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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    Version 8.13 30-Apr-2011
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
8    
9    2.  Two minor typos in pcre_internal.h have been fixed.
10    
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).
14    
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).
23    
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.
28    
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().
34    
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.
38    
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.
46    
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.
55    
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().
59    
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
62    
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.
68    
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.
72    
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.
77    
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).
86    
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.
90    
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.
95    
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.
102    
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.
106    
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
109    
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.
113    
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.
116    
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.
125    
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).
129    
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.
136    
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.
140    
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.
147    
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.
151    
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.
154    
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
157    
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.
161    
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).
165    
166    
167    Version 8.12 15-Jan-2011
168    ------------------------
169    
170    1.  Fixed some typos in the markup of the man pages, and wrote a script that
171        checks for such things as part of the documentation building process.
172    
173    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
174        --match-limit and --recursion-limit options (added for 8.11). In
175        particular, this made one of the standard tests fail. (The integer value
176        went into the wrong half of a long int.)
177    
178    3.  If the --colour option was given to pcregrep with -v (invert match), it
179        did strange things, either producing crazy output, or crashing. It should,
180        of course, ignore a request for colour when reporting lines that do not
181        match.
182    
183    4.  Another pcregrep bug caused similar problems if --colour was specified with
184        -M (multiline) and the pattern match finished with a line ending.
185    
186    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
187        matched in multiline mode, the following line was shown as part of the
188        match. This seems wrong, so I have changed it.
189    
190    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
191        the check for further matches in the same line (so they could be coloured)
192        to overrun the end of the current line. If another match was found, it was
193        incorrectly shown (and then shown again when found in the next line).
194    
195    7.  If pcregrep was compiled under Windows, there was a reference to the
196        function pcregrep_exit() before it was defined. I am assuming this was
197        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
198        reported by a user. I've moved the definition above the reference.
199    
200    
201    Version 8.11 10-Dec-2010
202    ------------------------
203    
204    1.  (*THEN) was not working properly if there were untried alternatives prior
205        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
206        backtracked to try for "b" instead of moving to the next alternative branch
207        at the same level (in this case, to look for "c"). The Perl documentation
208        is clear that when (*THEN) is backtracked onto, it goes to the "next
209        alternative in the innermost enclosing group".
210    
211    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
212        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
213        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
214        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
215        (*THEN).
216    
217    3.  If \s appeared in a character class, it removed the VT character from
218        the class, even if it had been included by some previous item, for example
219        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
220        of \s, but is part of the POSIX "space" class.)
221    
222    4.  A partial match never returns an empty string (because you can always
223        match an empty string at the end of the subject); however the checking for
224        an empty string was starting at the "start of match" point. This has been
225        changed to the "earliest inspected character" point, because the returned
226        data for a partial match starts at this character. This means that, for
227        example, /(?<=abc)def/ gives a partial match for the subject "abc"
228        (previously it gave "no match").
229    
230    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
231        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
232        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
233        has an implication that the given string is incomplete (because a partial
234        match is preferred over a full match). For this reason, these items now
235        give a partial match in this situation. [Aside: previously, the one case
236        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
237        match rather than a full match, which was wrong by the old rules, but is
238        now correct.]
239    
240    6.  There was a bug in the handling of #-introduced comments, recognized when
241        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
242        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
243        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
244        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
245        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
246        places in pcre_compile().
247    
248    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
249        comments when looking ahead for named forward references to subpatterns,
250        the only newline sequence it recognized was NL. It now handles newlines
251        according to the set newline convention.
252    
253    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
254        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
255        cater for a lack of strerror(). These oversights have been fixed.
256    
257    9.  Added --match-limit and --recursion-limit to pcregrep.
258    
259    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
260    
261    11. When the -o option was used, pcregrep was setting a return code of 1, even
262        when matches were found, and --line-buffered was not being honoured.
263    
264    12. Added an optional parentheses number to the -o and --only-matching options
265        of pcregrep.
266    
267    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
268        can match an empty string. The code to do it in pcretest and pcredemo
269        needed fixing:
270    
271        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
272            only one byte after an empty string match just before CRLF (this case
273            just got forgotten; "any" and "anycrlf" were OK).
274    
275        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
276            mode when an empty string match preceded an ASCII character followed by
277            a non-ASCII character. (The code for advancing by one character rather
278            than one byte was nonsense.)
279    
280        (c) The pcredemo.c sample program did not have any code at all to handle
281            the cases when CRLF is a valid newline sequence.
282    
283    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
284        as a starting offset was within the subject string. There is now a new
285        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
286        negative or greater than the length of the string. In order to test this,
287        pcretest is extended to allow the setting of negative starting offsets.
288    
289    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
290        starting offset points to the beginning of a UTF-8 character was
291        unnecessarily clumsy. I tidied it up.
292    
293    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
294        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
295    
296    17. Nobody had reported that the --include_dir option, which was added in
297        release 7.7 should have been called --include-dir (hyphen, not underscore)
298        for compatibility with GNU grep. I have changed it to --include-dir, but
299        left --include_dir as an undocumented synonym, and the same for
300        --exclude-dir, though that is not available in GNU grep, at least as of
301        release 2.5.4.
