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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.01 06-Jan-10  Version 8.21
5  ----------------------  ------------
7    1.  Updating the JIT compiler.
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
16    4.  Mark settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
45    10. Add a cast and remove a redundant test from the code.
47    11. JIT should use pcre_malloc/pcre_free for allocation.
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
53    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
55    14. Perl does not support \N without a following name in a [] class; PCRE now
56        also gives an error.
58    15. If a forward reference was repeated with an upper limit of around 2000,
59        it caused the error "internal error: overran compiling workspace". This
60        is now checked, and causes "too many forward references" instead.
62    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
63        incorrectly expecting the subject to contain another "a" after the start.
65    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
66        in the match, the SKIP should be ignored. This was not happening; instead
67        the SKIP was being treated as NOMATCH. For patterns such as
68        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
69        tested.
71    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
72        now much more compatible with Perl, in particular in cases where the result
73        is a non-match for a non-anchored pattern. For example, if
74        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
75        "m", where previously it did not return a name. A side effect of this
76        change is that for partial matches, the last encountered mark name is
77        returned, as for non matches. A number of tests that were previously not
78        Perl-compatible have been moved into the Perl-compatible test files. The
79        refactoring has had the pleasing side effect of removing one argument from
80        the match() function, thus reducing its stack requirements.
83    Version 8.20 21-Oct-2011
84    ------------------------
86    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
87        a POSIX class. After further experiments with Perl, which convinced me that
88        Perl has bugs and confusions, a closing square bracket is no longer allowed
89        in a POSIX name. This bug also affected patterns with classes that started
90        with full stops.
92    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
93        captured substring, but while checking the failing first alternative,
94        substring 1 is temporarily captured. If the output vector supplied to
95        pcre_exec() was not big enough for this capture, the yield of the function
96        was still zero ("insufficient space for captured substrings"). This cannot
97        be totally fixed without adding another stack variable, which seems a lot
98        of expense for a edge case. However, I have improved the situation in cases
99        such as /(a)(b)x|abc/ matched against "abc", where the return code
100        indicates that fewer than the maximum number of slots in the ovector have
101        been set.
103    3.  Related to (2) above: when there are more back references in a pattern than
104        slots in the output vector, pcre_exec() uses temporary memory during
105        matching, and copies in the captures as far as possible afterwards. It was
106        using the entire output vector, but this conflicts with the specification
107        that only 2/3 is used for passing back captured substrings. Now it uses
108        only the first 2/3, for compatibility. This is, of course, another edge
109        case.
111    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
112        main code base, and can be used by building with --enable-jit. When this is
113        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
114        runtime --no-jit option is given.
116    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
117        ovector, the return from the function was zero, implying that there were
118        other matches that did not fit. The correct "exactly full" value is now
119        returned.
121    6.  If a subpattern that was called recursively or as a subroutine contained
122        (*PRUNE) or any other control that caused it to give a non-standard return,
123        invalid errors such as "Error -26 (nested recursion at the same subject
124        position)" or even infinite loops could occur.
126    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
127        computing the minimum length on reaching *ACCEPT, and so ended up with the
128        wrong value of 1 rather than 0. Further investigation indicates that
129        computing a minimum subject length in the presence of *ACCEPT is difficult
130        (think back references, subroutine calls), and so I have changed the code
131        so that no minimum is registered for a pattern that contains *ACCEPT.
133    8.  If (*THEN) was present in the first (true) branch of a conditional group,
134        it was not handled as intended. [But see 16 below.]
136    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
137        Sheri Pierce.
139    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
140        the first byte in a match must be "a".
142    11. Change 17 for 8.13 increased the recursion depth for patterns like
143        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
144        pattern contains any instances of (*THEN). If it does not, the old
145        optimizations are restored. It would be nice to do this on a per-group
146        basis, but at the moment that is not feasible.
148    12. In some environments, the output of pcretest -C is CRLF terminated. This
149        broke RunTest's code that checks for the link size. A single white space
150        character after the value is now allowed for.
