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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.02 01-Mar-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    6.  The Unicode data tables have been updated to Unicode 6.1.0.
69    
70    
71    Version 8.30 04-February-2012
72    -----------------------------
73    
74    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
75        name is defined in ctype.h.
76    
77    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
78        only in quite long subpatterns.
79    
80    3.  Removed the function pcre_info(), which has been obsolete and deprecated
81        since it was replaced by pcre_fullinfo() in February 2000.
82    
83    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
84        match a (*MARK), and the match failed at the start of the subject, a
85        reference to memory before the start of the subject could occur. This bug
86        was introduced by fix 17 of release 8.21.
87    
88    5.  A reference to an unset group with zero minimum repetition was giving
89        totally wrong answers (in non-JavaScript-compatibility mode). For example,
90        /(another)?(\1?)test/ matched against "hello world test". This bug was
91        introduced in release 8.13.
92    
93    6.  Add support for 16-bit character strings (a large amount of work involving
94        many changes and refactorings).
95    
96    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
97        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
98        from a file.
99    
100    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
101        rounding is not applied in this particular case).
102    
103    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
104        if they appear, or are escaped, in patterns.
105    
106    10. Get rid of a number of -Wunused-but-set-variable warnings.
107    
108    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
109        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
110        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
111        also returns the mark "x". This bug applied to capturing parentheses,
112        non-capturing parentheses, and atomic parentheses. It also applied to some
113        assertions.
114    
115    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
116        information out of configure.ac instead of relying on pcre.h.generic, which
117        is not stored in the repository.
118    
119    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
120        -lreadline.
121    
122    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
123    
124    15. Applied Graycode's patch to put the top-level frame on the stack rather
125        than the heap when not using the stack for recursion. This gives a
126        performance improvement in many cases when recursion is not deep.
127    
128    16. Experimental code added to "pcretest -C" to output the stack frame size.
129    
130    
131    Version 8.21 12-Dec-2011
132    ------------------------
133    
134    1.  Updating the JIT compiler.
135    
136    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
137        are added as well.
138    
139    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
140        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
141        calling _pcre_jit_exec. Some extra comments are added.
142    
143    4.  (*MARK) settings inside atomic groups that do not contain any capturing
144        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
145        was introduced by change 18 for 8.20.
146    
147    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
148        ECMA-262 standard.
149    
150    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
151        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
152        This bug was probably introduced by change 9 of 8.13.
153    
154    7.  While fixing 6 above, I noticed that a number of other items were being
155        incorrectly rejected as "not fixed length". This arose partly because newer
156        opcodes had not been added to the fixed-length checking code. I have (a)
157        corrected the bug and added tests for these items, and (b) arranged for an
158        error to occur if an unknown opcode is encountered while checking for fixed
159        length instead of just assuming "not fixed length". The items that were
160        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
161        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
162        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
163    
164    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
165        being incorrectly compiled and would have given unpredicatble results.
166    
167    9.  A possessively repeated subpattern with minimum repeat count greater than
168        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
169        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
170        the first (A) could occur when it should not.
171    
172    10. Add a cast and remove a redundant test from the code.
173    
174    11. JIT should use pcre_malloc/pcre_free for allocation.
175    
176    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
177        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
178        is anything other than /usr, -L is still shown).
179    
180    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
181    
182    14. Perl does not support \N without a following name in a [] class; PCRE now
183        also gives an error.
184    
185    15. If a forward reference was repeated with an upper limit of around 2000,
186        it caused the error "internal error: overran compiling workspace". The
187        maximum number of forward references (including repeats) was limited by the
188        internal workspace, and dependent on the LINK_SIZE. The code has been
189        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
190        the default depends on LINK_SIZE. There is a new upper limit (for safety)
191        of around 200,000 forward references. While doing this, I also speeded up
192        the filling in of repeated forward references.
193    
194    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
195        incorrectly expecting the subject to contain another "a" after the start.
