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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.31
5    -----------------------------
6    
7    1.  Fixing a wrong JIT test case and some compiler warnings.
8    
9    2.  Removed a bashism from the RunTest script.
10    
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
14    
15    4.  Partial matching support is added to the JIT compiler.
16    
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
19    
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
23    
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
26    
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
29    
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
32    
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
35    
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
39    
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
42    
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
44    
45    9.  (*MARK) control verb is now supported by the JIT compiler.
46    
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
49    
50    11. Add PCRE_INFO_MAXLOOKBEHIND.
51    
52    12. Applied a (slightly modified) user-supplied patch that improves performance
53        when the heap is used for recursion (compiled with --disable-stack-for-
54        recursion). Instead of malloc and free for each heap frame each time a
55        logical recursion happens, frames are retained on a chain and re-used where
56        possible. This sometimes gives as much as 30% improvement.
57    
58    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
59        call.
60    
61    14. As documented, (*COMMIT) is now confined to within a positive assertion.
62    
63    15. It is now possible to link pcretest with libedit as an alternative to
64        libreadline.
65    
66    
67    Version 8.30 04-February-2012
68    -----------------------------
69    
70    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
71        name is defined in ctype.h.
72    
73    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
74        only in quite long subpatterns.
75    
76    3.  Removed the function pcre_info(), which has been obsolete and deprecated
77        since it was replaced by pcre_fullinfo() in February 2000.
78    
79    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
80        match a (*MARK), and the match failed at the start of the subject, a
81        reference to memory before the start of the subject could occur. This bug
82        was introduced by fix 17 of release 8.21.
83    
84    5.  A reference to an unset group with zero minimum repetition was giving
85        totally wrong answers (in non-JavaScript-compatibility mode). For example,
86        /(another)?(\1?)test/ matched against "hello world test". This bug was
87        introduced in release 8.13.
88    
89    6.  Add support for 16-bit character strings (a large amount of work involving
90        many changes and refactorings).
91    
92    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
93        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
94        from a file.
95    
96    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
97        rounding is not applied in this particular case).
98    
99    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
100        if they appear, or are escaped, in patterns.
101    
102    10. Get rid of a number of -Wunused-but-set-variable warnings.
103    
104    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
105        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
106        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
107        also returns the mark "x". This bug applied to capturing parentheses,
108        non-capturing parentheses, and atomic parentheses. It also applied to some
109        assertions.
110    
111    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
112        information out of configure.ac instead of relying on pcre.h.generic, which
113        is not stored in the repository.
114    
115    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
116        -lreadline.
117    
118    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
119    
120    15. Applied Graycode's patch to put the top-level frame on the stack rather
121        than the heap when not using the stack for recursion. This gives a
122        performance improvement in many cases when recursion is not deep.
123    
124    16. Experimental code added to "pcretest -C" to output the stack frame size.
125    
126    
127    Version 8.21 12-Dec-2011
128    ------------------------
129    
130    1.  Updating the JIT compiler.
131    
132    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
133        are added as well.
134    
135    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
136        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
137        calling _pcre_jit_exec. Some extra comments are added.
138    
139    4.  (*MARK) settings inside atomic groups that do not contain any capturing
140        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
141        was introduced by change 18 for 8.20.
142    
143    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
144        ECMA-262 standard.
145    
146    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
147        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
148        This bug was probably introduced by change 9 of 8.13.
149    
150    7.  While fixing 6 above, I noticed that a number of other items were being
151        incorrectly rejected as "not fixed length". This arose partly because newer
152        opcodes had not been added to the fixed-length checking code. I have (a)
153        corrected the bug and added tests for these items, and (b) arranged for an
154        error to occur if an unknown opcode is encountered while checking for fixed
155        length instead of just assuming "not fixed length". The items that were
156        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
157        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
158        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
159    
160    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
161        being incorrectly compiled and would have given unpredicatble results.
162    
163    9.  A possessively repeated subpattern with minimum repeat count greater than
164        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
165        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
166        the first (A) could occur when it should not.
167    
168    10. Add a cast and remove a redundant test from the code.
169    
170    11. JIT should use pcre_malloc/pcre_free for allocation.
171    
172    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
173        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
174        is anything other than /usr, -L is still shown).
175    
176    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
177    
178    14. Perl does not support \N without a following name in a [] class; PCRE now
179        also gives an error.
180    
181    15. If a forward reference was repeated with an upper limit of around 2000,
182        it caused the error "internal error: overran compiling workspace". The
183        maximum number of forward references (including repeats) was limited by the
184        internal workspace, and dependent on the LINK_SIZE. The code has been
185        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
186        the default depends on LINK_SIZE. There is a new upper limit (for safety)
187        of around 200,000 forward references. While doing this, I also speeded up
188        the filling in of repeated forward references.