152    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
153        For "fr", it uses the Windows-specific input and output files.
155    14. If (*THEN) appeared in a group that was called recursively or as a
156        subroutine, it did not work as intended. [But see next item.]
158    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
159        pattern fragments (but not containing any | characters). If A and B are
160        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
161        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
162        D. In other words, Perl considers parentheses that do not contain any |
163        characters to be part of a surrounding alternative, whereas PCRE was
164        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
165        differently. PCRE now behaves in the same way as Perl, except in the case
166        of subroutine/recursion calls such as (?1) which have in any case always
167        been different (but PCRE had them first :-).
169    16. Related to 15 above: Perl does not treat the | in a conditional group as
170        creating alternatives. Such a group is treated in the same way as an
171        ordinary group without any | characters when processing (*THEN). PCRE has
172        been changed to match Perl's behaviour.
174    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
175        RunGrepTest script failed.
177    18. Change 22 for version 13 caused atomic groups to use more stack. This is
178        inevitable for groups that contain captures, but it can lead to a lot of
179        stack use in large patterns. The old behaviour has been restored for atomic
180        groups that do not contain any capturing parentheses.
182    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
183        suppress the check for a minimum subject length at run time. (If it was
184        given to pcre_exec() or pcre_dfa_exec() it did work.)
186    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
187        fail to work when decoding hex characters in data strings in EBCDIC
188        environments.
190    21. It appears that in at least one Mac OS environment, the isxdigit() function
191        is implemented as a macro that evaluates to its argument more than once,
192        contravening the C 90 Standard (I haven't checked a later standard). There
193        was an instance in pcretest which caused it to go wrong when processing
194        \x{...} escapes in subject strings. The has been rewritten to avoid using
195        things like p++ in the argument of isxdigit().
198    Version 8.13 16-Aug-2011
199    ------------------------
201    1.  The Unicode data tables have been updated to Unicode 6.0.0.
203    2.  Two minor typos in pcre_internal.h have been fixed.
205    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
206        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
207        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
209    4.  There were a number of related bugs in the code for matching backrefences
210        caselessly in UTF-8 mode when codes for the characters concerned were
211        different numbers of bytes. For example, U+023A and U+2C65 are an upper
212        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
213        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
214        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
215        2-byte code at the end of the subject (it thought there wasn't enough data
216        left).
218    5.  Comprehensive information about what went wrong is now returned by
219        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
220        as the output vector has at least 2 elements. The offset of the start of
221        the failing character and a reason code are placed in the vector.
223    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
224        now returned is for the first byte of the failing character, instead of the
225        last byte inspected. This is an incompatible change, but I hope it is small
226        enough not to be a problem. It makes the returned offset consistent with
227        pcre_exec() and pcre_dfa_exec().
229    7.  pcretest now gives a text phrase as well as the error number when
230        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
231        failure, the offset and reason code are output.
233    8.  When \R was used with a maximizing quantifier it failed to skip backwards
234        over a \r\n pair if the subsequent match failed. Instead, it just skipped
235        back over a single character (\n). This seems wrong (because it treated the
236        two characters as a single entity when going forwards), conflicts with the
237        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
238        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
239        has been changed.
241    9.  Some internal refactoring has changed the processing so that the handling
242        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
243        time (the PCRE_DOTALL option was changed this way some time ago: version
244        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
245        which was always a bit of a fudge. It also means that there is one less
246        argument for the match() function, which reduces its stack requirements
247        slightly. This change also fixes an incompatibility with Perl: the pattern
248        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
250    10. More internal refactoring has drastically reduced the number of recursive
251        calls to match() for possessively repeated groups such as (abc)++ when
252        using pcre_exec().
254    11. While implementing 10, a number of bugs in the handling of groups were
255        discovered and fixed:
257        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
258        (a|)*(?1) gave a compile-time internal error.
259        ((a|)+)+  did not notice that the outer group could match an empty string.
260        (^a|^)+   was not marked as anchored.
261        (.*a|.*)+ was not marked as matching at start or after a newline.