196    
197    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
198        in the match, the SKIP should be ignored. This was not happening; instead
199        the SKIP was being treated as NOMATCH. For patterns such as
200        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
201        tested.
202    
203    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
204        now much more compatible with Perl, in particular in cases where the result
205        is a non-match for a non-anchored pattern. For example, if
206        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
207        "m", where previously it did not return a name. A side effect of this
208        change is that for partial matches, the last encountered mark name is
209        returned, as for non matches. A number of tests that were previously not
210        Perl-compatible have been moved into the Perl-compatible test files. The
211        refactoring has had the pleasing side effect of removing one argument from
212        the match() function, thus reducing its stack requirements.
213    
214    19. If the /S+ option was used in pcretest to study a pattern using JIT,
215        subsequent uses of /S (without +) incorrectly behaved like /S+.
216    
217    21. Retrieve executable code size support for the JIT compiler and fixing
218        some warnings.
219    
220    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
221        not work when the shorter character appeared right at the end of the
222        subject string.
223    
224    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
225        systems.
226    
227    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
228        output it when the /M option is used in pcretest.
229    
230    25. The CheckMan script was not being included in the distribution. Also, added
231        an explicit "perl" to run Perl scripts from the PrepareRelease script
232        because this is reportedly needed in Windows.
233    
234    26. If study data was being save in a file and studying had not found a set of
235        "starts with" bytes for the pattern, the data written to the file (though
236        never used) was taken from uninitialized memory and so caused valgrind to
237        complain.
238    
239    27. Updated RunTest.bat as provided by Sheri Pierce.
240    
241    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
242    
243    29. Computation of memory usage for the table of capturing group names was
244        giving an unnecessarily large value.
245    
246    
247    Version 8.20 21-Oct-2011
248    ------------------------
249    
250    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
251        a POSIX class. After further experiments with Perl, which convinced me that
252        Perl has bugs and confusions, a closing square bracket is no longer allowed
253        in a POSIX name. This bug also affected patterns with classes that started
254        with full stops.
255    
256    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
257        captured substring, but while checking the failing first alternative,
258        substring 1 is temporarily captured. If the output vector supplied to
259        pcre_exec() was not big enough for this capture, the yield of the function
260        was still zero ("insufficient space for captured substrings"). This cannot
261        be totally fixed without adding another stack variable, which seems a lot
262        of expense for a edge case. However, I have improved the situation in cases
263        such as /(a)(b)x|abc/ matched against "abc", where the return code
264        indicates that fewer than the maximum number of slots in the ovector have
265        been set.
266    
267    3.  Related to (2) above: when there are more back references in a pattern than
268        slots in the output vector, pcre_exec() uses temporary memory during
269        matching, and copies in the captures as far as possible afterwards. It was
270        using the entire output vector, but this conflicts with the specification
271        that only 2/3 is used for passing back captured substrings. Now it uses
272        only the first 2/3, for compatibility. This is, of course, another edge
273        case.
274    
275    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
276        main code base, and can be used by building with --enable-jit. When this is
277        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
278        runtime --no-jit option is given.
279    
280    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
281        ovector, the return from the function was zero, implying that there were
282        other matches that did not fit. The correct "exactly full" value is now
283        returned.
284    
285    6.  If a subpattern that was called recursively or as a subroutine contained
286        (*PRUNE) or any other control that caused it to give a non-standard return,
287        invalid errors such as "Error -26 (nested recursion at the same subject
288        position)" or even infinite loops could occur.
289    
290    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
291        computing the minimum length on reaching *ACCEPT, and so ended up with the
292        wrong value of 1 rather than 0. Further investigation indicates that
293        computing a minimum subject length in the presence of *ACCEPT is difficult
294        (think back references, subroutine calls), and so I have changed the code
295        so that no minimum is registered for a pattern that contains *ACCEPT.
296    
297    8.  If (*THEN) was present in the first (true) branch of a conditional group,
298        it was not handled as intended. [But see 16 below.]
