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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    19. Added binary file support to pcregrep, including the -a, --binary-files,
73        -I, and --text options.
74    
75    
76    Version 8.30 04-February-2012
77    -----------------------------
78    
79    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
80        name is defined in ctype.h.
81    
82    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
83        only in quite long subpatterns.
84    
85    3.  Removed the function pcre_info(), which has been obsolete and deprecated
86        since it was replaced by pcre_fullinfo() in February 2000.
87    
88    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
89        match a (*MARK), and the match failed at the start of the subject, a
90        reference to memory before the start of the subject could occur. This bug
91        was introduced by fix 17 of release 8.21.
92    
93    5.  A reference to an unset group with zero minimum repetition was giving
94        totally wrong answers (in non-JavaScript-compatibility mode). For example,
95        /(another)?(\1?)test/ matched against "hello world test". This bug was
96        introduced in release 8.13.
97    
98    6.  Add support for 16-bit character strings (a large amount of work involving
99        many changes and refactorings).
100    
101    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
102        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
103        from a file.
104    
105    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
106        rounding is not applied in this particular case).
107    
108    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
109        if they appear, or are escaped, in patterns.
110    
111    10. Get rid of a number of -Wunused-but-set-variable warnings.
112    
113    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
114        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
115        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
116        also returns the mark "x". This bug applied to capturing parentheses,
117        non-capturing parentheses, and atomic parentheses. It also applied to some
118        assertions.
119    
120    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
121        information out of configure.ac instead of relying on pcre.h.generic, which
122        is not stored in the repository.
123    
124    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
125        -lreadline.
126    
127    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
128    
129    15. Applied Graycode's patch to put the top-level frame on the stack rather
130        than the heap when not using the stack for recursion. This gives a
131        performance improvement in many cases when recursion is not deep.
132    
133    16. Experimental code added to "pcretest -C" to output the stack frame size.
134    
135    
136    Version 8.21 12-Dec-2011
137    ------------------------
138    
139    1.  Updating the JIT compiler.
140    
141    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
142        are added as well.
143    
144    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
145        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
146        calling _pcre_jit_exec. Some extra comments are added.
147    
148    4.  (*MARK) settings inside atomic groups that do not contain any capturing
149        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
150        was introduced by change 18 for 8.20.
151    
152    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
153        ECMA-262 standard.
154    
155    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
156        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
157        This bug was probably introduced by change 9 of 8.13.
158    
159    7.  While fixing 6 above, I noticed that a number of other items were being
160        incorrectly rejected as "not fixed length". This arose partly because newer
161        opcodes had not been added to the fixed-length checking code. I have (a)
162        corrected the bug and added tests for these items, and (b) arranged for an
163        error to occur if an unknown opcode is encountered while checking for fixed
164        length instead of just assuming "not fixed length". The items that were
165        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
166        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
167        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
168    
169    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
170        being incorrectly compiled and would have given unpredicatble results.
171    
172    9.  A possessively repeated subpattern with minimum repeat count greater than
173        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
174        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
175        the first (A) could occur when it should not.
176    
177    10. Add a cast and remove a redundant test from the code.
178    
179    11. JIT should use pcre_malloc/pcre_free for allocation.
180    
181    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
182        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
183        is anything other than /usr, -L is still shown).
184    
185    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
186    
187    14. Perl does not support \N without a following name in a [] class; PCRE now
188        also gives an error.
189    
190    15. If a forward reference was repeated with an upper limit of around 2000,
191        it caused the error "internal error: overran compiling workspace". The
192        maximum number of forward references (including repeats) was limited by the
193        internal workspace, and dependent on the LINK_SIZE. The code has been
194        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
195        the default depends on LINK_SIZE. There is a new upper limit (for safety)
196        of around 200,000 forward references. While doing this, I also speeded up
197        the filling in of repeated forward references.
198    
199    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
200        incorrectly expecting the subject to contain another "a" after the start.
201    
202    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
203        in the match, the SKIP should be ignored. This was not happening; instead
204        the SKIP was being treated as NOMATCH. For patterns such as
205        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
206        tested.