263    12. Yet more internal refactoring has removed another argument from the match()
264        function. Special calls to this function are now indicated by setting a
265        value in a variable in the "match data" data block.
267    13. Be more explicit in pcre_study() instead of relying on "default" for
268        opcodes that mean there is no starting character; this means that when new
269        ones are added and accidentally left out of pcre_study(), testing should
270        pick them up.
272    14. The -s option of pcretest has been documented for ages as being an old
273        synonym of -m (show memory usage). I have changed it to mean "force study
274        for every regex", that is, assume /S for every regex. This is similar to -i
275        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
276        using it. It makes it easier to run collections of tests with and without
277        study enabled, and thereby test pcre_study() more easily. All the standard
278        tests are now run with and without -s (but some patterns can be marked as
279        "never study" - see 20 below).
281    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
282        restoration of the capturing data to the outer values was not happening
283        correctly.
285    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
286        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
287        pattern had matched an empty string, and so incorrectly returned a no
288        match.
290    17. There was optimizing code for the last branch of non-capturing parentheses,
291        and also for the obeyed branch of a conditional subexpression, which used
292        tail recursion to cut down on stack usage. Unfortunately, now that there is
293        the possibility of (*THEN) occurring in these branches, tail recursion is
294        no longer possible because the return has to be checked for (*THEN). These
295        two optimizations have therefore been removed. [But see 8.20/11 above.]
297    18. If a pattern containing \R was studied, it was assumed that \R always
298        matched two bytes, thus causing the minimum subject length to be
299        incorrectly computed because \R can also match just one byte.
301    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
302        was incorrectly computed.
304    20. If /S is present twice on a test pattern in pcretest input, it now
305        *disables* studying, thereby overriding the use of -s on the command line
306        (see 14 above). This is necessary for one or two tests to keep the output
307        identical in both cases.
309    21. When (*ACCEPT) was used in an assertion that matched an empty string and
310        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
312    22. When an atomic group that contained a capturing parenthesis was
313        successfully matched, but the branch in which it appeared failed, the
314        capturing was not being forgotten if a higher numbered group was later
315        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
316        group 1 to "a", when in fact it should be unset. This applied to multi-
317        branched capturing and non-capturing groups, repeated or not, and also to
318        positive assertions (capturing in negative assertions does not happen
319        in PCRE) and also to nested atomic groups.
321    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
322        subject after a captured substring, to make it easier to tell which of a
323        number of identical substrings has been captured.
325    24. The way atomic groups are processed by pcre_exec() has been changed so that
326        if they are repeated, backtracking one repetition now resets captured
327        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
328        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
329        "aaa". Previously, it would have been "a". As part of this code
330        refactoring, the way recursive calls are handled has also been changed.
332    25. If an assertion condition captured any substrings, they were not passed
333        back unless some other capturing happened later. For example, if
334        (?(?=(a))a) was matched against "a", no capturing was returned.
336    26. When studying a pattern that contained subroutine calls or assertions,
337        the code for finding the minimum length of a possible match was handling
338        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
339        group 1 called group 2 while simultaneously a separate group 2 called group
340        1). A stack overflow occurred in this case. I have fixed this by limiting
341        the recursion depth to 10.
343    27. Updated RunTest.bat in the distribution to the version supplied by Tom
344        Fortmann. This supports explicit test numbers on the command line, and has
345        argument validation and error reporting.
347    28. An instance of \X with an unlimited repeat could fail if at any point the
348        first character it looked at was a mark character.
350    29. Some minor code refactoring concerning Unicode properties and scripts
351        should reduce the stack requirement of match() slightly.
353    30. Added the '=' option to pcretest to check the setting of unused capturing
354        slots at the end of the pattern, which are documented as being -1, but are
355        not included in the return count.
357    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
358        compiled something random. Now it gives a compile-time error (as does
359        Perl).
361    32. A *MARK encountered during the processing of a positive assertion is now
362        recorded and passed back (compatible with Perl).
364    33. If --only-matching or --colour was set on a pcregrep call whose pattern
365        had alternative anchored branches, the search for a second match in a line
366        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
367        matched the line "0102" twice. The same bug affected patterns that started
368        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
369        twice.
