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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.31 02-June-2012
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    34. Fixed typos in pcregrep: in two places there was SUPPORT_LIBZ2 instead of
124        SUPPORT_LIBBZ2. This caused a build problem when bzip2 but not gzip (zlib)
125        was enabled.
126    
127    35. Improve JIT code generation for greedy plus quantifier.
128    
129    36. When /((?:a?)*)*c/ or /((?>a?)*)*c/ was matched against "aac", it set group
130        1 to "aa" instead of to an empty string. The bug affected repeated groups
131        that could potentially match an empty string.
132    
133    37. Optimizing single character iterators in JIT.
134    
135    38. Wide characters specified with \uxxxx in JavaScript mode are now subject to
136        the same checks as \x{...} characters in non-JavaScript mode. Specifically,
137        codepoints that are too big for the mode are faulted, and in a UTF mode,
138        disallowed codepoints are also faulted.
139    
140    39. If PCRE was compiled with UTF support, in three places in the DFA
141        matcher there was code that should only have been obeyed in UTF mode, but
142        was being obeyed unconditionally. In 8-bit mode this could cause incorrect
143        processing when bytes with values greater than 127 were present. In 16-bit
144        mode the bug would be provoked by values in the range 0xfc00 to 0xdc00. In
145        both cases the values are those that cannot be the first data item in a UTF
146        character. The three items that might have provoked this were recursions,
147        possessively repeated groups, and atomic groups.
148    
149    40. Ensure that libpcre is explicitly listed in the link commands for pcretest
150        and pcregrep, because some OS require shared objects to be explicitly
151        passed to ld, causing the link step to fail if they are not.
152    
153    
154    Version 8.30 04-February-2012
155    -----------------------------
156    
157    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
158        name is defined in ctype.h.
159    
160    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
161        only in quite long subpatterns.
162    
163    3.  Removed the function pcre_info(), which has been obsolete and deprecated
164        since it was replaced by pcre_fullinfo() in February 2000.
165    
166    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
167        match a (*MARK), and the match failed at the start of the subject, a
168        reference to memory before the start of the subject could occur. This bug
169        was introduced by fix 17 of release 8.21.
170    
171    5.  A reference to an unset group with zero minimum repetition was giving
172        totally wrong answers (in non-JavaScript-compatibility mode). For example,
173        /(another)?(\1?)test/ matched against "hello world test". This bug was
174        introduced in release 8.13.
175    
176    6.  Add support for 16-bit character strings (a large amount of work involving
177        many changes and refactorings).
178    
179    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
180        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
181        from a file.
182    
183    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
184        rounding is not applied in this particular case).
185    
186    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
187        if they appear, or are escaped, in patterns.
188    
189    10. Get rid of a number of -Wunused-but-set-variable warnings.
190    
191    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
192        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
193        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
194        also returns the mark "x". This bug applied to capturing parentheses,
195        non-capturing parentheses, and atomic parentheses. It also applied to some
196        assertions.
197    
198    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
199        information out of configure.ac instead of relying on pcre.h.generic, which
200        is not stored in the repository.
201    
202    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
203        -lreadline.
204    
205    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
206    
207    15. Applied Graycode's patch to put the top-level frame on the stack rather
208        than the heap when not using the stack for recursion. This gives a
209        performance improvement in many cases when recursion is not deep.
210    
211    16. Experimental code added to "pcretest -C" to output the stack frame size.
212    
213    
214    Version 8.21 12-Dec-2011
215    ------------------------
216    
217    1.  Updating the JIT compiler.
218    
219    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
220        are added as well.
221    
222    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
223        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
224        calling _pcre_jit_exec. Some extra comments are added.
225    
226    4.  (*MARK) settings inside atomic groups that do not contain any capturing
227        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
228        was introduced by change 18 for 8.20.