299    
300    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
301        Sheri Pierce.
302    
303    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
304        the first byte in a match must be "a".
305    
306    11. Change 17 for 8.13 increased the recursion depth for patterns like
307        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
308        pattern contains any instances of (*THEN). If it does not, the old
309        optimizations are restored. It would be nice to do this on a per-group
310        basis, but at the moment that is not feasible.
311    
312    12. In some environments, the output of pcretest -C is CRLF terminated. This
313        broke RunTest's code that checks for the link size. A single white space
314        character after the value is now allowed for.
315    
316    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
317        For "fr", it uses the Windows-specific input and output files.
318    
319    14. If (*THEN) appeared in a group that was called recursively or as a
320        subroutine, it did not work as intended. [But see next item.]
321    
322    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
323        pattern fragments (but not containing any | characters). If A and B are
324        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
325        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
326        D. In other words, Perl considers parentheses that do not contain any |
327        characters to be part of a surrounding alternative, whereas PCRE was
328        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
329        differently. PCRE now behaves in the same way as Perl, except in the case
330        of subroutine/recursion calls such as (?1) which have in any case always
331        been different (but PCRE had them first :-).
332    
333    16. Related to 15 above: Perl does not treat the | in a conditional group as
334        creating alternatives. Such a group is treated in the same way as an
335        ordinary group without any | characters when processing (*THEN). PCRE has
336        been changed to match Perl's behaviour.
337    
338    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
339        RunGrepTest script failed.
340    
341    18. Change 22 for version 13 caused atomic groups to use more stack. This is
342        inevitable for groups that contain captures, but it can lead to a lot of
343        stack use in large patterns. The old behaviour has been restored for atomic
344        groups that do not contain any capturing parentheses.
345    
346    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
347        suppress the check for a minimum subject length at run time. (If it was
348        given to pcre_exec() or pcre_dfa_exec() it did work.)
349    
350    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
351        fail to work when decoding hex characters in data strings in EBCDIC
352        environments.
353    
354    21. It appears that in at least one Mac OS environment, the isxdigit() function
355        is implemented as a macro that evaluates to its argument more than once,
356        contravening the C 90 Standard (I haven't checked a later standard). There
357        was an instance in pcretest which caused it to go wrong when processing
358        \x{...} escapes in subject strings. The has been rewritten to avoid using
359        things like p++ in the argument of isxdigit().
360    
361    
362    Version 8.13 16-Aug-2011
363    ------------------------
364    
365    1.  The Unicode data tables have been updated to Unicode 6.0.0.
366    
367    2.  Two minor typos in pcre_internal.h have been fixed.
368    
369    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
370        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
371        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
372    
373    4.  There were a number of related bugs in the code for matching backrefences
374        caselessly in UTF-8 mode when codes for the characters concerned were
375        different numbers of bytes. For example, U+023A and U+2C65 are an upper
376        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
377        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
378        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
379        2-byte code at the end of the subject (it thought there wasn't enough data
380        left).
381    
382    5.  Comprehensive information about what went wrong is now returned by
383        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
384        as the output vector has at least 2 elements. The offset of the start of
385        the failing character and a reason code are placed in the vector.
386    
387    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
388        now returned is for the first byte of the failing character, instead of the
389        last byte inspected. This is an incompatible change, but I hope it is small
390        enough not to be a problem. It makes the returned offset consistent with
391        pcre_exec() and pcre_dfa_exec().
392    
393    7.  pcretest now gives a text phrase as well as the error number when
394        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
395        failure, the offset and reason code are output.
396    
397    8.  When \R was used with a maximizing quantifier it failed to skip backwards
398        over a \r\n pair if the subsequent match failed. Instead, it just skipped
399        back over a single character (\n). This seems wrong (because it treated the
400        two characters as a single entity when going forwards), conflicts with the
401        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
402        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
403        has been changed.
