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revision 626 by ph10, Wed Jul 20 17:51:54 2011 UTC revision 911 by zherczeg, Fri Feb 10 08:05:30 2012 UTC
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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    1.  Fixing a wrong JIT test case and some compiler warnings.
7    
8    
9    Version 8.30 04-February-2012
10    -----------------------------
11    
12    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
13        name is defined in ctype.h.
14    
15    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
16        only in quite long subpatterns.
17    
18    3.  Removed the function pcre_info(), which has been obsolete and deprecated
19        since it was replaced by pcre_fullinfo() in February 2000.
20    
21    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
22        match a (*MARK), and the match failed at the start of the subject, a
23        reference to memory before the start of the subject could occur. This bug
24        was introduced by fix 17 of release 8.21.
25    
26    5.  A reference to an unset group with zero minimum repetition was giving
27        totally wrong answers (in non-JavaScript-compatibility mode). For example,
28        /(another)?(\1?)test/ matched against "hello world test". This bug was
29        introduced in release 8.13.
30    
31    6.  Add support for 16-bit character strings (a large amount of work involving
32        many changes and refactorings).
33    
34    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
35        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
36        from a file.
37    
38    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
39        rounding is not applied in this particular case).
40    
41    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
42        if they appear, or are escaped, in patterns.
43    
44    10. Get rid of a number of -Wunused-but-set-variable warnings.
45    
46    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
47        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
48        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
49        also returns the mark "x". This bug applied to capturing parentheses,
50        non-capturing parentheses, and atomic parentheses. It also applied to some
51        assertions.
52    
53    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
54        information out of configure.ac instead of relying on pcre.h.generic, which
55        is not stored in the repository.
56    
57    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
58        -lreadline.
59    
60    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
61    
62    15. Applied Graycode's patch to put the top-level frame on the stack rather
63        than the heap when not using the stack for recursion. This gives a
64        performance improvement in many cases when recursion is not deep.
65    
66    16. Experimental code added to "pcretest -C" to output the stack frame size.
67    
68    
69    Version 8.21 12-Dec-2011
70    ------------------------
71    
72    1.  Updating the JIT compiler.
73    
74    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
75        are added as well.
76    
77    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
78        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
79        calling _pcre_jit_exec. Some extra comments are added.
80    
81    4.  (*MARK) settings inside atomic groups that do not contain any capturing
82        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
83        was introduced by change 18 for 8.20.
84    
85    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
86        ECMA-262 standard.
87    
88    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
89        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
90        This bug was probably introduced by change 9 of 8.13.
91    
92    7.  While fixing 6 above, I noticed that a number of other items were being
93        incorrectly rejected as "not fixed length". This arose partly because newer
94        opcodes had not been added to the fixed-length checking code. I have (a)
95        corrected the bug and added tests for these items, and (b) arranged for an
96        error to occur if an unknown opcode is encountered while checking for fixed
97        length instead of just assuming "not fixed length". The items that were
98        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
99        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
100        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
101    
102    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
103        being incorrectly compiled and would have given unpredicatble results.
104    
105    9.  A possessively repeated subpattern with minimum repeat count greater than
106        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
107        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
108        the first (A) could occur when it should not.
109    
110    10. Add a cast and remove a redundant test from the code.
111    
112    11. JIT should use pcre_malloc/pcre_free for allocation.
113    
114    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
115        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
116        is anything other than /usr, -L is still shown).
117    
118    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
119    
120    14. Perl does not support \N without a following name in a [] class; PCRE now
121        also gives an error.
122    
123    15. If a forward reference was repeated with an upper limit of around 2000,
124        it caused the error "internal error: overran compiling workspace". The
125        maximum number of forward references (including repeats) was limited by the
126        internal workspace, and dependent on the LINK_SIZE. The code has been
127        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
128        the default depends on LINK_SIZE. There is a new upper limit (for safety)
129        of around 200,000 forward references. While doing this, I also speeded up
130        the filling in of repeated forward references.
131    
132    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
133        incorrectly expecting the subject to contain another "a" after the start.
134    
135    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
136        in the match, the SKIP should be ignored. This was not happening; instead
137        the SKIP was being treated as NOMATCH. For patterns such as
138        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
139        tested.