229    
230    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
231        ECMA-262 standard.
232    
233    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
234        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
235        This bug was probably introduced by change 9 of 8.13.
236    
237    7.  While fixing 6 above, I noticed that a number of other items were being
238        incorrectly rejected as "not fixed length". This arose partly because newer
239        opcodes had not been added to the fixed-length checking code. I have (a)
240        corrected the bug and added tests for these items, and (b) arranged for an
241        error to occur if an unknown opcode is encountered while checking for fixed
242        length instead of just assuming "not fixed length". The items that were
243        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
244        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
245        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
246    
247    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
248        being incorrectly compiled and would have given unpredicatble results.
249    
250    9.  A possessively repeated subpattern with minimum repeat count greater than
251        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
252        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
253        the first (A) could occur when it should not.
254    
255    10. Add a cast and remove a redundant test from the code.
256    
257    11. JIT should use pcre_malloc/pcre_free for allocation.
258    
259    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
260        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
261        is anything other than /usr, -L is still shown).
262    
263    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
264    
265    14. Perl does not support \N without a following name in a [] class; PCRE now
266        also gives an error.
267    
268    15. If a forward reference was repeated with an upper limit of around 2000,
269        it caused the error "internal error: overran compiling workspace". The
270        maximum number of forward references (including repeats) was limited by the
271        internal workspace, and dependent on the LINK_SIZE. The code has been
272        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
273        the default depends on LINK_SIZE. There is a new upper limit (for safety)
274        of around 200,000 forward references. While doing this, I also speeded up
275        the filling in of repeated forward references.
276    
277    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
278        incorrectly expecting the subject to contain another "a" after the start.
279    
280    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
281        in the match, the SKIP should be ignored. This was not happening; instead
282        the SKIP was being treated as NOMATCH. For patterns such as
283        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
284        tested.
285    
286    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
287        now much more compatible with Perl, in particular in cases where the result
288        is a non-match for a non-anchored pattern. For example, if
289        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
290        "m", where previously it did not return a name. A side effect of this
291        change is that for partial matches, the last encountered mark name is
292        returned, as for non matches. A number of tests that were previously not
293        Perl-compatible have been moved into the Perl-compatible test files. The
294        refactoring has had the pleasing side effect of removing one argument from
295        the match() function, thus reducing its stack requirements.
296    
297    19. If the /S+ option was used in pcretest to study a pattern using JIT,
298        subsequent uses of /S (without +) incorrectly behaved like /S+.
299    
300    21. Retrieve executable code size support for the JIT compiler and fixing
301        some warnings.
302    
303    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
304        not work when the shorter character appeared right at the end of the
305        subject string.
306    
307    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
308        systems.
309    
310    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
311        output it when the /M option is used in pcretest.
312    
313    25. The CheckMan script was not being included in the distribution. Also, added
314        an explicit "perl" to run Perl scripts from the PrepareRelease script
315        because this is reportedly needed in Windows.
316    
317    26. If study data was being save in a file and studying had not found a set of
318        "starts with" bytes for the pattern, the data written to the file (though
319        never used) was taken from uninitialized memory and so caused valgrind to
320        complain.
321    
322    27. Updated RunTest.bat as provided by Sheri Pierce.
323    
324    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
325    
326    29. Computation of memory usage for the table of capturing group names was
327        giving an unnecessarily large value.
328    
329    
330    Version 8.20 21-Oct-2011
331    ------------------------
332    
333    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
334        a POSIX class. After further experiments with Perl, which convinced me that
335        Perl has bugs and confusions, a closing square bracket is no longer allowed
336        in a POSIX name. This bug also affected patterns with classes that started
337        with full stops.
338    
339    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
340        captured substring, but while checking the failing first alternative,
341        substring 1 is temporarily captured. If the output vector supplied to
342        pcre_exec() was not big enough for this capture, the yield of the function
343        was still zero ("insufficient space for captured substrings"). This cannot
344        be totally fixed without adding another stack variable, which seems a lot
345        of expense for a edge case. However, I have improved the situation in cases
346        such as /(a)(b)x|abc/ matched against "abc", where the return code
347        indicates that fewer than the maximum number of slots in the ovector have
348        been set.
