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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.02 01-Mar-2010  Version 8.13 30-Apr-2011
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
9    2.  Two minor typos in pcre_internal.h have been fixed.
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
110    20. If /S is present twice on a test pattern in pcretest input, it *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
141    25. When studying a pattern that contained subroutine calls or assertions,
142        the code for finding the minimum length of a possible match was handling
143        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
144        group 1 called group 2 while simultaneously a separate group 2 called group
145        1). A stack overflow occurred in this case. I have fixed this by limiting
146        the recursion depth to 10.
148    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
152    27. An instance of \X with an unlimited repeat could fail if at any point the
153        first character it looked at was a mark character.
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
158    29. Added the '=' option to pcretest to check the setting of unused capturing
159        slots at the end of the pattern, which are documented as being -1, but are
160        not included in the return count.
162    30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
163        compiled something random. Now it gives a compile-time error (as does
164        Perl).
166    31. A *MARK encountered during the processing of a positive assertion is now
167        recorded and passed back (compatible with Perl).
169    32. If --only-matching or --colour was set on a pcregrep call whose pattern
170        had alternative anchored branches, the search for a second match in a line
171        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
172        matched the line "0102" twice. The same bug affected patterns that started
173        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
174        twice.
176    33. Previously, PCRE did not allow quantification of assertions. However, Perl
177        does, and because of capturing effects, quantifying parenthesized
178        assertions may at times be useful. Quantifiers are now allowed for
179        parenthesized assertions.
181    34. A minor code tidy in pcre_compile() when checking options for \R usage.
184    Version 8.12 15-Jan-2011
185    ------------------------
187    1.  Fixed some typos in the markup of the man pages, and wrote a script that
188        checks for such things as part of the documentation building process.
190    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
191        --match-limit and --recursion-limit options (added for 8.11). In
192        particular, this made one of the standard tests fail. (The integer value
193        went into the wrong half of a long int.)
195    3.  If the --colour option was given to pcregrep with -v (invert match), it
196        did strange things, either producing crazy output, or crashing. It should,
197        of course, ignore a request for colour when reporting lines that do not
198        match.
200    4.  Another pcregrep bug caused similar problems if --colour was specified with
201        -M (multiline) and the pattern match finished with a line ending.
203    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
204        matched in multiline mode, the following line was shown as part of the
205        match. This seems wrong, so I have changed it.
207    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
208        the check for further matches in the same line (so they could be coloured)
209        to overrun the end of the current line. If another match was found, it was
210        incorrectly shown (and then shown again when found in the next line).
212    7.  If pcregrep was compiled under Windows, there was a reference to the
213        function pcregrep_exit() before it was defined. I am assuming this was
214        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
215        reported by a user. I've moved the definition above the reference.
218    Version 8.11 10-Dec-2010
219    ------------------------
221    1.  (*THEN) was not working properly if there were untried alternatives prior
222        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
223        backtracked to try for "b" instead of moving to the next alternative branch
224        at the same level (in this case, to look for "c"). The Perl documentation
225        is clear that when (*THEN) is backtracked onto, it goes to the "next
226        alternative in the innermost enclosing group".
228    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
229        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
230        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
231        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
232        (*THEN).
234    3.  If \s appeared in a character class, it removed the VT character from
235        the class, even if it had been included by some previous item, for example
236        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
237        of \s, but is part of the POSIX "space" class.)
239    4.  A partial match never returns an empty string (because you can always
240        match an empty string at the end of the subject); however the checking for
241        an empty string was starting at the "start of match" point. This has been
242        changed to the "earliest inspected character" point, because the returned
243        data for a partial match starts at this character. This means that, for
244        example, /(?<=abc)def/ gives a partial match for the subject "abc"
245        (previously it gave "no match").
247    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
248        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
249        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
250        has an implication that the given string is incomplete (because a partial
251        match is preferred over a full match). For this reason, these items now
252        give a partial match in this situation. [Aside: previously, the one case
253        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
254        match rather than a full match, which was wrong by the old rules, but is
255        now correct.]
257    6.  There was a bug in the handling of #-introduced comments, recognized when
258        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
259        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
260        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
261        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
262        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
263        places in pcre_compile().
