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revision 457 by ph10, Sat Oct 3 16:24:08 2009 UTC revision 740 by zherczeg, Mon Oct 31 06:10:14 2011 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.21
5    ------------
6    
7    1.  Updating the JIT compiler.
8    
9    
10    Version 8.20 21-Oct-2011
11    ------------------------
12    
13    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
14        a POSIX class. After further experiments with Perl, which convinced me that
15        Perl has bugs and confusions, a closing square bracket is no longer allowed
16        in a POSIX name. This bug also affected patterns with classes that started
17        with full stops.
18    
19    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
20        captured substring, but while checking the failing first alternative,
21        substring 1 is temporarily captured. If the output vector supplied to
22        pcre_exec() was not big enough for this capture, the yield of the function
23        was still zero ("insufficient space for captured substrings"). This cannot
24        be totally fixed without adding another stack variable, which seems a lot
25        of expense for a edge case. However, I have improved the situation in cases
26        such as /(a)(b)x|abc/ matched against "abc", where the return code
27        indicates that fewer than the maximum number of slots in the ovector have
28        been set.
29    
30    3.  Related to (2) above: when there are more back references in a pattern than
31        slots in the output vector, pcre_exec() uses temporary memory during
32        matching, and copies in the captures as far as possible afterwards. It was
33        using the entire output vector, but this conflicts with the specification
34        that only 2/3 is used for passing back captured substrings. Now it uses
35        only the first 2/3, for compatibility. This is, of course, another edge
36        case.
37    
38    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
39        main code base, and can be used by building with --enable-jit. When this is
40        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
41        runtime --no-jit option is given.
42    
43    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
44        ovector, the return from the function was zero, implying that there were
45        other matches that did not fit. The correct "exactly full" value is now
46        returned.
47    
48    6.  If a subpattern that was called recursively or as a subroutine contained
49        (*PRUNE) or any other control that caused it to give a non-standard return,
50        invalid errors such as "Error -26 (nested recursion at the same subject
51        position)" or even infinite loops could occur.
52    
53    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
54        computing the minimum length on reaching *ACCEPT, and so ended up with the
55        wrong value of 1 rather than 0. Further investigation indicates that
56        computing a minimum subject length in the presence of *ACCEPT is difficult
57        (think back references, subroutine calls), and so I have changed the code
58        so that no minimum is registered for a pattern that contains *ACCEPT.
59    
60    8.  If (*THEN) was present in the first (true) branch of a conditional group,
61        it was not handled as intended. [But see 16 below.]
62    
63    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
64        Sheri Pierce.
65    
66    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
67        the first byte in a match must be "a".
68    
69    11. Change 17 for 8.13 increased the recursion depth for patterns like
70        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
71        pattern contains any instances of (*THEN). If it does not, the old
72        optimizations are restored. It would be nice to do this on a per-group
73        basis, but at the moment that is not feasible.
74    
75    12. In some environments, the output of pcretest -C is CRLF terminated. This
76        broke RunTest's code that checks for the link size. A single white space
77        character after the value is now allowed for.
78    
79    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
80        For "fr", it uses the Windows-specific input and output files.
81    
82    14. If (*THEN) appeared in a group that was called recursively or as a
83        subroutine, it did not work as intended. [But see next item.]
84    
85    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
86        pattern fragments (but not containing any | characters). If A and B are
87        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
88        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
89        D. In other words, Perl considers parentheses that do not contain any |
90        characters to be part of a surrounding alternative, whereas PCRE was
91        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
92        differently. PCRE now behaves in the same way as Perl, except in the case
93        of subroutine/recursion calls such as (?1) which have in any case always
94        been different (but PCRE had them first :-).
95    
96    16. Related to 15 above: Perl does not treat the | in a conditional group as
97        creating alternatives. Such a group is treated in the same way as an
98        ordinary group without any | characters when processing (*THEN). PCRE has
99        been changed to match Perl's behaviour.
100    
101    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
102        RunGrepTest script failed.
103    
104    18. Change 22 for version 13 caused atomic groups to use more stack. This is
105        inevitable for groups that contain captures, but it can lead to a lot of
106        stack use in large patterns. The old behaviour has been restored for atomic
107        groups that do not contain any capturing parentheses.
108    
109    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
110        suppress the check for a minimum subject length at run time. (If it was
111        given to pcre_exec() or pcre_dfa_exec() it did work.)
112    
113    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
114        fail to work when decoding hex characters in data strings in EBCDIC
115        environments.
116    
117    21. It appears that in at least one Mac OS environment, the isxdigit() function
118        is implemented as a macro that evaluates to its argument more than once,
119        contravening the C 90 Standard (I haven't checked a later standard). There
120        was an instance in pcretest which caused it to go wrong when processing
121        \x{...} escapes in subject strings. The has been rewritten to avoid using
122        things like p++ in the argument of isxdigit().
123    
124    
125    Version 8.13 16-Aug-2011
126    ------------------------
127    
128    1.  The Unicode data tables have been updated to Unicode 6.0.0.