349    
350    3.  Related to (2) above: when there are more back references in a pattern than
351        slots in the output vector, pcre_exec() uses temporary memory during
352        matching, and copies in the captures as far as possible afterwards. It was
353        using the entire output vector, but this conflicts with the specification
354        that only 2/3 is used for passing back captured substrings. Now it uses
355        only the first 2/3, for compatibility. This is, of course, another edge
356        case.
357    
358    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
359        main code base, and can be used by building with --enable-jit. When this is
360        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
361        runtime --no-jit option is given.
362    
363    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
364        ovector, the return from the function was zero, implying that there were
365        other matches that did not fit. The correct "exactly full" value is now
366        returned.
367    
368    6.  If a subpattern that was called recursively or as a subroutine contained
369        (*PRUNE) or any other control that caused it to give a non-standard return,
370        invalid errors such as "Error -26 (nested recursion at the same subject
371        position)" or even infinite loops could occur.
372    
373    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
374        computing the minimum length on reaching *ACCEPT, and so ended up with the
375        wrong value of 1 rather than 0. Further investigation indicates that
376        computing a minimum subject length in the presence of *ACCEPT is difficult
377        (think back references, subroutine calls), and so I have changed the code
378        so that no minimum is registered for a pattern that contains *ACCEPT.
379    
380    8.  If (*THEN) was present in the first (true) branch of a conditional group,
381        it was not handled as intended. [But see 16 below.]
382    
383    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
384        Sheri Pierce.
385    
386    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
387        the first byte in a match must be "a".
388    
389    11. Change 17 for 8.13 increased the recursion depth for patterns like
390        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
391        pattern contains any instances of (*THEN). If it does not, the old
392        optimizations are restored. It would be nice to do this on a per-group
393        basis, but at the moment that is not feasible.
394    
395    12. In some environments, the output of pcretest -C is CRLF terminated. This
396        broke RunTest's code that checks for the link size. A single white space
397        character after the value is now allowed for.
398    
399    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
400        For "fr", it uses the Windows-specific input and output files.
401    
402    14. If (*THEN) appeared in a group that was called recursively or as a
403        subroutine, it did not work as intended. [But see next item.]
404    
405    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
406        pattern fragments (but not containing any | characters). If A and B are
407        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
408        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
409        D. In other words, Perl considers parentheses that do not contain any |
410        characters to be part of a surrounding alternative, whereas PCRE was
411        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
412        differently. PCRE now behaves in the same way as Perl, except in the case
413        of subroutine/recursion calls such as (?1) which have in any case always
414        been different (but PCRE had them first :-).
415    
416    16. Related to 15 above: Perl does not treat the | in a conditional group as
417        creating alternatives. Such a group is treated in the same way as an
418        ordinary group without any | characters when processing (*THEN). PCRE has
419        been changed to match Perl's behaviour.
420    
421    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
422        RunGrepTest script failed.
423    
424    18. Change 22 for version 13 caused atomic groups to use more stack. This is
425        inevitable for groups that contain captures, but it can lead to a lot of
426        stack use in large patterns. The old behaviour has been restored for atomic
427        groups that do not contain any capturing parentheses.
428    
429    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
430        suppress the check for a minimum subject length at run time. (If it was
431        given to pcre_exec() or pcre_dfa_exec() it did work.)
432    
433    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
434        fail to work when decoding hex characters in data strings in EBCDIC
435        environments.
436    
437    21. It appears that in at least one Mac OS environment, the isxdigit() function
438        is implemented as a macro that evaluates to its argument more than once,
439        contravening the C 90 Standard (I haven't checked a later standard). There
440        was an instance in pcretest which caused it to go wrong when processing
441        \x{...} escapes in subject strings. The has been rewritten to avoid using
442        things like p++ in the argument of isxdigit().