140    
141    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
142        now much more compatible with Perl, in particular in cases where the result
143        is a non-match for a non-anchored pattern. For example, if
144        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
145        "m", where previously it did not return a name. A side effect of this
146        change is that for partial matches, the last encountered mark name is
147        returned, as for non matches. A number of tests that were previously not
148        Perl-compatible have been moved into the Perl-compatible test files. The
149        refactoring has had the pleasing side effect of removing one argument from
150        the match() function, thus reducing its stack requirements.
151    
152    19. If the /S+ option was used in pcretest to study a pattern using JIT,
153        subsequent uses of /S (without +) incorrectly behaved like /S+.
154    
155    21. Retrieve executable code size support for the JIT compiler and fixing
156        some warnings.
157    
158    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
159        not work when the shorter character appeared right at the end of the
160        subject string.
161    
162    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
163        systems.
164    
165    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
166        output it when the /M option is used in pcretest.
167    
168    25. The CheckMan script was not being included in the distribution. Also, added
169        an explicit "perl" to run Perl scripts from the PrepareRelease script
170        because this is reportedly needed in Windows.
171    
172    26. If study data was being save in a file and studying had not found a set of
173        "starts with" bytes for the pattern, the data written to the file (though
174        never used) was taken from uninitialized memory and so caused valgrind to
175        complain.
176    
177    27. Updated RunTest.bat as provided by Sheri Pierce.
178    
179    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
180    
181    29. Computation of memory usage for the table of capturing group names was
182        giving an unnecessarily large value.
183    
184    
185    Version 8.20 21-Oct-2011
186    ------------------------
187    
188    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
189        a POSIX class. After further experiments with Perl, which convinced me that
190        Perl has bugs and confusions, a closing square bracket is no longer allowed
191        in a POSIX name. This bug also affected patterns with classes that started
192        with full stops.
193    
194    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
195        captured substring, but while checking the failing first alternative,
196        substring 1 is temporarily captured. If the output vector supplied to
197        pcre_exec() was not big enough for this capture, the yield of the function
198        was still zero ("insufficient space for captured substrings"). This cannot
199        be totally fixed without adding another stack variable, which seems a lot
200        of expense for a edge case. However, I have improved the situation in cases
201        such as /(a)(b)x|abc/ matched against "abc", where the return code
202        indicates that fewer than the maximum number of slots in the ovector have
203        been set.
204    
205    3.  Related to (2) above: when there are more back references in a pattern than
206        slots in the output vector, pcre_exec() uses temporary memory during
207        matching, and copies in the captures as far as possible afterwards. It was
208        using the entire output vector, but this conflicts with the specification
209        that only 2/3 is used for passing back captured substrings. Now it uses
210        only the first 2/3, for compatibility. This is, of course, another edge
211        case.
212    
213    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
214        main code base, and can be used by building with --enable-jit. When this is
215        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
216        runtime --no-jit option is given.
217    
218    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
219        ovector, the return from the function was zero, implying that there were
220        other matches that did not fit. The correct "exactly full" value is now
221        returned.
222    
223    6.  If a subpattern that was called recursively or as a subroutine contained
224        (*PRUNE) or any other control that caused it to give a non-standard return,
225        invalid errors such as "Error -26 (nested recursion at the same subject
226        position)" or even infinite loops could occur.
227    
228    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
229        computing the minimum length on reaching *ACCEPT, and so ended up with the
230        wrong value of 1 rather than 0. Further investigation indicates that
231        computing a minimum subject length in the presence of *ACCEPT is difficult
232        (think back references, subroutine calls), and so I have changed the code
233        so that no minimum is registered for a pattern that contains *ACCEPT.
234    
235    8.  If (*THEN) was present in the first (true) branch of a conditional group,
236        it was not handled as intended. [But see 16 below.]
237    
238    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
239        Sheri Pierce.
240    
241    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
242        the first byte in a match must be "a".
243    
244    11. Change 17 for 8.13 increased the recursion depth for patterns like
245        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
246        pattern contains any instances of (*THEN). If it does not, the old
247        optimizations are restored. It would be nice to do this on a per-group
248        basis, but at the moment that is not feasible.
