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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.10 03-Jun-2010  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    20. The madvise function is renamed for posix_madvise for QNX compatibility
76        reasons. Fixed by Giuseppe D'Angelo.
77    
78    21. Fixed a bug for backward assertions with REVERSE 0 in the JIT compiler.
79    
80    22. Changed the option for creating symbolic links for 16-bit man pages from
81        -s to -sf so that re-installing does not cause issues.
82    
83    23. Support PCRE_NO_START_OPTIMIZE in JIT as (*MARK) support requires it.
84    
85    24. Fixed a very old bug in pcretest that caused errors with restarted DFA
86        matches in certain environments (the workspace was not being correctly
87        retained). Also added to pcre_dfa_exec() a simple plausibility check on
88        some of the workspace data at the beginning of a restart.
89    
90    25. \s*\R was auto-possessifying the \s* when it should not, whereas \S*\R
91        was not doing so when it should - probably a typo introduced by SVN 528
92        (change 8.10/14).
93    
94    26. When PCRE_UCP was not set, \w+\x{c4} was incorrectly auto-possessifying the
95        \w+ when the character tables indicated that \x{c4} was a word character.
96        There were several related cases, all because the tests for doing a table
97        lookup were testing for characters less than 127 instead of 255.
98    
99    27. If a pattern contains capturing parentheses that are not used in a match,
100        their slots in the ovector are set to -1. For those that are higher than
101        any matched groups, this happens at the end of processing. In the case when
102        there were back references that the ovector was too small to contain
103        (causing temporary malloc'd memory to be used during matching), and the
104        highest capturing number was not used, memory off the end of the ovector
105        was incorrectly being set to -1. (It was using the size of the temporary
106        memory instead of the true size.)
107    
108    28. To catch bugs like 27 using valgrind, when pcretest is asked to specify an
109        ovector size, it uses memory at the end of the block that it has got.
110    
111    29. Check for an overlong MARK name and give an error at compile time. The
112        limit is 255 for the 8-bit library and 65535 for the 16-bit library.
113    
114    30. JIT compiler update.
115    
116    31. JIT is now supported on jailbroken iOS devices. Thanks for Ruiger
117        Rill for the patch.
118    
119    
120    Version 8.30 04-February-2012
121    -----------------------------
122    
123    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
124        name is defined in ctype.h.
125    
126    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
127        only in quite long subpatterns.
128    
129    3.  Removed the function pcre_info(), which has been obsolete and deprecated
130        since it was replaced by pcre_fullinfo() in February 2000.
131    
132    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
133        match a (*MARK), and the match failed at the start of the subject, a
134        reference to memory before the start of the subject could occur. This bug
135        was introduced by fix 17 of release 8.21.
136    
137    5.  A reference to an unset group with zero minimum repetition was giving
138        totally wrong answers (in non-JavaScript-compatibility mode). For example,
139        /(another)?(\1?)test/ matched against "hello world test". This bug was
140        introduced in release 8.13.
141    
142    6.  Add support for 16-bit character strings (a large amount of work involving
143        many changes and refactorings).
144    
145    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
146        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
147        from a file.
148    
149    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
150        rounding is not applied in this particular case).
151    
152    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
153        if they appear, or are escaped, in patterns.
154    
155    10. Get rid of a number of -Wunused-but-set-variable warnings.
156    
157    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
158        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
159        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
160        also returns the mark "x". This bug applied to capturing parentheses,
161        non-capturing parentheses, and atomic parentheses. It also applied to some
162        assertions.
163    
164    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
165        information out of configure.ac instead of relying on pcre.h.generic, which
166        is not stored in the repository.
167    
168    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
169        -lreadline.
170    
171    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
172    
173    15. Applied Graycode's patch to put the top-level frame on the stack rather
174        than the heap when not using the stack for recursion. This gives a
175        performance improvement in many cases when recursion is not deep.
176    
177    16. Experimental code added to "pcretest -C" to output the stack frame size.
178    
179    
180    Version 8.21 12-Dec-2011
181    ------------------------
182    
183    1.  Updating the JIT compiler.
184    
185    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
186        are added as well.
187    
188    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
189        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
190        calling _pcre_jit_exec. Some extra comments are added.
