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revision 643 by ph10, Fri Jul 29 15:56:39 2011 UTC revision 941 by zherczeg, Tue Feb 28 11:33:34 2012 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.31
5    -----------------------------
6    
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    
69    Version 8.30 04-February-2012
70    -----------------------------
71    
72    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
73        name is defined in ctype.h.
74    
75    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
76        only in quite long subpatterns.
77    
78    3.  Removed the function pcre_info(), which has been obsolete and deprecated
79        since it was replaced by pcre_fullinfo() in February 2000.
80    
81    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
82        match a (*MARK), and the match failed at the start of the subject, a
83        reference to memory before the start of the subject could occur. This bug
84        was introduced by fix 17 of release 8.21.
85    
86    5.  A reference to an unset group with zero minimum repetition was giving
87        totally wrong answers (in non-JavaScript-compatibility mode). For example,
88        /(another)?(\1?)test/ matched against "hello world test". This bug was
89        introduced in release 8.13.
90    
91    6.  Add support for 16-bit character strings (a large amount of work involving
92        many changes and refactorings).
93    
94    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
95        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
96        from a file.
97    
98    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
99        rounding is not applied in this particular case).
100    
101    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
102        if they appear, or are escaped, in patterns.
103    
104    10. Get rid of a number of -Wunused-but-set-variable warnings.
105    
106    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
107        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
108        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
109        also returns the mark "x". This bug applied to capturing parentheses,
110        non-capturing parentheses, and atomic parentheses. It also applied to some
111        assertions.
112    
113    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
114        information out of configure.ac instead of relying on pcre.h.generic, which
115        is not stored in the repository.
116    
117    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
118        -lreadline.
119    
120    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
121    
122    15. Applied Graycode's patch to put the top-level frame on the stack rather
123        than the heap when not using the stack for recursion. This gives a
124        performance improvement in many cases when recursion is not deep.
125    
126    16. Experimental code added to "pcretest -C" to output the stack frame size.
127    
128    
129    Version 8.21 12-Dec-2011
130    ------------------------
131    
132    1.  Updating the JIT compiler.
133    
134    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
135        are added as well.
136    
137    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
138        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
139        calling _pcre_jit_exec. Some extra comments are added.
140    
141    4.  (*MARK) settings inside atomic groups that do not contain any capturing
142        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
143        was introduced by change 18 for 8.20.
144    
145    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
146        ECMA-262 standard.
147    
148    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
149        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
150        This bug was probably introduced by change 9 of 8.13.
151    
152    7.  While fixing 6 above, I noticed that a number of other items were being
153        incorrectly rejected as "not fixed length". This arose partly because newer
154        opcodes had not been added to the fixed-length checking code. I have (a)
155        corrected the bug and added tests for these items, and (b) arranged for an
156        error to occur if an unknown opcode is encountered while checking for fixed
157        length instead of just assuming "not fixed length". The items that were
158        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
159        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
160        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
161    
162    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
163        being incorrectly compiled and would have given unpredicatble results.
164    
165    9.  A possessively repeated subpattern with minimum repeat count greater than
166        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
167        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
168        the first (A) could occur when it should not.
169    
170    10. Add a cast and remove a redundant test from the code.
171    
172    11. JIT should use pcre_malloc/pcre_free for allocation.
173    
174    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
175        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
176        is anything other than /usr, -L is still shown).
177    
178    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
179    
180    14. Perl does not support \N without a following name in a [] class; PCRE now
181        also gives an error.
182    
183    15. If a forward reference was repeated with an upper limit of around 2000,
184        it caused the error "internal error: overran compiling workspace". The
185        maximum number of forward references (including repeats) was limited by the
186        internal workspace, and dependent on the LINK_SIZE. The code has been
187        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
188        the default depends on LINK_SIZE. There is a new upper limit (for safety)
189        of around 200,000 forward references. While doing this, I also speeded up
190        the filling in of repeated forward references.
191    
192    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
193        incorrectly expecting the subject to contain another "a" after the start.
194    
195    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
196        in the match, the SKIP should be ignored. This was not happening; instead
197        the SKIP was being treated as NOMATCH. For patterns such as
198        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
199        tested.
200    
201    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
202        now much more compatible with Perl, in particular in cases where the result
203        is a non-match for a non-anchored pattern. For example, if
204        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
205        "m", where previously it did not return a name. A side effect of this
206        change is that for partial matches, the last encountered mark name is
207        returned, as for non matches. A number of tests that were previously not
208        Perl-compatible have been moved into the Perl-compatible test files. The
209        refactoring has had the pleasing side effect of removing one argument from
210        the match() function, thus reducing its stack requirements.