302    
303    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
304        characters from a string of bytes) have been redefined so as not to use
305        loops, in order to improve performance in some environments. At the same
306        time, I abstracted some of the common code into auxiliary macros to save
307        repetition (this should not affect the compiled code).
308    
309    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
310        compile-time error is now given if \c is not followed by an ASCII
311        character, that is, a byte less than 128. (In EBCDIC mode, the code is
312        different, and any byte value is allowed.)
313    
314    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
315        START_OPTIMIZE option, which is now allowed at compile time - but just
316        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
317        to pcregrep and other applications that have no direct access to PCRE
318        options. The new /Y option in pcretest sets this option when calling
319        pcre_compile().
320    
321    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
322        back references. Groups containing recursive back references were forced to
323        be atomic by that change, but in the case of named groups, the amount of
324        memory required was incorrectly computed, leading to "Failed: internal
325        error: code overflow". This has been fixed.
326    
327    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
328        pcretest.c, to avoid build problems in some Borland environments.
329    
330    
331    Version 8.10 25-Jun-2010
332    ------------------------
333    
334    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
335        THEN.
336    
337    2.  (*ACCEPT) was not working when inside an atomic group.
338    
339    3.  Inside a character class, \B is treated as a literal by default, but
340        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
341        causes the error). The code is unchanged, but I tidied the documentation.
342    
343    4.  Inside a character class, PCRE always treated \R and \X as literals,
344        whereas Perl faults them if its -w option is set. I have changed PCRE so
345        that it faults them when PCRE_EXTRA is set.
346    
347    5.  Added support for \N, which always matches any character other than
348        newline. (It is the same as "." when PCRE_DOTALL is not set.)
349    
350    6.  When compiling pcregrep with newer versions of gcc which may have
351        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
352        declared with attribute warn_unused_result" were given. Just casting the
353        result to (void) does not stop the warnings; a more elaborate fudge is
354        needed. I've used a macro to implement this.
355    
356    7.  Minor change to pcretest.c to avoid a compiler warning.
357    
358    8.  Added four artifical Unicode properties to help with an option to make
359        \s etc use properties (see next item). The new properties are: Xan
360        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
361    
362    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
363        use Unicode properties. (*UCP) at the start of a pattern can be used to set
364        this option. Modified pcretest to add /W to test this facility. Added
365        REG_UCP to make it available via the POSIX interface.
366    
367    10. Added --line-buffered to pcregrep.
368    
369    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
370        studied, and the match started with a letter with a code point greater than
371        127 whose first byte was different to the first byte of the other case of
372        the letter, the other case of this starting letter was not recognized
373        (#976).
374    
375    12. If a pattern that was studied started with a repeated Unicode property
376        test, for example, \p{Nd}+, there was the theoretical possibility of
377        setting up an incorrect bitmap of starting bytes, but fortunately it could
378        not have actually happened in practice until change 8 above was made (it
379        added property types that matched character-matching opcodes).
380    
381    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
382        possible starting bytes for non-anchored patterns.
383    
384    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
385        \R, and also a number of cases that involve Unicode properties, both
386        explicit and implicit when PCRE_UCP is set.
387    
388    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
389        input, it could crash or give wrong results if characters with values
390        greater than 0xc0 were present in the subject string. (Detail: it assumed
391        UTF-8 input when processing these items.)
392    
393    16. Added a lot of (int) casts to avoid compiler warnings in systems where
394        size_t is 64-bit (#991).
395    
396    17. Added a check for running out of memory when PCRE is compiled with
397        --disable-stack-for-recursion (#990).
398    
399    18. If the last data line in a file for pcretest does not have a newline on
400        the end, a newline was missing in the output.
401    
402    19. The default pcre_chartables.c file recognizes only ASCII characters (values
403        less than 128) in its various bitmaps. However, there is a facility for
404        generating tables according to the current locale when PCRE is compiled. It
405        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
406        characters, are recognized by isspace() and therefore were getting set in
407        these tables, and indeed these tables seem to approximate to ISO 8859. This
408        caused a problem in UTF-8 mode when pcre_study() was used to create a list
409        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
410        which of course cannot start UTF-8 characters. I have changed the code so
411        that only real ASCII characters (less than 128) and the correct starting
412        bytes for UTF-8 encodings are set for characters greater than 127 when in
413        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
414        altogether.)
415    
416    20. Added the /T option to pcretest so as to be able to run tests with non-
417        standard character tables, thus making it possible to include the tests
418        used for 19 above in the standard set of tests.
419    
420    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
421        reference to a subpattern the other side of a comment that contains an
422        opening parenthesis caused either an internal compiling error, or a
423        reference to the wrong subpattern.
424    
425    
426  Version 8.02 19-Mar-2010  Version 8.02 19-Mar-2010
427  ------------------------  ------------------------
428    

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