129    
130    2.  Two minor typos in pcre_internal.h have been fixed.
131    
132    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
133        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
134        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
135    
136    4.  There were a number of related bugs in the code for matching backrefences
137        caselessly in UTF-8 mode when codes for the characters concerned were
138        different numbers of bytes. For example, U+023A and U+2C65 are an upper
139        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
140        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
141        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
142        2-byte code at the end of the subject (it thought there wasn't enough data
143        left).
144    
145    5.  Comprehensive information about what went wrong is now returned by
146        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
147        as the output vector has at least 2 elements. The offset of the start of
148        the failing character and a reason code are placed in the vector.
149    
150    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
151        now returned is for the first byte of the failing character, instead of the
152        last byte inspected. This is an incompatible change, but I hope it is small
153        enough not to be a problem. It makes the returned offset consistent with
154        pcre_exec() and pcre_dfa_exec().
155    
156    7.  pcretest now gives a text phrase as well as the error number when
157        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
158        failure, the offset and reason code are output.
159    
160    8.  When \R was used with a maximizing quantifier it failed to skip backwards
161        over a \r\n pair if the subsequent match failed. Instead, it just skipped
162        back over a single character (\n). This seems wrong (because it treated the
163        two characters as a single entity when going forwards), conflicts with the
164        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
165        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
166        has been changed.
167    
168    9.  Some internal refactoring has changed the processing so that the handling
169        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
170        time (the PCRE_DOTALL option was changed this way some time ago: version
171        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
172        which was always a bit of a fudge. It also means that there is one less
173        argument for the match() function, which reduces its stack requirements
174        slightly. This change also fixes an incompatibility with Perl: the pattern
175        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
176    
177    10. More internal refactoring has drastically reduced the number of recursive
178        calls to match() for possessively repeated groups such as (abc)++ when
179        using pcre_exec().
180    
181    11. While implementing 10, a number of bugs in the handling of groups were
182        discovered and fixed:
183    
184        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
185        (a|)*(?1) gave a compile-time internal error.
186        ((a|)+)+  did not notice that the outer group could match an empty string.
187        (^a|^)+   was not marked as anchored.
188        (.*a|.*)+ was not marked as matching at start or after a newline.
189    
190    12. Yet more internal refactoring has removed another argument from the match()
191        function. Special calls to this function are now indicated by setting a
192        value in a variable in the "match data" data block.
193    
194    13. Be more explicit in pcre_study() instead of relying on "default" for
195        opcodes that mean there is no starting character; this means that when new
196        ones are added and accidentally left out of pcre_study(), testing should
197        pick them up.
198    
199    14. The -s option of pcretest has been documented for ages as being an old
200        synonym of -m (show memory usage). I have changed it to mean "force study
201        for every regex", that is, assume /S for every regex. This is similar to -i
202        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
203        using it. It makes it easier to run collections of tests with and without
204        study enabled, and thereby test pcre_study() more easily. All the standard
205        tests are now run with and without -s (but some patterns can be marked as
206        "never study" - see 20 below).
207    
208    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
209        restoration of the capturing data to the outer values was not happening
210        correctly.
211    
212    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
213        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
214        pattern had matched an empty string, and so incorrectly returned a no
215        match.
216    
217    17. There was optimizing code for the last branch of non-capturing parentheses,
218        and also for the obeyed branch of a conditional subexpression, which used
219        tail recursion to cut down on stack usage. Unfortunately, now that there is
220        the possibility of (*THEN) occurring in these branches, tail recursion is
221        no longer possible because the return has to be checked for (*THEN). These
222        two optimizations have therefore been removed. [But see 8.20/11 above.]
223    
224    18. If a pattern containing \R was studied, it was assumed that \R always
225        matched two bytes, thus causing the minimum subject length to be
226        incorrectly computed because \R can also match just one byte.
227    
228    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
229        was incorrectly computed.
230    
231    20. If /S is present twice on a test pattern in pcretest input, it now
232        *disables* studying, thereby overriding the use of -s on the command line
233        (see 14 above). This is necessary for one or two tests to keep the output
234        identical in both cases.
235    
236    21. When (*ACCEPT) was used in an assertion that matched an empty string and
237        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
238    
239    22. When an atomic group that contained a capturing parenthesis was
240        successfully matched, but the branch in which it appeared failed, the
241        capturing was not being forgotten if a higher numbered group was later
242        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
243        group 1 to "a", when in fact it should be unset. This applied to multi-
244        branched capturing and non-capturing groups, repeated or not, and also to
245        positive assertions (capturing in negative assertions does not happen
246        in PCRE) and also to nested atomic groups.
247    
248    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
249        subject after a captured substring, to make it easier to tell which of a
250        number of identical substrings has been captured.
251    
252    24. The way atomic groups are processed by pcre_exec() has been changed so that
253        if they are repeated, backtracking one repetition now resets captured
254        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
255        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
256        "aaa". Previously, it would have been "a". As part of this code
257        refactoring, the way recursive calls are handled has also been changed.