211    
212    19. If the /S+ option was used in pcretest to study a pattern using JIT,
213        subsequent uses of /S (without +) incorrectly behaved like /S+.
214    
215    21. Retrieve executable code size support for the JIT compiler and fixing
216        some warnings.
217    
218    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
219        not work when the shorter character appeared right at the end of the
220        subject string.
221    
222    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
223        systems.
224    
225    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
226        output it when the /M option is used in pcretest.
227    
228    25. The CheckMan script was not being included in the distribution. Also, added
229        an explicit "perl" to run Perl scripts from the PrepareRelease script
230        because this is reportedly needed in Windows.
231    
232    26. If study data was being save in a file and studying had not found a set of
233        "starts with" bytes for the pattern, the data written to the file (though
234        never used) was taken from uninitialized memory and so caused valgrind to
235        complain.
236    
237    27. Updated RunTest.bat as provided by Sheri Pierce.
238    
239    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
240    
241    29. Computation of memory usage for the table of capturing group names was
242        giving an unnecessarily large value.
243    
244    
245    Version 8.20 21-Oct-2011
246    ------------------------
247    
248    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
249        a POSIX class. After further experiments with Perl, which convinced me that
250        Perl has bugs and confusions, a closing square bracket is no longer allowed
251        in a POSIX name. This bug also affected patterns with classes that started
252        with full stops.
253    
254    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
255        captured substring, but while checking the failing first alternative,
256        substring 1 is temporarily captured. If the output vector supplied to
257        pcre_exec() was not big enough for this capture, the yield of the function
258        was still zero ("insufficient space for captured substrings"). This cannot
259        be totally fixed without adding another stack variable, which seems a lot
260        of expense for a edge case. However, I have improved the situation in cases
261        such as /(a)(b)x|abc/ matched against "abc", where the return code
262        indicates that fewer than the maximum number of slots in the ovector have
263        been set.
264    
265    3.  Related to (2) above: when there are more back references in a pattern than
266        slots in the output vector, pcre_exec() uses temporary memory during
267        matching, and copies in the captures as far as possible afterwards. It was
268        using the entire output vector, but this conflicts with the specification
269        that only 2/3 is used for passing back captured substrings. Now it uses
270        only the first 2/3, for compatibility. This is, of course, another edge
271        case.
272    
273    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
274        main code base, and can be used by building with --enable-jit. When this is
275        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
276        runtime --no-jit option is given.
277    
278    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
279        ovector, the return from the function was zero, implying that there were
280        other matches that did not fit. The correct "exactly full" value is now
281        returned.
282    
283    6.  If a subpattern that was called recursively or as a subroutine contained
284        (*PRUNE) or any other control that caused it to give a non-standard return,
285        invalid errors such as "Error -26 (nested recursion at the same subject
286        position)" or even infinite loops could occur.
287    
288    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
289        computing the minimum length on reaching *ACCEPT, and so ended up with the
290        wrong value of 1 rather than 0. Further investigation indicates that
291        computing a minimum subject length in the presence of *ACCEPT is difficult
292        (think back references, subroutine calls), and so I have changed the code
293        so that no minimum is registered for a pattern that contains *ACCEPT.
294    
295    8.  If (*THEN) was present in the first (true) branch of a conditional group,
296        it was not handled as intended. [But see 16 below.]
297    
298    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
299        Sheri Pierce.
300    
301    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
302        the first byte in a match must be "a".
303    
304    11. Change 17 for 8.13 increased the recursion depth for patterns like
305        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
306        pattern contains any instances of (*THEN). If it does not, the old
307        optimizations are restored. It would be nice to do this on a per-group
308        basis, but at the moment that is not feasible.
309    
310    12. In some environments, the output of pcretest -C is CRLF terminated. This
311        broke RunTest's code that checks for the link size. A single white space
312        character after the value is now allowed for.
313    
314    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
315        For "fr", it uses the Windows-specific input and output files.
316    
317    14. If (*THEN) appeared in a group that was called recursively or as a
318        subroutine, it did not work as intended. [But see next item.]
319    
320    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
321        pattern fragments (but not containing any | characters). If A and B are
322        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
323        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
324        D. In other words, Perl considers parentheses that do not contain any |
325        characters to be part of a surrounding alternative, whereas PCRE was
326        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
327        differently. PCRE now behaves in the same way as Perl, except in the case
328        of subroutine/recursion calls such as (?1) which have in any case always
329        been different (but PCRE had them first :-).