404    
405    9.  Some internal refactoring has changed the processing so that the handling
406        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
407        time (the PCRE_DOTALL option was changed this way some time ago: version
408        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
409        which was always a bit of a fudge. It also means that there is one less
410        argument for the match() function, which reduces its stack requirements
411        slightly. This change also fixes an incompatibility with Perl: the pattern
412        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
413    
414    10. More internal refactoring has drastically reduced the number of recursive
415        calls to match() for possessively repeated groups such as (abc)++ when
416        using pcre_exec().
417    
418    11. While implementing 10, a number of bugs in the handling of groups were
419        discovered and fixed:
420    
421        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
422        (a|)*(?1) gave a compile-time internal error.
423        ((a|)+)+  did not notice that the outer group could match an empty string.
424        (^a|^)+   was not marked as anchored.
425        (.*a|.*)+ was not marked as matching at start or after a newline.
426    
427    12. Yet more internal refactoring has removed another argument from the match()
428        function. Special calls to this function are now indicated by setting a
429        value in a variable in the "match data" data block.
430    
431    13. Be more explicit in pcre_study() instead of relying on "default" for
432        opcodes that mean there is no starting character; this means that when new
433        ones are added and accidentally left out of pcre_study(), testing should
434        pick them up.
435    
436    14. The -s option of pcretest has been documented for ages as being an old
437        synonym of -m (show memory usage). I have changed it to mean "force study
438        for every regex", that is, assume /S for every regex. This is similar to -i
439        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
440        using it. It makes it easier to run collections of tests with and without
441        study enabled, and thereby test pcre_study() more easily. All the standard
442        tests are now run with and without -s (but some patterns can be marked as
443        "never study" - see 20 below).
444    
445    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
446        restoration of the capturing data to the outer values was not happening
447        correctly.
448    
449    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
450        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
451        pattern had matched an empty string, and so incorrectly returned a no
452        match.
453    
454    17. There was optimizing code for the last branch of non-capturing parentheses,
455        and also for the obeyed branch of a conditional subexpression, which used
456        tail recursion to cut down on stack usage. Unfortunately, now that there is
457        the possibility of (*THEN) occurring in these branches, tail recursion is
458        no longer possible because the return has to be checked for (*THEN). These
459        two optimizations have therefore been removed. [But see 8.20/11 above.]
460    
461    18. If a pattern containing \R was studied, it was assumed that \R always
462        matched two bytes, thus causing the minimum subject length to be
463        incorrectly computed because \R can also match just one byte.
464    
465    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
466        was incorrectly computed.
467    
468    20. If /S is present twice on a test pattern in pcretest input, it now
469        *disables* studying, thereby overriding the use of -s on the command line
470        (see 14 above). This is necessary for one or two tests to keep the output
471        identical in both cases.
472    
473    21. When (*ACCEPT) was used in an assertion that matched an empty string and
474        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
475    
476    22. When an atomic group that contained a capturing parenthesis was
477        successfully matched, but the branch in which it appeared failed, the
478        capturing was not being forgotten if a higher numbered group was later
479        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
480        group 1 to "a", when in fact it should be unset. This applied to multi-
481        branched capturing and non-capturing groups, repeated or not, and also to
482        positive assertions (capturing in negative assertions does not happen
483        in PCRE) and also to nested atomic groups.
484    
485    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
486        subject after a captured substring, to make it easier to tell which of a
487        number of identical substrings has been captured.
488    
489    24. The way atomic groups are processed by pcre_exec() has been changed so that
490        if they are repeated, backtracking one repetition now resets captured
491        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
492        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
493        "aaa". Previously, it would have been "a". As part of this code
494        refactoring, the way recursive calls are handled has also been changed.
495    
496    25. If an assertion condition captured any substrings, they were not passed
497        back unless some other capturing happened later. For example, if
498        (?(?=(a))a) was matched against "a", no capturing was returned.