189    
190    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
191        incorrectly expecting the subject to contain another "a" after the start.
192    
193    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
194        in the match, the SKIP should be ignored. This was not happening; instead
195        the SKIP was being treated as NOMATCH. For patterns such as
196        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
197        tested.
198    
199    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
200        now much more compatible with Perl, in particular in cases where the result
201        is a non-match for a non-anchored pattern. For example, if
202        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
203        "m", where previously it did not return a name. A side effect of this
204        change is that for partial matches, the last encountered mark name is
205        returned, as for non matches. A number of tests that were previously not
206        Perl-compatible have been moved into the Perl-compatible test files. The
207        refactoring has had the pleasing side effect of removing one argument from
208        the match() function, thus reducing its stack requirements.
209    
210    19. If the /S+ option was used in pcretest to study a pattern using JIT,
211        subsequent uses of /S (without +) incorrectly behaved like /S+.
212    
213    21. Retrieve executable code size support for the JIT compiler and fixing
214        some warnings.
215    
216    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
217        not work when the shorter character appeared right at the end of the
218        subject string.
219    
220    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
221        systems.
222    
223    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
224        output it when the /M option is used in pcretest.
225    
226    25. The CheckMan script was not being included in the distribution. Also, added
227        an explicit "perl" to run Perl scripts from the PrepareRelease script
228        because this is reportedly needed in Windows.
229    
230    26. If study data was being save in a file and studying had not found a set of
231        "starts with" bytes for the pattern, the data written to the file (though
232        never used) was taken from uninitialized memory and so caused valgrind to
233        complain.
234    
235    27. Updated RunTest.bat as provided by Sheri Pierce.
236    
237    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
238    
239    29. Computation of memory usage for the table of capturing group names was
240        giving an unnecessarily large value.
241    
242    
243    Version 8.20 21-Oct-2011
244    ------------------------
245    
246    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
247        a POSIX class. After further experiments with Perl, which convinced me that
248        Perl has bugs and confusions, a closing square bracket is no longer allowed
249        in a POSIX name. This bug also affected patterns with classes that started
250        with full stops.
251    
252    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
253        captured substring, but while checking the failing first alternative,
254        substring 1 is temporarily captured. If the output vector supplied to
255        pcre_exec() was not big enough for this capture, the yield of the function
256        was still zero ("insufficient space for captured substrings"). This cannot
257        be totally fixed without adding another stack variable, which seems a lot
258        of expense for a edge case. However, I have improved the situation in cases
259        such as /(a)(b)x|abc/ matched against "abc", where the return code
260        indicates that fewer than the maximum number of slots in the ovector have
261        been set.
262    
263    3.  Related to (2) above: when there are more back references in a pattern than
264        slots in the output vector, pcre_exec() uses temporary memory during
265        matching, and copies in the captures as far as possible afterwards. It was
266        using the entire output vector, but this conflicts with the specification
267        that only 2/3 is used for passing back captured substrings. Now it uses
268        only the first 2/3, for compatibility. This is, of course, another edge
269        case.
270    
271    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
272        main code base, and can be used by building with --enable-jit. When this is
273        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
274        runtime --no-jit option is given.
275    
276    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
277        ovector, the return from the function was zero, implying that there were
278        other matches that did not fit. The correct "exactly full" value is now
279        returned.
280    
281    6.  If a subpattern that was called recursively or as a subroutine contained
282        (*PRUNE) or any other control that caused it to give a non-standard return,
283        invalid errors such as "Error -26 (nested recursion at the same subject
284        position)" or even infinite loops could occur.
285    
286    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
287        computing the minimum length on reaching *ACCEPT, and so ended up with the
288        wrong value of 1 rather than 0. Further investigation indicates that
289        computing a minimum subject length in the presence of *ACCEPT is difficult
290        (think back references, subroutine calls), and so I have changed the code
291        so that no minimum is registered for a pattern that contains *ACCEPT.
292    
293    8.  If (*THEN) was present in the first (true) branch of a conditional group,
294        it was not handled as intended. [But see 16 below.]
295    
296    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
297        Sheri Pierce.
298    
299    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
300        the first byte in a match must be "a".
301    
302    11. Change 17 for 8.13 increased the recursion depth for patterns like
303        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
304        pattern contains any instances of (*THEN). If it does not, the old
305        optimizations are restored. It would be nice to do this on a per-group
306        basis, but at the moment that is not feasible.
307    
308    12. In some environments, the output of pcretest -C is CRLF terminated. This
309        broke RunTest's code that checks for the link size. A single white space
310        character after the value is now allowed for.
