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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.11 10-Oct-2010  Version 8.20 23-Sep-2011
5    ------------------------
7    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
8        a POSIX class. After further experiments with Perl, which convinced me that
9        Perl has bugs and confusions, a closing square bracket is no longer allowed
10        in a POSIX name. This bug also affected patterns with classes that started
11        with full stops.
13    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
14        captured substring, but while checking the failing first alternative,
15        substring 1 is temporarily captured. If the output vector supplied to
16        pcre_exec() was not big enough for this capture, the yield of the function
17        was still zero ("insufficient space for captured substrings"). This cannot
18        be totally fixed without adding another stack variable, which seems a lot
19        of expense for a edge case. However, I have improved the situation in cases
20        such as /(a)(b)x|abc/ matched against "abc", where the return code
21        indicates that fewer than the maximum number of slots in the ovector have
22        been set.
24    3.  Related to (2) above: when there are more back references in a pattern than
25        slots in the output vector, pcre_exec() uses temporary memory during
26        matching, and copies in the captures as far as possible afterwards. It was
27        using the entire output vector, but this conflicts with the specification
28        that only 2/3 is used for passing back captured substrings. Now it uses
29        only the first 2/3, for compatibility. This is, of course, another edge
30        case.
32    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
33        main code base, and can be used by building with --enable-jit. When this is
34        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
35        runtime --no-jit option is given.
37    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
38        ovector, the return from the function was zero, implying that there were
39        other matches that did not fit. The correct "exactly full" value is now
40        returned.
42    6.  If a subpattern that was called recursively or as a subroutine contained
43        (*PRUNE) or any other control that caused it to give a non-standard return,
44        invalid errors such as "Error -26 (nested recursion at the same subject
45        position)" or even infinite loops could occur.
47    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
48        computing the minimum length on reaching *ACCEPT, and so ended up with the
49        wrong value of 1 rather than 0. Further investigation indicates that
50        computing a minimum subject length in the presence of *ACCEPT is difficult
51        (think back references, subroutine calls), and so I have changed the code
52        so that no minimum is registered for a pattern that contains *ACCEPT.
54    8.  If (*THEN) was present in the first (true) branch of a conditional group,
55        it was not handled as intended.
57    9.  Replaced RunTest.bat with the much improved version provided by Sheri
58        Pierce.
60    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
61        the first byte in a match must be "a".
63    11. Change 17 for 8.13 increased the recursion depth for patterns like
64        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
65        pattern contains any instances of (*THEN). If it does not, the old
66        optimizations are restored. It would be nice to do this on a per-group
67        basis, but at the moment that is not feasible.
69    12. In some environments, the output of pcretest -C is CRLF terminated. This
70        broke RunTest's code that checks for the link size. A single white space
71        after the value is now allowed for.
73    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
74        For "fr", it uses the Windows-specific input and output files.
76    14. If (*THEN) appeared in a group that was called recursively or as a
77        subroutine, it did not work as intended.
80    Version 8.13 16-Aug-2011
81    ------------------------
83    1.  The Unicode data tables have been updated to Unicode 6.0.0.
85    2.  Two minor typos in pcre_internal.h have been fixed.
87    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
88        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
89        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
91    4.  There were a number of related bugs in the code for matching backrefences
92        caselessly in UTF-8 mode when codes for the characters concerned were
93        different numbers of bytes. For example, U+023A and U+2C65 are an upper
94        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
95        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
96        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
97        2-byte code at the end of the subject (it thought there wasn't enough data
98        left).
100    5.  Comprehensive information about what went wrong is now returned by
101        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
102        as the output vector has at least 2 elements. The offset of the start of
103        the failing character and a reason code are placed in the vector.
105    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
106        now returned is for the first byte of the failing character, instead of the
107        last byte inspected. This is an incompatible change, but I hope it is small
108        enough not to be a problem. It makes the returned offset consistent with
109        pcre_exec() and pcre_dfa_exec().
111    7.  pcretest now gives a text phrase as well as the error number when
112        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
113        failure, the offset and reason code are output.
115    8.  When \R was used with a maximizing quantifier it failed to skip backwards
116        over a \r\n pair if the subsequent match failed. Instead, it just skipped
117        back over a single character (\n). This seems wrong (because it treated the
118        two characters as a single entity when going forwards), conflicts with the
119        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
120        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
121        has been changed.
