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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.31
5    -----------------------------
6    
7    1.  Fixing a wrong JIT test case and some compiler warnings.
8    
9    2.  Removed a bashism from the RunTest script.
10    
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
14    
15    4.  Partial matching support is added to the JIT compiler.
16    
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
19    
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
23    
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
26    
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
29    
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
32    
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
35    
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
39    
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
42    
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
44    
45    9.  (*MARK) control verb is now supported by the JIT compiler.
46    
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
49    
50    11. Add PCRE_INFO_MAXLOOKBEHIND.
51    
52    12. Applied a (slightly modified) user-supplied patch that improves performance
53        when the heap is used for recursion (compiled with --disable-stack-for-
54        recursion). Instead of malloc and free for each heap frame each time a
55        logical recursion happens, frames are retained on a chain and re-used where
56        possible. This sometimes gives as much as 30% improvement.
57    
58    13. As documented, (*COMMIT) is now confined to within a recursive subpattern
59        call.
60    
61    14. As documented, (*COMMIT) is now confined to within a positive assertion.
62    
63    15. It is now possible to link pcretest with libedit as an alternative to
64        libreadline.
65    
66    16. (*COMMIT) control verb is now supported by the JIT compiler.
67    
68    17. The Unicode data tables have been updated to Unicode 6.1.0.
69    
70    18. Added --file-list option to pcregrep.
71    
72    
73    Version 8.30 04-February-2012
74    -----------------------------
75    
76    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
77        name is defined in ctype.h.
78    
79    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
80        only in quite long subpatterns.
81    
82    3.  Removed the function pcre_info(), which has been obsolete and deprecated
83        since it was replaced by pcre_fullinfo() in February 2000.
84    
85    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
86        match a (*MARK), and the match failed at the start of the subject, a
87        reference to memory before the start of the subject could occur. This bug
88        was introduced by fix 17 of release 8.21.
89    
90    5.  A reference to an unset group with zero minimum repetition was giving
91        totally wrong answers (in non-JavaScript-compatibility mode). For example,
92        /(another)?(\1?)test/ matched against "hello world test". This bug was
93        introduced in release 8.13.
94    
95    6.  Add support for 16-bit character strings (a large amount of work involving
96        many changes and refactorings).
97    
98    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
99        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
100        from a file.
101    
102    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
103        rounding is not applied in this particular case).
104    
105    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
106        if they appear, or are escaped, in patterns.
107    
108    10. Get rid of a number of -Wunused-but-set-variable warnings.
109    
110    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
111        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
112        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
113        also returns the mark "x". This bug applied to capturing parentheses,
114        non-capturing parentheses, and atomic parentheses. It also applied to some
115        assertions.
116    
117    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
118        information out of configure.ac instead of relying on pcre.h.generic, which
119        is not stored in the repository.
120    
121    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
122        -lreadline.
123    
124    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
125    
126    15. Applied Graycode's patch to put the top-level frame on the stack rather
127        than the heap when not using the stack for recursion. This gives a
128        performance improvement in many cases when recursion is not deep.
129    
130    16. Experimental code added to "pcretest -C" to output the stack frame size.
131    
132    
133    Version 8.21 12-Dec-2011
134    ------------------------
135    
136    1.  Updating the JIT compiler.
137    
138    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
139        are added as well.
140    
141    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
142        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
143        calling _pcre_jit_exec. Some extra comments are added.
144    
145    4.  (*MARK) settings inside atomic groups that do not contain any capturing
146        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
147        was introduced by change 18 for 8.20.
148    
149    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
150        ECMA-262 standard.
151    
152    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
153        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
154        This bug was probably introduced by change 9 of 8.13.
155    
156    7.  While fixing 6 above, I noticed that a number of other items were being
157        incorrectly rejected as "not fixed length". This arose partly because newer
158        opcodes had not been added to the fixed-length checking code. I have (a)
159        corrected the bug and added tests for these items, and (b) arranged for an
160        error to occur if an unknown opcode is encountered while checking for fixed
161        length instead of just assuming "not fixed length". The items that were
162        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
163        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
164        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
165    
166    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
167        being incorrectly compiled and would have given unpredicatble results.