258    
259    25. If an assertion condition captured any substrings, they were not passed
260        back unless some other capturing happened later. For example, if
261        (?(?=(a))a) was matched against "a", no capturing was returned.
262    
263    26. When studying a pattern that contained subroutine calls or assertions,
264        the code for finding the minimum length of a possible match was handling
265        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
266        group 1 called group 2 while simultaneously a separate group 2 called group
267        1). A stack overflow occurred in this case. I have fixed this by limiting
268        the recursion depth to 10.
269    
270    27. Updated RunTest.bat in the distribution to the version supplied by Tom
271        Fortmann. This supports explicit test numbers on the command line, and has
272        argument validation and error reporting.
273    
274    28. An instance of \X with an unlimited repeat could fail if at any point the
275        first character it looked at was a mark character.
276    
277    29. Some minor code refactoring concerning Unicode properties and scripts
278        should reduce the stack requirement of match() slightly.
279    
280    30. Added the '=' option to pcretest to check the setting of unused capturing
281        slots at the end of the pattern, which are documented as being -1, but are
282        not included in the return count.
283    
284    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
285        compiled something random. Now it gives a compile-time error (as does
286        Perl).
287    
288    32. A *MARK encountered during the processing of a positive assertion is now
289        recorded and passed back (compatible with Perl).
290    
291    33. If --only-matching or --colour was set on a pcregrep call whose pattern
292        had alternative anchored branches, the search for a second match in a line
293        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
294        matched the line "0102" twice. The same bug affected patterns that started
295        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
296        twice.
297    
298    34. Previously, PCRE did not allow quantification of assertions. However, Perl
299        does, and because of capturing effects, quantifying parenthesized
300        assertions may at times be useful. Quantifiers are now allowed for
301        parenthesized assertions.
302    
303    35. A minor code tidy in pcre_compile() when checking options for \R usage.
304    
305    36. \g was being checked for fancy things in a character class, when it should
306        just be a literal "g".
307    
308    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
309        appearance of a nested POSIX class supersedes an apparent external class.
310        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
311        unescaped square brackets may also appear as part of class names. For
312        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
313        more like Perl. (But see 8.20/1 above.)
314    
315    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
316        was because it thought it was \N{name}, which is not supported).
317    
318    39. Add minix to OS list not supporting the -S option in pcretest.
319    
320    40. PCRE tries to detect cases of infinite recursion at compile time, but it
321        cannot analyze patterns in sufficient detail to catch mutual recursions
322        such as ((?1))((?2)). There is now a runtime test that gives an error if a
323        subgroup is called recursively as a subpattern for a second time at the
324        same position in the subject string. In previous releases this might have
325        been caught by the recursion limit, or it might have run out of stack.
326    
327    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
328        happen only once. PCRE was, however incorrectly giving a compile time error
329        "recursive call could loop indefinitely" because it cannot analyze the
330        pattern in sufficient detail. The compile time test no longer happens when
331        PCRE is compiling a conditional subpattern, but actual runaway loops are
332        now caught at runtime (see 40 above).
333    
334    42. It seems that Perl allows any characters other than a closing parenthesis
335        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
336        has been changed to be the same.
337    
338    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
339        as not to get warnings when autogen.sh is called. Also changed
340        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
341    
342    44. To help people who use pcregrep to scan files containing exceedingly long
343        lines, the following changes have been made:
344    
345        (a) The default value of the buffer size parameter has been increased from
346            8K to 20K. (The actual buffer used is three times this size.)
347    
348        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
349            PCRE is built.
350    
351        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
352            to be set at run time.
353    
354        (d) Numerical values in pcregrep options can be followed by K or M, for
355            example --buffer-size=50K.
356    
357        (e) If a line being scanned overflows pcregrep's buffer, an error is now
358            given and the return code is set to 2.
359    
360    45. Add a pointer to the latest mark to the callout data block.
361    
362    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
363        partial match of an empty string instead of no match. This was specific to
364        the use of ".".
365    
366    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
367        complete match instead of a partial match. This bug was dependent on both
368        the PCRE_UTF8 and PCRE_DOTALL options being set.
369    
370    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
371        starting byte set, because \b was not being ignored.
372    
373    
374    Version 8.12 15-Jan-2011
375    ------------------------
376    
377    1.  Fixed some typos in the markup of the man pages, and wrote a script that
378        checks for such things as part of the documentation building process.
379    
380    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
381        --match-limit and --recursion-limit options (added for 8.11). In
382        particular, this made one of the standard tests fail. (The integer value
383        went into the wrong half of a long int.)
384    
385    3.  If the --colour option was given to pcregrep with -v (invert match), it
386        did strange things, either producing crazy output, or crashing. It should,
387        of course, ignore a request for colour when reporting lines that do not
388        match.
389    
390    4.  Another pcregrep bug caused similar problems if --colour was specified with
391        -M (multiline) and the pattern match finished with a line ending.
