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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    
138    Version 8.12 15-Jan-2011
139    ------------------------
140    
141    1.  Fixed some typos in the markup of the man pages, and wrote a script that
142        checks for such things as part of the documentation building process.
143    
144    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
145        --match-limit and --recursion-limit options (added for 8.11). In
146        particular, this made one of the standard tests fail. (The integer value
147        went into the wrong half of a long int.)
148    
149    3.  If the --colour option was given to pcregrep with -v (invert match), it
150        did strange things, either producing crazy output, or crashing. It should,
151        of course, ignore a request for colour when reporting lines that do not
152        match.
153    
154    4.  Another pcregrep bug caused similar problems if --colour was specified with
155        -M (multiline) and the pattern match finished with a line ending.
156    
157    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
158        matched in multiline mode, the following line was shown as part of the
159        match. This seems wrong, so I have changed it.
160    
161    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
162        the check for further matches in the same line (so they could be coloured)
163        to overrun the end of the current line. If another match was found, it was
164        incorrectly shown (and then shown again when found in the next line).
165    
166    7.  If pcregrep was compiled under Windows, there was a reference to the
167        function pcregrep_exit() before it was defined. I am assuming this was
168        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
169        reported by a user. I've moved the definition above the reference.
170    
171    
172    Version 8.11 10-Dec-2010
173    ------------------------
174    
175    1.  (*THEN) was not working properly if there were untried alternatives prior
176        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
177        backtracked to try for "b" instead of moving to the next alternative branch
178        at the same level (in this case, to look for "c"). The Perl documentation
179        is clear that when (*THEN) is backtracked onto, it goes to the "next
180        alternative in the innermost enclosing group".
181    
182    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
183        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
184        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
185        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
186        (*THEN).
187    
188    3.  If \s appeared in a character class, it removed the VT character from
189        the class, even if it had been included by some previous item, for example
190        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
191        of \s, but is part of the POSIX "space" class.)
192    
193    4.  A partial match never returns an empty string (because you can always
194        match an empty string at the end of the subject); however the checking for
195        an empty string was starting at the "start of match" point. This has been
196        changed to the "earliest inspected character" point, because the returned
197        data for a partial match starts at this character. This means that, for
198        example, /(?<=abc)def/ gives a partial match for the subject "abc"
199        (previously it gave "no match").
200    
201    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
202        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
203        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
204        has an implication that the given string is incomplete (because a partial
205        match is preferred over a full match). For this reason, these items now
206        give a partial match in this situation. [Aside: previously, the one case
207        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
208        match rather than a full match, which was wrong by the old rules, but is
209        now correct.]
210    
211    6.  There was a bug in the handling of #-introduced comments, recognized when
212        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
213        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
214        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
215        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
216        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
217        places in pcre_compile().
218    
219    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
220        comments when looking ahead for named forward references to subpatterns,
221        the only newline sequence it recognized was NL. It now handles newlines
222        according to the set newline convention.
223    
224    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
225        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
226        cater for a lack of strerror(). These oversights have been fixed.
227    
228    9.  Added --match-limit and --recursion-limit to pcregrep.
229    
230    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
231    
232    11. When the -o option was used, pcregrep was setting a return code of 1, even
233        when matches were found, and --line-buffered was not being honoured.
234    
235    12. Added an optional parentheses number to the -o and --only-matching options
236        of pcregrep.
237    
238    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
239        can match an empty string. The code to do it in pcretest and pcredemo
240        needed fixing:
241    
242        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
243            only one byte after an empty string match just before CRLF (this case
244            just got forgotten; "any" and "anycrlf" were OK).
245    
246        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
247            mode when an empty string match preceded an ASCII character followed by
248            a non-ASCII character. (The code for advancing by one character rather
249            than one byte was nonsense.)
250    
251        (c) The pcredemo.c sample program did not have any code at all to handle
252            the cases when CRLF is a valid newline sequence.
253    
254    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
255        as a starting offset was within the subject string. There is now a new
256        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
257        negative or greater than the length of the string. In order to test this,
258        pcretest is extended to allow the setting of negative starting offsets.
259    
260    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
261        starting offset points to the beginning of a UTF-8 character was
262        unnecessarily clumsy. I tidied it up.
263    
264    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
265        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
266    
267    17. Nobody had reported that the --include_dir option, which was added in
268        release 7.7 should have been called --include-dir (hyphen, not underscore)
269        for compatibility with GNU grep. I have changed it to --include-dir, but
270        left --include_dir as an undocumented synonym, and the same for
271        --exclude-dir, though that is not available in GNU grep, at least as of
272        release 2.5.4.
273    
274    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
275        characters from a string of bytes) have been redefined so as not to use
276        loops, in order to improve performance in some environments. At the same
277        time, I abstracted some of the common code into auxiliary macros to save
278        repetition (this should not affect the compiled code).
279    
280    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
281        compile-time error is now given if \c is not followed by an ASCII
282        character, that is, a byte less than 128. (In EBCDIC mode, the code is
283        different, and any byte value is allowed.)