499    
500    26. When studying a pattern that contained subroutine calls or assertions,
501        the code for finding the minimum length of a possible match was handling
502        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
503        group 1 called group 2 while simultaneously a separate group 2 called group
504        1). A stack overflow occurred in this case. I have fixed this by limiting
505        the recursion depth to 10.
506    
507    27. Updated RunTest.bat in the distribution to the version supplied by Tom
508        Fortmann. This supports explicit test numbers on the command line, and has
509        argument validation and error reporting.
510    
511    28. An instance of \X with an unlimited repeat could fail if at any point the
512        first character it looked at was a mark character.
513    
514    29. Some minor code refactoring concerning Unicode properties and scripts
515        should reduce the stack requirement of match() slightly.
516    
517    30. Added the '=' option to pcretest to check the setting of unused capturing
518        slots at the end of the pattern, which are documented as being -1, but are
519        not included in the return count.
520    
521    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
522        compiled something random. Now it gives a compile-time error (as does
523        Perl).
524    
525    32. A *MARK encountered during the processing of a positive assertion is now
526        recorded and passed back (compatible with Perl).
527    
528    33. If --only-matching or --colour was set on a pcregrep call whose pattern
529        had alternative anchored branches, the search for a second match in a line
530        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
531        matched the line "0102" twice. The same bug affected patterns that started
532        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
533        twice.
534    
535    34. Previously, PCRE did not allow quantification of assertions. However, Perl
536        does, and because of capturing effects, quantifying parenthesized
537        assertions may at times be useful. Quantifiers are now allowed for
538        parenthesized assertions.
539    
540    35. A minor code tidy in pcre_compile() when checking options for \R usage.
541    
542    36. \g was being checked for fancy things in a character class, when it should
543        just be a literal "g".
544    
545    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
546        appearance of a nested POSIX class supersedes an apparent external class.
547        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
548        unescaped square brackets may also appear as part of class names. For
549        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
550        more like Perl. (But see 8.20/1 above.)
551    
552    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
553        was because it thought it was \N{name}, which is not supported).
554    
555    39. Add minix to OS list not supporting the -S option in pcretest.
556    
557    40. PCRE tries to detect cases of infinite recursion at compile time, but it
558        cannot analyze patterns in sufficient detail to catch mutual recursions
559        such as ((?1))((?2)). There is now a runtime test that gives an error if a
560        subgroup is called recursively as a subpattern for a second time at the
561        same position in the subject string. In previous releases this might have
562        been caught by the recursion limit, or it might have run out of stack.
563    
564    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
565        happen only once. PCRE was, however incorrectly giving a compile time error
566        "recursive call could loop indefinitely" because it cannot analyze the
567        pattern in sufficient detail. The compile time test no longer happens when
568        PCRE is compiling a conditional subpattern, but actual runaway loops are
569        now caught at runtime (see 40 above).
570    
571    42. It seems that Perl allows any characters other than a closing parenthesis
572        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
573        has been changed to be the same.
574    
575    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
576        as not to get warnings when autogen.sh is called. Also changed
577        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
578    
579    44. To help people who use pcregrep to scan files containing exceedingly long
580        lines, the following changes have been made:
581    
582        (a) The default value of the buffer size parameter has been increased from
583            8K to 20K. (The actual buffer used is three times this size.)
584    
585        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
586            PCRE is built.
587    
588        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
589            to be set at run time.
590    
591        (d) Numerical values in pcregrep options can be followed by K or M, for
592            example --buffer-size=50K.
593    
594        (e) If a line being scanned overflows pcregrep's buffer, an error is now
595            given and the return code is set to 2.
596    
597    45. Add a pointer to the latest mark to the callout data block.
598    
599    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
600        partial match of an empty string instead of no match. This was specific to
601        the use of ".".
602    
603    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
604        complete match instead of a partial match. This bug was dependent on both
605        the PCRE_UTF8 and PCRE_DOTALL options being set.