249    
250    12. In some environments, the output of pcretest -C is CRLF terminated. This
251        broke RunTest's code that checks for the link size. A single white space
252        character after the value is now allowed for.
253    
254    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
255        For "fr", it uses the Windows-specific input and output files.
256    
257    14. If (*THEN) appeared in a group that was called recursively or as a
258        subroutine, it did not work as intended. [But see next item.]
259    
260    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
261        pattern fragments (but not containing any | characters). If A and B are
262        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
263        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
264        D. In other words, Perl considers parentheses that do not contain any |
265        characters to be part of a surrounding alternative, whereas PCRE was
266        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
267        differently. PCRE now behaves in the same way as Perl, except in the case
268        of subroutine/recursion calls such as (?1) which have in any case always
269        been different (but PCRE had them first :-).
270    
271    16. Related to 15 above: Perl does not treat the | in a conditional group as
272        creating alternatives. Such a group is treated in the same way as an
273        ordinary group without any | characters when processing (*THEN). PCRE has
274        been changed to match Perl's behaviour.
275    
276    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
277        RunGrepTest script failed.
278    
279    18. Change 22 for version 13 caused atomic groups to use more stack. This is
280        inevitable for groups that contain captures, but it can lead to a lot of
281        stack use in large patterns. The old behaviour has been restored for atomic
282        groups that do not contain any capturing parentheses.
283    
284    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
285        suppress the check for a minimum subject length at run time. (If it was
286        given to pcre_exec() or pcre_dfa_exec() it did work.)
287    
288    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
289        fail to work when decoding hex characters in data strings in EBCDIC
290        environments.
291    
292    21. It appears that in at least one Mac OS environment, the isxdigit() function
293        is implemented as a macro that evaluates to its argument more than once,
294        contravening the C 90 Standard (I haven't checked a later standard). There
295        was an instance in pcretest which caused it to go wrong when processing
296        \x{...} escapes in subject strings. The has been rewritten to avoid using
297        things like p++ in the argument of isxdigit().
298    
299    
300    Version 8.13 16-Aug-2011
301  ------------------------  ------------------------
302    
303  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 316  Version 8.13 30-Apr-2011
316      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
317      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
318      left).      left).
319    
320  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
321      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
322      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
323      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
324    
325  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
326      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
327      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
328      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
329      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
330    
331  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
332      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
333      failure, the offset and reason code are output.      failure, the offset and reason code are output.
334    
335  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
336      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
337      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
338      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
339      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
340      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
341      has been changed.      has been changed.
342    
343  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
344      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
345      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
346      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,
347      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
348      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
349      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
350      (?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.
351    
352  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
353      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
354      using pcre_exec().      using pcre_exec().
355    
356  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
357      discovered and fixed:      discovered and fixed:
358    
359      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
360      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
361      ((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.
362      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
363      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
364    
365  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
366      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
367      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
368    
369  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
370      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
371      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
372      pick them up.      pick them up.
373    
374  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
375      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
376      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
377      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
378      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
379      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
380      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
381      "never study" - see 20 below).      "never study" - see 20 below).
382    
383  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
384      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
385      correctly.      correctly.
386    
387  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
388      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
389      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
390      match.      match.
391    
392  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,
393      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
394      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
395      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
396      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
397      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
398    
399  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
400      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
401      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
402    
403  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
404      was incorrectly computed.      was incorrectly computed.
405    
406  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
407      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
408      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
409        identical in both cases.
410    
411  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
412      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.
413    
414  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
415      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
416      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
417      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
418      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-
419      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
420      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
421      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
422    
423  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
424      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
425      number of identical substrings has been captured).      number of identical substrings has been captured.
426    
427  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
428      if they are repeated, backtracking one repetition now resets captured      if they are repeated, backtracking one repetition now resets captured
429      values correctly. For example, if ((?>(a+)b)+aabab) is matched against      values correctly. For example, if ((?>(a+)b)+aabab) is matched against
430      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
431      "aaa". Previously, it would have been "a". As part of this code      "aaa". Previously, it would have been "a". As part of this code
432      refactoring, the way recursive calls are handled has also been changed.      refactoring, the way recursive calls are handled has also been changed.