392    
393    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
394        matched in multiline mode, the following line was shown as part of the
395        match. This seems wrong, so I have changed it.
396    
397    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
398        the check for further matches in the same line (so they could be coloured)
399        to overrun the end of the current line. If another match was found, it was
400        incorrectly shown (and then shown again when found in the next line).
401    
402    7.  If pcregrep was compiled under Windows, there was a reference to the
403        function pcregrep_exit() before it was defined. I am assuming this was
404        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
405        reported by a user. I've moved the definition above the reference.
406    
407    
408    Version 8.11 10-Dec-2010
409    ------------------------
410    
411    1.  (*THEN) was not working properly if there were untried alternatives prior
412        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
413        backtracked to try for "b" instead of moving to the next alternative branch
414        at the same level (in this case, to look for "c"). The Perl documentation
415        is clear that when (*THEN) is backtracked onto, it goes to the "next
416        alternative in the innermost enclosing group".
417    
418    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
419        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
420        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
421        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
422        (*THEN).
423    
424    3.  If \s appeared in a character class, it removed the VT character from
425        the class, even if it had been included by some previous item, for example
426        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
427        of \s, but is part of the POSIX "space" class.)
428    
429    4.  A partial match never returns an empty string (because you can always
430        match an empty string at the end of the subject); however the checking for
431        an empty string was starting at the "start of match" point. This has been
432        changed to the "earliest inspected character" point, because the returned
433        data for a partial match starts at this character. This means that, for
434        example, /(?<=abc)def/ gives a partial match for the subject "abc"
435        (previously it gave "no match").
436    
437    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
438        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
439        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
440        has an implication that the given string is incomplete (because a partial
441        match is preferred over a full match). For this reason, these items now
442        give a partial match in this situation. [Aside: previously, the one case
443        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
444        match rather than a full match, which was wrong by the old rules, but is
445        now correct.]
446    
447    6.  There was a bug in the handling of #-introduced comments, recognized when
448        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
449        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
450        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
451        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
452        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
453        places in pcre_compile().
454    
455    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
456        comments when looking ahead for named forward references to subpatterns,
457        the only newline sequence it recognized was NL. It now handles newlines
458        according to the set newline convention.
459    
460    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
461        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
462        cater for a lack of strerror(). These oversights have been fixed.
463    
464    9.  Added --match-limit and --recursion-limit to pcregrep.
465    
466    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
467    
468    11. When the -o option was used, pcregrep was setting a return code of 1, even
469        when matches were found, and --line-buffered was not being honoured.
470    
471    12. Added an optional parentheses number to the -o and --only-matching options
472        of pcregrep.
473    
474    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
475        can match an empty string. The code to do it in pcretest and pcredemo
476        needed fixing:
477    
478        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
479            only one byte after an empty string match just before CRLF (this case
480            just got forgotten; "any" and "anycrlf" were OK).
481    
482        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
483            mode when an empty string match preceded an ASCII character followed by
484            a non-ASCII character. (The code for advancing by one character rather
485            than one byte was nonsense.)
486    
487        (c) The pcredemo.c sample program did not have any code at all to handle
488            the cases when CRLF is a valid newline sequence.
489    
490    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
491        as a starting offset was within the subject string. There is now a new
492        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
493        negative or greater than the length of the string. In order to test this,
494        pcretest is extended to allow the setting of negative starting offsets.
495    
496    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
497        starting offset points to the beginning of a UTF-8 character was
498        unnecessarily clumsy. I tidied it up.
499    
500    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
501        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
502    
503    17. Nobody had reported that the --include_dir option, which was added in
504        release 7.7 should have been called --include-dir (hyphen, not underscore)
505        for compatibility with GNU grep. I have changed it to --include-dir, but
506        left --include_dir as an undocumented synonym, and the same for
507        --exclude-dir, though that is not available in GNU grep, at least as of
508        release 2.5.4.
509    
510    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
511        characters from a string of bytes) have been redefined so as not to use
512        loops, in order to improve performance in some environments. At the same
513        time, I abstracted some of the common code into auxiliary macros to save
514        repetition (this should not affect the compiled code).
515    
516    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
517        compile-time error is now given if \c is not followed by an ASCII
518        character, that is, a byte less than 128. (In EBCDIC mode, the code is
519        different, and any byte value is allowed.)
520    
521    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
522        START_OPTIMIZE option, which is now allowed at compile time - but just
523        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
524        to pcregrep and other applications that have no direct access to PCRE
525        options. The new /Y option in pcretest sets this option when calling
526        pcre_compile().
527    
528    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
529        back references. Groups containing recursive back references were forced to
530        be atomic by that change, but in the case of named groups, the amount of
531        memory required was incorrectly computed, leading to "Failed: internal
532        error: code overflow". This has been fixed.
533    
534    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
535        pcretest.c, to avoid build problems in some Borland environments.
536    
537    
538    Version 8.10 25-Jun-2010
539    ------------------------
540    
541    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
542        THEN.
543    
544    2.  (*ACCEPT) was not working when inside an atomic group.
