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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.30 04-February-2012
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 its output to pcretest -C.
56    
57    15. Applied Graycode's patch to put the top-level frame on the stack rather
58        than the heap when not using the stack for recursion. This gives a
59        performance improvement in many cases when recursion is not deep.
60    
61    16. Experimental code added to "pcretest -C" to output the stack frame size.
62    
63    
64    Version 8.21 12-Dec-2011
65    ------------------------
66    
67    1.  Updating the JIT compiler.
68    
69    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
70        are added as well.
71    
72    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
73        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
74        calling _pcre_jit_exec. Some extra comments are added.
75    
76    4.  (*MARK) settings inside atomic groups that do not contain any capturing
77        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
78        was introduced by change 18 for 8.20.
79    
80    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
81        ECMA-262 standard.
82    
83    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
84        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
85        This bug was probably introduced by change 9 of 8.13.
86    
87    7.  While fixing 6 above, I noticed that a number of other items were being
88        incorrectly rejected as "not fixed length". This arose partly because newer
89        opcodes had not been added to the fixed-length checking code. I have (a)
90        corrected the bug and added tests for these items, and (b) arranged for an
91        error to occur if an unknown opcode is encountered while checking for fixed
92        length instead of just assuming "not fixed length". The items that were
93        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
94        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
95        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
96    
97    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
98        being incorrectly compiled and would have given unpredicatble results.
99    
100    9.  A possessively repeated subpattern with minimum repeat count greater than
101        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
102        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
103        the first (A) could occur when it should not.
104    
105    10. Add a cast and remove a redundant test from the code.
106    
107    11. JIT should use pcre_malloc/pcre_free for allocation.
108    
109    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
110        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
111        is anything other than /usr, -L is still shown).
112    
113    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
114    
115    14. Perl does not support \N without a following name in a [] class; PCRE now
116        also gives an error.
117    
118    15. If a forward reference was repeated with an upper limit of around 2000,
119        it caused the error "internal error: overran compiling workspace". The
120        maximum number of forward references (including repeats) was limited by the
121        internal workspace, and dependent on the LINK_SIZE. The code has been
122        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
123        the default depends on LINK_SIZE. There is a new upper limit (for safety)
124        of around 200,000 forward references. While doing this, I also speeded up
125        the filling in of repeated forward references.
126    
127    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
128        incorrectly expecting the subject to contain another "a" after the start.
129    
130    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
131        in the match, the SKIP should be ignored. This was not happening; instead
132        the SKIP was being treated as NOMATCH. For patterns such as
133        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
134        tested.
135    
136    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
137        now much more compatible with Perl, in particular in cases where the result
138        is a non-match for a non-anchored pattern. For example, if
139        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
140        "m", where previously it did not return a name. A side effect of this
141        change is that for partial matches, the last encountered mark name is
142        returned, as for non matches. A number of tests that were previously not
143        Perl-compatible have been moved into the Perl-compatible test files. The
144        refactoring has had the pleasing side effect of removing one argument from
145        the match() function, thus reducing its stack requirements.
146    
147    19. If the /S+ option was used in pcretest to study a pattern using JIT,
148        subsequent uses of /S (without +) incorrectly behaved like /S+.
149    
150    21. Retrieve executable code size support for the JIT compiler and fixing
151        some warnings.
152    
153    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
154        not work when the shorter character appeared right at the end of the
155        subject string.
156    
157    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
158        systems.
159    
160    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
161        output it when the /M option is used in pcretest.
162    
163    25. The CheckMan script was not being included in the distribution. Also, added
164        an explicit "perl" to run Perl scripts from the PrepareRelease script
165        because this is reportedly needed in Windows.
166    
167    26. If study data was being save in a file and studying had not found a set of
168        "starts with" bytes for the pattern, the data written to the file (though
169        never used) was taken from uninitialized memory and so caused valgrind to
170        complain.
171    
172    27. Updated RunTest.bat as provided by Sheri Pierce.
173    
174    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
175    
176    29. Computation of memory usage for the table of capturing group names was
177        giving an unnecessarily large value.
178    
179    
180    Version 8.20 21-Oct-2011
181    ------------------------
182    
183    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
184        a POSIX class. After further experiments with Perl, which convinced me that
185        Perl has bugs and confusions, a closing square bracket is no longer allowed
186        in a POSIX name. This bug also affected patterns with classes that started
187        with full stops.
188    
189    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
190        captured substring, but while checking the failing first alternative,
191        substring 1 is temporarily captured. If the output vector supplied to
192        pcre_exec() was not big enough for this capture, the yield of the function
193        was still zero ("insufficient space for captured substrings"). This cannot
194        be totally fixed without adding another stack variable, which seems a lot
195        of expense for a edge case. However, I have improved the situation in cases
196        such as /(a)(b)x|abc/ matched against "abc", where the return code
197        indicates that fewer than the maximum number of slots in the ovector have
198        been set.