207    
208    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
209        now much more compatible with Perl, in particular in cases where the result
210        is a non-match for a non-anchored pattern. For example, if
211        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
212        "m", where previously it did not return a name. A side effect of this
213        change is that for partial matches, the last encountered mark name is
214        returned, as for non matches. A number of tests that were previously not
215        Perl-compatible have been moved into the Perl-compatible test files. The
216        refactoring has had the pleasing side effect of removing one argument from
217        the match() function, thus reducing its stack requirements.
218    
219    19. If the /S+ option was used in pcretest to study a pattern using JIT,
220        subsequent uses of /S (without +) incorrectly behaved like /S+.
221    
222    21. Retrieve executable code size support for the JIT compiler and fixing
223        some warnings.
224    
225    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
226        not work when the shorter character appeared right at the end of the
227        subject string.
228    
229    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
230        systems.
231    
232    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
233        output it when the /M option is used in pcretest.
234    
235    25. The CheckMan script was not being included in the distribution. Also, added
236        an explicit "perl" to run Perl scripts from the PrepareRelease script
237        because this is reportedly needed in Windows.
238    
239    26. If study data was being save in a file and studying had not found a set of
240        "starts with" bytes for the pattern, the data written to the file (though
241        never used) was taken from uninitialized memory and so caused valgrind to
242        complain.
243    
244    27. Updated RunTest.bat as provided by Sheri Pierce.
245    
246    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
247    
248    29. Computation of memory usage for the table of capturing group names was
249        giving an unnecessarily large value.
250    
251    
252    Version 8.20 21-Oct-2011
253    ------------------------
254    
255    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
256        a POSIX class. After further experiments with Perl, which convinced me that
257        Perl has bugs and confusions, a closing square bracket is no longer allowed
258        in a POSIX name. This bug also affected patterns with classes that started
259        with full stops.
260    
261    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
262        captured substring, but while checking the failing first alternative,
263        substring 1 is temporarily captured. If the output vector supplied to
264        pcre_exec() was not big enough for this capture, the yield of the function
265        was still zero ("insufficient space for captured substrings"). This cannot
266        be totally fixed without adding another stack variable, which seems a lot
267        of expense for a edge case. However, I have improved the situation in cases
268        such as /(a)(b)x|abc/ matched against "abc", where the return code
269        indicates that fewer than the maximum number of slots in the ovector have
270        been set.
271    
272    3.  Related to (2) above: when there are more back references in a pattern than
273        slots in the output vector, pcre_exec() uses temporary memory during
274        matching, and copies in the captures as far as possible afterwards. It was
275        using the entire output vector, but this conflicts with the specification
276        that only 2/3 is used for passing back captured substrings. Now it uses
277        only the first 2/3, for compatibility. This is, of course, another edge
278        case.
279    
280    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
281        main code base, and can be used by building with --enable-jit. When this is
282        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
283        runtime --no-jit option is given.
284    
285    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
286        ovector, the return from the function was zero, implying that there were
287        other matches that did not fit. The correct "exactly full" value is now
288        returned.
289    
290    6.  If a subpattern that was called recursively or as a subroutine contained
291        (*PRUNE) or any other control that caused it to give a non-standard return,
292        invalid errors such as "Error -26 (nested recursion at the same subject
293        position)" or even infinite loops could occur.
294    
295    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
296        computing the minimum length on reaching *ACCEPT, and so ended up with the
297        wrong value of 1 rather than 0. Further investigation indicates that
298        computing a minimum subject length in the presence of *ACCEPT is difficult
299        (think back references, subroutine calls), and so I have changed the code
300        so that no minimum is registered for a pattern that contains *ACCEPT.
301    
302    8.  If (*THEN) was present in the first (true) branch of a conditional group,
303        it was not handled as intended. [But see 16 below.]
304    
305    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
306        Sheri Pierce.
307    
308    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
309        the first byte in a match must be "a".
310    
311    11. Change 17 for 8.13 increased the recursion depth for patterns like
312        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
313        pattern contains any instances of (*THEN). If it does not, the old
314        optimizations are restored. It would be nice to do this on a per-group
315        basis, but at the moment that is not feasible.
316    
317    12. In some environments, the output of pcretest -C is CRLF terminated. This
318        broke RunTest's code that checks for the link size. A single white space
319        character after the value is now allowed for.