311    
312    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
313        For "fr", it uses the Windows-specific input and output files.
314    
315    14. If (*THEN) appeared in a group that was called recursively or as a
316        subroutine, it did not work as intended. [But see next item.]
317    
318    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
319        pattern fragments (but not containing any | characters). If A and B are
320        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
321        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
322        D. In other words, Perl considers parentheses that do not contain any |
323        characters to be part of a surrounding alternative, whereas PCRE was
324        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
325        differently. PCRE now behaves in the same way as Perl, except in the case
326        of subroutine/recursion calls such as (?1) which have in any case always
327        been different (but PCRE had them first :-).
328    
329    16. Related to 15 above: Perl does not treat the | in a conditional group as
330        creating alternatives. Such a group is treated in the same way as an
331        ordinary group without any | characters when processing (*THEN). PCRE has
332        been changed to match Perl's behaviour.
333    
334    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
335        RunGrepTest script failed.
336    
337    18. Change 22 for version 13 caused atomic groups to use more stack. This is
338        inevitable for groups that contain captures, but it can lead to a lot of
339        stack use in large patterns. The old behaviour has been restored for atomic
340        groups that do not contain any capturing parentheses.
341    
342    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
343        suppress the check for a minimum subject length at run time. (If it was
344        given to pcre_exec() or pcre_dfa_exec() it did work.)
345    
346    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
347        fail to work when decoding hex characters in data strings in EBCDIC
348        environments.
349    
350    21. It appears that in at least one Mac OS environment, the isxdigit() function
351        is implemented as a macro that evaluates to its argument more than once,
352        contravening the C 90 Standard (I haven't checked a later standard). There
353        was an instance in pcretest which caused it to go wrong when processing
354        \x{...} escapes in subject strings. The has been rewritten to avoid using
355        things like p++ in the argument of isxdigit().
356    
357    
358    Version 8.13 16-Aug-2011
359  ------------------------  ------------------------
360    
361  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 374  Version 8.13 30-Apr-2011
374      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
375      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
376      left).      left).
377    
378  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
379      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
380      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
381      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
382    
383  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
384      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
385      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
386      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
387      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
388    
389  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
390      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
391      failure, the offset and reason code are output.      failure, the offset and reason code are output.
392    
393  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
394      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
395      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
396      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
397      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
398      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
399      has been changed.      has been changed.
400    
401  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
402      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
403      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
404      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,
405      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
406      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
407      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
408      (?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.
409    
410  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
411      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
412      using pcre_exec().      using pcre_exec().
413    
414  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
415      discovered and fixed:      discovered and fixed:
416    
417      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
418      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
419      ((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.
420      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
421      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
422    
423  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
424      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
425      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
426    
427  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
428      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
429      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
430      pick them up.      pick them up.
431    
432  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
433      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
434      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
435      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
436      using it. It makes it easier to run collection of tests with study enabled,      using it. It makes it easier to run collections of tests with and without
437      and thereby test pcre_study() more easily.      study enabled, and thereby test pcre_study() more easily. All the standard
438        tests are now run with and without -s (but some patterns can be marked as
439        "never study" - see 20 below).
440    
441  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
442      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
443      correctly.      correctly.
444    
445  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
446      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
447      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
448      match.      match.
449    
450    17. There was optimizing code for the last branch of non-capturing parentheses,
451        and also for the obeyed branch of a conditional subexpression, which used
452        tail recursion to cut down on stack usage. Unfortunately, now that there is
453        the possibility of (*THEN) occurring in these branches, tail recursion is
454        no longer possible because the return has to be checked for (*THEN). These
455        two optimizations have therefore been removed. [But see 8.20/11 above.]
456    
457    18. If a pattern containing \R was studied, it was assumed that \R always
458        matched two bytes, thus causing the minimum subject length to be
459        incorrectly computed because \R can also match just one byte.
460    
461    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
462        was incorrectly computed.
463    
464    20. If /S is present twice on a test pattern in pcretest input, it now
465        *disables* studying, thereby overriding the use of -s on the command line
466        (see 14 above). This is necessary for one or two tests to keep the output
467        identical in both cases.
468    
469    21. When (*ACCEPT) was used in an assertion that matched an empty string and
470        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
471    
472    22. When an atomic group that contained a capturing parenthesis was
473        successfully matched, but the branch in which it appeared failed, the
474        capturing was not being forgotten if a higher numbered group was later
475        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
476        group 1 to "a", when in fact it should be unset. This applied to multi-
477        branched capturing and non-capturing groups, repeated or not, and also to
478        positive assertions (capturing in negative assertions does not happen
479        in PCRE) and also to nested atomic groups.