168    
169    9.  A possessively repeated subpattern with minimum repeat count greater than
170        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
171        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
172        the first (A) could occur when it should not.
173    
174    10. Add a cast and remove a redundant test from the code.
175    
176    11. JIT should use pcre_malloc/pcre_free for allocation.
177    
178    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
179        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
180        is anything other than /usr, -L is still shown).
181    
182    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
183    
184    14. Perl does not support \N without a following name in a [] class; PCRE now
185        also gives an error.
186    
187    15. If a forward reference was repeated with an upper limit of around 2000,
188        it caused the error "internal error: overran compiling workspace". The
189        maximum number of forward references (including repeats) was limited by the
190        internal workspace, and dependent on the LINK_SIZE. The code has been
191        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
192        the default depends on LINK_SIZE. There is a new upper limit (for safety)
193        of around 200,000 forward references. While doing this, I also speeded up
194        the filling in of repeated forward references.
195    
196    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
197        incorrectly expecting the subject to contain another "a" after the start.
198    
199    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
200        in the match, the SKIP should be ignored. This was not happening; instead
201        the SKIP was being treated as NOMATCH. For patterns such as
202        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
203        tested.
204    
205    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
206        now much more compatible with Perl, in particular in cases where the result
207        is a non-match for a non-anchored pattern. For example, if
208        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
209        "m", where previously it did not return a name. A side effect of this
210        change is that for partial matches, the last encountered mark name is
211        returned, as for non matches. A number of tests that were previously not
212        Perl-compatible have been moved into the Perl-compatible test files. The
213        refactoring has had the pleasing side effect of removing one argument from
214        the match() function, thus reducing its stack requirements.
215    
216    19. If the /S+ option was used in pcretest to study a pattern using JIT,
217        subsequent uses of /S (without +) incorrectly behaved like /S+.
218    
219    21. Retrieve executable code size support for the JIT compiler and fixing
220        some warnings.
221    
222    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
223        not work when the shorter character appeared right at the end of the
224        subject string.
225    
226    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
227        systems.
228    
229    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
230        output it when the /M option is used in pcretest.
231    
232    25. The CheckMan script was not being included in the distribution. Also, added
233        an explicit "perl" to run Perl scripts from the PrepareRelease script
234        because this is reportedly needed in Windows.
235    
236    26. If study data was being save in a file and studying had not found a set of
237        "starts with" bytes for the pattern, the data written to the file (though
238        never used) was taken from uninitialized memory and so caused valgrind to
239        complain.
240    
241    27. Updated RunTest.bat as provided by Sheri Pierce.
242    
243    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
244    
245    29. Computation of memory usage for the table of capturing group names was
246        giving an unnecessarily large value.
247    
248    
249    Version 8.20 21-Oct-2011
250    ------------------------
251    
252    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
253        a POSIX class. After further experiments with Perl, which convinced me that
254        Perl has bugs and confusions, a closing square bracket is no longer allowed
255        in a POSIX name. This bug also affected patterns with classes that started
256        with full stops.
257    
258    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
259        captured substring, but while checking the failing first alternative,
260        substring 1 is temporarily captured. If the output vector supplied to
261        pcre_exec() was not big enough for this capture, the yield of the function
262        was still zero ("insufficient space for captured substrings"). This cannot
263        be totally fixed without adding another stack variable, which seems a lot
264        of expense for a edge case. However, I have improved the situation in cases
265        such as /(a)(b)x|abc/ matched against "abc", where the return code
266        indicates that fewer than the maximum number of slots in the ovector have
267        been set.
268    
269    3.  Related to (2) above: when there are more back references in a pattern than
270        slots in the output vector, pcre_exec() uses temporary memory during
271        matching, and copies in the captures as far as possible afterwards. It was
272        using the entire output vector, but this conflicts with the specification
273        that only 2/3 is used for passing back captured substrings. Now it uses
274        only the first 2/3, for compatibility. This is, of course, another edge
275        case.