199    
200    3.  Related to (2) above: when there are more back references in a pattern than
201        slots in the output vector, pcre_exec() uses temporary memory during
202        matching, and copies in the captures as far as possible afterwards. It was
203        using the entire output vector, but this conflicts with the specification
204        that only 2/3 is used for passing back captured substrings. Now it uses
205        only the first 2/3, for compatibility. This is, of course, another edge
206        case.
207    
208    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
209        main code base, and can be used by building with --enable-jit. When this is
210        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
211        runtime --no-jit option is given.
212    
213    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
214        ovector, the return from the function was zero, implying that there were
215        other matches that did not fit. The correct "exactly full" value is now
216        returned.
217    
218    6.  If a subpattern that was called recursively or as a subroutine contained
219        (*PRUNE) or any other control that caused it to give a non-standard return,
220        invalid errors such as "Error -26 (nested recursion at the same subject
221        position)" or even infinite loops could occur.
222    
223    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
224        computing the minimum length on reaching *ACCEPT, and so ended up with the
225        wrong value of 1 rather than 0. Further investigation indicates that
226        computing a minimum subject length in the presence of *ACCEPT is difficult
227        (think back references, subroutine calls), and so I have changed the code
228        so that no minimum is registered for a pattern that contains *ACCEPT.
229    
230    8.  If (*THEN) was present in the first (true) branch of a conditional group,
231        it was not handled as intended. [But see 16 below.]
232    
233    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
234        Sheri Pierce.
235    
236    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
237        the first byte in a match must be "a".
238    
239    11. Change 17 for 8.13 increased the recursion depth for patterns like
240        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
241        pattern contains any instances of (*THEN). If it does not, the old
242        optimizations are restored. It would be nice to do this on a per-group
243        basis, but at the moment that is not feasible.
244    
245    12. In some environments, the output of pcretest -C is CRLF terminated. This
246        broke RunTest's code that checks for the link size. A single white space
247        character after the value is now allowed for.
248    
249    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
250        For "fr", it uses the Windows-specific input and output files.
251    
252    14. If (*THEN) appeared in a group that was called recursively or as a
253        subroutine, it did not work as intended. [But see next item.]
254    
255    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
256        pattern fragments (but not containing any | characters). If A and B are
257        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
258        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
259        D. In other words, Perl considers parentheses that do not contain any |
260        characters to be part of a surrounding alternative, whereas PCRE was
261        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
262        differently. PCRE now behaves in the same way as Perl, except in the case
263        of subroutine/recursion calls such as (?1) which have in any case always
264        been different (but PCRE had them first :-).
265    
266    16. Related to 15 above: Perl does not treat the | in a conditional group as
267        creating alternatives. Such a group is treated in the same way as an
268        ordinary group without any | characters when processing (*THEN). PCRE has
269        been changed to match Perl's behaviour.
270    
271    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
272        RunGrepTest script failed.
273    
274    18. Change 22 for version 13 caused atomic groups to use more stack. This is
275        inevitable for groups that contain captures, but it can lead to a lot of
276        stack use in large patterns. The old behaviour has been restored for atomic
277        groups that do not contain any capturing parentheses.
278    
279    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
280        suppress the check for a minimum subject length at run time. (If it was
281        given to pcre_exec() or pcre_dfa_exec() it did work.)
282    
283    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
284        fail to work when decoding hex characters in data strings in EBCDIC
285        environments.
286    
287    21. It appears that in at least one Mac OS environment, the isxdigit() function
288        is implemented as a macro that evaluates to its argument more than once,
289        contravening the C 90 Standard (I haven't checked a later standard). There
290        was an instance in pcretest which caused it to go wrong when processing
291        \x{...} escapes in subject strings. The has been rewritten to avoid using
292        things like p++ in the argument of isxdigit().
293    
294    
295    Version 8.13 16-Aug-2011
296  ------------------------  ------------------------
297    
298  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 311  Version 8.13 30-Apr-2011
311      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
312      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
313      left).      left).
314    
315  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
316      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
317      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
318      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
319    
320  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
321      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
322      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
323      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
324      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
325    
326  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
327      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
328      failure, the offset and reason code are output.      failure, the offset and reason code are output.
329    
330  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
331      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
332      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
333      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
334      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
335      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
336      has been changed.      has been changed.
337    
338  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
339      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
340      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
341      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,
342      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
343      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
344      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
345      (?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.
346    
347  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
348      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
349      using pcre_exec().      using pcre_exec().
350    
351  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
352      discovered and fixed:      discovered and fixed:
353    
354      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
355      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
356      ((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.
357      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
358      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
359    
360  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
361      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
362      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
363    
364  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
365      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
366      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
367      pick them up.      pick them up.
368    
369  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
370      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
371      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
372      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
373      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
374      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
375      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
376      "never study" - see 20 below).      "never study" - see 20 below).
377    
378  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
379      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
380      correctly.      correctly.
381    
382  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
383      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
384      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
385      match.      match.
