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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    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    32. Put spaces around SLJIT_PRINT_D in the JIT compiler. Required by CXX11.
120    
121    33. Variable renamings in the PCRE-JIT compiler. No functionality change.
122    
123    
124    Version 8.30 04-February-2012
125    -----------------------------
126    
127    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
128        name is defined in ctype.h.
129    
130    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
131        only in quite long subpatterns.
132    
133    3.  Removed the function pcre_info(), which has been obsolete and deprecated
134        since it was replaced by pcre_fullinfo() in February 2000.
135    
136    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
137        match a (*MARK), and the match failed at the start of the subject, a
138        reference to memory before the start of the subject could occur. This bug
139        was introduced by fix 17 of release 8.21.
140    
141    5.  A reference to an unset group with zero minimum repetition was giving
142        totally wrong answers (in non-JavaScript-compatibility mode). For example,
143        /(another)?(\1?)test/ matched against "hello world test". This bug was
144        introduced in release 8.13.
145    
146    6.  Add support for 16-bit character strings (a large amount of work involving
147        many changes and refactorings).
148    
149    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
150        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
151        from a file.
152    
153    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
154        rounding is not applied in this particular case).
155    
156    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
157        if they appear, or are escaped, in patterns.
158    
159    10. Get rid of a number of -Wunused-but-set-variable warnings.
160    
161    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
162        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
163        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
164        also returns the mark "x". This bug applied to capturing parentheses,
165        non-capturing parentheses, and atomic parentheses. It also applied to some
166        assertions.
167    
168    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
169        information out of configure.ac instead of relying on pcre.h.generic, which
170        is not stored in the repository.
171    
172    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
173        -lreadline.
174    
175    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
176    
177    15. Applied Graycode's patch to put the top-level frame on the stack rather
178        than the heap when not using the stack for recursion. This gives a
179        performance improvement in many cases when recursion is not deep.
180    
181    16. Experimental code added to "pcretest -C" to output the stack frame size.
182    
183    
184    Version 8.21 12-Dec-2011
185    ------------------------
186    
187    1.  Updating the JIT compiler.
188    
189    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
190        are added as well.
191    
192    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
193        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
194        calling _pcre_jit_exec. Some extra comments are added.
195    
196    4.  (*MARK) settings inside atomic groups that do not contain any capturing
197        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
198        was introduced by change 18 for 8.20.
199    
200    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
201        ECMA-262 standard.
202    
203    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
204        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
205        This bug was probably introduced by change 9 of 8.13.
206    
207    7.  While fixing 6 above, I noticed that a number of other items were being
208        incorrectly rejected as "not fixed length". This arose partly because newer
209        opcodes had not been added to the fixed-length checking code. I have (a)
210        corrected the bug and added tests for these items, and (b) arranged for an
211        error to occur if an unknown opcode is encountered while checking for fixed
212        length instead of just assuming "not fixed length". The items that were
213        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
214        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
215        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
216    
217    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
218        being incorrectly compiled and would have given unpredicatble results.
219    
220    9.  A possessively repeated subpattern with minimum repeat count greater than
221        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
222        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
223        the first (A) could occur when it should not.
224    
225    10. Add a cast and remove a redundant test from the code.
226    
227    11. JIT should use pcre_malloc/pcre_free for allocation.
228    
229    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
230        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
231        is anything other than /usr, -L is still shown).
232    
233    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
234    
235    14. Perl does not support \N without a following name in a [] class; PCRE now
236        also gives an error.
237    
238    15. If a forward reference was repeated with an upper limit of around 2000,
239        it caused the error "internal error: overran compiling workspace". The
240        maximum number of forward references (including repeats) was limited by the
241        internal workspace, and dependent on the LINK_SIZE. The code has been
242        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
243        the default depends on LINK_SIZE. There is a new upper limit (for safety)
244        of around 200,000 forward references. While doing this, I also speeded up
245        the filling in of repeated forward references.
246    
247    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
248        incorrectly expecting the subject to contain another "a" after the start.
249    
250    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
251        in the match, the SKIP should be ignored. This was not happening; instead
252        the SKIP was being treated as NOMATCH. For patterns such as
253        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
254        tested.