276    
277    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
278        main code base, and can be used by building with --enable-jit. When this is
279        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
280        runtime --no-jit option is given.
281    
282    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
283        ovector, the return from the function was zero, implying that there were
284        other matches that did not fit. The correct "exactly full" value is now
285        returned.
286    
287    6.  If a subpattern that was called recursively or as a subroutine contained
288        (*PRUNE) or any other control that caused it to give a non-standard return,
289        invalid errors such as "Error -26 (nested recursion at the same subject
290        position)" or even infinite loops could occur.
291    
292    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
293        computing the minimum length on reaching *ACCEPT, and so ended up with the
294        wrong value of 1 rather than 0. Further investigation indicates that
295        computing a minimum subject length in the presence of *ACCEPT is difficult
296        (think back references, subroutine calls), and so I have changed the code
297        so that no minimum is registered for a pattern that contains *ACCEPT.
298    
299    8.  If (*THEN) was present in the first (true) branch of a conditional group,
300        it was not handled as intended. [But see 16 below.]
301    
302    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
303        Sheri Pierce.
304    
305    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
306        the first byte in a match must be "a".
307    
308    11. Change 17 for 8.13 increased the recursion depth for patterns like
309        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
310        pattern contains any instances of (*THEN). If it does not, the old
311        optimizations are restored. It would be nice to do this on a per-group
312        basis, but at the moment that is not feasible.
313    
314    12. In some environments, the output of pcretest -C is CRLF terminated. This
315        broke RunTest's code that checks for the link size. A single white space
316        character after the value is now allowed for.
317    
318    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
319        For "fr", it uses the Windows-specific input and output files.
320    
321    14. If (*THEN) appeared in a group that was called recursively or as a
322        subroutine, it did not work as intended. [But see next item.]
323    
324    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
325        pattern fragments (but not containing any | characters). If A and B are
326        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
327        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
328        D. In other words, Perl considers parentheses that do not contain any |
329        characters to be part of a surrounding alternative, whereas PCRE was
330        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
331        differently. PCRE now behaves in the same way as Perl, except in the case
332        of subroutine/recursion calls such as (?1) which have in any case always
333        been different (but PCRE had them first :-).
334    
335    16. Related to 15 above: Perl does not treat the | in a conditional group as
336        creating alternatives. Such a group is treated in the same way as an
337        ordinary group without any | characters when processing (*THEN). PCRE has
338        been changed to match Perl's behaviour.
339    
340    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
341        RunGrepTest script failed.
342    
343    18. Change 22 for version 13 caused atomic groups to use more stack. This is
344        inevitable for groups that contain captures, but it can lead to a lot of
345        stack use in large patterns. The old behaviour has been restored for atomic
346        groups that do not contain any capturing parentheses.
347    
348    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
349        suppress the check for a minimum subject length at run time. (If it was
350        given to pcre_exec() or pcre_dfa_exec() it did work.)
351    
352    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
353        fail to work when decoding hex characters in data strings in EBCDIC
354        environments.
355    
356    21. It appears that in at least one Mac OS environment, the isxdigit() function
357        is implemented as a macro that evaluates to its argument more than once,
358        contravening the C 90 Standard (I haven't checked a later standard). There
359        was an instance in pcretest which caused it to go wrong when processing
360        \x{...} escapes in subject strings. The has been rewritten to avoid using
361        things like p++ in the argument of isxdigit().
362    
363    
364    Version 8.13 16-Aug-2011
365  ------------------------  ------------------------
366    
367  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 380  Version 8.13 30-Apr-2011
380      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
381      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
382      left).      left).
383    
384  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
385      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
386      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
387      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
388    
389  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
390      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
391      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
392      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
393      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
394    
395  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
396      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
397      failure, the offset and reason code are output.      failure, the offset and reason code are output.
398    
399  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
400      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
401      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
402      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
403      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
404      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
405      has been changed.      has been changed.