371    34. Previously, PCRE did not allow quantification of assertions. However, Perl
372        does, and because of capturing effects, quantifying parenthesized
373        assertions may at times be useful. Quantifiers are now allowed for
374        parenthesized assertions.
376    35. A minor code tidy in pcre_compile() when checking options for \R usage.
378    36. \g was being checked for fancy things in a character class, when it should
379        just be a literal "g".
381    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
382        appearance of a nested POSIX class supersedes an apparent external class.
383        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
384        unescaped square brackets may also appear as part of class names. For
385        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
386        more like Perl. (But see 8.20/1 above.)
388    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
389        was because it thought it was \N{name}, which is not supported).
391    39. Add minix to OS list not supporting the -S option in pcretest.
393    40. PCRE tries to detect cases of infinite recursion at compile time, but it
394        cannot analyze patterns in sufficient detail to catch mutual recursions
395        such as ((?1))((?2)). There is now a runtime test that gives an error if a
396        subgroup is called recursively as a subpattern for a second time at the
397        same position in the subject string. In previous releases this might have
398        been caught by the recursion limit, or it might have run out of stack.
400    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
401        happen only once. PCRE was, however incorrectly giving a compile time error
402        "recursive call could loop indefinitely" because it cannot analyze the
403        pattern in sufficient detail. The compile time test no longer happens when
404        PCRE is compiling a conditional subpattern, but actual runaway loops are
405        now caught at runtime (see 40 above).
407    42. It seems that Perl allows any characters other than a closing parenthesis
408        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
409        has been changed to be the same.
411    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
412        as not to get warnings when autogen.sh is called. Also changed
413        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
415    44. To help people who use pcregrep to scan files containing exceedingly long
416        lines, the following changes have been made:
418        (a) The default value of the buffer size parameter has been increased from
419            8K to 20K. (The actual buffer used is three times this size.)
421        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
422            PCRE is built.
424        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
425            to be set at run time.
427        (d) Numerical values in pcregrep options can be followed by K or M, for
428            example --buffer-size=50K.
430        (e) If a line being scanned overflows pcregrep's buffer, an error is now
431            given and the return code is set to 2.
433    45. Add a pointer to the latest mark to the callout data block.
435    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
436        partial match of an empty string instead of no match. This was specific to
437        the use of ".".
439    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
440        complete match instead of a partial match. This bug was dependent on both
441        the PCRE_UTF8 and PCRE_DOTALL options being set.
443    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
444        starting byte set, because \b was not being ignored.
447    Version 8.12 15-Jan-2011
448    ------------------------
450    1.  Fixed some typos in the markup of the man pages, and wrote a script that
451        checks for such things as part of the documentation building process.
453    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
454        --match-limit and --recursion-limit options (added for 8.11). In
455        particular, this made one of the standard tests fail. (The integer value
456        went into the wrong half of a long int.)
458    3.  If the --colour option was given to pcregrep with -v (invert match), it
459        did strange things, either producing crazy output, or crashing. It should,
460        of course, ignore a request for colour when reporting lines that do not
461        match.
463    4.  Another pcregrep bug caused similar problems if --colour was specified with
464        -M (multiline) and the pattern match finished with a line ending.
466    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
467        matched in multiline mode, the following line was shown as part of the
468        match. This seems wrong, so I have changed it.
470    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
471        the check for further matches in the same line (so they could be coloured)
472        to overrun the end of the current line. If another match was found, it was
473        incorrectly shown (and then shown again when found in the next line).
475    7.  If pcregrep was compiled under Windows, there was a reference to the
476        function pcregrep_exit() before it was defined. I am assuming this was
477        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
478        reported by a user. I've moved the definition above the reference.
481    Version 8.11 10-Dec-2010
482    ------------------------
484    1.  (*THEN) was not working properly if there were untried alternatives prior
485        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
486        backtracked to try for "b" instead of moving to the next alternative branch
487        at the same level (in this case, to look for "c"). The Perl documentation
488        is clear that when (*THEN) is backtracked onto, it goes to the "next
489        alternative in the innermost enclosing group".