265    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
266        comments when looking ahead for named forward references to subpatterns,
267        the only newline sequence it recognized was NL. It now handles newlines
268        according to the set newline convention.
270    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
271        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
272        cater for a lack of strerror(). These oversights have been fixed.
274    9.  Added --match-limit and --recursion-limit to pcregrep.
276    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
278    11. When the -o option was used, pcregrep was setting a return code of 1, even
279        when matches were found, and --line-buffered was not being honoured.
281    12. Added an optional parentheses number to the -o and --only-matching options
282        of pcregrep.
284    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
285        can match an empty string. The code to do it in pcretest and pcredemo
286        needed fixing:
288        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
289            only one byte after an empty string match just before CRLF (this case
290            just got forgotten; "any" and "anycrlf" were OK).
292        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
293            mode when an empty string match preceded an ASCII character followed by
294            a non-ASCII character. (The code for advancing by one character rather
295            than one byte was nonsense.)
297        (c) The pcredemo.c sample program did not have any code at all to handle
298            the cases when CRLF is a valid newline sequence.
300    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
301        as a starting offset was within the subject string. There is now a new
302        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
303        negative or greater than the length of the string. In order to test this,
304        pcretest is extended to allow the setting of negative starting offsets.
306    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
307        starting offset points to the beginning of a UTF-8 character was
308        unnecessarily clumsy. I tidied it up.
310    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
311        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
313    17. Nobody had reported that the --include_dir option, which was added in
314        release 7.7 should have been called --include-dir (hyphen, not underscore)
315        for compatibility with GNU grep. I have changed it to --include-dir, but
316        left --include_dir as an undocumented synonym, and the same for
317        --exclude-dir, though that is not available in GNU grep, at least as of
318        release 2.5.4.
320    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
321        characters from a string of bytes) have been redefined so as not to use
322        loops, in order to improve performance in some environments. At the same
323        time, I abstracted some of the common code into auxiliary macros to save
324        repetition (this should not affect the compiled code).
326    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
327        compile-time error is now given if \c is not followed by an ASCII
328        character, that is, a byte less than 128. (In EBCDIC mode, the code is
329        different, and any byte value is allowed.)
331    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
332        START_OPTIMIZE option, which is now allowed at compile time - but just
333        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
334        to pcregrep and other applications that have no direct access to PCRE
335        options. The new /Y option in pcretest sets this option when calling
336        pcre_compile().
338    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
339        back references. Groups containing recursive back references were forced to
340        be atomic by that change, but in the case of named groups, the amount of
341        memory required was incorrectly computed, leading to "Failed: internal
342        error: code overflow". This has been fixed.
344    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
345        pcretest.c, to avoid build problems in some Borland environments.
348    Version 8.10 25-Jun-2010
349    ------------------------
351    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
352        THEN.
354    2.  (*ACCEPT) was not working when inside an atomic group.
356    3.  Inside a character class, \B is treated as a literal by default, but
357        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
358        causes the error). The code is unchanged, but I tidied the documentation.
360    4.  Inside a character class, PCRE always treated \R and \X as literals,
361        whereas Perl faults them if its -w option is set. I have changed PCRE so
362        that it faults them when PCRE_EXTRA is set.
364    5.  Added support for \N, which always matches any character other than
365        newline. (It is the same as "." when PCRE_DOTALL is not set.)
367    6.  When compiling pcregrep with newer versions of gcc which may have
368        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
369        declared with attribute warn_unused_result" were given. Just casting the
370        result to (void) does not stop the warnings; a more elaborate fudge is
371        needed. I've used a macro to implement this.
373    7.  Minor change to pcretest.c to avoid a compiler warning.
375    8.  Added four artifical Unicode properties to help with an option to make
376        \s etc use properties (see next item). The new properties are: Xan
377        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
379    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
380        use Unicode properties. (*UCP) at the start of a pattern can be used to set
381        this option. Modified pcretest to add /W to test this facility. Added
382        REG_UCP to make it available via the POSIX interface.
384    10. Added --line-buffered to pcregrep.
386    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
387        studied, and the match started with a letter with a code point greater than
388        127 whose first byte was different to the first byte of the other case of
389        the letter, the other case of this starting letter was not recognized
390        (#976).