545    
546    3.  Inside a character class, \B is treated as a literal by default, but
547        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
548        causes the error). The code is unchanged, but I tidied the documentation.
549    
550    4.  Inside a character class, PCRE always treated \R and \X as literals,
551        whereas Perl faults them if its -w option is set. I have changed PCRE so
552        that it faults them when PCRE_EXTRA is set.
553    
554    5.  Added support for \N, which always matches any character other than
555        newline. (It is the same as "." when PCRE_DOTALL is not set.)
556    
557    6.  When compiling pcregrep with newer versions of gcc which may have
558        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
559        declared with attribute warn_unused_result" were given. Just casting the
560        result to (void) does not stop the warnings; a more elaborate fudge is
561        needed. I've used a macro to implement this.
562    
563    7.  Minor change to pcretest.c to avoid a compiler warning.
564    
565    8.  Added four artifical Unicode properties to help with an option to make
566        \s etc use properties (see next item). The new properties are: Xan
567        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
568    
569    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
570        use Unicode properties. (*UCP) at the start of a pattern can be used to set
571        this option. Modified pcretest to add /W to test this facility. Added
572        REG_UCP to make it available via the POSIX interface.
573    
574    10. Added --line-buffered to pcregrep.
575    
576    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
577        studied, and the match started with a letter with a code point greater than
578        127 whose first byte was different to the first byte of the other case of
579        the letter, the other case of this starting letter was not recognized
580        (#976).
581    
582    12. If a pattern that was studied started with a repeated Unicode property
583        test, for example, \p{Nd}+, there was the theoretical possibility of
584        setting up an incorrect bitmap of starting bytes, but fortunately it could
585        not have actually happened in practice until change 8 above was made (it
586        added property types that matched character-matching opcodes).
587    
588    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
589        possible starting bytes for non-anchored patterns.
590    
591    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
592        \R, and also a number of cases that involve Unicode properties, both
593        explicit and implicit when PCRE_UCP is set.
594    
595    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
596        input, it could crash or give wrong results if characters with values
597        greater than 0xc0 were present in the subject string. (Detail: it assumed
598        UTF-8 input when processing these items.)
599    
600    16. Added a lot of (int) casts to avoid compiler warnings in systems where
601        size_t is 64-bit (#991).
602    
603    17. Added a check for running out of memory when PCRE is compiled with
604        --disable-stack-for-recursion (#990).
605    
606    18. If the last data line in a file for pcretest does not have a newline on
607        the end, a newline was missing in the output.
608    
609    19. The default pcre_chartables.c file recognizes only ASCII characters (values
610        less than 128) in its various bitmaps. However, there is a facility for
611        generating tables according to the current locale when PCRE is compiled. It
612        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
613        characters, are recognized by isspace() and therefore were getting set in
614        these tables, and indeed these tables seem to approximate to ISO 8859. This
615        caused a problem in UTF-8 mode when pcre_study() was used to create a list
616        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
617        which of course cannot start UTF-8 characters. I have changed the code so
618        that only real ASCII characters (less than 128) and the correct starting
619        bytes for UTF-8 encodings are set for characters greater than 127 when in
620        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
621        altogether.)
622    
623    20. Added the /T option to pcretest so as to be able to run tests with non-
624        standard character tables, thus making it possible to include the tests
625        used for 19 above in the standard set of tests.
626    
627    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
628        reference to a subpattern the other side of a comment that contains an
629        opening parenthesis caused either an internal compiling error, or a
630        reference to the wrong subpattern.
631    
632    
633    Version 8.02 19-Mar-2010
634    ------------------------
635    
636    1.  The Unicode data tables have been updated to Unicode 5.2.0.
637    
638    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
639        configured.
640    
641    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
642        original author of that file, following a query about its status.
643    
644    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
645        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
646    
647    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
648        quantifier applied to a forward-referencing subroutine call, could compile
649        incorrect code or give the error "internal error: previously-checked
650        referenced subpattern not found".
651    
652    6.  Both MS Visual Studio and Symbian OS have problems with initializing
653        variables to point to external functions. For these systems, therefore,
654        pcre_malloc etc. are now initialized to local functions that call the
655        relevant global functions.
656    
657    7.  There were two entries missing in the vectors called coptable and poptable
658        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
659        I've fixed the data, and added a kludgy way of testing at compile time that
660        the lengths are correct (equal to the number of opcodes).
661    
662    8.  Following on from 7, I added a similar kludge to check the length of the
663        eint vector in pcreposix.c.
664    
665    9.  Error texts for pcre_compile() are held as one long string to avoid too
666        much relocation at load time. To find a text, the string is searched,
667        counting zeros. There was no check for running off the end of the string,
668        which could happen if a new error number was added without updating the
669        string.
670    
671    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
672    
673    11. \K was not working if it appeared in an atomic group or in a group that
674        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
675        \K is "not well defined" if used in an assertion. PCRE now accepts it if
676        the assertion is positive, but not if it is negative.