480    
481    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
482        subject after a captured substring, to make it easier to tell which of a
483        number of identical substrings has been captured.
484    
485    24. The way atomic groups are processed by pcre_exec() has been changed so that
486        if they are repeated, backtracking one repetition now resets captured
487        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
488        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
489        "aaa". Previously, it would have been "a". As part of this code
490        refactoring, the way recursive calls are handled has also been changed.
491    
492    25. If an assertion condition captured any substrings, they were not passed
493        back unless some other capturing happened later. For example, if
494        (?(?=(a))a) was matched against "a", no capturing was returned.
495    
496    26. When studying a pattern that contained subroutine calls or assertions,
497        the code for finding the minimum length of a possible match was handling
498        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
499        group 1 called group 2 while simultaneously a separate group 2 called group
500        1). A stack overflow occurred in this case. I have fixed this by limiting
501        the recursion depth to 10.
502    
503    27. Updated RunTest.bat in the distribution to the version supplied by Tom
504        Fortmann. This supports explicit test numbers on the command line, and has
505        argument validation and error reporting.
506    
507    28. An instance of \X with an unlimited repeat could fail if at any point the
508        first character it looked at was a mark character.
509    
510    29. Some minor code refactoring concerning Unicode properties and scripts
511        should reduce the stack requirement of match() slightly.
512    
513    30. Added the '=' option to pcretest to check the setting of unused capturing
514        slots at the end of the pattern, which are documented as being -1, but are
515        not included in the return count.
516    
517    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
518        compiled something random. Now it gives a compile-time error (as does
519        Perl).
520    
521    32. A *MARK encountered during the processing of a positive assertion is now
522        recorded and passed back (compatible with Perl).
523    
524    33. If --only-matching or --colour was set on a pcregrep call whose pattern
525        had alternative anchored branches, the search for a second match in a line
526        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
527        matched the line "0102" twice. The same bug affected patterns that started
528        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
529        twice.
530    
531    34. Previously, PCRE did not allow quantification of assertions. However, Perl
532        does, and because of capturing effects, quantifying parenthesized
533        assertions may at times be useful. Quantifiers are now allowed for
534        parenthesized assertions.
535    
536    35. A minor code tidy in pcre_compile() when checking options for \R usage.
537    
538    36. \g was being checked for fancy things in a character class, when it should
539        just be a literal "g".
540    
541    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
542        appearance of a nested POSIX class supersedes an apparent external class.
543        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
544        unescaped square brackets may also appear as part of class names. For
545        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
546        more like Perl. (But see 8.20/1 above.)
547    
548    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
549        was because it thought it was \N{name}, which is not supported).
550    
551    39. Add minix to OS list not supporting the -S option in pcretest.
552    
553    40. PCRE tries to detect cases of infinite recursion at compile time, but it
554        cannot analyze patterns in sufficient detail to catch mutual recursions
555        such as ((?1))((?2)). There is now a runtime test that gives an error if a
556        subgroup is called recursively as a subpattern for a second time at the
557        same position in the subject string. In previous releases this might have
558        been caught by the recursion limit, or it might have run out of stack.
559    
560    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
561        happen only once. PCRE was, however incorrectly giving a compile time error
562        "recursive call could loop indefinitely" because it cannot analyze the
563        pattern in sufficient detail. The compile time test no longer happens when
564        PCRE is compiling a conditional subpattern, but actual runaway loops are
565        now caught at runtime (see 40 above).
566    
567    42. It seems that Perl allows any characters other than a closing parenthesis
568        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
569        has been changed to be the same.
570    
571    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
572        as not to get warnings when autogen.sh is called. Also changed
573        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
574    
575    44. To help people who use pcregrep to scan files containing exceedingly long
576        lines, the following changes have been made:
577    
578        (a) The default value of the buffer size parameter has been increased from
579            8K to 20K. (The actual buffer used is three times this size.)
580    
581        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
582            PCRE is built.
583    
584        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
585            to be set at run time.
586    
587        (d) Numerical values in pcregrep options can be followed by K or M, for
588            example --buffer-size=50K.
589    
590        (e) If a line being scanned overflows pcregrep's buffer, an error is now
591            given and the return code is set to 2.
592    
593    45. Add a pointer to the latest mark to the callout data block.
594    
595    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
596        partial match of an empty string instead of no match. This was specific to
597        the use of ".".
598    
599    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
600        complete match instead of a partial match. This bug was dependent on both
601        the PCRE_UTF8 and PCRE_DOTALL options being set.
602    
603    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
604        starting byte set, because \b was not being ignored.
605    
606    
607  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
608  ------------------------  ------------------------

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