255    
256    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
257        now much more compatible with Perl, in particular in cases where the result
258        is a non-match for a non-anchored pattern. For example, if
259        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
260        "m", where previously it did not return a name. A side effect of this
261        change is that for partial matches, the last encountered mark name is
262        returned, as for non matches. A number of tests that were previously not
263        Perl-compatible have been moved into the Perl-compatible test files. The
264        refactoring has had the pleasing side effect of removing one argument from
265        the match() function, thus reducing its stack requirements.
266    
267    19. If the /S+ option was used in pcretest to study a pattern using JIT,
268        subsequent uses of /S (without +) incorrectly behaved like /S+.
269    
270    21. Retrieve executable code size support for the JIT compiler and fixing
271        some warnings.
272    
273    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
274        not work when the shorter character appeared right at the end of the
275        subject string.
276    
277    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
278        systems.
279    
280    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
281        output it when the /M option is used in pcretest.
282    
283    25. The CheckMan script was not being included in the distribution. Also, added
284        an explicit "perl" to run Perl scripts from the PrepareRelease script
285        because this is reportedly needed in Windows.
286    
287    26. If study data was being save in a file and studying had not found a set of
288        "starts with" bytes for the pattern, the data written to the file (though
289        never used) was taken from uninitialized memory and so caused valgrind to
290        complain.
291    
292    27. Updated RunTest.bat as provided by Sheri Pierce.
293    
294    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
295    
296    29. Computation of memory usage for the table of capturing group names was
297        giving an unnecessarily large value.
298    
299    
300    Version 8.20 21-Oct-2011
301    ------------------------
302    
303    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
304        a POSIX class. After further experiments with Perl, which convinced me that
305        Perl has bugs and confusions, a closing square bracket is no longer allowed
306        in a POSIX name. This bug also affected patterns with classes that started
307        with full stops.
308    
309    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
310        captured substring, but while checking the failing first alternative,
311        substring 1 is temporarily captured. If the output vector supplied to
312        pcre_exec() was not big enough for this capture, the yield of the function
313        was still zero ("insufficient space for captured substrings"). This cannot
314        be totally fixed without adding another stack variable, which seems a lot
315        of expense for a edge case. However, I have improved the situation in cases
316        such as /(a)(b)x|abc/ matched against "abc", where the return code
317        indicates that fewer than the maximum number of slots in the ovector have
318        been set.
319    
320    3.  Related to (2) above: when there are more back references in a pattern than
321        slots in the output vector, pcre_exec() uses temporary memory during
322        matching, and copies in the captures as far as possible afterwards. It was
323        using the entire output vector, but this conflicts with the specification
324        that only 2/3 is used for passing back captured substrings. Now it uses
325        only the first 2/3, for compatibility. This is, of course, another edge
326        case.
327    
328    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
329        main code base, and can be used by building with --enable-jit. When this is
330        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
331        runtime --no-jit option is given.
332    
333    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
334        ovector, the return from the function was zero, implying that there were
335        other matches that did not fit. The correct "exactly full" value is now
336        returned.
337    
338    6.  If a subpattern that was called recursively or as a subroutine contained
339        (*PRUNE) or any other control that caused it to give a non-standard return,
340        invalid errors such as "Error -26 (nested recursion at the same subject
341        position)" or even infinite loops could occur.
342    
343    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
344        computing the minimum length on reaching *ACCEPT, and so ended up with the
345        wrong value of 1 rather than 0. Further investigation indicates that
346        computing a minimum subject length in the presence of *ACCEPT is difficult
347        (think back references, subroutine calls), and so I have changed the code
348        so that no minimum is registered for a pattern that contains *ACCEPT.
349    
350    8.  If (*THEN) was present in the first (true) branch of a conditional group,
351        it was not handled as intended. [But see 16 below.]
352    
353    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
354        Sheri Pierce.
355    
356    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
357        the first byte in a match must be "a".
358    
359    11. Change 17 for 8.13 increased the recursion depth for patterns like
360        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
361        pattern contains any instances of (*THEN). If it does not, the old
362        optimizations are restored. It would be nice to do this on a per-group
363        basis, but at the moment that is not feasible.