491    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
492        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
493        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
494        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
495        (*THEN).
497    3.  If \s appeared in a character class, it removed the VT character from
498        the class, even if it had been included by some previous item, for example
499        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
500        of \s, but is part of the POSIX "space" class.)
502    4.  A partial match never returns an empty string (because you can always
503        match an empty string at the end of the subject); however the checking for
504        an empty string was starting at the "start of match" point. This has been
505        changed to the "earliest inspected character" point, because the returned
506        data for a partial match starts at this character. This means that, for
507        example, /(?<=abc)def/ gives a partial match for the subject "abc"
508        (previously it gave "no match").
510    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
511        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
512        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
513        has an implication that the given string is incomplete (because a partial
514        match is preferred over a full match). For this reason, these items now
515        give a partial match in this situation. [Aside: previously, the one case
516        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
517        match rather than a full match, which was wrong by the old rules, but is
518        now correct.]
520    6.  There was a bug in the handling of #-introduced comments, recognized when
521        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
522        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
523        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
524        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
525        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
526        places in pcre_compile().
528    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
529        comments when looking ahead for named forward references to subpatterns,
530        the only newline sequence it recognized was NL. It now handles newlines
531        according to the set newline convention.
533    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
534        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
535        cater for a lack of strerror(). These oversights have been fixed.
537    9.  Added --match-limit and --recursion-limit to pcregrep.
539    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
541    11. When the -o option was used, pcregrep was setting a return code of 1, even
542        when matches were found, and --line-buffered was not being honoured.
544    12. Added an optional parentheses number to the -o and --only-matching options
545        of pcregrep.
547    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
548        can match an empty string. The code to do it in pcretest and pcredemo
549        needed fixing:
551        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
552            only one byte after an empty string match just before CRLF (this case
553            just got forgotten; "any" and "anycrlf" were OK).
555        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
556            mode when an empty string match preceded an ASCII character followed by
557            a non-ASCII character. (The code for advancing by one character rather
558            than one byte was nonsense.)
560        (c) The pcredemo.c sample program did not have any code at all to handle
561            the cases when CRLF is a valid newline sequence.
563    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
564        as a starting offset was within the subject string. There is now a new
565        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
566        negative or greater than the length of the string. In order to test this,
567        pcretest is extended to allow the setting of negative starting offsets.
569    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
570        starting offset points to the beginning of a UTF-8 character was
571        unnecessarily clumsy. I tidied it up.
573    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
574        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
576    17. Nobody had reported that the --include_dir option, which was added in
577        release 7.7 should have been called --include-dir (hyphen, not underscore)
578        for compatibility with GNU grep. I have changed it to --include-dir, but
579        left --include_dir as an undocumented synonym, and the same for
580        --exclude-dir, though that is not available in GNU grep, at least as of
581        release 2.5.4.
583    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
584        characters from a string of bytes) have been redefined so as not to use
585        loops, in order to improve performance in some environments. At the same
586        time, I abstracted some of the common code into auxiliary macros to save
587        repetition (this should not affect the compiled code).
589    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
590        compile-time error is now given if \c is not followed by an ASCII
591        character, that is, a byte less than 128. (In EBCDIC mode, the code is
592        different, and any byte value is allowed.)
594    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
595        START_OPTIMIZE option, which is now allowed at compile time - but just
596        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
597        to pcregrep and other applications that have no direct access to PCRE
598        options. The new /Y option in pcretest sets this option when calling
599        pcre_compile().
601    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
602        back references. Groups containing recursive back references were forced to
603        be atomic by that change, but in the case of named groups, the amount of
604        memory required was incorrectly computed, leading to "Failed: internal
605        error: code overflow". This has been fixed.
607    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
608        pcretest.c, to avoid build problems in some Borland environments.
611    Version 8.10 25-Jun-2010
612    ------------------------
614    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
615        THEN.
617    2.  (*ACCEPT) was not working when inside an atomic group.