191    
192    4.  (*MARK) settings inside atomic groups that do not contain any capturing
193        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
194        was introduced by change 18 for 8.20.
195    
196    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
197        ECMA-262 standard.
198    
199    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
200        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
201        This bug was probably introduced by change 9 of 8.13.
202    
203    7.  While fixing 6 above, I noticed that a number of other items were being
204        incorrectly rejected as "not fixed length". This arose partly because newer
205        opcodes had not been added to the fixed-length checking code. I have (a)
206        corrected the bug and added tests for these items, and (b) arranged for an
207        error to occur if an unknown opcode is encountered while checking for fixed
208        length instead of just assuming "not fixed length". The items that were
209        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
210        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
211        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
212    
213    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
214        being incorrectly compiled and would have given unpredicatble results.
215    
216    9.  A possessively repeated subpattern with minimum repeat count greater than
217        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
218        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
219        the first (A) could occur when it should not.
220    
221    10. Add a cast and remove a redundant test from the code.
222    
223    11. JIT should use pcre_malloc/pcre_free for allocation.
224    
225    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
226        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
227        is anything other than /usr, -L is still shown).
228    
229    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
230    
231    14. Perl does not support \N without a following name in a [] class; PCRE now
232        also gives an error.
233    
234    15. If a forward reference was repeated with an upper limit of around 2000,
235        it caused the error "internal error: overran compiling workspace". The
236        maximum number of forward references (including repeats) was limited by the
237        internal workspace, and dependent on the LINK_SIZE. The code has been
238        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
239        the default depends on LINK_SIZE. There is a new upper limit (for safety)
240        of around 200,000 forward references. While doing this, I also speeded up
241        the filling in of repeated forward references.
242    
243    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
244        incorrectly expecting the subject to contain another "a" after the start.
245    
246    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
247        in the match, the SKIP should be ignored. This was not happening; instead
248        the SKIP was being treated as NOMATCH. For patterns such as
249        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
250        tested.
251    
252    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
253        now much more compatible with Perl, in particular in cases where the result
254        is a non-match for a non-anchored pattern. For example, if
255        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
256        "m", where previously it did not return a name. A side effect of this
257        change is that for partial matches, the last encountered mark name is
258        returned, as for non matches. A number of tests that were previously not
259        Perl-compatible have been moved into the Perl-compatible test files. The
260        refactoring has had the pleasing side effect of removing one argument from
261        the match() function, thus reducing its stack requirements.
262    
263    19. If the /S+ option was used in pcretest to study a pattern using JIT,
264        subsequent uses of /S (without +) incorrectly behaved like /S+.
265    
266    21. Retrieve executable code size support for the JIT compiler and fixing
267        some warnings.
268    
269    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
270        not work when the shorter character appeared right at the end of the
271        subject string.
272    
273    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
274        systems.
275    
276    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
277        output it when the /M option is used in pcretest.
278    
279    25. The CheckMan script was not being included in the distribution. Also, added
280        an explicit "perl" to run Perl scripts from the PrepareRelease script
281        because this is reportedly needed in Windows.
282    
283    26. If study data was being save in a file and studying had not found a set of
284        "starts with" bytes for the pattern, the data written to the file (though
285        never used) was taken from uninitialized memory and so caused valgrind to
286        complain.
287    
288    27. Updated RunTest.bat as provided by Sheri Pierce.
289    
290    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
291    
292    29. Computation of memory usage for the table of capturing group names was
293        giving an unnecessarily large value.
294    
295    
296    Version 8.20 21-Oct-2011
297    ------------------------
298    
299    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
300        a POSIX class. After further experiments with Perl, which convinced me that
301        Perl has bugs and confusions, a closing square bracket is no longer allowed
302        in a POSIX name. This bug also affected patterns with classes that started
303        with full stops.
304    
305    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
306        captured substring, but while checking the failing first alternative,
307        substring 1 is temporarily captured. If the output vector supplied to
308        pcre_exec() was not big enough for this capture, the yield of the function
309        was still zero ("insufficient space for captured substrings"). This cannot
310        be totally fixed without adding another stack variable, which seems a lot
311        of expense for a edge case. However, I have improved the situation in cases
312        such as /(a)(b)x|abc/ matched against "abc", where the return code
313        indicates that fewer than the maximum number of slots in the ovector have
314        been set.