606    
607    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
608        starting byte set, because \b was not being ignored.
609    
610    
611    Version 8.12 15-Jan-2011
612    ------------------------
613    
614    1.  Fixed some typos in the markup of the man pages, and wrote a script that
615        checks for such things as part of the documentation building process.
616    
617    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
618        --match-limit and --recursion-limit options (added for 8.11). In
619        particular, this made one of the standard tests fail. (The integer value
620        went into the wrong half of a long int.)
621    
622    3.  If the --colour option was given to pcregrep with -v (invert match), it
623        did strange things, either producing crazy output, or crashing. It should,
624        of course, ignore a request for colour when reporting lines that do not
625        match.
626    
627    4.  Another pcregrep bug caused similar problems if --colour was specified with
628        -M (multiline) and the pattern match finished with a line ending.
629    
630    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
631        matched in multiline mode, the following line was shown as part of the
632        match. This seems wrong, so I have changed it.
633    
634    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
635        the check for further matches in the same line (so they could be coloured)
636        to overrun the end of the current line. If another match was found, it was
637        incorrectly shown (and then shown again when found in the next line).
638    
639    7.  If pcregrep was compiled under Windows, there was a reference to the
640        function pcregrep_exit() before it was defined. I am assuming this was
641        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
642        reported by a user. I've moved the definition above the reference.
643    
644    
645    Version 8.11 10-Dec-2010
646    ------------------------
647    
648    1.  (*THEN) was not working properly if there were untried alternatives prior
649        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
650        backtracked to try for "b" instead of moving to the next alternative branch
651        at the same level (in this case, to look for "c"). The Perl documentation
652        is clear that when (*THEN) is backtracked onto, it goes to the "next
653        alternative in the innermost enclosing group".
654    
655    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
656        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
657        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
658        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
659        (*THEN).
660    
661    3.  If \s appeared in a character class, it removed the VT character from
662        the class, even if it had been included by some previous item, for example
663        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
664        of \s, but is part of the POSIX "space" class.)
665    
666    4.  A partial match never returns an empty string (because you can always
667        match an empty string at the end of the subject); however the checking for
668        an empty string was starting at the "start of match" point. This has been
669        changed to the "earliest inspected character" point, because the returned
670        data for a partial match starts at this character. This means that, for
671        example, /(?<=abc)def/ gives a partial match for the subject "abc"
672        (previously it gave "no match").
673    
674    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
675        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
676        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
677        has an implication that the given string is incomplete (because a partial
678        match is preferred over a full match). For this reason, these items now
679        give a partial match in this situation. [Aside: previously, the one case
680        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
681        match rather than a full match, which was wrong by the old rules, but is
682        now correct.]
683    
684    6.  There was a bug in the handling of #-introduced comments, recognized when
685        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
686        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
687        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
688        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
689        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
690        places in pcre_compile().
691    
692    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
693        comments when looking ahead for named forward references to subpatterns,
694        the only newline sequence it recognized was NL. It now handles newlines
695        according to the set newline convention.
696    
697    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
698        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
699        cater for a lack of strerror(). These oversights have been fixed.
700    
701    9.  Added --match-limit and --recursion-limit to pcregrep.
702    
703    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
704    
705    11. When the -o option was used, pcregrep was setting a return code of 1, even
706        when matches were found, and --line-buffered was not being honoured.
707    
708    12. Added an optional parentheses number to the -o and --only-matching options
709        of pcregrep.
710    
711    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
712        can match an empty string. The code to do it in pcretest and pcredemo
713        needed fixing:
714    
715        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
716            only one byte after an empty string match just before CRLF (this case
717            just got forgotten; "any" and "anycrlf" were OK).
718    
719        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
720            mode when an empty string match preceded an ASCII character followed by
721            a non-ASCII character. (The code for advancing by one character rather
722            than one byte was nonsense.)