392    12. If a pattern that was studied started with a repeated Unicode property
393        test, for example, \p{Nd}+, there was the theoretical possibility of
394        setting up an incorrect bitmap of starting bytes, but fortunately it could
395        not have actually happened in practice until change 8 above was made (it
396        added property types that matched character-matching opcodes).
398    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
399        possible starting bytes for non-anchored patterns.
401    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
402        \R, and also a number of cases that involve Unicode properties, both
403        explicit and implicit when PCRE_UCP is set.
405    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
406        input, it could crash or give wrong results if characters with values
407        greater than 0xc0 were present in the subject string. (Detail: it assumed
408        UTF-8 input when processing these items.)
410    16. Added a lot of (int) casts to avoid compiler warnings in systems where
411        size_t is 64-bit (#991).
413    17. Added a check for running out of memory when PCRE is compiled with
414        --disable-stack-for-recursion (#990).
416    18. If the last data line in a file for pcretest does not have a newline on
417        the end, a newline was missing in the output.
419    19. The default pcre_chartables.c file recognizes only ASCII characters (values
420        less than 128) in its various bitmaps. However, there is a facility for
421        generating tables according to the current locale when PCRE is compiled. It
422        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
423        characters, are recognized by isspace() and therefore were getting set in
424        these tables, and indeed these tables seem to approximate to ISO 8859. This
425        caused a problem in UTF-8 mode when pcre_study() was used to create a list
426        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
427        which of course cannot start UTF-8 characters. I have changed the code so
428        that only real ASCII characters (less than 128) and the correct starting
429        bytes for UTF-8 encodings are set for characters greater than 127 when in
430        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
431        altogether.)
433    20. Added the /T option to pcretest so as to be able to run tests with non-
434        standard character tables, thus making it possible to include the tests
435        used for 19 above in the standard set of tests.
437    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
438        reference to a subpattern the other side of a comment that contains an
439        opening parenthesis caused either an internal compiling error, or a
440        reference to the wrong subpattern.
443    Version 8.02 19-Mar-2010
444  ------------------------  ------------------------
446  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.
448    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
449        configured.
451    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
452        original author of that file, following a query about its status.
454    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
455        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
457    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
458        quantifier applied to a forward-referencing subroutine call, could compile
459        incorrect code or give the error "internal error: previously-checked
460        referenced subpattern not found".
462    6.  Both MS Visual Studio and Symbian OS have problems with initializing
463        variables to point to external functions. For these systems, therefore,
464        pcre_malloc etc. are now initialized to local functions that call the
465        relevant global functions.
467    7.  There were two entries missing in the vectors called coptable and poptable
468        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
469        I've fixed the data, and added a kludgy way of testing at compile time that
470        the lengths are correct (equal to the number of opcodes).
472    8.  Following on from 7, I added a similar kludge to check the length of the
473        eint vector in pcreposix.c.
475    9.  Error texts for pcre_compile() are held as one long string to avoid too
476        much relocation at load time. To find a text, the string is searched,
477        counting zeros. There was no check for running off the end of the string,
478        which could happen if a new error number was added without updating the
479        string.
481    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
483    11. \K was not working if it appeared in an atomic group or in a group that
484        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
485        \K is "not well defined" if used in an assertion. PCRE now accepts it if
486        the assertion is positive, but not if it is negative.
488    12. Change 11 fortuitously reduced the size of the stack frame used in the
489        "match()" function of pcre_exec.c by one pointer. Forthcoming
490        implementation of support for (*MARK) will need an extra pointer on the
491        stack; I have reserved it now, so that the stack frame size does not
492        decrease.
494    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
495        item in branch that calls a recursion is a subroutine call - as in the
496        second branch in the above example - was incorrectly given the compile-
497        time error "recursive call could loop indefinitely" because pcre_compile()
498        was not correctly checking the subroutine for matching a non-empty string.
500    14. The checks for overrunning compiling workspace could trigger after an
501        overrun had occurred. This is a "should never occur" error, but it can be
502        triggered by pathological patterns such as hundreds of nested parentheses.
503        The checks now trigger 100 bytes before the end of the workspace.
505    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
508  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
509  ------------------------  ------------------------

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