123    9.  Some internal refactoring has changed the processing so that the handling
124        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
125        time (the PCRE_DOTALL option was changed this way some time ago: version
126        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
127        which was always a bit of a fudge. It also means that there is one less
128        argument for the match() function, which reduces its stack requirements
129        slightly. This change also fixes an incompatibility with Perl: the pattern
130        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
132    10. More internal refactoring has drastically reduced the number of recursive
133        calls to match() for possessively repeated groups such as (abc)++ when
134        using pcre_exec().
136    11. While implementing 10, a number of bugs in the handling of groups were
137        discovered and fixed:
139        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
140        (a|)*(?1) gave a compile-time internal error.
141        ((a|)+)+  did not notice that the outer group could match an empty string.
142        (^a|^)+   was not marked as anchored.
143        (.*a|.*)+ was not marked as matching at start or after a newline.
145    12. Yet more internal refactoring has removed another argument from the match()
146        function. Special calls to this function are now indicated by setting a
147        value in a variable in the "match data" data block.
149    13. Be more explicit in pcre_study() instead of relying on "default" for
150        opcodes that mean there is no starting character; this means that when new
151        ones are added and accidentally left out of pcre_study(), testing should
152        pick them up.
154    14. The -s option of pcretest has been documented for ages as being an old
155        synonym of -m (show memory usage). I have changed it to mean "force study
156        for every regex", that is, assume /S for every regex. This is similar to -i
157        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
158        using it. It makes it easier to run collections of tests with and without
159        study enabled, and thereby test pcre_study() more easily. All the standard
160        tests are now run with and without -s (but some patterns can be marked as
161        "never study" - see 20 below).
163    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
164        restoration of the capturing data to the outer values was not happening
165        correctly.
167    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
168        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
169        pattern had matched an empty string, and so incorrectly returned a no
170        match.
172    17. There was optimizing code for the last branch of non-capturing parentheses,
173        and also for the obeyed branch of a conditional subexpression, which used
174        tail recursion to cut down on stack usage. Unfortunately, now that there is
175        the possibility of (*THEN) occurring in these branches, tail recursion is
176        no longer possible because the return has to be checked for (*THEN). These
177        two optimizations have therefore been removed. [But see 8.20/11 above.]
179    18. If a pattern containing \R was studied, it was assumed that \R always
180        matched two bytes, thus causing the minimum subject length to be
181        incorrectly computed because \R can also match just one byte.
183    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
184        was incorrectly computed.
186    20. If /S is present twice on a test pattern in pcretest input, it now
187        *disables* studying, thereby overriding the use of -s on the command line
188        (see 14 above). This is necessary for one or two tests to keep the output
189        identical in both cases.
191    21. When (*ACCEPT) was used in an assertion that matched an empty string and
192        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
194    22. When an atomic group that contained a capturing parenthesis was
195        successfully matched, but the branch in which it appeared failed, the
196        capturing was not being forgotten if a higher numbered group was later
197        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
198        group 1 to "a", when in fact it should be unset. This applied to multi-
199        branched capturing and non-capturing groups, repeated or not, and also to
200        positive assertions (capturing in negative assertions does not happen
201        in PCRE) and also to nested atomic groups.
203    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
204        subject after a captured substring, to make it easier to tell which of a
205        number of identical substrings has been captured.
207    24. The way atomic groups are processed by pcre_exec() has been changed so that
208        if they are repeated, backtracking one repetition now resets captured
209        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
210        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
211        "aaa". Previously, it would have been "a". As part of this code
212        refactoring, the way recursive calls are handled has also been changed.
214    25. If an assertion condition captured any substrings, they were not passed
215        back unless some other capturing happened later. For example, if
216        (?(?=(a))a) was matched against "a", no capturing was returned.
218    26. When studying a pattern that contained subroutine calls or assertions,
219        the code for finding the minimum length of a possible match was handling
220        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
221        group 1 called group 2 while simultaneously a separate group 2 called group
222        1). A stack overflow occurred in this case. I have fixed this by limiting
223        the recursion depth to 10.
225    27. Updated RunTest.bat in the distribution to the version supplied by Tom
226        Fortmann. This supports explicit test numbers on the command line, and has
227        argument validation and error reporting.
229    28. An instance of \X with an unlimited repeat could fail if at any point the
230        first character it looked at was a mark character.
232    29. Some minor code refactoring concerning Unicode properties and scripts
233        should reduce the stack requirement of match() slightly.
235    30. Added the '=' option to pcretest to check the setting of unused capturing
236        slots at the end of the pattern, which are documented as being -1, but are
237        not included in the return count.