330    
331    16. Related to 15 above: Perl does not treat the | in a conditional group as
332        creating alternatives. Such a group is treated in the same way as an
333        ordinary group without any | characters when processing (*THEN). PCRE has
334        been changed to match Perl's behaviour.
335    
336    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
337        RunGrepTest script failed.
338    
339    18. Change 22 for version 13 caused atomic groups to use more stack. This is
340        inevitable for groups that contain captures, but it can lead to a lot of
341        stack use in large patterns. The old behaviour has been restored for atomic
342        groups that do not contain any capturing parentheses.
343    
344    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
345        suppress the check for a minimum subject length at run time. (If it was
346        given to pcre_exec() or pcre_dfa_exec() it did work.)
347    
348    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
349        fail to work when decoding hex characters in data strings in EBCDIC
350        environments.
351    
352    21. It appears that in at least one Mac OS environment, the isxdigit() function
353        is implemented as a macro that evaluates to its argument more than once,
354        contravening the C 90 Standard (I haven't checked a later standard). There
355        was an instance in pcretest which caused it to go wrong when processing
356        \x{...} escapes in subject strings. The has been rewritten to avoid using
357        things like p++ in the argument of isxdigit().
358    
359    
360    Version 8.13 16-Aug-2011
361  ------------------------  ------------------------
362    
363  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 376  Version 8.13 30-Apr-2011
376      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
377      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
378      left).      left).
379    
380  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
381      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
382      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
383      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
384    
385  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
386      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
387      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
388      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
389      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
390    
391  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
392      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
393      failure, the offset and reason code are output.      failure, the offset and reason code are output.
394    
395  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
396      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
397      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
398      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
399      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
400      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
401      has been changed.      has been changed.
402    
403  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
404      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
405      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
406      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,
407      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
408      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
409      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
410      (?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.
411    
412  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
413      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
414      using pcre_exec().      using pcre_exec().
415    
416  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
417      discovered and fixed:      discovered and fixed:
418    
419      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
420      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
421      ((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.
422      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
423      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
424    
425  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
426      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
427      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
428    
429  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
430      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
431      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
432      pick them up.      pick them up.
433    
434  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
435      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
436      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
437      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
438      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
439      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
440      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
441      "never study" - see 20 below).      "never study" - see 20 below).
442    
443  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
444      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
445      correctly.      correctly.
446    
447  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
448      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
449      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
450      match.      match.
451    
452  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,
453      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
454      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
455      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
456      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
457      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
458    
459  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
460      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
461      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
462    
463  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
464      was incorrectly computed.      was incorrectly computed.
465    
466  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
467      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
468      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
469        identical in both cases.
470    
471  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
472      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.
473    
474  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
475      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
476      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
477      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
478      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-
479      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
480      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
481      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
482    
483  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
484      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
485      number of identical substrings has been captured).      number of identical substrings has been captured.
486    
487  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
488      if they are repeated, backtracking one repetition now resets captured      if they are repeated, backtracking one repetition now resets captured
489      values correctly. For example, if ((?>(a+)b)+aabab) is matched against      values correctly. For example, if ((?>(a+)b)+aabab) is matched against
490      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
491      "aaa". Previously, it would have been "a". As part of this code      "aaa". Previously, it would have been "a". As part of this code
492      refactoring, the way recursive calls are handled has also been changed.      refactoring, the way recursive calls are handled has also been changed.
493    
494  24. If an assertion condition captured any substrings, they were not passed  25. If an assertion condition captured any substrings, they were not passed
495      back unless some other capturing happened later. For example, if      back unless some other capturing happened later. For example, if
496      (?(?=(a))a) was matched against "a", no capturing was returned.      (?(?=(a))a) was matched against "a", no capturing was returned.
497    
498  25. When studying a pattern that contained subroutine calls or assertions,  26. When studying a pattern that contained subroutine calls or assertions,
499      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
500      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
501      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
502      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
503      the recursion depth to 10.      the recursion depth to 10.
504    
505  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
506      Fortmann. This supports explicit test numbers on the command line, and has      Fortmann. This supports explicit test numbers on the command line, and has
507      argument validation and error reporting.      argument validation and error reporting.
508    
509  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
510      first character it looked at was a mark character.      first character it looked at was a mark character.
511    
512  28. Some minor code refactoring concerning Unicode properties and scripts  29. Some minor code refactoring concerning Unicode properties and scripts
513      should reduce the stack requirement of match() slightly.      should reduce the stack requirement of match() slightly.
514    
515  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
516      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
517      not included in the return count.      not included in the return count.
518    
519  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
520      compiled something random. Now it gives a compile-time error (as does      compiled something random. Now it gives a compile-time error (as does
521      Perl).      Perl).
522    
523  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
524      recorded and passed back (compatible with Perl).      recorded and passed back (compatible with Perl).