364    
365    12. In some environments, the output of pcretest -C is CRLF terminated. This
366        broke RunTest's code that checks for the link size. A single white space
367        character after the value is now allowed for.
368    
369    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
370        For "fr", it uses the Windows-specific input and output files.
371    
372    14. If (*THEN) appeared in a group that was called recursively or as a
373        subroutine, it did not work as intended. [But see next item.]
374    
375    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
376        pattern fragments (but not containing any | characters). If A and B are
377        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
378        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
379        D. In other words, Perl considers parentheses that do not contain any |
380        characters to be part of a surrounding alternative, whereas PCRE was
381        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
382        differently. PCRE now behaves in the same way as Perl, except in the case
383        of subroutine/recursion calls such as (?1) which have in any case always
384        been different (but PCRE had them first :-).
385    
386    16. Related to 15 above: Perl does not treat the | in a conditional group as
387        creating alternatives. Such a group is treated in the same way as an
388        ordinary group without any | characters when processing (*THEN). PCRE has
389        been changed to match Perl's behaviour.
390    
391    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
392        RunGrepTest script failed.
393    
394    18. Change 22 for version 13 caused atomic groups to use more stack. This is
395        inevitable for groups that contain captures, but it can lead to a lot of
396        stack use in large patterns. The old behaviour has been restored for atomic
397        groups that do not contain any capturing parentheses.
398    
399    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
400        suppress the check for a minimum subject length at run time. (If it was
401        given to pcre_exec() or pcre_dfa_exec() it did work.)
402    
403    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
404        fail to work when decoding hex characters in data strings in EBCDIC
405        environments.
406    
407    21. It appears that in at least one Mac OS environment, the isxdigit() function
408        is implemented as a macro that evaluates to its argument more than once,
409        contravening the C 90 Standard (I haven't checked a later standard). There
410        was an instance in pcretest which caused it to go wrong when processing
411        \x{...} escapes in subject strings. The has been rewritten to avoid using
412        things like p++ in the argument of isxdigit().
413    
414    
415    Version 8.13 16-Aug-2011
416  ------------------------  ------------------------
417    
418  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 431  Version 8.13 30-Apr-2011
431      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
432      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
433      left).      left).
434    
435  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
436      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
437      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
438      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
439    
440  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
441      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
442      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
443      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
444      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
445    
446  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
447      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
448      failure, the offset and reason code are output.      failure, the offset and reason code are output.
449    
450  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
451      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
452      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
453      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
454      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
455      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
456      has been changed.      has been changed.
457    
458  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
459      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
460      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
461      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,
462      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
463      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
464      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
465      (?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.
466    
467  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
468      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
469      using pcre_exec().      using pcre_exec().
470    
471  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
472      discovered and fixed:      discovered and fixed:
473    
474      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
475      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
476      ((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.
477      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
478      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
479    
480  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
481      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
482      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
483    
484  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
485      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
486      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
487      pick them up.      pick them up.
488    
489  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
490      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
491      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
492      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
493      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
494      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
495      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
496      "never study" - see 20 below).      "never study" - see 20 below).
497    
498  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
499      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
500      correctly.      correctly.
501    
502  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
503      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
504      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
505      match.      match.
506    
507  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,
508      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
509      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
510      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
511      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
512      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
513    
514  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
515      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
516      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
517    
518  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
519      was incorrectly computed.      was incorrectly computed.
520    
521  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
522      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
523      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
524        identical in both cases.
525    
526  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
527      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.
528    
529  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
530      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
531      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
532      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
533      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-
534      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
535      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
536      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
537    
538  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
539      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
540      number of identical substrings has been captured).      number of identical substrings has been captured.
541    
542  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
543      if they are repeated, backtracking one repetition now resets captured      if they are repeated, backtracking one repetition now resets captured
544      values correctly. For example, if ((?>(a+)b)+aabab) is matched against      values correctly. For example, if ((?>(a+)b)+aabab) is matched against
545      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
546      "aaa". Previously, it would have been "a". As part of this code      "aaa". Previously, it would have been "a". As part of this code
547      refactoring, the way recursive calls are handled has also been changed.      refactoring, the way recursive calls are handled has also been changed.
