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revision 614 by ph10, Sat Jul 9 10:48:16 2011 UTC revision 890 by ph10, Wed Jan 18 16:25:19 2012 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.30
5    ------------
6    
7    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
8        name is defined in ctype.h.
9    
10    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
11        only in quite long subpatterns.
12    
13    3.  Removed the function pcre_info(), which has been obsolete and deprecated
14        since it was replaced by pcre_fullinfo() in February 2000.
15    
16    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
17        match a (*MARK), and the match failed at the start of the subject, a
18        reference to memory before the start of the subject could occur. This bug
19        was introduced by fix 17 of release 8.21.
20    
21    5.  A reference to an unset group with zero minimum repetition was giving
22        totally wrong answers (in non-JavaScript-compatibility mode). For example,
23        /(another)?(\1?)test/ matched against "hello world test". This bug was
24        introduced in release 8.13.
25    
26    6.  Add support for 16-bit character strings (a large amount of work involving
27        many changes and refactorings).
28    
29    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
30        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
31        from a file.
32    
33    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
34        rounding is not applied in this particular case).
35    
36    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
37        if they appear, or are escaped, in patterns.
38    
39    10. Get rid of a number of -Wunused-but-set-variable warnings.
40    
41    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
42        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
43        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
44        also returns the mark "x". This bug applied to capturing parentheses,
45        non-capturing parentheses, and atomic parentheses. It also applied to some
46        assertions.
47    
48    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
49        information out of configure.ac instead of relying on pcre.h.generic, which
50        is not stored in the repository.
51    
52    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
53        -lreadline.
54    
55    14. ZH added PCRE_CONFIG_JITTARGET; added it's output to pcretest -C.
56    
57    
58    Version 8.21 12-Dec-2011
59    ------------------------
60    
61    1.  Updating the JIT compiler.
62    
63    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
64        are added as well.
65    
66    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
67        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
68        calling _pcre_jit_exec. Some extra comments are added.
69    
70    4.  (*MARK) settings inside atomic groups that do not contain any capturing
71        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
72        was introduced by change 18 for 8.20.
73    
74    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
75        ECMA-262 standard.
76    
77    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
78        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
79        This bug was probably introduced by change 9 of 8.13.
80    
81    7.  While fixing 6 above, I noticed that a number of other items were being
82        incorrectly rejected as "not fixed length". This arose partly because newer
83        opcodes had not been added to the fixed-length checking code. I have (a)
84        corrected the bug and added tests for these items, and (b) arranged for an
85        error to occur if an unknown opcode is encountered while checking for fixed
86        length instead of just assuming "not fixed length". The items that were
87        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
88        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
89        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
90    
91    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
92        being incorrectly compiled and would have given unpredicatble results.
93    
94    9.  A possessively repeated subpattern with minimum repeat count greater than
95        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
96        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
97        the first (A) could occur when it should not.
98    
99    10. Add a cast and remove a redundant test from the code.
100    
101    11. JIT should use pcre_malloc/pcre_free for allocation.
102    
103    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
104        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
105        is anything other than /usr, -L is still shown).
106    
107    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
108    
109    14. Perl does not support \N without a following name in a [] class; PCRE now
110        also gives an error.
111    
112    15. If a forward reference was repeated with an upper limit of around 2000,
113        it caused the error "internal error: overran compiling workspace". The
114        maximum number of forward references (including repeats) was limited by the
115        internal workspace, and dependent on the LINK_SIZE. The code has been
116        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
117        the default depends on LINK_SIZE. There is a new upper limit (for safety)
118        of around 200,000 forward references. While doing this, I also speeded up
119        the filling in of repeated forward references.
120    
121    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
122        incorrectly expecting the subject to contain another "a" after the start.
123    
124    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
125        in the match, the SKIP should be ignored. This was not happening; instead
126        the SKIP was being treated as NOMATCH. For patterns such as
127        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
128        tested.