320    
321    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
322        For "fr", it uses the Windows-specific input and output files.
323    
324    14. If (*THEN) appeared in a group that was called recursively or as a
325        subroutine, it did not work as intended. [But see next item.]
326    
327    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
328        pattern fragments (but not containing any | characters). If A and B are
329        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
330        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
331        D. In other words, Perl considers parentheses that do not contain any |
332        characters to be part of a surrounding alternative, whereas PCRE was
333        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
334        differently. PCRE now behaves in the same way as Perl, except in the case
335        of subroutine/recursion calls such as (?1) which have in any case always
336        been different (but PCRE had them first :-).
337    
338    16. Related to 15 above: Perl does not treat the | in a conditional group as
339        creating alternatives. Such a group is treated in the same way as an
340        ordinary group without any | characters when processing (*THEN). PCRE has
341        been changed to match Perl's behaviour.
342    
343    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
344        RunGrepTest script failed.
345    
346    18. Change 22 for version 13 caused atomic groups to use more stack. This is
347        inevitable for groups that contain captures, but it can lead to a lot of
348        stack use in large patterns. The old behaviour has been restored for atomic
349        groups that do not contain any capturing parentheses.
350    
351    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
352        suppress the check for a minimum subject length at run time. (If it was
353        given to pcre_exec() or pcre_dfa_exec() it did work.)
354    
355    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
356        fail to work when decoding hex characters in data strings in EBCDIC
357        environments.
358    
359    21. It appears that in at least one Mac OS environment, the isxdigit() function
360        is implemented as a macro that evaluates to its argument more than once,
361        contravening the C 90 Standard (I haven't checked a later standard). There
362        was an instance in pcretest which caused it to go wrong when processing
363        \x{...} escapes in subject strings. The has been rewritten to avoid using
364        things like p++ in the argument of isxdigit().
365    
366    
367    Version 8.13 16-Aug-2011
368  ------------------------  ------------------------
369    
370  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 383  Version 8.13 30-Apr-2011
383      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
384      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
385      left).      left).
386    
387  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
388      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
389      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
390      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
391    
392  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
393      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
394      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
395      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
396      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
397    
398  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
399      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
400      failure, the offset and reason code are output.      failure, the offset and reason code are output.
401    
402  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
403      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
404      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
405      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
406      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
407      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
408      has been changed.      has been changed.
409    
410  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
411      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
412      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
413      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,
414      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
415      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
416      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
417      (?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.
418    
419  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
420      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
421      using pcre_exec().      using pcre_exec().
422    
423  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
424      discovered and fixed:      discovered and fixed:
425    
426      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
427      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
428      ((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.
429      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
430      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
431    
432  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
433      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
434      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
435    
436  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
437      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
438      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
439      pick them up.      pick them up.
440    
441  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
442      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
443      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
444      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
445      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
446      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
447      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
448      "never study" - see 20 below).      "never study" - see 20 below).
449    
450  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
451      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
452      correctly.      correctly.
453    
454  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
455      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
456      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
457      match.      match.
458    
459  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,
460      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
461      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
462      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
463      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
464      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
465    
466  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
467      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
468      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
469    
470  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
471      was incorrectly computed.      was incorrectly computed.
472    
473  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
474      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
475      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
476        identical in both cases.
477    
478  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
479      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.
480    
481  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
482      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
483      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
484      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
485      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-
486      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
487      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
488      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
489    
490  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
491      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
492      number of identical substrings has been captured).      number of identical substrings has been captured.
493    
494  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
495      if they are repeated, backtracking one repetition now resets captured      if they are repeated, backtracking one repetition now resets captured
496      values correctly. For example, if ((?>(a+)b)+aabab) is matched against      values correctly. For example, if ((?>(a+)b)+aabab) is matched against
497      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
498      "aaa". Previously, it would have been "a". As part of this code      "aaa". Previously, it would have been "a". As part of this code
499      refactoring, the way recursive calls are handled has also been changed.      refactoring, the way recursive calls are handled has also been changed.