619    3.  Inside a character class, \B is treated as a literal by default, but
620        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
621        causes the error). The code is unchanged, but I tidied the documentation.
623    4.  Inside a character class, PCRE always treated \R and \X as literals,
624        whereas Perl faults them if its -w option is set. I have changed PCRE so
625        that it faults them when PCRE_EXTRA is set.
627    5.  Added support for \N, which always matches any character other than
628        newline. (It is the same as "." when PCRE_DOTALL is not set.)
630    6.  When compiling pcregrep with newer versions of gcc which may have
631        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
632        declared with attribute warn_unused_result" were given. Just casting the
633        result to (void) does not stop the warnings; a more elaborate fudge is
634        needed. I've used a macro to implement this.
636    7.  Minor change to pcretest.c to avoid a compiler warning.
638    8.  Added four artifical Unicode properties to help with an option to make
639        \s etc use properties (see next item). The new properties are: Xan
640        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
642    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
643        use Unicode properties. (*UCP) at the start of a pattern can be used to set
644        this option. Modified pcretest to add /W to test this facility. Added
645        REG_UCP to make it available via the POSIX interface.
647    10. Added --line-buffered to pcregrep.
649    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
650        studied, and the match started with a letter with a code point greater than
651        127 whose first byte was different to the first byte of the other case of
652        the letter, the other case of this starting letter was not recognized
653        (#976).
655    12. If a pattern that was studied started with a repeated Unicode property
656        test, for example, \p{Nd}+, there was the theoretical possibility of
657        setting up an incorrect bitmap of starting bytes, but fortunately it could
658        not have actually happened in practice until change 8 above was made (it
659        added property types that matched character-matching opcodes).
661    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
662        possible starting bytes for non-anchored patterns.
664    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
665        \R, and also a number of cases that involve Unicode properties, both
666        explicit and implicit when PCRE_UCP is set.
668    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
669        input, it could crash or give wrong results if characters with values
670        greater than 0xc0 were present in the subject string. (Detail: it assumed
671        UTF-8 input when processing these items.)
673    16. Added a lot of (int) casts to avoid compiler warnings in systems where
674        size_t is 64-bit (#991).
676    17. Added a check for running out of memory when PCRE is compiled with
677        --disable-stack-for-recursion (#990).
679    18. If the last data line in a file for pcretest does not have a newline on
680        the end, a newline was missing in the output.
682    19. The default pcre_chartables.c file recognizes only ASCII characters (values
683        less than 128) in its various bitmaps. However, there is a facility for
684        generating tables according to the current locale when PCRE is compiled. It
685        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
686        characters, are recognized by isspace() and therefore were getting set in
687        these tables, and indeed these tables seem to approximate to ISO 8859. This
688        caused a problem in UTF-8 mode when pcre_study() was used to create a list
689        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
690        which of course cannot start UTF-8 characters. I have changed the code so
691        that only real ASCII characters (less than 128) and the correct starting
692        bytes for UTF-8 encodings are set for characters greater than 127 when in
693        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
694        altogether.)
696    20. Added the /T option to pcretest so as to be able to run tests with non-
697        standard character tables, thus making it possible to include the tests
698        used for 19 above in the standard set of tests.
700    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
701        reference to a subpattern the other side of a comment that contains an
702        opening parenthesis caused either an internal compiling error, or a
703        reference to the wrong subpattern.
706    Version 8.02 19-Mar-2010
707    ------------------------
709    1.  The Unicode data tables have been updated to Unicode 5.2.0.
711    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
712        configured.
714    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
715        original author of that file, following a query about its status.
717    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
718        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
720    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
721        quantifier applied to a forward-referencing subroutine call, could compile
722        incorrect code or give the error "internal error: previously-checked
723        referenced subpattern not found".
725    6.  Both MS Visual Studio and Symbian OS have problems with initializing
726        variables to point to external functions. For these systems, therefore,
727        pcre_malloc etc. are now initialized to local functions that call the
728        relevant global functions.