129    
130    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
131        now much more compatible with Perl, in particular in cases where the result
132        is a non-match for a non-anchored pattern. For example, if
133        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
134        "m", where previously it did not return a name. A side effect of this
135        change is that for partial matches, the last encountered mark name is
136        returned, as for non matches. A number of tests that were previously not
137        Perl-compatible have been moved into the Perl-compatible test files. The
138        refactoring has had the pleasing side effect of removing one argument from
139        the match() function, thus reducing its stack requirements.
140    
141    19. If the /S+ option was used in pcretest to study a pattern using JIT,
142        subsequent uses of /S (without +) incorrectly behaved like /S+.
143    
144    21. Retrieve executable code size support for the JIT compiler and fixing
145        some warnings.
146    
147    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
148        not work when the shorter character appeared right at the end of the
149        subject string.
150    
151    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
152        systems.
153    
154    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
155        output it when the /M option is used in pcretest.
156    
157    25. The CheckMan script was not being included in the distribution. Also, added
158        an explicit "perl" to run Perl scripts from the PrepareRelease script
159        because this is reportedly needed in Windows.
160    
161    26. If study data was being save in a file and studying had not found a set of
162        "starts with" bytes for the pattern, the data written to the file (though
163        never used) was taken from uninitialized memory and so caused valgrind to
164        complain.
165    
166    27. Updated RunTest.bat as provided by Sheri Pierce.
167    
168    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
169    
170    29. Computation of memory usage for the table of capturing group names was
171        giving an unnecessarily large value.
172    
173    
174    Version 8.20 21-Oct-2011
175    ------------------------
176    
177    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
178        a POSIX class. After further experiments with Perl, which convinced me that
179        Perl has bugs and confusions, a closing square bracket is no longer allowed
180        in a POSIX name. This bug also affected patterns with classes that started
181        with full stops.
182    
183    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
184        captured substring, but while checking the failing first alternative,
185        substring 1 is temporarily captured. If the output vector supplied to
186        pcre_exec() was not big enough for this capture, the yield of the function
187        was still zero ("insufficient space for captured substrings"). This cannot
188        be totally fixed without adding another stack variable, which seems a lot
189        of expense for a edge case. However, I have improved the situation in cases
190        such as /(a)(b)x|abc/ matched against "abc", where the return code
191        indicates that fewer than the maximum number of slots in the ovector have
192        been set.
193    
194    3.  Related to (2) above: when there are more back references in a pattern than
195        slots in the output vector, pcre_exec() uses temporary memory during
196        matching, and copies in the captures as far as possible afterwards. It was
197        using the entire output vector, but this conflicts with the specification
198        that only 2/3 is used for passing back captured substrings. Now it uses
199        only the first 2/3, for compatibility. This is, of course, another edge
200        case.
201    
202    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
203        main code base, and can be used by building with --enable-jit. When this is
204        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
205        runtime --no-jit option is given.
206    
207    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
208        ovector, the return from the function was zero, implying that there were
209        other matches that did not fit. The correct "exactly full" value is now
210        returned.
211    
212    6.  If a subpattern that was called recursively or as a subroutine contained
213        (*PRUNE) or any other control that caused it to give a non-standard return,
214        invalid errors such as "Error -26 (nested recursion at the same subject
215        position)" or even infinite loops could occur.
216    
217    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
218        computing the minimum length on reaching *ACCEPT, and so ended up with the
219        wrong value of 1 rather than 0. Further investigation indicates that
220        computing a minimum subject length in the presence of *ACCEPT is difficult
221        (think back references, subroutine calls), and so I have changed the code
222        so that no minimum is registered for a pattern that contains *ACCEPT.
223    
224    8.  If (*THEN) was present in the first (true) branch of a conditional group,
225        it was not handled as intended. [But see 16 below.]
226    
227    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
228        Sheri Pierce.
229    
230    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
231        the first byte in a match must be "a".
232    
233    11. Change 17 for 8.13 increased the recursion depth for patterns like
234        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
235        pattern contains any instances of (*THEN). If it does not, the old
236        optimizations are restored. It would be nice to do this on a per-group
237        basis, but at the moment that is not feasible.
