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revision 513 by ph10, Mon May 3 11:13:37 2010 UTC revision 619 by ph10, Sun Jul 17 13:23:14 2011 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.10 03 May-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.
142    Version 8.12 15-Jan-2011
143    ------------------------
145    1.  Fixed some typos in the markup of the man pages, and wrote a script that
146        checks for such things as part of the documentation building process.
148    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
149        --match-limit and --recursion-limit options (added for 8.11). In
150        particular, this made one of the standard tests fail. (The integer value
151        went into the wrong half of a long int.)
153    3.  If the --colour option was given to pcregrep with -v (invert match), it
154        did strange things, either producing crazy output, or crashing. It should,
155        of course, ignore a request for colour when reporting lines that do not
156        match.
158    4.  Another pcregrep bug caused similar problems if --colour was specified with
159        -M (multiline) and the pattern match finished with a line ending.
161    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
162        matched in multiline mode, the following line was shown as part of the
163        match. This seems wrong, so I have changed it.
165    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
166        the check for further matches in the same line (so they could be coloured)
167        to overrun the end of the current line. If another match was found, it was
168        incorrectly shown (and then shown again when found in the next line).
170    7.  If pcregrep was compiled under Windows, there was a reference to the
171        function pcregrep_exit() before it was defined. I am assuming this was
172        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
173        reported by a user. I've moved the definition above the reference.
176    Version 8.11 10-Dec-2010
177    ------------------------
179    1.  (*THEN) was not working properly if there were untried alternatives prior
180        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
181        backtracked to try for "b" instead of moving to the next alternative branch
182        at the same level (in this case, to look for "c"). The Perl documentation
183        is clear that when (*THEN) is backtracked onto, it goes to the "next
184        alternative in the innermost enclosing group".
186    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
187        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
188        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
189        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
190        (*THEN).
192    3.  If \s appeared in a character class, it removed the VT character from
193        the class, even if it had been included by some previous item, for example
194        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
195        of \s, but is part of the POSIX "space" class.)
197    4.  A partial match never returns an empty string (because you can always
198        match an empty string at the end of the subject); however the checking for
199        an empty string was starting at the "start of match" point. This has been
200        changed to the "earliest inspected character" point, because the returned
201        data for a partial match starts at this character. This means that, for
202        example, /(?<=abc)def/ gives a partial match for the subject "abc"
203        (previously it gave "no match").
205    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
206        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
207        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
208        has an implication that the given string is incomplete (because a partial
209        match is preferred over a full match). For this reason, these items now
210        give a partial match in this situation. [Aside: previously, the one case
211        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
212        match rather than a full match, which was wrong by the old rules, but is
213        now correct.]
215    6.  There was a bug in the handling of #-introduced comments, recognized when
216        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
217        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
218        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
219        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
220        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
221        places in pcre_compile().
223    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
224        comments when looking ahead for named forward references to subpatterns,
225        the only newline sequence it recognized was NL. It now handles newlines
226        according to the set newline convention.
228    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
229        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
230        cater for a lack of strerror(). These oversights have been fixed.
232    9.  Added --match-limit and --recursion-limit to pcregrep.
234    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
236    11. When the -o option was used, pcregrep was setting a return code of 1, even
237        when matches were found, and --line-buffered was not being honoured.
239    12. Added an optional parentheses number to the -o and --only-matching options
240        of pcregrep.
242    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
243        can match an empty string. The code to do it in pcretest and pcredemo
244        needed fixing:
246        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
247            only one byte after an empty string match just before CRLF (this case
248            just got forgotten; "any" and "anycrlf" were OK).
250        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
251            mode when an empty string match preceded an ASCII character followed by
252            a non-ASCII character. (The code for advancing by one character rather
253            than one byte was nonsense.)
255        (c) The pcredemo.c sample program did not have any code at all to handle
256            the cases when CRLF is a valid newline sequence.
258    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
259        as a starting offset was within the subject string. There is now a new
260        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
261        negative or greater than the length of the string. In order to test this,
262        pcretest is extended to allow the setting of negative starting offsets.
264    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
265        starting offset points to the beginning of a UTF-8 character was
266        unnecessarily clumsy. I tidied it up.
268    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
269        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
271    17. Nobody had reported that the --include_dir option, which was added in
272        release 7.7 should have been called --include-dir (hyphen, not underscore)
273        for compatibility with GNU grep. I have changed it to --include-dir, but
274        left --include_dir as an undocumented synonym, and the same for
275        --exclude-dir, though that is not available in GNU grep, at least as of
276        release 2.5.4.
278    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
279        characters from a string of bytes) have been redefined so as not to use
280        loops, in order to improve performance in some environments. At the same
281        time, I abstracted some of the common code into auxiliary macros to save
282        repetition (this should not affect the compiled code).