730    7.  There were two entries missing in the vectors called coptable and poptable
731        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
732        I've fixed the data, and added a kludgy way of testing at compile time that
733        the lengths are correct (equal to the number of opcodes).
735    8.  Following on from 7, I added a similar kludge to check the length of the
736        eint vector in pcreposix.c.
738    9.  Error texts for pcre_compile() are held as one long string to avoid too
739        much relocation at load time. To find a text, the string is searched,
740        counting zeros. There was no check for running off the end of the string,
741        which could happen if a new error number was added without updating the
742        string.
744    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
746    11. \K was not working if it appeared in an atomic group or in a group that
747        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
748        \K is "not well defined" if used in an assertion. PCRE now accepts it if
749        the assertion is positive, but not if it is negative.
751    12. Change 11 fortuitously reduced the size of the stack frame used in the
752        "match()" function of pcre_exec.c by one pointer. Forthcoming
753        implementation of support for (*MARK) will need an extra pointer on the
754        stack; I have reserved it now, so that the stack frame size does not
755        decrease.
757    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
758        item in branch that calls a recursion is a subroutine call - as in the
759        second branch in the above example - was incorrectly given the compile-
760        time error "recursive call could loop indefinitely" because pcre_compile()
761        was not correctly checking the subroutine for matching a non-empty string.
763    14. The checks for overrunning compiling workspace could trigger after an
764        overrun had occurred. This is a "should never occur" error, but it can be
765        triggered by pathological patterns such as hundreds of nested parentheses.
766        The checks now trigger 100 bytes before the end of the workspace.
768    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
771    Version 8.01 19-Jan-2010
772    ------------------------
774  1.  If a pattern contained a conditional subpattern with only one branch (in  1.  If a pattern contained a conditional subpattern with only one branch (in
775      particular, this includes all (DEFINE) patterns), a call to pcre_study()      particular, this includes all (*DEFINE) patterns), a call to pcre_study()
776      computed the wrong minimum data length (which is of course zero for such      computed the wrong minimum data length (which is of course zero for such
777      subpatterns).      subpatterns). This could cause incorrect "no match" results.
779  2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of  2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
780      the pattern is reset in the first branch, pcre_compile() failed with      the pattern is reset in the first branch, pcre_compile() failed with
# Line 61  Version 8.01 06-Jan-10 Line 828  Version 8.01 06-Jan-10
828      custom one, because of the following reported problem in Windows:      custom one, because of the following reported problem in Windows:
830        - libbz2 uses the Pascal calling convention (WINAPI) for the functions        - libbz2 uses the Pascal calling convention (WINAPI) for the functions
831          under Win32.            under Win32.
832        - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",        - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
833          therefore missing the function definition.            therefore missing the function definition.
834        - The compiler thus generates a "C" signature for the test function.        - The compiler thus generates a "C" signature for the test function.
835        - The linker fails to find the "C" function.        - The linker fails to find the "C" function.
836        - PCRE fails to configure if asked to do so against libbz2.        - PCRE fails to configure if asked to do so against libbz2.
# Line 113  Version 8.01 06-Jan-10 Line 880  Version 8.01 06-Jan-10
880      equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for      equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
881      instance, but it only takes 2 args instead of 3!"      instance, but it only takes 2 args instead of 3!"
883    18. A subtle bug concerned with back references has been fixed by a change of
884        specification, with a corresponding code fix. A pattern such as
885        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
886        refers, was giving matches when it shouldn't. For example, xa=xaaa would
887        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
888        same bug. Such groups have to be quantified to be useful, or contained
889        inside another quantified group. (If there's no repetition, the reference
890        can never match.) The problem arises because, having left the group and
891        moved on to the rest of the pattern, a later failure that backtracks into
892        the group uses the captured value from the final iteration of the group
893        rather than the correct earlier one. I have fixed this in PCRE by forcing
894        any group that contains a reference to itself to be an atomic group; that
895        is, there cannot be any backtracking into it once it has completed. This is
896        similar to recursive and subroutine calls.
899  Version 8.00 19-Oct-09  Version 8.00 19-Oct-09
900  ----------------------  ----------------------

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