406    
407  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
408      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
409      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
410      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,
411      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
412      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
413      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
414      (?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.
415    
416  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
417      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
418      using pcre_exec().      using pcre_exec().
419    
420  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
421      discovered and fixed:      discovered and fixed:
422    
423      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
424      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
425      ((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.
426      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
427      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
428    
429  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
430      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
431      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
432    
433  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
434      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
435      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
436      pick them up.      pick them up.
437    
438  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
439      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
440      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
441      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
442      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
443      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
444      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
445      "never study" - see 20 below).      "never study" - see 20 below).
446    
447  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
448      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
449      correctly.      correctly.
450    
451  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
452      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
453      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
454      match.      match.
455    
456  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,
457      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
458      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
459      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
460      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
461      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
462    
463  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
464      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
465      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
466    
467  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
468      was incorrectly computed.      was incorrectly computed.
469    
470  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
471      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
472      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
473        identical in both cases.
474    
475  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
476      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.
477    
478  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
479      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
480      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
481      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
482      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-
483      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
484      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
485      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
486    
487  23. Add the ++ qualifier feature to pcretest, to show the remainder of the  23. Add the ++ qualifier feature to pcretest, to show the remainder of the
488      subject after a captured substring (to make it easier to tell which of a      subject after a captured substring, to make it easier to tell which of a
489      number of identical substrings has been captured).      number of identical substrings has been captured.
490    
491  24. The way atomic groups are processed by pcre_exec() has been changed so that  24. The way atomic groups are processed by pcre_exec() has been changed so that
492      if they are repeated, backtracking one repetition now resets captured      if they are repeated, backtracking one repetition now resets captured
493      values correctly. For example, if ((?>(a+)b)+aabab) is matched against      values correctly. For example, if ((?>(a+)b)+aabab) is matched against
494      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
495      "aaa". Previously, it would have been "a". As part of this code      "aaa". Previously, it would have been "a". As part of this code
496      refactoring, the way recursive calls are handled has also been changed.      refactoring, the way recursive calls are handled has also been changed.
497    
498  24. If an assertion condition captured any substrings, they were not passed  25. If an assertion condition captured any substrings, they were not passed
499      back unless some other capturing happened later. For example, if      back unless some other capturing happened later. For example, if
500      (?(?=(a))a) was matched against "a", no capturing was returned.      (?(?=(a))a) was matched against "a", no capturing was returned.
501    
502  25. When studying a pattern that contained subroutine calls or assertions,  26. When studying a pattern that contained subroutine calls or assertions,
503      the code for finding the minimum length of a possible match was handling      the code for finding the minimum length of a possible match was handling
504      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
505      group 1 called group 2 while simultaneously a separate group 2 called group      group 1 called group 2 while simultaneously a separate group 2 called group
506      1). A stack overflow occurred in this case. I have fixed this by limiting      1). A stack overflow occurred in this case. I have fixed this by limiting
507      the recursion depth to 10.      the recursion depth to 10.
508    
509  26. Updated RunTest.bat in the distribution to the version supplied by Tom  27. Updated RunTest.bat in the distribution to the version supplied by Tom
510      Fortmann. This supports explicit test numbers on the command line, and has      Fortmann. This supports explicit test numbers on the command line, and has
511      argument validation and error reporting.      argument validation and error reporting.
512    
513  27. An instance of \X with an unlimited repeat could fail if at any point the  28. An instance of \X with an unlimited repeat could fail if at any point the
514      first character it looked at was a mark character.      first character it looked at was a mark character.
515    
516  28. Some minor code refactoring concerning Unicode properties and scripts  29. Some minor code refactoring concerning Unicode properties and scripts
517      should reduce the stack requirement of match() slightly.      should reduce the stack requirement of match() slightly.
518    
519  29. Added the '=' option to pcretest to check the setting of unused capturing  30. Added the '=' option to pcretest to check the setting of unused capturing
520      slots at the end of the pattern, which are documented as being -1, but are      slots at the end of the pattern, which are documented as being -1, but are
521      not included in the return count.      not included in the return count.