315    
316    3.  Related to (2) above: when there are more back references in a pattern than
317        slots in the output vector, pcre_exec() uses temporary memory during
318        matching, and copies in the captures as far as possible afterwards. It was
319        using the entire output vector, but this conflicts with the specification
320        that only 2/3 is used for passing back captured substrings. Now it uses
321        only the first 2/3, for compatibility. This is, of course, another edge
322        case.
323    
324    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
325        main code base, and can be used by building with --enable-jit. When this is
326        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
327        runtime --no-jit option is given.
328    
329    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
330        ovector, the return from the function was zero, implying that there were
331        other matches that did not fit. The correct "exactly full" value is now
332        returned.
333    
334    6.  If a subpattern that was called recursively or as a subroutine contained
335        (*PRUNE) or any other control that caused it to give a non-standard return,
336        invalid errors such as "Error -26 (nested recursion at the same subject
337        position)" or even infinite loops could occur.
338    
339    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
340        computing the minimum length on reaching *ACCEPT, and so ended up with the
341        wrong value of 1 rather than 0. Further investigation indicates that
342        computing a minimum subject length in the presence of *ACCEPT is difficult
343        (think back references, subroutine calls), and so I have changed the code
344        so that no minimum is registered for a pattern that contains *ACCEPT.
345    
346    8.  If (*THEN) was present in the first (true) branch of a conditional group,
347        it was not handled as intended. [But see 16 below.]
348    
349    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
350        Sheri Pierce.
351    
352    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
353        the first byte in a match must be "a".
354    
355    11. Change 17 for 8.13 increased the recursion depth for patterns like
356        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
357        pattern contains any instances of (*THEN). If it does not, the old
358        optimizations are restored. It would be nice to do this on a per-group
359        basis, but at the moment that is not feasible.
360    
361    12. In some environments, the output of pcretest -C is CRLF terminated. This
362        broke RunTest's code that checks for the link size. A single white space
363        character after the value is now allowed for.
364    
365    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
366        For "fr", it uses the Windows-specific input and output files.
367    
368    14. If (*THEN) appeared in a group that was called recursively or as a
369        subroutine, it did not work as intended. [But see next item.]
370    
371    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
372        pattern fragments (but not containing any | characters). If A and B are
373        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
374        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
375        D. In other words, Perl considers parentheses that do not contain any |
376        characters to be part of a surrounding alternative, whereas PCRE was
377        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
378        differently. PCRE now behaves in the same way as Perl, except in the case
379        of subroutine/recursion calls such as (?1) which have in any case always
380        been different (but PCRE had them first :-).
381    
382    16. Related to 15 above: Perl does not treat the | in a conditional group as
383        creating alternatives. Such a group is treated in the same way as an
384        ordinary group without any | characters when processing (*THEN). PCRE has
385        been changed to match Perl's behaviour.
386    
387    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
388        RunGrepTest script failed.
389    
390    18. Change 22 for version 13 caused atomic groups to use more stack. This is
391        inevitable for groups that contain captures, but it can lead to a lot of
392        stack use in large patterns. The old behaviour has been restored for atomic
393        groups that do not contain any capturing parentheses.
394    
395    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
396        suppress the check for a minimum subject length at run time. (If it was
397        given to pcre_exec() or pcre_dfa_exec() it did work.)
398    
399    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
400        fail to work when decoding hex characters in data strings in EBCDIC
401        environments.
402    
403    21. It appears that in at least one Mac OS environment, the isxdigit() function
404        is implemented as a macro that evaluates to its argument more than once,
405        contravening the C 90 Standard (I haven't checked a later standard). There
406        was an instance in pcretest which caused it to go wrong when processing
407        \x{...} escapes in subject strings. The has been rewritten to avoid using
408        things like p++ in the argument of isxdigit().
409    
410    
411    Version 8.13 16-Aug-2011
412    ------------------------
413    
414    1.  The Unicode data tables have been updated to Unicode 6.0.0.
415    
416    2.  Two minor typos in pcre_internal.h have been fixed.