443    
444    
445    Version 8.13 16-Aug-2011
446  ------------------------  ------------------------
447    
448  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 461  Version 8.13 30-Apr-2011
461      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
462      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
463      left).      left).
464    
465  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
466      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
467      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
468      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
469    
470  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
471      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
472      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
473      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
474      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
475    
476  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
477      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
478      failure, the offset and reason code are output.      failure, the offset and reason code are output.
479    
480  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
481      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
482      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
483      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
484      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
485      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
486      has been changed.      has been changed.
487    
488  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
489      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
490      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
491      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,
492      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
493      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
494      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
495      (?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.
496    
497  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
498      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
499      using pcre_exec().      using pcre_exec().
500    
501  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
502      discovered and fixed:      discovered and fixed:
503    
504      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
505      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
506      ((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.
507      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
508      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
509    
510  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
511      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
512      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
513    
514  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
515      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
516      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
517      pick them up.      pick them up.
518    
519    14. The -s option of pcretest has been documented for ages as being an old
520        synonym of -m (show memory usage). I have changed it to mean "force study
521        for every regex", that is, assume /S for every regex. This is similar to -i
522        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
523        using it. It makes it easier to run collections of tests with and without
524        study enabled, and thereby test pcre_study() more easily. All the standard
525        tests are now run with and without -s (but some patterns can be marked as
526        "never study" - see 20 below).
527    
528    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
529        restoration of the capturing data to the outer values was not happening
530        correctly.
531    
532    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
533        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
534        pattern had matched an empty string, and so incorrectly returned a no
535        match.
536    
537    17. There was optimizing code for the last branch of non-capturing parentheses,
538        and also for the obeyed branch of a conditional subexpression, which used
539        tail recursion to cut down on stack usage. Unfortunately, now that there is
540        the possibility of (*THEN) occurring in these branches, tail recursion is
541        no longer possible because the return has to be checked for (*THEN). These
542        two optimizations have therefore been removed. [But see 8.20/11 above.]
543    
544    18. If a pattern containing \R was studied, it was assumed that \R always
545        matched two bytes, thus causing the minimum subject length to be
546        incorrectly computed because \R can also match just one byte.
547    
548    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
549        was incorrectly computed.
550    
551    20. If /S is present twice on a test pattern in pcretest input, it now
552        *disables* studying, thereby overriding the use of -s on the command line
553        (see 14 above). This is necessary for one or two tests to keep the output
554        identical in both cases.
555    
556    21. When (*ACCEPT) was used in an assertion that matched an empty string and
557        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
558    
559    22. When an atomic group that contained a capturing parenthesis was
560        successfully matched, but the branch in which it appeared failed, the
561        capturing was not being forgotten if a higher numbered group was later
562        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
563        group 1 to "a", when in fact it should be unset. This applied to multi-
564        branched capturing and non-capturing groups, repeated or not, and also to
565        positive assertions (capturing in negative assertions does not happen
566        in PCRE) and also to nested atomic groups.
567    
568    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
569        subject after a captured substring, to make it easier to tell which of a
570        number of identical substrings has been captured.
571    
572    24. The way atomic groups are processed by pcre_exec() has been changed so that
573        if they are repeated, backtracking one repetition now resets captured
574        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
575        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
576        "aaa". Previously, it would have been "a". As part of this code
577        refactoring, the way recursive calls are handled has also been changed.
578    
579    25. If an assertion condition captured any substrings, they were not passed
580        back unless some other capturing happened later. For example, if
581        (?(?=(a))a) was matched against "a", no capturing was returned.
582    
583    26. When studying a pattern that contained subroutine calls or assertions,
584        the code for finding the minimum length of a possible match was handling
585        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
586        group 1 called group 2 while simultaneously a separate group 2 called group
587        1). A stack overflow occurred in this case. I have fixed this by limiting
588        the recursion depth to 10.