239    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
240        compiled something random. Now it gives a compile-time error (as does
241        Perl).
243    32. A *MARK encountered during the processing of a positive assertion is now
244        recorded and passed back (compatible with Perl).
246    33. If --only-matching or --colour was set on a pcregrep call whose pattern
247        had alternative anchored branches, the search for a second match in a line
248        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
249        matched the line "0102" twice. The same bug affected patterns that started
250        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
251        twice.
253    34. Previously, PCRE did not allow quantification of assertions. However, Perl
254        does, and because of capturing effects, quantifying parenthesized
255        assertions may at times be useful. Quantifiers are now allowed for
256        parenthesized assertions.
258    35. A minor code tidy in pcre_compile() when checking options for \R usage.
260    36. \g was being checked for fancy things in a character class, when it should
261        just be a literal "g".
263    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
264        appearance of a nested POSIX class supersedes an apparent external class.
265        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
266        unescaped square brackets may also appear as part of class names. For
267        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
268        more like Perl. (But see 8.20/1 above.)
270    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
271        was because it thought it was \N{name}, which is not supported).
273    39. Add minix to OS list not supporting the -S option in pcretest.
275    40. PCRE tries to detect cases of infinite recursion at compile time, but it
276        cannot analyze patterns in sufficient detail to catch mutual recursions
277        such as ((?1))((?2)). There is now a runtime test that gives an error if a
278        subgroup is called recursively as a subpattern for a second time at the
279        same position in the subject string. In previous releases this might have
280        been caught by the recursion limit, or it might have run out of stack.
282    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
283        happen only once. PCRE was, however incorrectly giving a compile time error
284        "recursive call could loop indefinitely" because it cannot analyze the
285        pattern in sufficient detail. The compile time test no longer happens when
286        PCRE is compiling a conditional subpattern, but actual runaway loops are
287        now caught at runtime (see 40 above).
289    42. It seems that Perl allows any characters other than a closing parenthesis
290        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
291        has been changed to be the same.
293    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
294        as not to get warnings when autogen.sh is called. Also changed
295        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
297    44. To help people who use pcregrep to scan files containing exceedingly long
298        lines, the following changes have been made:
300        (a) The default value of the buffer size parameter has been increased from
301            8K to 20K. (The actual buffer used is three times this size.)
303        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
304            PCRE is built.
306        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
307            to be set at run time.
309        (d) Numerical values in pcregrep options can be followed by K or M, for
310            example --buffer-size=50K.
312        (e) If a line being scanned overflows pcregrep's buffer, an error is now
313            given and the return code is set to 2.
315    45. Add a pointer to the latest mark to the callout data block.
317    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
318        partial match of an empty string instead of no match. This was specific to
319        the use of ".".
321    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
322        complete match instead of a partial match. This bug was dependent on both
323        the PCRE_UTF8 and PCRE_DOTALL options being set.
325    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
326        starting byte set, because \b was not being ignored.
329    Version 8.12 15-Jan-2011
330    ------------------------
332    1.  Fixed some typos in the markup of the man pages, and wrote a script that
333        checks for such things as part of the documentation building process.
335    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
336        --match-limit and --recursion-limit options (added for 8.11). In
337        particular, this made one of the standard tests fail. (The integer value
338        went into the wrong half of a long int.)
340    3.  If the --colour option was given to pcregrep with -v (invert match), it
341        did strange things, either producing crazy output, or crashing. It should,
342        of course, ignore a request for colour when reporting lines that do not
343        match.
345    4.  Another pcregrep bug caused similar problems if --colour was specified with
346        -M (multiline) and the pattern match finished with a line ending.
348    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
349        matched in multiline mode, the following line was shown as part of the
350        match. This seems wrong, so I have changed it.
352    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
353        the check for further matches in the same line (so they could be coloured)
354        to overrun the end of the current line. If another match was found, it was
355        incorrectly shown (and then shown again when found in the next line).
357    7.  If pcregrep was compiled under Windows, there was a reference to the
358        function pcregrep_exit() before it was defined. I am assuming this was
359        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
360        reported by a user. I've moved the definition above the reference.