417    
418    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
419        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
420        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
421    
422    4.  There were a number of related bugs in the code for matching backrefences
423        caselessly in UTF-8 mode when codes for the characters concerned were
424        different numbers of bytes. For example, U+023A and U+2C65 are an upper
425        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
426        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
427        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
428        2-byte code at the end of the subject (it thought there wasn't enough data
429        left).
430    
431    5.  Comprehensive information about what went wrong is now returned by
432        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
433        as the output vector has at least 2 elements. The offset of the start of
434        the failing character and a reason code are placed in the vector.
435    
436    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
437        now returned is for the first byte of the failing character, instead of the
438        last byte inspected. This is an incompatible change, but I hope it is small
439        enough not to be a problem. It makes the returned offset consistent with
440        pcre_exec() and pcre_dfa_exec().
441    
442    7.  pcretest now gives a text phrase as well as the error number when
443        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
444        failure, the offset and reason code are output.
445    
446    8.  When \R was used with a maximizing quantifier it failed to skip backwards
447        over a \r\n pair if the subsequent match failed. Instead, it just skipped
448        back over a single character (\n). This seems wrong (because it treated the
449        two characters as a single entity when going forwards), conflicts with the
450        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
451        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
452        has been changed.
453    
454    9.  Some internal refactoring has changed the processing so that the handling
455        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
456        time (the PCRE_DOTALL option was changed this way some time ago: version
457        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
458        which was always a bit of a fudge. It also means that there is one less
459        argument for the match() function, which reduces its stack requirements
460        slightly. This change also fixes an incompatibility with Perl: the pattern
461        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
462    
463    10. More internal refactoring has drastically reduced the number of recursive
464        calls to match() for possessively repeated groups such as (abc)++ when
465        using pcre_exec().
466    
467    11. While implementing 10, a number of bugs in the handling of groups were
468        discovered and fixed:
469    
470        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
471        (a|)*(?1) gave a compile-time internal error.
472        ((a|)+)+  did not notice that the outer group could match an empty string.
473        (^a|^)+   was not marked as anchored.
474        (.*a|.*)+ was not marked as matching at start or after a newline.
475    
476    12. Yet more internal refactoring has removed another argument from the match()
477        function. Special calls to this function are now indicated by setting a
478        value in a variable in the "match data" data block.
479    
480    13. Be more explicit in pcre_study() instead of relying on "default" for
481        opcodes that mean there is no starting character; this means that when new
482        ones are added and accidentally left out of pcre_study(), testing should
483        pick them up.
484    
485    14. The -s option of pcretest has been documented for ages as being an old
486        synonym of -m (show memory usage). I have changed it to mean "force study
487        for every regex", that is, assume /S for every regex. This is similar to -i
488        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
489        using it. It makes it easier to run collections of tests with and without
490        study enabled, and thereby test pcre_study() more easily. All the standard
491        tests are now run with and without -s (but some patterns can be marked as
492        "never study" - see 20 below).
493    
494    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
495        restoration of the capturing data to the outer values was not happening
496        correctly.
497    
498    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
499        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
500        pattern had matched an empty string, and so incorrectly returned a no
501        match.
502    
503    17. There was optimizing code for the last branch of non-capturing parentheses,
504        and also for the obeyed branch of a conditional subexpression, which used
505        tail recursion to cut down on stack usage. Unfortunately, now that there is
506        the possibility of (*THEN) occurring in these branches, tail recursion is
507        no longer possible because the return has to be checked for (*THEN). These
508        two optimizations have therefore been removed. [But see 8.20/11 above.]
509    
510    18. If a pattern containing \R was studied, it was assumed that \R always
511        matched two bytes, thus causing the minimum subject length to be
512        incorrectly computed because \R can also match just one byte.
513    
514    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
515        was incorrectly computed.
516    
517    20. If /S is present twice on a test pattern in pcretest input, it now
518        *disables* studying, thereby overriding the use of -s on the command line
519        (see 14 above). This is necessary for one or two tests to keep the output
520        identical in both cases.
521    
522    21. When (*ACCEPT) was used in an assertion that matched an empty string and
523        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
524    
525    22. When an atomic group that contained a capturing parenthesis was
526        successfully matched, but the branch in which it appeared failed, the
527        capturing was not being forgotten if a higher numbered group was later
528        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
529        group 1 to "a", when in fact it should be unset. This applied to multi-
530        branched capturing and non-capturing groups, repeated or not, and also to
531        positive assertions (capturing in negative assertions does not happen
532        in PCRE) and also to nested atomic groups.