723    
724        (c) The pcredemo.c sample program did not have any code at all to handle
725            the cases when CRLF is a valid newline sequence.
726    
727    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
728        as a starting offset was within the subject string. There is now a new
729        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
730        negative or greater than the length of the string. In order to test this,
731        pcretest is extended to allow the setting of negative starting offsets.
732    
733    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
734        starting offset points to the beginning of a UTF-8 character was
735        unnecessarily clumsy. I tidied it up.
736    
737    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
738        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
739    
740    17. Nobody had reported that the --include_dir option, which was added in
741        release 7.7 should have been called --include-dir (hyphen, not underscore)
742        for compatibility with GNU grep. I have changed it to --include-dir, but
743        left --include_dir as an undocumented synonym, and the same for
744        --exclude-dir, though that is not available in GNU grep, at least as of
745        release 2.5.4.
746    
747    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
748        characters from a string of bytes) have been redefined so as not to use
749        loops, in order to improve performance in some environments. At the same
750        time, I abstracted some of the common code into auxiliary macros to save
751        repetition (this should not affect the compiled code).
752    
753    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
754        compile-time error is now given if \c is not followed by an ASCII
755        character, that is, a byte less than 128. (In EBCDIC mode, the code is
756        different, and any byte value is allowed.)
757    
758    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
759        START_OPTIMIZE option, which is now allowed at compile time - but just
760        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
761        to pcregrep and other applications that have no direct access to PCRE
762        options. The new /Y option in pcretest sets this option when calling
763        pcre_compile().
764    
765    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
766        back references. Groups containing recursive back references were forced to
767        be atomic by that change, but in the case of named groups, the amount of
768        memory required was incorrectly computed, leading to "Failed: internal
769        error: code overflow". This has been fixed.
770    
771    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
772        pcretest.c, to avoid build problems in some Borland environments.
773    
774    
775    Version 8.10 25-Jun-2010
776    ------------------------
777    
778    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
779        THEN.
780    
781    2.  (*ACCEPT) was not working when inside an atomic group.
782    
783    3.  Inside a character class, \B is treated as a literal by default, but
784        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
785        causes the error). The code is unchanged, but I tidied the documentation.
786    
787    4.  Inside a character class, PCRE always treated \R and \X as literals,
788        whereas Perl faults them if its -w option is set. I have changed PCRE so
789        that it faults them when PCRE_EXTRA is set.
790    
791    5.  Added support for \N, which always matches any character other than
792        newline. (It is the same as "." when PCRE_DOTALL is not set.)
793    
794    6.  When compiling pcregrep with newer versions of gcc which may have
795        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
796        declared with attribute warn_unused_result" were given. Just casting the
797        result to (void) does not stop the warnings; a more elaborate fudge is
798        needed. I've used a macro to implement this.
799    
800    7.  Minor change to pcretest.c to avoid a compiler warning.
801    
802    8.  Added four artifical Unicode properties to help with an option to make
803        \s etc use properties (see next item). The new properties are: Xan
804        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
805    
806    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
807        use Unicode properties. (*UCP) at the start of a pattern can be used to set
808        this option. Modified pcretest to add /W to test this facility. Added
809        REG_UCP to make it available via the POSIX interface.
810    
811    10. Added --line-buffered to pcregrep.
812    
813    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
814        studied, and the match started with a letter with a code point greater than
815        127 whose first byte was different to the first byte of the other case of
816        the letter, the other case of this starting letter was not recognized
817        (#976).
818    
819    12. If a pattern that was studied started with a repeated Unicode property
820        test, for example, \p{Nd}+, there was the theoretical possibility of
821        setting up an incorrect bitmap of starting bytes, but fortunately it could
822        not have actually happened in practice until change 8 above was made (it
823        added property types that matched character-matching opcodes).
824    
825    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
826        possible starting bytes for non-anchored patterns.
827    
828    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
829        \R, and also a number of cases that involve Unicode properties, both
830        explicit and implicit when PCRE_UCP is set.
