnings when autogen.sh is called. Also changed
601        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
602    
603    44. To help people who use pcregrep to scan files containing exceedingly long
604        lines, the following changes have been made:
605    
606        (a) The default value of the buffer size parameter has been increased from
607            8K to 20K. (The actual buffer used is three times this size.)
608    
609        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
610            PCRE is built.
611    
612        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
613            to be set at run time.
614    
615        (d) Numerical values in pcregrep options can be followed by K or M, for
616            example --buffer-size=50K.
617    
618        (e) If a line being scanned overflows pcregrep's buffer, an error is now
619            given and the return code is set to 2.
620    
621    45. Add a pointer to the latest mark to the callout data block.
622    
623    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
624        partial match of an empty string instead of no match. This was specific to
625        the use of ".".
626    
627    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
628        complete match instead of a partial match. This bug was dependent on both
629        the PCRE_UTF8 and PCRE_DOTALL options being set.
630    
631    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
632        starting byte set, because \b was not being ignored.
633    
634    
635  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

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