677    
678    12. Change 11 fortuitously reduced the size of the stack frame used in the
679        "match()" function of pcre_exec.c by one pointer. Forthcoming
680        implementation of support for (*MARK) will need an extra pointer on the
681        stack; I have reserved it now, so that the stack frame size does not
682        decrease.
683    
684    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
685        item in branch that calls a recursion is a subroutine call - as in the
686        second branch in the above example - was incorrectly given the compile-
687        time error "recursive call could loop indefinitely" because pcre_compile()
688        was not correctly checking the subroutine for matching a non-empty string.
689    
690    14. The checks for overrunning compiling workspace could trigger after an
691        overrun had occurred. This is a "should never occur" error, but it can be
692        triggered by pathological patterns such as hundreds of nested parentheses.
693        The checks now trigger 100 bytes before the end of the workspace.
694    
695    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
696    
697    
698    Version 8.01 19-Jan-2010
699    ------------------------
700    
701    1.  If a pattern contained a conditional subpattern with only one branch (in
702        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
703        computed the wrong minimum data length (which is of course zero for such
704        subpatterns). This could cause incorrect "no match" results.
705    
706    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
707        the pattern is reset in the first branch, pcre_compile() failed with
708        "internal error: code overflow at offset...". This happened only when
709        the reset was to the original external option setting. (An optimization
710        abstracts leading options settings into an external setting, which was the
711        cause of this.)
712    
713    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
714        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
715        assertion pattern did not match (meaning that the assertion was true), it
716        was incorrectly treated as false if the SKIP had been reached during the
717        matching. This also applied to assertions used as conditions.
718    
719    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
720        assertion subpattern, including such a pattern used as a condition,
721        unpredictable results occurred, instead of the error return
722        PCRE_ERROR_DFA_UITEM.
723    
724    5.  The C++ GlobalReplace function was not working like Perl for the special
725        situation when an empty string is matched. It now does the fancy magic
726        stuff that is necessary.
727    
728    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
729        removed. (These were left over from very, very early versions of PCRE.)
730    
731    7.  Some cosmetic changes to the code to make life easier when compiling it
732        as part of something else:
733    
734        (a) Change DEBUG to PCRE_DEBUG.
735    
736        (b) In pcre_compile(), rename the member of the "branch_chain" structure
737            called "current" as "current_branch", to prevent a collision with the
738            Linux macro when compiled as a kernel module.
739    
740        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
741            prevent a collision with the Linux macro when compiled as a kernel
742            module.
743    
744    8.  In pcre_compile() there are some checks for integer overflows that used to
745        cast potentially large values to (double). This has been changed to that
746        when building, a check for int64_t is made, and if it is found, it is used
747        instead, thus avoiding the use of floating point arithmetic. (There is no
748        other use of FP in PCRE.) If int64_t is not found, the fallback is to
749        double.
750    
751    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
752        2005 (difference between two addresses compared to an unsigned value).
753    
754    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
755        custom one, because of the following reported problem in Windows:
756    
757          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
758              under Win32.
759          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
760              therefore missing the function definition.
761          - The compiler thus generates a "C" signature for the test function.
762          - The linker fails to find the "C" function.
763          - PCRE fails to configure if asked to do so against libbz2.
764    
765    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
766        messages were output:
767    
768          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
769          rerunning libtoolize, to keep the correct libtool macros in-tree.
770          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
771    
772        I have done both of these things.
773    
774    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
775        most of the time, it *can* run out if it is given a pattern that contains a
776        runaway infinite recursion. I updated the discussion in the pcrestack man
777        page.
778    
779    13. Now that we have gone to the x.xx style of version numbers, the minor
780        version may start with zero. Using 08 or 09 is a bad idea because users
781        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
782        interpreted as invalid octal numbers. I've updated the previous comment in
783        configure.ac, and also added a check that gives an error if 08 or 09 are
784        used.
785    
786    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
787        causing partial matching to fail when the end of the subject matched \W
788        in a UTF-8 pattern where \W was quantified with a minimum of 3.
789    
790    15. There were some discrepancies between the declarations in pcre_internal.h
791        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
792        their definitions. The declarations used "const uschar *" and the
793        definitions used USPTR. Even though USPTR is normally defined as "const
794        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
795        reported that: "This difference in casting confuses some C++ compilers, for
796        example, SunCC recognizes above declarations as different functions and
797        generates broken code for hbpcre." I have changed the declarations to use
798        USPTR.
799    
800    16. GNU libtool is named differently on some systems. The autogen.sh script now
801        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
802        (FreeBSD).
803    
804    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
805        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
806        comment: "Figure out how to create a longlong from a string: strtoll and
807        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
808        instance, but it only takes 2 args instead of 3!"