831    
832    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
833        input, it could crash or give wrong results if characters with values
834        greater than 0xc0 were present in the subject string. (Detail: it assumed
835        UTF-8 input when processing these items.)
836    
837    16. Added a lot of (int) casts to avoid compiler warnings in systems where
838        size_t is 64-bit (#991).
839    
840    17. Added a check for running out of memory when PCRE is compiled with
841        --disable-stack-for-recursion (#990).
842    
843    18. If the last data line in a file for pcretest does not have a newline on
844        the end, a newline was missing in the output.
845    
846    19. The default pcre_chartables.c file recognizes only ASCII characters (values
847        less than 128) in its various bitmaps. However, there is a facility for
848        generating tables according to the current locale when PCRE is compiled. It
849        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
850        characters, are recognized by isspace() and therefore were getting set in
851        these tables, and indeed these tables seem to approximate to ISO 8859. This
852        caused a problem in UTF-8 mode when pcre_study() was used to create a list
853        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
854        which of course cannot start UTF-8 characters. I have changed the code so
855        that only real ASCII characters (less than 128) and the correct starting
856        bytes for UTF-8 encodings are set for characters greater than 127 when in
857        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
858        altogether.)
859    
860    20. Added the /T option to pcretest so as to be able to run tests with non-
861        standard character tables, thus making it possible to include the tests
862        used for 19 above in the standard set of tests.
863    
864    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
865        reference to a subpattern the other side of a comment that contains an
866        opening parenthesis caused either an internal compiling error, or a
867        reference to the wrong subpattern.
868    
869    
870    Version 8.02 19-Mar-2010
871  ------------------------  ------------------------
872    
873  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.
874    
875  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
876      configured.      configured.
877    
878  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
879      original author of that file, following a query about its status.      original author of that file, following a query about its status.
880    
881    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
882        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
883    
884    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
885        quantifier applied to a forward-referencing subroutine call, could compile
886        incorrect code or give the error "internal error: previously-checked
887        referenced subpattern not found".
888    
889    6.  Both MS Visual Studio and Symbian OS have problems with initializing
890        variables to point to external functions. For these systems, therefore,
891        pcre_malloc etc. are now initialized to local functions that call the
892        relevant global functions.
893    
894    7.  There were two entries missing in the vectors called coptable and poptable
895        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
896        I've fixed the data, and added a kludgy way of testing at compile time that
897        the lengths are correct (equal to the number of opcodes).
898    
899    8.  Following on from 7, I added a similar kludge to check the length of the
900        eint vector in pcreposix.c.
901    
902    9.  Error texts for pcre_compile() are held as one long string to avoid too
903        much relocation at load time. To find a text, the string is searched,
904        counting zeros. There was no check for running off the end of the string,
905        which could happen if a new error number was added without updating the
906        string.
907    
908    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
909    
910    11. \K was not working if it appeared in an atomic group or in a group that
911        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
912        \K is "not well defined" if used in an assertion. PCRE now accepts it if
913        the assertion is positive, but not if it is negative.
914    
915    12. Change 11 fortuitously reduced the size of the stack frame used in the
916        "match()" function of pcre_exec.c by one pointer. Forthcoming
917        implementation of support for (*MARK) will need an extra pointer on the
918        stack; I have reserved it now, so that the stack frame size does not
919        decrease.
920    
921    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
922        item in branch that calls a recursion is a subroutine call - as in the
923        second branch in the above example - was incorrectly given the compile-
924        time error "recursive call could loop indefinitely" because pcre_compile()
925        was not correctly checking the subroutine for matching a non-empty string.
926    
927    14. The checks for overrunning compiling workspace could trigger after an
928        overrun had occurred. This is a "should never occur" error, but it can be
929        triggered by pathological patterns such as hundreds of nested parentheses.
930        The checks now trigger 100 bytes before the end of the workspace.
931    
932    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
933    
934    
935  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010

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