238    
239    12. In some environments, the output of pcretest -C is CRLF terminated. This
240        broke RunTest's code that checks for the link size. A single white space
241        character after the value is now allowed for.
242    
243    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
244        For "fr", it uses the Windows-specific input and output files.
245    
246    14. If (*THEN) appeared in a group that was called recursively or as a
247        subroutine, it did not work as intended. [But see next item.]
248    
249    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
250        pattern fragments (but not containing any | characters). If A and B are
251        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
252        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
253        D. In other words, Perl considers parentheses that do not contain any |
254        characters to be part of a surrounding alternative, whereas PCRE was
255        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
256        differently. PCRE now behaves in the same way as Perl, except in the case
257        of subroutine/recursion calls such as (?1) which have in any case always
258        been different (but PCRE had them first :-).
259    
260    16. Related to 15 above: Perl does not treat the | in a conditional group as
261        creating alternatives. Such a group is treated in the same way as an
262        ordinary group without any | characters when processing (*THEN). PCRE has
263        been changed to match Perl's behaviour.
264    
265    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
266        RunGrepTest script failed.
267    
268    18. Change 22 for version 13 caused atomic groups to use more stack. This is
269        inevitable for groups that contain captures, but it can lead to a lot of
270        stack use in large patterns. The old behaviour has been restored for atomic
271        groups that do not contain any capturing parentheses.
272    
273    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
274        suppress the check for a minimum subject length at run time. (If it was
275        given to pcre_exec() or pcre_dfa_exec() it did work.)
276    
277    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
278        fail to work when decoding hex characters in data strings in EBCDIC
279        environments.
280    
281    21. It appears that in at least one Mac OS environment, the isxdigit() function
282        is implemented as a macro that evaluates to its argument more than once,
283        contravening the C 90 Standard (I haven't checked a later standard). There
284        was an instance in pcretest which caused it to go wrong when processing
285        \x{...} escapes in subject strings. The has been rewritten to avoid using
286        things like p++ in the argument of isxdigit().
287    
288    
289    Version 8.13 16-Aug-2011
290  ------------------------  ------------------------
291    
292  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 305  Version 8.13 30-Apr-2011
305      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
306      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
307      left).      left).
308    
309  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
310      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
311      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
312      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
313    
314  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
315      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
316      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
317      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
318      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
319    
320  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
321      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
322      failure, the offset and reason code are output.      failure, the offset and reason code are output.
323    
324  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
325      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
326      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
327      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
328      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
329      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
330      has been changed.      has been changed.
331    
332  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
333      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
334      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
335      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,
336      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
337      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
338      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
339      (?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.
340    
341  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
342      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
343      using pcre_exec().      using pcre_exec().
344    
345  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
346      discovered and fixed:      discovered and fixed:
347    
348      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
349      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
350      ((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.
351      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
352      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
353    
354  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
355      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
356      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
357    
358  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
359      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
360      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
361      pick them up.      pick them up.
362    
363  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
364      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
365      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
366      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
367      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
368      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
369      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
370      "never study" - see 20 below).      "never study" - see 20 below).
371    
372  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
373      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
374      correctly.      correctly.
375    
376  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
377      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
378      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
379      match.      match.
380    
381  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,
382      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
383      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
384      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
385      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
386      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
387    
388  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
389      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
390      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
391    
392  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
393      was incorrectly computed.      was incorrectly computed.
394    
395  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
396      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
397      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
398        identical in both cases.
399    
400  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
401      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.
402    
403  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
404      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
405      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
406      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
407      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-
408      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
409      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
410      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
411    
412    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
413        subject after a captured substring, to make it easier to tell which of a
414        number of identical substrings has been captured.
415    
416    24. The way atomic groups are processed by pcre_exec() has been changed so that
417        if they are repeated, backtracking one repetition now resets captured
418        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
419        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
420        "aaa". Previously, it would have been "a". As part of this code
421        refactoring, the way recursive calls are handled has also been changed.
422    
423    25. If an assertion condition captured any substrings, they were not passed
424        back unless some other capturing happened later. For example, if
425        (?(?=(a))a) was matched against "a", no capturing was returned.