433    
434  24. If an assertion condition captured any substrings, they were not passed  25. If an assertion condition captured any substrings, they were not passed
435      back unless some other capturing happened later. For example, if      back unless some other capturing happened later. For example, if
436      (?(?=(a))a) was matched against "a", no capturing was returned.      (?(?=(a))a) was matched against "a", no capturing was returned.
437    
438  25. When studying a pattern that contained subroutine calls or assertions,  26. When studying a pattern that contained subroutine calls or assertions,
439      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
440      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
441      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
442      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
443      the recursion depth to 10.      the recursion depth to 10.
444    
445  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
446      Fortmann. This supports explicit test numbers on the command line, and has      Fortmann. This supports explicit test numbers on the command line, and has
447      argument validation and error reporting.      argument validation and error reporting.
448    
449  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
450      first character it looked at was a mark character.      first character it looked at was a mark character.
451    
452  28. Some minor code refactoring concerning Unicode properties and scripts  29. Some minor code refactoring concerning Unicode properties and scripts
453      should reduce the stack requirement of match() slightly.      should reduce the stack requirement of match() slightly.
454    
455  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
456      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
457      not included in the return count.      not included in the return count.
458    
459    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
460        compiled something random. Now it gives a compile-time error (as does
461        Perl).
462    
463    32. A *MARK encountered during the processing of a positive assertion is now
464        recorded and passed back (compatible with Perl).
465    
466    33. If --only-matching or --colour was set on a pcregrep call whose pattern
467        had alternative anchored branches, the search for a second match in a line
468        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
469        matched the line "0102" twice. The same bug affected patterns that started
470        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
471        twice.
472    
473    34. Previously, PCRE did not allow quantification of assertions. However, Perl
474        does, and because of capturing effects, quantifying parenthesized
475        assertions may at times be useful. Quantifiers are now allowed for
476        parenthesized assertions.
477    
478    35. A minor code tidy in pcre_compile() when checking options for \R usage.
479    
480    36. \g was being checked for fancy things in a character class, when it should
481        just be a literal "g".
482    
483    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
484        appearance of a nested POSIX class supersedes an apparent external class.
485        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
486        unescaped square brackets may also appear as part of class names. For
487        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
488        more like Perl. (But see 8.20/1 above.)
489    
490    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
491        was because it thought it was \N{name}, which is not supported).
492    
493    39. Add minix to OS list not supporting the -S option in pcretest.
494    
495    40. PCRE tries to detect cases of infinite recursion at compile time, but it
496        cannot analyze patterns in sufficient detail to catch mutual recursions
497        such as ((?1))((?2)). There is now a runtime test that gives an error if a
498        subgroup is called recursively as a subpattern for a second time at the
499        same position in the subject string. In previous releases this might have
500        been caught by the recursion limit, or it might have run out of stack.
501    
502    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
503        happen only once. PCRE was, however incorrectly giving a compile time error
504        "recursive call could loop indefinitely" because it cannot analyze the
505        pattern in sufficient detail. The compile time test no longer happens when
506        PCRE is compiling a conditional subpattern, but actual runaway loops are
507        now caught at runtime (see 40 above).
508    
509    42. It seems that Perl allows any characters other than a closing parenthesis
510        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
511        has been changed to be the same.
512    
513    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
514        as not to get warnings when autogen.sh is called. Also changed
515        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
516    
517    44. To help people who use pcregrep to scan files containing exceedingly long
518        lines, the following changes have been made:
519    
520        (a) The default value of the buffer size parameter has been increased from
521            8K to 20K. (The actual buffer used is three times this size.)
522    
523        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
524            PCRE is built.
525    
526        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
527            to be set at run time.
528    
529        (d) Numerical values in pcregrep options can be followed by K or M, for
530            example --buffer-size=50K.
531    
532        (e) If a line being scanned overflows pcregrep's buffer, an error is now
533            given and the return code is set to 2.
534    
535    45. Add a pointer to the latest mark to the callout data block.
536    
537    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
538        partial match of an empty string instead of no match. This was specific to
539        the use of ".".
540    
541    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
542        complete match instead of a partial match. This bug was dependent on both
543        the PCRE_UTF8 and PCRE_DOTALL options being set.
544    
545    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
546        starting byte set, because \b was not being ignored.
547    
548    
549  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

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