500    
501  24. If an assertion condition captured any substrings, they were not passed  25. If an assertion condition captured any substrings, they were not passed
502      back unless some other capturing happened later. For example, if      back unless some other capturing happened later. For example, if
503      (?(?=(a))a) was matched against "a", no capturing was returned.      (?(?=(a))a) was matched against "a", no capturing was returned.
504    
505  25. When studying a pattern that contained subroutine calls or assertions,  26. When studying a pattern that contained subroutine calls or assertions,
506      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
507      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
508      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
509      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
510      the recursion depth to 10.      the recursion depth to 10.
511    
512  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
513      Fortmann. This supports explicit test numbers on the command line, and has      Fortmann. This supports explicit test numbers on the command line, and has
514      argument validation and error reporting.      argument validation and error reporting.
515    
516  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
517      first character it looked at was a mark character.      first character it looked at was a mark character.
518    
519  28. Some minor code refactoring concerning Unicode properties and scripts  29. Some minor code refactoring concerning Unicode properties and scripts
520      should reduce the stack requirement of match() slightly.      should reduce the stack requirement of match() slightly.
521    
522  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
523      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
524      not included in the return count.      not included in the return count.
525    
526  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
527      compiled something random. Now it gives a compile-time error (as does      compiled something random. Now it gives a compile-time error (as does
528      Perl).      Perl).
529    
530  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
531      recorded and passed back (compatible with Perl).      recorded and passed back (compatible with Perl).
532    
533    33. If --only-matching or --colour was set on a pcregrep call whose pattern
534        had alternative anchored branches, the search for a second match in a line
535        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
536        matched the line "0102" twice. The same bug affected patterns that started
537        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
538        twice.
539    
540    34. Previously, PCRE did not allow quantification of assertions. However, Perl
541        does, and because of capturing effects, quantifying parenthesized
542        assertions may at times be useful. Quantifiers are now allowed for
543        parenthesized assertions.
544    
545    35. A minor code tidy in pcre_compile() when checking options for \R usage.
546    
547    36. \g was being checked for fancy things in a character class, when it should
548        just be a literal "g".
549    
550    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
551        appearance of a nested POSIX class supersedes an apparent external class.
552        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
553        unescaped square brackets may also appear as part of class names. For
554        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
555        more like Perl. (But see 8.20/1 above.)
556    
557    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
558        was because it thought it was \N{name}, which is not supported).
559    
560    39. Add minix to OS list not supporting the -S option in pcretest.
561    
562    40. PCRE tries to detect cases of infinite recursion at compile time, but it
563        cannot analyze patterns in sufficient detail to catch mutual recursions
564        such as ((?1))((?2)). There is now a runtime test that gives an error if a
565        subgroup is called recursively as a subpattern for a second time at the
566        same position in the subject string. In previous releases this might have
567        been caught by the recursion limit, or it might have run out of stack.
568    
569    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
570        happen only once. PCRE was, however incorrectly giving a compile time error
571        "recursive call could loop indefinitely" because it cannot analyze the
572        pattern in sufficient detail. The compile time test no longer happens when
573        PCRE is compiling a conditional subpattern, but actual runaway loops are
574        now caught at runtime (see 40 above).
575    
576    42. It seems that Perl allows any characters other than a closing parenthesis
577        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
578        has been changed to be the same.
579    
580    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
581        as not to get warnings when autogen.sh is called. Also changed
582        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
583    
584    44. To help people who use pcregrep to scan files containing exceedingly long
585        lines, the following changes have been made:
586    
587        (a) The default value of the buffer size parameter has been increased from
588            8K to 20K. (The actual buffer used is three times this size.)
589    
590        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
591            PCRE is built.
592    
593        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
594            to be set at run time.
595    
596        (d) Numerical values in pcregrep options can be followed by K or M, for
597            example --buffer-size=50K.
598    
599        (e) If a line being scanned overflows pcregrep's buffer, an error is now
600            given and the return code is set to 2.
601    
602    45. Add a pointer to the latest mark to the callout data block.
603    
604    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
605        partial match of an empty string instead of no match. This was specific to
606        the use of ".".
607    
608    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
609        complete match instead of a partial match. This bug was dependent on both
610        the PCRE_UTF8 and PCRE_DOTALL options being set.
611    
612    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
613        starting byte set, because \b was not being ignored.
614    
615    
616  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

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