426    
427    26. When studying a pattern that contained subroutine calls or assertions,
428        the code for finding the minimum length of a possible match was handling
429        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
430        group 1 called group 2 while simultaneously a separate group 2 called group
431        1). A stack overflow occurred in this case. I have fixed this by limiting
432        the recursion depth to 10.
433    
434    27. Updated RunTest.bat in the distribution to the version supplied by Tom
435        Fortmann. This supports explicit test numbers on the command line, and has
436        argument validation and error reporting.
437    
438    28. An instance of \X with an unlimited repeat could fail if at any point the
439        first character it looked at was a mark character.
440    
441    29. Some minor code refactoring concerning Unicode properties and scripts
442        should reduce the stack requirement of match() slightly.
443    
444    30. Added the '=' option to pcretest to check the setting of unused capturing
445        slots at the end of the pattern, which are documented as being -1, but are
446        not included in the return count.
447    
448    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
449        compiled something random. Now it gives a compile-time error (as does
450        Perl).
451    
452    32. A *MARK encountered during the processing of a positive assertion is now
453        recorded and passed back (compatible with Perl).
454    
455    33. If --only-matching or --colour was set on a pcregrep call whose pattern
456        had alternative anchored branches, the search for a second match in a line
457        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
458        matched the line "0102" twice. The same bug affected patterns that started
459        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
460        twice.
461    
462    34. Previously, PCRE did not allow quantification of assertions. However, Perl
463        does, and because of capturing effects, quantifying parenthesized
464        assertions may at times be useful. Quantifiers are now allowed for
465        parenthesized assertions.
466    
467    35. A minor code tidy in pcre_compile() when checking options for \R usage.
468    
469    36. \g was being checked for fancy things in a character class, when it should
470        just be a literal "g".
471    
472    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
473        appearance of a nested POSIX class supersedes an apparent external class.
474        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
475        unescaped square brackets may also appear as part of class names. For
476        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
477        more like Perl. (But see 8.20/1 above.)
478    
479    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
480        was because it thought it was \N{name}, which is not supported).
481    
482    39. Add minix to OS list not supporting the -S option in pcretest.
483    
484    40. PCRE tries to detect cases of infinite recursion at compile time, but it
485        cannot analyze patterns in sufficient detail to catch mutual recursions
486        such as ((?1))((?2)). There is now a runtime test that gives an error if a
487        subgroup is called recursively as a subpattern for a second time at the
488        same position in the subject string. In previous releases this might have
489        been caught by the recursion limit, or it might have run out of stack.
490    
491    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
492        happen only once. PCRE was, however incorrectly giving a compile time error
493        "recursive call could loop indefinitely" because it cannot analyze the
494        pattern in sufficient detail. The compile time test no longer happens when
495        PCRE is compiling a conditional subpattern, but actual runaway loops are
496        now caught at runtime (see 40 above).
497    
498    42. It seems that Perl allows any characters other than a closing parenthesis
499        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
500        has been changed to be the same.
501    
502    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
503        as not to get warnings when autogen.sh is called. Also changed
504        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
505    
506    44. To help people who use pcregrep to scan files containing exceedingly long
507        lines, the following changes have been made:
508    
509        (a) The default value of the buffer size parameter has been increased from
510            8K to 20K. (The actual buffer used is three times this size.)
511    
512        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
513            PCRE is built.
514    
515        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
516            to be set at run time.
517    
518        (d) Numerical values in pcregrep options can be followed by K or M, for
519            example --buffer-size=50K.
520    
521        (e) If a line being scanned overflows pcregrep's buffer, an error is now
522            given and the return code is set to 2.
523    
524    45. Add a pointer to the latest mark to the callout data block.
525    
526    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
527        partial match of an empty string instead of no match. This was specific to
528        the use of ".".
529    
530    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
531        complete match instead of a partial match. This bug was dependent on both
532        the PCRE_UTF8 and PCRE_DOTALL options being set.
533    
534    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
535        starting byte set, because \b was not being ignored.
536    
537    
538  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

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