533    
534    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
535        subject after a captured substring, to make it easier to tell which of a
536        number of identical substrings has been captured.
537    
538    24. The way atomic groups are processed by pcre_exec() has been changed so that
539        if they are repeated, backtracking one repetition now resets captured
540        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
541        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
542        "aaa". Previously, it would have been "a". As part of this code
543        refactoring, the way recursive calls are handled has also been changed.
544    
545    25. If an assertion condition captured any substrings, they were not passed
546        back unless some other capturing happened later. For example, if
547        (?(?=(a))a) was matched against "a", no capturing was returned.
548    
549    26. When studying a pattern that contained subroutine calls or assertions,
550        the code for finding the minimum length of a possible match was handling
551        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
552        group 1 called group 2 while simultaneously a separate group 2 called group
553        1). A stack overflow occurred in this case. I have fixed this by limiting
554        the recursion depth to 10.
555    
556    27. Updated RunTest.bat in the distribution to the version supplied by Tom
557        Fortmann. This supports explicit test numbers on the command line, and has
558        argument validation and error reporting.
559    
560    28. An instance of \X with an unlimited repeat could fail if at any point the
561        first character it looked at was a mark character.
562    
563    29. Some minor code refactoring concerning Unicode properties and scripts
564        should reduce the stack requirement of match() slightly.
565    
566    30. Added the '=' option to pcretest to check the setting of unused capturing
567        slots at the end of the pattern, which are documented as being -1, but are
568        not included in the return count.
569    
570    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
571        compiled something random. Now it gives a compile-time error (as does
572        Perl).
573    
574    32. A *MARK encountered during the processing of a positive assertion is now
575        recorded and passed back (compatible with Perl).
576    
577    33. If --only-matching or --colour was set on a pcregrep call whose pattern
578        had alternative anchored branches, the search for a second match in a line
579        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
580        matched the line "0102" twice. The same bug affected patterns that started
581        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
582        twice.
583    
584    34. Previously, PCRE did not allow quantification of assertions. However, Perl
585        does, and because of capturing effects, quantifying parenthesized
586        assertions may at times be useful. Quantifiers are now allowed for
587        parenthesized assertions.
588    
589    35. A minor code tidy in pcre_compile() when checking options for \R usage.
590    
591    36. \g was being checked for fancy things in a character class, when it should
592        just be a literal "g".
593    
594    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
595        appearance of a nested POSIX class supersedes an apparent external class.
596        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
597        unescaped square brackets may also appear as part of class names. For
598        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
599        more like Perl. (But see 8.20/1 above.)
600    
601    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
602        was because it thought it was \N{name}, which is not supported).
603    
604    39. Add minix to OS list not supporting the -S option in pcretest.
605    
606    40. PCRE tries to detect cases of infinite recursion at compile time, but it
607        cannot analyze patterns in sufficient detail to catch mutual recursions
608        such as ((?1))((?2)). There is now a runtime test that gives an error if a
609        subgroup is called recursively as a subpattern for a second time at the
610        same position in the subject string. In previous releases this might have
611        been caught by the recursion limit, or it might have run out of stack.
612    
613    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
614        happen only once. PCRE was, however incorrectly giving a compile time error
615        "recursive call could loop indefinitely" because it cannot analyze the
616        pattern in sufficient detail. The compile time test no longer happens when
617        PCRE is compiling a conditional subpattern, but actual runaway loops are
618        now caught at runtime (see 40 above).
619    
620    42. It seems that Perl allows any characters other than a closing parenthesis
621        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
622        has been changed to be the same.
623    
624    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
625        as not to get warnings when autogen.sh is called. Also changed
626        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
627    
628    44. To help people who use pcregrep to scan files containing exceedingly long
629        lines, the following changes have been made:
630    
631        (a) The default value of the buffer size parameter has been increased from
632            8K to 20K. (The actual buffer used is three times this size.)
633    
634        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
635            PCRE is built.
636    
637        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
638            to be set at run time.
639    
640        (d) Numerical values in pcregrep options can be followed by K or M, for
641            example --buffer-size=50K.