284    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
285        compile-time error is now given if \c is not followed by an ASCII
286        character, that is, a byte less than 128. (In EBCDIC mode, the code is
287        different, and any byte value is allowed.)
289    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
290        START_OPTIMIZE option, which is now allowed at compile time - but just
291        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
292        to pcregrep and other applications that have no direct access to PCRE
293        options. The new /Y option in pcretest sets this option when calling
294        pcre_compile().
296    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
297        back references. Groups containing recursive back references were forced to
298        be atomic by that change, but in the case of named groups, the amount of
299        memory required was incorrectly computed, leading to "Failed: internal
300        error: code overflow". This has been fixed.
302    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
303        pcretest.c, to avoid build problems in some Borland environments.
306    Version 8.10 25-Jun-2010
307  ------------------------  ------------------------
309  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
# Line 9  Version 8.10 03 May-2010 Line 311  Version 8.10 03 May-2010
312  2.  (*ACCEPT) was not working when inside an atomic group.  2.  (*ACCEPT) was not working when inside an atomic group.
314  3.  Inside a character class, \B is treated as a literal by default, but  3.  Inside a character class, \B is treated as a literal by default, but
315      faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option      faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
316      causes the error). The code is unchanged, but I tidied the documentation.      causes the error). The code is unchanged, but I tidied the documentation.
318  4.  Inside a character class, PCRE always treated \R and \X as literals,  4.  Inside a character class, PCRE always treated \R and \X as literals,
319      whereas Perl faults them if its -w option is set. I have changed PCRE so      whereas Perl faults them if its -w option is set. I have changed PCRE so
320      that it faults them when PCRE_EXTRA is set.      that it faults them when PCRE_EXTRA is set.
322    5.  Added support for \N, which always matches any character other than
323        newline. (It is the same as "." when PCRE_DOTALL is not set.)
325    6.  When compiling pcregrep with newer versions of gcc which may have
326        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
327        declared with attribute warn_unused_result" were given. Just casting the
328        result to (void) does not stop the warnings; a more elaborate fudge is
329        needed. I've used a macro to implement this.
331    7.  Minor change to pcretest.c to avoid a compiler warning.
333    8.  Added four artifical Unicode properties to help with an option to make
334        \s etc use properties (see next item). The new properties are: Xan
335        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
337    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
338        use Unicode properties. (*UCP) at the start of a pattern can be used to set
339        this option. Modified pcretest to add /W to test this facility. Added
340        REG_UCP to make it available via the POSIX interface.
342    10. Added --line-buffered to pcregrep.
344    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
345        studied, and the match started with a letter with a code point greater than
346        127 whose first byte was different to the first byte of the other case of
347        the letter, the other case of this starting letter was not recognized
348        (#976).
350    12. If a pattern that was studied started with a repeated Unicode property
351        test, for example, \p{Nd}+, there was the theoretical possibility of
352        setting up an incorrect bitmap of starting bytes, but fortunately it could
353        not have actually happened in practice until change 8 above was made (it
354        added property types that matched character-matching opcodes).
356    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
357        possible starting bytes for non-anchored patterns.
359    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
360        \R, and also a number of cases that involve Unicode properties, both
361        explicit and implicit when PCRE_UCP is set.
363    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
364        input, it could crash or give wrong results if characters with values
365        greater than 0xc0 were present in the subject string. (Detail: it assumed
366        UTF-8 input when processing these items.)
368    16. Added a lot of (int) casts to avoid compiler warnings in systems where
369        size_t is 64-bit (#991).
371    17. Added a check for running out of memory when PCRE is compiled with
372        --disable-stack-for-recursion (#990).
374    18. If the last data line in a file for pcretest does not have a newline on
375        the end, a newline was missing in the output.
377    19. The default pcre_chartables.c file recognizes only ASCII characters (values
378        less than 128) in its various bitmaps. However, there is a facility for
379        generating tables according to the current locale when PCRE is compiled. It
380        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
381        characters, are recognized by isspace() and therefore were getting set in
382        these tables, and indeed these tables seem to approximate to ISO 8859. This
383        caused a problem in UTF-8 mode when pcre_study() was used to create a list
384        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
385        which of course cannot start UTF-8 characters. I have changed the code so
386        that only real ASCII characters (less than 128) and the correct starting
387        bytes for UTF-8 encodings are set for characters greater than 127 when in
388        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
389        altogether.)
391    20. Added the /T option to pcretest so as to be able to run tests with non-
392        standard character tables, thus making it possible to include the tests
393        used for 19 above in the standard set of tests.
395    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
396        reference to a subpattern the other side of a comment that contains an
397        opening parenthesis caused either an internal compiling error, or a
398        reference to the wrong subpattern.
401  Version 8.02 19-Mar-2010  Version 8.02 19-Mar-2010
402  ------------------------  ------------------------

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