386    
387  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,
388      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
389      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
390      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
391      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
392      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
393    
394  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
395      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
396      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
397    
398  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
399      was incorrectly computed.      was incorrectly computed.
400    
401  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
402      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
403      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
404        identical in both cases.
405    
406  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
407      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.
408    
409  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
410      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
411      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
412      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
413      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-
414      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
415      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
416      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
417    
418    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
419        subject after a captured substring, to make it easier to tell which of a
420        number of identical substrings has been captured.
421    
422    24. The way atomic groups are processed by pcre_exec() has been changed so that
423        if they are repeated, backtracking one repetition now resets captured
424        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
425        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
426        "aaa". Previously, it would have been "a". As part of this code
427        refactoring, the way recursive calls are handled has also been changed.
428    
429    25. If an assertion condition captured any substrings, they were not passed
430        back unless some other capturing happened later. For example, if
431        (?(?=(a))a) was matched against "a", no capturing was returned.
432    
433    26. When studying a pattern that contained subroutine calls or assertions,
434        the code for finding the minimum length of a possible match was handling
435        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
436        group 1 called group 2 while simultaneously a separate group 2 called group
437        1). A stack overflow occurred in this case. I have fixed this by limiting
438        the recursion depth to 10.
439    
440    27. Updated RunTest.bat in the distribution to the version supplied by Tom
441        Fortmann. This supports explicit test numbers on the command line, and has
442        argument validation and error reporting.
443    
444    28. An instance of \X with an unlimited repeat could fail if at any point the
445        first character it looked at was a mark character.
446    
447    29. Some minor code refactoring concerning Unicode properties and scripts
448        should reduce the stack requirement of match() slightly.
449    
450    30. Added the '=' option to pcretest to check the setting of unused capturing
451        slots at the end of the pattern, which are documented as being -1, but are
452        not included in the return count.
453    
454    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
455        compiled something random. Now it gives a compile-time error (as does
456        Perl).
457    
458    32. A *MARK encountered during the processing of a positive assertion is now
459        recorded and passed back (compatible with Perl).
460    
461    33. If --only-matching or --colour was set on a pcregrep call whose pattern
462        had alternative anchored branches, the search for a second match in a line
463        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
464        matched the line "0102" twice. The same bug affected patterns that started
465        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
466        twice.
467    
468    34. Previously, PCRE did not allow quantification of assertions. However, Perl
469        does, and because of capturing effects, quantifying parenthesized
470        assertions may at times be useful. Quantifiers are now allowed for
471        parenthesized assertions.
472    
473    35. A minor code tidy in pcre_compile() when checking options for \R usage.
474    
475    36. \g was being checked for fancy things in a character class, when it should
476        just be a literal "g".
477    
478    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
479        appearance of a nested POSIX class supersedes an apparent external class.
480        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
481        unescaped square brackets may also appear as part of class names. For
482        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
483        more like Perl. (But see 8.20/1 above.)
484    
485    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
486        was because it thought it was \N{name}, which is not supported).
487    
488    39. Add minix to OS list not supporting the -S option in pcretest.
489    
490    40. PCRE tries to detect cases of infinite recursion at compile time, but it
491        cannot analyze patterns in sufficient detail to catch mutual recursions
492        such as ((?1))((?2)). There is now a runtime test that gives an error if a
493        subgroup is called recursively as a subpattern for a second time at the
494        same position in the subject string. In previous releases this might have
495        been caught by the recursion limit, or it might have run out of stack.
496    
497    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
498        happen only once. PCRE was, however incorrectly giving a compile time error
499        "recursive call could loop indefinitely" because it cannot analyze the
500        pattern in sufficient detail. The compile time test no longer happens when
501        PCRE is compiling a conditional subpattern, but actual runaway loops are
502        now caught at runtime (see 40 above).
503    
504    42. It seems that Perl allows any characters other than a closing parenthesis
505        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
506        has been changed to be the same.
507    
508    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
509        as not to get warnings when autogen.sh is called. Also changed
510        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
511    
512    44. To help people who use pcregrep to scan files containing exceedingly long
513        lines, the following changes have been made:
514    
515        (a) The default value of the buffer size parameter has been increased from
516            8K to 20K. (The actual buffer used is three times this size.)
517    
518        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
519            PCRE is built.
520    
521        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
522            to be set at run time.
523    
524        (d) Numerical values in pcregrep options can be followed by K or M, for
525            example --buffer-size=50K.
526    
527        (e) If a line being scanned overflows pcregrep's buffer, an error is now
528            given and the return code is set to 2.
529    
530    45. Add a pointer to the latest mark to the callout data block.
531    
532    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
533        partial match of an empty string instead of no match. This was specific to
534        the use of ".".
535    
536    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
537        complete match instead of a partial match. This bug was dependent on both
538        the PCRE_UTF8 and PCRE_DOTALL options being set.
539    
540    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
541        starting byte set, because \b was not being ignored.
542    
543    
544  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

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