809    
810    18. A subtle bug concerned with back references has been fixed by a change of
811        specification, with a corresponding code fix. A pattern such as
812        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
813        refers, was giving matches when it shouldn't. For example, xa=xaaa would
814        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
815        same bug. Such groups have to be quantified to be useful, or contained
816        inside another quantified group. (If there's no repetition, the reference
817        can never match.) The problem arises because, having left the group and
818        moved on to the rest of the pattern, a later failure that backtracks into
819        the group uses the captured value from the final iteration of the group
820        rather than the correct earlier one. I have fixed this in PCRE by forcing
821        any group that contains a reference to itself to be an atomic group; that
822        is, there cannot be any backtracking into it once it has completed. This is
823        similar to recursive and subroutine calls.
824    
825    
826    Version 8.00 19-Oct-09
827  ----------------------  ----------------------
828    
829  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
830      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
831      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
832      error.      error.
833    
834  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
835      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
836      in a Windows environment.      in a Windows environment.
837    
838  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
839      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
840      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
841      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
842      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
843      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
844      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
845    
846  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
847      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
848      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
849      the old behaviour.      the old behaviour.
850    
851  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
852      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
853      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
854      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
855    
856  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
857      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
858    
859  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
860      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
861      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
862      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
863      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
864      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
865    
866  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
867      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
868      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
869      which had an unlimited repeat of a nested, fixed maximum repeat of a wide      which had an unlimited repeat of a nested, fixed maximum repeat of a wide
870      character. Chaos in the form of incorrect output or a compiling loop could      character. Chaos in the form of incorrect output or a compiling loop could
871      result.      result.
872    
873  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
874      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
875      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
876      slots in the offset vector, the offset of the earliest inspected character      slots in the offset vector, the offset of the earliest inspected character
877      for the match and the offset of the end of the subject are set in them when      for the match and the offset of the end of the subject are set in them when
878      PCRE_ERROR_PARTIAL is returned.      PCRE_ERROR_PARTIAL is returned.
879    
880  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
881      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
882      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
883      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
884      pcre_exec().  
885    11. Partial matching with pcre_exec() is now more intuitive. A partial match
886  11. Partial matching with pcre_exec() is now more intuitive. A partial match      used to be given if ever the end of the subject was reached; now it is
887      used to be given if ever the end of the subject was reached; now it is      given only if matching could not proceed because another character was
888      given only if matching could not proceed because another character was      needed. This makes a difference in some odd cases such as Z(*FAIL) with the
889      needed. This makes a difference in some odd cases such as Z(*FAIL) with the      string "Z", which now yields "no match" instead of "partial match". In the
890      string "Z", which now yields "no match" instead of "partial match". In the      case of pcre_dfa_exec(), "no match" is given if every matching path for the
891      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
892      final character ended with (*FAIL).  
   
893  12. Restarting a match using pcre_dfa_exec() after a partial match did not work  12. Restarting a match using pcre_dfa_exec() after a partial match did not work
894      if the pattern had a "must contain" character that was already found in the      if the pattern had a "must contain" character that was already found in the
895      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
896      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
897      "g". If the first part-match was for the string "dog", restarting with      "g". If the first part-match was for the string "dog", restarting with
898      "sbody" failed. This bug has been fixed.      "sbody" failed. This bug has been fixed.
899    
900  13. The string returned by pcre_dfa_exec() after a partial match has been  13. The string returned by pcre_dfa_exec() after a partial match has been
901      changed so that it starts at the first inspected character rather than the      changed so that it starts at the first inspected character rather than the
902      first character of the match. This makes a difference only if the pattern      first character of the match. This makes a difference only if the pattern
903      starts with a lookbehind assertion or \b or \B (\K is not supported by      starts with a lookbehind assertion or \b or \B (\K is not supported by
904      pcre_dfa_exec()). It's an incompatible change, but it makes the two      pcre_dfa_exec()). It's an incompatible change, but it makes the two
905      matching functions compatible, and I think it's the right thing to do.      matching functions compatible, and I think it's the right thing to do.
906    
907  14. Added a pcredemo man page, created automatically from the pcredemo.c file,  14. Added a pcredemo man page, created automatically from the pcredemo.c file,
908      so that the demonstration program is easily available in environments where      so that the demonstration program is easily available in environments where
909      PCRE has not been installed from source.      PCRE has not been installed from source.
910    
911  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
912      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
913      library.      library.
914    
915  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
916      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
917      is not the first non-POSIX option to be added. Clearly some people find      is not the first non-POSIX option to be added. Clearly some people find
918      these options useful.      these options useful.
919    
920  17. If a caller to the POSIX matching function regexec() passes a non-zero  17. If a caller to the POSIX matching function regexec() passes a non-zero
921      value for nmatch with a NULL value for pmatch, the value of      value for nmatch with a NULL value for pmatch, the value of
922      nmatch is forced to zero.      nmatch is forced to zero.