548    
549  24. If an assertion condition captured any substrings, they were not passed  25. If an assertion condition captured any substrings, they were not passed
550      back unless some other capturing happened later. For example, if      back unless some other capturing happened later. For example, if
551      (?(?=(a))a) was matched against "a", no capturing was returned.      (?(?=(a))a) was matched against "a", no capturing was returned.
552    
553  25. When studying a pattern that contained subroutine calls or assertions,  26. When studying a pattern that contained subroutine calls or assertions,
554      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
555      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
556      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
557      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
558      the recursion depth to 10.      the recursion depth to 10.
559    
560  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
561      Fortmann. This supports explicit test numbers on the command line, and has      Fortmann. This supports explicit test numbers on the command line, and has
562      argument validation and error reporting.      argument validation and error reporting.
563    
564    28. An instance of \X with an unlimited repeat could fail if at any point the
565        first character it looked at was a mark character.
566    
567    29. Some minor code refactoring concerning Unicode properties and scripts
568        should reduce the stack requirement of match() slightly.
569    
570    30. Added the '=' option to pcretest to check the setting of unused capturing
571        slots at the end of the pattern, which are documented as being -1, but are
572        not included in the return count.
573    
574    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
575        compiled something random. Now it gives a compile-time error (as does
576        Perl).
577    
578    32. A *MARK encountered during the processing of a positive assertion is now
579        recorded and passed back (compatible with Perl).
580    
581    33. If --only-matching or --colour was set on a pcregrep call whose pattern
582        had alternative anchored branches, the search for a second match in a line
583        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
584        matched the line "0102" twice. The same bug affected patterns that started
585        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
586        twice.
587    
588    34. Previously, PCRE did not allow quantification of assertions. However, Perl
589        does, and because of capturing effects, quantifying parenthesized
590        assertions may at times be useful. Quantifiers are now allowed for
591        parenthesized assertions.
592    
593    35. A minor code tidy in pcre_compile() when checking options for \R usage.
594    
595    36. \g was being checked for fancy things in a character class, when it should
596        just be a literal "g".
597    
598    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
599        appearance of a nested POSIX class supersedes an apparent external class.
600        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
601        unescaped square brackets may also appear as part of class names. For
602        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
603        more like Perl. (But see 8.20/1 above.)
604    
605    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
606        was because it thought it was \N{name}, which is not supported).
607    
608    39. Add minix to OS list not supporting the -S option in pcretest.
609    
610    40. PCRE tries to detect cases of infinite recursion at compile time, but it
611        cannot analyze patterns in sufficient detail to catch mutual recursions
612        such as ((?1))((?2)). There is now a runtime test that gives an error if a
613        subgroup is called recursively as a subpattern for a second time at the
614        same position in the subject string. In previous releases this might have
615        been caught by the recursion limit, or it might have run out of stack.
616    
617    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
618        happen only once. PCRE was, however incorrectly giving a compile time error
619        "recursive call could loop indefinitely" because it cannot analyze the
620        pattern in sufficient detail. The compile time test no longer happens when
621        PCRE is compiling a conditional subpattern, but actual runaway loops are
622        now caught at runtime (see 40 above).
623    
624    42. It seems that Perl allows any characters other than a closing parenthesis
625        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
626        has been changed to be the same.
627    
628    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
629        as not to get warnings when autogen.sh is called. Also changed
630        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
631    
632    44. To help people who use pcregrep to scan files containing exceedingly long
633        lines, the following changes have been made:
634    
635        (a) The default value of the buffer size parameter has been increased from
636            8K to 20K. (The actual buffer used is three times this size.)
637    
638        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
639            PCRE is built.
640    
641        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
642            to be set at run time.
643    
644        (d) Numerical values in pcregrep options can be followed by K or M, for
645            example --buffer-size=50K.
646    
647        (e) If a line being scanned overflows pcregrep's buffer, an error is now
648            given and the return code is set to 2.
649    
650    45. Add a pointer to the latest mark to the callout data block.
651    
652    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
653        partial match of an empty string instead of no match. This was specific to
654        the use of ".".
655    
656    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
657        complete match instead of a partial match. This bug was dependent on both
658        the PCRE_UTF8 and PCRE_DOTALL options being set.
659    
660    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
661        starting byte set, because \b was not being ignored.
662    
663    
664  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

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