642    
643        (e) If a line being scanned overflows pcregrep's buffer, an error is now
644            given and the return code is set to 2.
645    
646    45. Add a pointer to the latest mark to the callout data block.
647    
648    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
649        partial match of an empty string instead of no match. This was specific to
650        the use of ".".
651    
652    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
653        complete match instead of a partial match. This bug was dependent on both
654        the PCRE_UTF8 and PCRE_DOTALL options being set.
655    
656    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
657        starting byte set, because \b was not being ignored.
658    
659    
660    Version 8.12 15-Jan-2011
661    ------------------------
662    
663    1.  Fixed some typos in the markup of the man pages, and wrote a script that
664        checks for such things as part of the documentation building process.
665    
666    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
667        --match-limit and --recursion-limit options (added for 8.11). In
668        particular, this made one of the standard tests fail. (The integer value
669        went into the wrong half of a long int.)
670    
671    3.  If the --colour option was given to pcregrep with -v (invert match), it
672        did strange things, either producing crazy output, or crashing. It should,
673        of course, ignore a request for colour when reporting lines that do not
674        match.
675    
676    4.  Another pcregrep bug caused similar problems if --colour was specified with
677        -M (multiline) and the pattern match finished with a line ending.
678    
679    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
680        matched in multiline mode, the following line was shown as part of the
681        match. This seems wrong, so I have changed it.
682    
683    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
684        the check for further matches in the same line (so they could be coloured)
685        to overrun the end of the current line. If another match was found, it was
686        incorrectly shown (and then shown again when found in the next line).
687    
688    7.  If pcregrep was compiled under Windows, there was a reference to the
689        function pcregrep_exit() before it was defined. I am assuming this was
690        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
691        reported by a user. I've moved the definition above the reference.
692    
693    
694    Version 8.11 10-Dec-2010
695    ------------------------
696    
697    1.  (*THEN) was not working properly if there were untried alternatives prior
698        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
699        backtracked to try for "b" instead of moving to the next alternative branch
700        at the same level (in this case, to look for "c"). The Perl documentation
701        is clear that when (*THEN) is backtracked onto, it goes to the "next
702        alternative in the innermost enclosing group".
703    
704    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
705        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
706        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
707        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
708        (*THEN).
709    
710    3.  If \s appeared in a character class, it removed the VT character from
711        the class, even if it had been included by some previous item, for example
712        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
713        of \s, but is part of the POSIX "space" class.)
714    
715    4.  A partial match never returns an empty string (because you can always
716        match an empty string at the end of the subject); however the checking for
717        an empty string was starting at the "start of match" point. This has been
718        changed to the "earliest inspected character" point, because the returned
719        data for a partial match starts at this character. This means that, for
720        example, /(?<=abc)def/ gives a partial match for the subject "abc"
721        (previously it gave "no match").
722    
723    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
724        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
725        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
726        has an implication that the given string is incomplete (because a partial
727        match is preferred over a full match). For this reason, these items now
728        give a partial match in this situation. [Aside: previously, the one case
729        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
730        match rather than a full match, which was wrong by the old rules, but is
731        now correct.]
732    
733    6.  There was a bug in the handling of #-introduced comments, recognized when
734        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
735        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
736        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
737        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
738        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
739        places in pcre_compile().
740    
741    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
742        comments when looking ahead for named forward references to subpatterns,
743        the only newline sequence it recognized was NL. It now handles newlines
744        according to the set newline convention.
745    
746    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
747        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
748        cater for a lack of strerror(). These oversights have been fixed.
749    
750    9.  Added --match-limit and --recursion-limit to pcregrep.
751    
752    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
753    
754    11. When the -o option was used, pcregrep was setting a return code of 1, even
755        when matches were found, and --line-buffered was not being honoured.
756    
757    12. Added an optional parentheses number to the -o and --only-matching options
758        of pcregrep.
759    
760    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
761        can match an empty string. The code to do it in pcretest and pcredemo
762        needed fixing:
763    
764        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
765            only one byte after an empty string match just before CRLF (this case
766            just got forgotten; "any" and "anycrlf" were OK).
767    
768        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
769            mode when an empty string match preceded an ASCII character followed by
770            a non-ASCII character. (The code for advancing by one character rather
771            than one byte was nonsense.)