522    
523  30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE  31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
524      compiled something random. Now it gives a compile-time error (as does      compiled something random. Now it gives a compile-time error (as does
525      Perl).      Perl).
526    
527  31. A *MARK encountered during the processing of a positive assertion is now  32. A *MARK encountered during the processing of a positive assertion is now
528      recorded and passed back (compatible with Perl).      recorded and passed back (compatible with Perl).
529    
530  32. If --only-matching or --colour was set on a pcregrep call whose pattern  33. If --only-matching or --colour was set on a pcregrep call whose pattern
531      had alternative anchored branches, the search for a second match in a line      had alternative anchored branches, the search for a second match in a line
532      was done as if at the line start. Thus, for example, /^01|^02/ incorrectly      was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
533      matched the line "0102" twice. The same bug affected patterns that started      matched the line "0102" twice. The same bug affected patterns that started
534      with a backwards assertion. For example /\b01|\b02/ also matched "0102"      with a backwards assertion. For example /\b01|\b02/ also matched "0102"
535      twice.      twice.
536    
537  33. Previously, PCRE did not allow quantification of assertions. However, Perl  34. Previously, PCRE did not allow quantification of assertions. However, Perl
538      does, and because of capturing effects, quantifying parenthesized      does, and because of capturing effects, quantifying parenthesized
539      assertions may at times be useful. Quantifiers are now allowed for      assertions may at times be useful. Quantifiers are now allowed for
540      parenthesized assertions.      parenthesized assertions.
541    
542  34. A minor code tidy in pcre_compile() when checking options for \R usage.  35. A minor code tidy in pcre_compile() when checking options for \R usage.
543    
544    36. \g was being checked for fancy things in a character class, when it should
545        just be a literal "g".
546    
547    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
548        appearance of a nested POSIX class supersedes an apparent external class.
549        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
550        unescaped square brackets may also appear as part of class names. For
551        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
552        more like Perl. (But see 8.20/1 above.)
553    
554    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
555        was because it thought it was \N{name}, which is not supported).
556    
557    39. Add minix to OS list not supporting the -S option in pcretest.
558    
559    40. PCRE tries to detect cases of infinite recursion at compile time, but it
560        cannot analyze patterns in sufficient detail to catch mutual recursions
561        such as ((?1))((?2)). There is now a runtime test that gives an error if a
562        subgroup is called recursively as a subpattern for a second time at the
563        same position in the subject string. In previous releases this might have
564        been caught by the recursion limit, or it might have run out of stack.
565    
566    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
567        happen only once. PCRE was, however incorrectly giving a compile time error
568        "recursive call could loop indefinitely" because it cannot analyze the
569        pattern in sufficient detail. The compile time test no longer happens when
570        PCRE is compiling a conditional subpattern, but actual runaway loops are
571        now caught at runtime (see 40 above).
572    
573    42. It seems that Perl allows any characters other than a closing parenthesis
574        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
575        has been changed to be the same.
576    
577    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
578        as not to get warnings when autogen.sh is called. Also changed
579        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
580    
581    44. To help people who use pcregrep to scan files containing exceedingly long
582        lines, the following changes have been made:
583    
584        (a) The default value of the buffer size parameter has been increased from
585            8K to 20K. (The actual buffer used is three times this size.)
586    
587        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
588            PCRE is built.
589    
590        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
591            to be set at run time.
592    
593        (d) Numerical values in pcregrep options can be followed by K or M, for
594            example --buffer-size=50K.
595    
596        (e) If a line being scanned overflows pcregrep's buffer, an error is now
597            given and the return code is set to 2.
598    
599    45. Add a pointer to the latest mark to the callout data block.
600    
601    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
602        partial match of an empty string instead of no match. This was specific to
603        the use of ".".
604    
605    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
606        complete match instead of a partial match. This bug was dependent on both
607        the PCRE_UTF8 and PCRE_DOTALL options being set.
608    
609    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
610        starting byte set, because \b was not being ignored.
611    
612    
613  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

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