525    
526  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
527      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
528      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
529      matched the line "0102" twice. The same bug affected patterns that started      matched the line "0102" twice. The same bug affected patterns that started
530      with a backwards assertion. For example /\b01|\b02/ also matched "0102"      with a backwards assertion. For example /\b01|\b02/ also matched "0102"
531      twice.      twice.
532    
533  33. Previously, PCRE did not allow quantification of assertions. However, Perl  34. Previously, PCRE did not allow quantification of assertions. However, Perl
534      does, and because of capturing effects, quantifying parenthesized      does, and because of capturing effects, quantifying parenthesized
535      assertions may at times be useful. Quantifiers are now allowed for      assertions may at times be useful. Quantifiers are now allowed for
536      parenthesized assertions.      parenthesized assertions.
   
 34. A minor code tidy in pcre_compile() when checking options for \R usage.  
537    
538  35. \g was being checked for fancy things in a character class, when it should  35. A minor code tidy in pcre_compile() when checking options for \R usage.
539    
540    36. \g was being checked for fancy things in a character class, when it should
541      just be a literal "g".      just be a literal "g".
542    
543  36. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the  37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
544      appearance of a nested POSIX class supersedes an apparent external class.      appearance of a nested POSIX class supersedes an apparent external class.
545      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,      For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
546      unescaped square brackets may also appear as part of class names. For      unescaped square brackets may also appear as part of class names. For
547      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves      example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
548      more like Perl.      more like Perl. (But see 8.20/1 above.)
549    
550  37. PCRE was giving an error for \N with a braced quantifier such as {1,} (this  38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
551      was because it thought it was \N{name}, which is not supported).      was because it thought it was \N{name}, which is not supported).
   
 38. Add minix to OS list not supporting the -S option in pcretest.  
552    
553  39. PCRE tries to detect cases of infinite recursion at compile time, but it  39. Add minix to OS list not supporting the -S option in pcretest.
554    
555    40. PCRE tries to detect cases of infinite recursion at compile time, but it
556      cannot analyze patterns in sufficient detail to catch mutual recursions      cannot analyze patterns in sufficient detail to catch mutual recursions
557      such as ((?1))((?2)). There is now a runtime test that gives an error if a      such as ((?1))((?2)). There is now a runtime test that gives an error if a
558      subgroup is called recursively as a subpattern for a second time at the      subgroup is called recursively as a subpattern for a second time at the
559      same position in the subject string. In previous releases this might have      same position in the subject string. In previous releases this might have
560      been caught by the recursion limit, or it might have run out of stack.      been caught by the recursion limit, or it might have run out of stack.
561    
562  40. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can  41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
563      happen only once. PCRE was, however incorrectly giving a compile time error      happen only once. PCRE was, however incorrectly giving a compile time error
564      "recursive call could loop indefinitely" because it cannot analyze the      "recursive call could loop indefinitely" because it cannot analyze the
565      pattern in sufficient detail. The compile time test no longer happens when      pattern in sufficient detail. The compile time test no longer happens when
566      PCRE is compiling a conditional subpattern, but actual runaway loops are      PCRE is compiling a conditional subpattern, but actual runaway loops are
567      now caught at runtime (see 39 above).      now caught at runtime (see 40 above).
568    
569  41. It seems that Perl allows any characters other than a closing parenthesis  42. It seems that Perl allows any characters other than a closing parenthesis
570      to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE      to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
571      has been changed to be the same.      has been changed to be the same.
572    
573    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
574        as not to get warnings when autogen.sh is called. Also changed
575        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
576    
577    44. To help people who use pcregrep to scan files containing exceedingly long
578        lines, the following changes have been made:
579    
580        (a) The default value of the buffer size parameter has been increased from
581            8K to 20K. (The actual buffer used is three times this size.)
582    
583        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
584            PCRE is built.
585    
586        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
587            to be set at run time.
588    
589        (d) Numerical values in pcregrep options can be followed by K or M, for
590            example --buffer-size=50K.
591    
592        (e) If a line being scanned overflows pcregrep's buffer, an error is now
593            given and the return code is set to 2.
594    
595    45. Add a pointer to the latest mark to the callout data block.
596    
597    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
598        partial match of an empty string instead of no match. This was specific to
599        the use of ".".
600    
601    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
602        complete match instead of a partial match. This bug was dependent on both
603        the PCRE_UTF8 and PCRE_DOTALL options being set.
604    
605    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
606        starting byte set, because \b was not being ignored.
607    
608    
609  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

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