923    
924  18. RunGrepTest did not have a test for the availability of the -u option of  18. RunGrepTest did not have a test for the availability of the -u option of
925      the diff command, as RunTest does. It now checks in the same way as      the diff command, as RunTest does. It now checks in the same way as
926      RunTest, and also checks for the -b option.      RunTest, and also checks for the -b option.
927    
928  19. If an odd number of negated classes containing just a single character  19. If an odd number of negated classes containing just a single character
929      interposed, within parentheses, between a forward reference to a named      interposed, within parentheses, between a forward reference to a named
930      subpattern and the definition of the subpattern, compilation crashed with      subpattern and the definition of the subpattern, compilation crashed with
931      an internal error, complaining that it could not find the referenced      an internal error, complaining that it could not find the referenced
932      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
933      [The bug was that it was starting one character too far in when skipping      [The bug was that it was starting one character too far in when skipping
934      over the character class, thus treating the ] as data rather than      over the character class, thus treating the ] as data rather than
935      terminating the class. This meant it could skip too much.]      terminating the class. This meant it could skip too much.]
936    
937  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
938      /g option in pcretest when the pattern contains \K, which makes it possible      /g option in pcretest when the pattern contains \K, which makes it possible
939      to have an empty string match not at the start, even when the pattern is      to have an empty string match not at the start, even when the pattern is
940      anchored. Updated pcretest and pcredemo to use this option.      anchored. Updated pcretest and pcredemo to use this option.
941    
942  21. If the maximum number of capturing subpatterns in a recursion was greater  21. If the maximum number of capturing subpatterns in a recursion was greater
943      than the maximum at the outer level, the higher number was returned, but      than the maximum at the outer level, the higher number was returned, but
944      with unset values at the outer level. The correct (outer level) value is      with unset values at the outer level. The correct (outer level) value is
945      now given.      now given.
946    
947  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
948      PCRE did not set those parentheses (unlike Perl). I have now found a way to      PCRE did not set those parentheses (unlike Perl). I have now found a way to
949      make it do so. The string so far is captured, making this feature      make it do so. The string so far is captured, making this feature
950      compatible with Perl.      compatible with Perl.
951    
952  23. The tests have been re-organized, adding tests 11 and 12, to make it  23. The tests have been re-organized, adding tests 11 and 12, to make it
953      possible to check the Perl 5.10 features against Perl 5.10.      possible to check the Perl 5.10 features against Perl 5.10.
954    
955  24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine  24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
956      pattern matches a fixed length string. PCRE did not allow this; now it      pattern matches a fixed length string. PCRE did not allow this; now it
957      does. Neither allows recursion.      does. Neither allows recursion.
958    
959  25. I finally figured out how to implement a request to provide the minimum  25. I finally figured out how to implement a request to provide the minimum
960      length of subject string that was needed in order to match a given pattern.      length of subject string that was needed in order to match a given pattern.
961      (It was back references and recursion that I had previously got hung up      (It was back references and recursion that I had previously got hung up
962      on.) This code has now been added to pcre_study(); it finds a lower bound      on.) This code has now been added to pcre_study(); it finds a lower bound
963      to the length of subject needed. It is not necessarily the greatest lower      to the length of subject needed. It is not necessarily the greatest lower
964      bound, but using it to avoid searching strings that are too short does give      bound, but using it to avoid searching strings that are too short does give
965      some useful speed-ups. The value is available to calling programs via      some useful speed-ups. The value is available to calling programs via
966      pcre_fullinfo().      pcre_fullinfo().
967    
968  26. While implementing 25, I discovered to my embarrassment that pcretest had  26. While implementing 25, I discovered to my embarrassment that pcretest had
969      not been passing the result of pcre_study() to pcre_dfa_exec(), so the      not been passing the result of pcre_study() to pcre_dfa_exec(), so the
970      study optimizations had never been tested with that matching function.      study optimizations had never been tested with that matching function.
971      Oops. What is worse, even when it was passed study data, there was a bug in      Oops. What is worse, even when it was passed study data, there was a bug in
972      pcre_dfa_exec() that meant it never actually used it. Double oops. There      pcre_dfa_exec() that meant it never actually used it. Double oops. There
973      were also very few tests of studied patterns with pcre_dfa_exec().      were also very few tests of studied patterns with pcre_dfa_exec().
974    
975  27. If (?| is used to create subpatterns with duplicate numbers, they are now  27. If (?| is used to create subpatterns with duplicate numbers, they are now
976      allowed to have the same name, even if PCRE_DUPNAMES is not set. However,      allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
977      on the other side of the coin, they are no longer allowed to have different      on the other side of the coin, they are no longer allowed to have different
978      names, because these cannot be distinguished in PCRE, and this has caused      names, because these cannot be distinguished in PCRE, and this has caused
979      confusion. (This is a difference from Perl.)      confusion. (This is a difference from Perl.)
980    
981    28. When duplicate subpattern names are present (necessarily with different
982        numbers, as required by 27 above), and a test is made by name in a
983        conditional pattern, either for a subpattern having been matched, or for
984        recursion in such a pattern, all the associated numbered subpatterns are
985        tested, and the overall condition is true if the condition is true for any
986        one of them. This is the way Perl works, and is also more like the way
987        testing by number works.
988    
989    
990  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
991  ---------------------  ---------------------

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