589    
590    27. Updated RunTest.bat in the distribution to the version supplied by Tom
591        Fortmann. This supports explicit test numbers on the command line, and has
592        argument validation and error reporting.
593    
594    28. An instance of \X with an unlimited repeat could fail if at any point the
595        first character it looked at was a mark character.
596    
597    29. Some minor code refactoring concerning Unicode properties and scripts
598        should reduce the stack requirement of match() slightly.
599    
600    30. Added the '=' option to pcretest to check the setting of unused capturing
601        slots at the end of the pattern, which are documented as being -1, but are
602        not included in the return count.
603    
604    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
605        compiled something random. Now it gives a compile-time error (as does
606        Perl).
607    
608    32. A *MARK encountered during the processing of a positive assertion is now
609        recorded and passed back (compatible with Perl).
610    
611    33. If --only-matching or --colour was set on a pcregrep call whose pattern
612        had alternative anchored branches, the search for a second match in a line
613        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
614        matched the line "0102" twice. The same bug affected patterns that started
615        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
616        twice.
617    
618    34. Previously, PCRE did not allow quantification of assertions. However, Perl
619        does, and because of capturing effects, quantifying parenthesized
620        assertions may at times be useful. Quantifiers are now allowed for
621        parenthesized assertions.
622    
623    35. A minor code tidy in pcre_compile() when checking options for \R usage.
624    
625    36. \g was being checked for fancy things in a character class, when it should
626        just be a literal "g".
627    
628    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
629        appearance of a nested POSIX class supersedes an apparent external class.
630        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
631        unescaped square brackets may also appear as part of class names. For
632        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
633        more like Perl. (But see 8.20/1 above.)
634    
635    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
636        was because it thought it was \N{name}, which is not supported).
637    
638    39. Add minix to OS list not supporting the -S option in pcretest.
639    
640    40. PCRE tries to detect cases of infinite recursion at compile time, but it
641        cannot analyze patterns in sufficient detail to catch mutual recursions
642        such as ((?1))((?2)). There is now a runtime test that gives an error if a
643        subgroup is called recursively as a subpattern for a second time at the
644        same position in the subject string. In previous releases this might have
645        been caught by the recursion limit, or it might have run out of stack.
646    
647    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
648        happen only once. PCRE was, however incorrectly giving a compile time error
649        "recursive call could loop indefinitely" because it cannot analyze the
650        pattern in sufficient detail. The compile time test no longer happens when
651        PCRE is compiling a conditional subpattern, but actual runaway loops are
652        now caught at runtime (see 40 above).
653    
654    42. It seems that Perl allows any characters other than a closing parenthesis
655        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
656        has been changed to be the same.
657    
658    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
659        as not to get warnings when autogen.sh is called. Also changed
660        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
661    
662    44. To help people who use pcregrep to scan files containing exceedingly long
663        lines, the following changes have been made:
664    
665        (a) The default value of the buffer size parameter has been increased from
666            8K to 20K. (The actual buffer used is three times this size.)
667    
668        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
669            PCRE is built.
670    
671        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
672            to be set at run time.
673    
674        (d) Numerical values in pcregrep options can be followed by K or M, for
675            example --buffer-size=50K.
676    
677        (e) If a line being scanned overflows pcregrep's buffer, an error is now
678            given and the return code is set to 2.
679    
680    45. Add a pointer to the latest mark to the callout data block.
681    
682    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
683        partial match of an empty string instead of no match. This was specific to
684        the use of ".".
685    
686    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
687        complete match instead of a partial match. This bug was dependent on both
688        the PCRE_UTF8 and PCRE_DOTALL options being set.
689    
690    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
691        starting byte set, because \b was not being ignored.
692    
693    
694  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
695  ------------------------  ------------------------

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