363    Version 8.11 10-Dec-2010
364  ------------------------  ------------------------
366  1.  (*THEN) was not working properly if there were untried alternatives prior  1.  (*THEN) was not working properly if there were untried alternatives prior
367      to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it      to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
368      backtracked to try for "b" instead of moving to the next alternative branch      backtracked to try for "b" instead of moving to the next alternative branch
369      at the same level (in this case, to look for "c"). The Perl documentation      at the same level (in this case, to look for "c"). The Perl documentation
370      is clear that when (*THEN) is backtracked onto, it goes to the "next      is clear that when (*THEN) is backtracked onto, it goes to the "next
371      alternative in the innermost enclosing group".      alternative in the innermost enclosing group".
373  2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern  2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
374      such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should      such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
375      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
376      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
377      (*THEN).      (*THEN).
379  3.  If \s appeared in a character class, it removed the VT character from  3.  If \s appeared in a character class, it removed the VT character from
380      the class, even if it had been included by some previous item, for example      the class, even if it had been included by some previous item, for example
381      in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part      in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
382      of \s, but is part of the POSIX "space" class.)      of \s, but is part of the POSIX "space" class.)
384    4.  A partial match never returns an empty string (because you can always
385        match an empty string at the end of the subject); however the checking for
386        an empty string was starting at the "start of match" point. This has been
387        changed to the "earliest inspected character" point, because the returned
388        data for a partial match starts at this character. This means that, for
389        example, /(?<=abc)def/ gives a partial match for the subject "abc"
390        (previously it gave "no match").
392    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
393        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
394        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
395        has an implication that the given string is incomplete (because a partial
396        match is preferred over a full match). For this reason, these items now
397        give a partial match in this situation. [Aside: previously, the one case
398        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
399        match rather than a full match, which was wrong by the old rules, but is
400        now correct.]
402    6.  There was a bug in the handling of #-introduced comments, recognized when
403        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
404        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
405        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
406        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
407        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
408        places in pcre_compile().
410    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
411        comments when looking ahead for named forward references to subpatterns,
412        the only newline sequence it recognized was NL. It now handles newlines
413        according to the set newline convention.
415    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
416        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
417        cater for a lack of strerror(). These oversights have been fixed.
419    9.  Added --match-limit and --recursion-limit to pcregrep.
421    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
423    11. When the -o option was used, pcregrep was setting a return code of 1, even
424        when matches were found, and --line-buffered was not being honoured.
426    12. Added an optional parentheses number to the -o and --only-matching options
427        of pcregrep.
429    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
430        can match an empty string. The code to do it in pcretest and pcredemo
431        needed fixing:
433        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
434            only one byte after an empty string match just before CRLF (this case
435            just got forgotten; "any" and "anycrlf" were OK).
437        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
438            mode when an empty string match preceded an ASCII character followed by
439            a non-ASCII character. (The code for advancing by one character rather
440            than one byte was nonsense.)
442        (c) The pcredemo.c sample program did not have any code at all to handle
443            the cases when CRLF is a valid newline sequence.
445    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
446        as a starting offset was within the subject string. There is now a new
447        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
448        negative or greater than the length of the string. In order to test this,
449        pcretest is extended to allow the setting of negative starting offsets.
451    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
452        starting offset points to the beginning of a UTF-8 character was
453        unnecessarily clumsy. I tidied it up.
455    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
456        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
458    17. Nobody had reported that the --include_dir option, which was added in
459        release 7.7 should have been called --include-dir (hyphen, not underscore)
460        for compatibility with GNU grep. I have changed it to --include-dir, but
461        left --include_dir as an undocumented synonym, and the same for
462        --exclude-dir, though that is not available in GNU grep, at least as of
463        release 2.5.4.
465    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
466        characters from a string of bytes) have been redefined so as not to use
467        loops, in order to improve performance in some environments. At the same
468        time, I abstracted some of the common code into auxiliary macros to save
469        repetition (this should not affect the compiled code).
471    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
472        compile-time error is now given if \c is not followed by an ASCII
473        character, that is, a byte less than 128. (In EBCDIC mode, the code is
474        different, and any byte value is allowed.)
476    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
477        START_OPTIMIZE option, which is now allowed at compile time - but just
478        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
479        to pcregrep and other applications that have no direct access to PCRE
480        options. The new /Y option in pcretest sets this option when calling
481        pcre_compile().
483    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
484        back references. Groups containing recursive back references were forced to
485        be atomic by that change, but in the case of named groups, the amount of
486        memory required was incorrectly computed, leading to "Failed: internal
487        error: code overflow". This has been fixed.
489    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
490        pcretest.c, to avoid build problems in some Borland environments.
493  Version 8.10 25-Jun-2010  Version 8.10 25-Jun-2010

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