772    
773        (c) The pcredemo.c sample program did not have any code at all to handle
774            the cases when CRLF is a valid newline sequence.
775    
776    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
777        as a starting offset was within the subject string. There is now a new
778        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
779        negative or greater than the length of the string. In order to test this,
780        pcretest is extended to allow the setting of negative starting offsets.
781    
782    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
783        starting offset points to the beginning of a UTF-8 character was
784        unnecessarily clumsy. I tidied it up.
785    
786    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
787        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
788    
789    17. Nobody had reported that the --include_dir option, which was added in
790        release 7.7 should have been called --include-dir (hyphen, not underscore)
791        for compatibility with GNU grep. I have changed it to --include-dir, but
792        left --include_dir as an undocumented synonym, and the same for
793        --exclude-dir, though that is not available in GNU grep, at least as of
794        release 2.5.4.
795    
796    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
797        characters from a string of bytes) have been redefined so as not to use
798        loops, in order to improve performance in some environments. At the same
799        time, I abstracted some of the common code into auxiliary macros to save
800        repetition (this should not affect the compiled code).
801    
802    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
803        compile-time error is now given if \c is not followed by an ASCII
804        character, that is, a byte less than 128. (In EBCDIC mode, the code is
805        different, and any byte value is allowed.)
806    
807    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
808        START_OPTIMIZE option, which is now allowed at compile time - but just
809        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
810        to pcregrep and other applications that have no direct access to PCRE
811        options. The new /Y option in pcretest sets this option when calling
812        pcre_compile().
813    
814    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
815        back references. Groups containing recursive back references were forced to
816        be atomic by that change, but in the case of named groups, the amount of
817        memory required was incorrectly computed, leading to "Failed: internal
818        error: code overflow". This has been fixed.
819    
820    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
821        pcretest.c, to avoid build problems in some Borland environments.
822    
823    
824    Version 8.10 25-Jun-2010
825  ------------------------  ------------------------
826    
827  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
# Line 42  Version 8.10 03-Jun-2010 Line 862  Version 8.10 03-Jun-2010
862  11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was  11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
863      studied, and the match started with a letter with a code point greater than      studied, and the match started with a letter with a code point greater than
864      127 whose first byte was different to the first byte of the other case of      127 whose first byte was different to the first byte of the other case of
865      the letter, the other case of this starting letter was not recognized      the letter, the other case of this starting letter was not recognized
866      (#976).      (#976).
867    
868  12. If a pattern that was studied started with a repeated Unicode property  12. If a pattern that was studied started with a repeated Unicode property
# Line 68  Version 8.10 03-Jun-2010 Line 888  Version 8.10 03-Jun-2010
888    
889  17. Added a check for running out of memory when PCRE is compiled with  17. Added a check for running out of memory when PCRE is compiled with
890      --disable-stack-for-recursion (#990).      --disable-stack-for-recursion (#990).
891    
892  18. If the last data line in a file for pcretest does not have a newline on  18. If the last data line in a file for pcretest does not have a newline on
893      the end, a newline was missing in the output.      the end, a newline was missing in the output.
894    
895    19. The default pcre_chartables.c file recognizes only ASCII characters (values
896        less than 128) in its various bitmaps. However, there is a facility for
897        generating tables according to the current locale when PCRE is compiled. It
898        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
899        characters, are recognized by isspace() and therefore were getting set in
900        these tables, and indeed these tables seem to approximate to ISO 8859. This
901        caused a problem in UTF-8 mode when pcre_study() was used to create a list
902        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
903        which of course cannot start UTF-8 characters. I have changed the code so
904        that only real ASCII characters (less than 128) and the correct starting
905        bytes for UTF-8 encodings are set for characters greater than 127 when in
906        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
907        altogether.)
908    
909    20. Added the /T option to pcretest so as to be able to run tests with non-
910        standard character tables, thus making it possible to include the tests
911        used for 19 above in the standard set of tests.
912    
913    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
914        reference to a subpattern the other side of a comment that contains an
915        opening parenthesis caused either an internal compiling error, or a
916        reference to the wrong subpattern.
917    
918    
919  Version 8.02 19-Mar-2010  Version 8.02 19-Mar-2010

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