284    
285    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
286        START_OPTIMIZE option, which is now allowed at compile time - but just
287        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
288        to pcregrep and other applications that have no direct access to PCRE
289        options. The new /Y option in pcretest sets this option when calling
290        pcre_compile().
291    
292    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
293        back references. Groups containing recursive back references were forced to
294        be atomic by that change, but in the case of named groups, the amount of
295        memory required was incorrectly computed, leading to "Failed: internal
296        error: code overflow". This has been fixed.
297    
298    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
299        pcretest.c, to avoid build problems in some Borland environments.
300    
301    
302    Version 8.10 25-Jun-2010
303    ------------------------
304    
305    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
306        THEN.
307    
308    2.  (*ACCEPT) was not working when inside an atomic group.
309    
310    3.  Inside a character class, \B is treated as a literal by default, but
311        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
312        causes the error). The code is unchanged, but I tidied the documentation.
313    
314    4.  Inside a character class, PCRE always treated \R and \X as literals,
315        whereas Perl faults them if its -w option is set. I have changed PCRE so
316        that it faults them when PCRE_EXTRA is set.
317    
318    5.  Added support for \N, which always matches any character other than
319        newline. (It is the same as "." when PCRE_DOTALL is not set.)
320    
321    6.  When compiling pcregrep with newer versions of gcc which may have
322        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
323        declared with attribute warn_unused_result" were given. Just casting the
324        result to (void) does not stop the warnings; a more elaborate fudge is
325        needed. I've used a macro to implement this.
326    
327    7.  Minor change to pcretest.c to avoid a compiler warning.
328    
329    8.  Added four artifical Unicode properties to help with an option to make
330        \s etc use properties (see next item). The new properties are: Xan
331        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
332    
333    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
334        use Unicode properties. (*UCP) at the start of a pattern can be used to set
335        this option. Modified pcretest to add /W to test this facility. Added
336        REG_UCP to make it available via the POSIX interface.
337    
338    10. Added --line-buffered to pcregrep.
339    
340    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
341        studied, and the match started with a letter with a code point greater than
342        127 whose first byte was different to the first byte of the other case of
343        the letter, the other case of this starting letter was not recognized
344        (#976).
345    
346    12. If a pattern that was studied started with a repeated Unicode property
347        test, for example, \p{Nd}+, there was the theoretical possibility of
348        setting up an incorrect bitmap of starting bytes, but fortunately it could
349        not have actually happened in practice until change 8 above was made (it
350        added property types that matched character-matching opcodes).
351    
352    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
353        possible starting bytes for non-anchored patterns.
354    
355    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
356        \R, and also a number of cases that involve Unicode properties, both
357        explicit and implicit when PCRE_UCP is set.
358    
359    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
360        input, it could crash or give wrong results if characters with values
361        greater than 0xc0 were present in the subject string. (Detail: it assumed
362        UTF-8 input when processing these items.)
363    
364    16. Added a lot of (int) casts to avoid compiler warnings in systems where
365        size_t is 64-bit (#991).
366    
367    17. Added a check for running out of memory when PCRE is compiled with
368        --disable-stack-for-recursion (#990).
369    
370    18. If the last data line in a file for pcretest does not have a newline on
371        the end, a newline was missing in the output.
372    
373    19. The default pcre_chartables.c file recognizes only ASCII characters (values
374        less than 128) in its various bitmaps. However, there is a facility for
375        generating tables according to the current locale when PCRE is compiled. It
376        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
377        characters, are recognized by isspace() and therefore were getting set in
378        these tables, and indeed these tables seem to approximate to ISO 8859. This
379        caused a problem in UTF-8 mode when pcre_study() was used to create a list
380        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
381        which of course cannot start UTF-8 characters. I have changed the code so
382        that only real ASCII characters (less than 128) and the correct starting
383        bytes for UTF-8 encodings are set for characters greater than 127 when in
384        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
385        altogether.)
386    
387    20. Added the /T option to pcretest so as to be able to run tests with non-
388        standard character tables, thus making it possible to include the tests
389        used for 19 above in the standard set of tests.
390    
391    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
392        reference to a subpattern the other side of a comment that contains an
393        opening parenthesis caused either an internal compiling error, or a
394        reference to the wrong subpattern.
395    
396    
397    Version 8.02 19-Mar-2010
398    ------------------------
399    
400    1.  The Unicode data tables have been updated to Unicode 5.2.0.
401    
402    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
403        configured.
404    
405    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
406        original author of that file, following a query about its status.
407    
408    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
409        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
410    
411    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
412        quantifier applied to a forward-referencing subroutine call, could compile
413        incorrect code or give the error "internal error: previously-checked
414        referenced subpattern not found".
415    
416    6.  Both MS Visual Studio and Symbian OS have problems with initializing
417        variables to point to external functions. For these systems, therefore,
418        pcre_malloc etc. are now initialized to local functions that call the
419        relevant global functions.
420    
421    7.  There were two entries missing in the vectors called coptable and poptable
422        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
423        I've fixed the data, and added a kludgy way of testing at compile time that
424        the lengths are correct (equal to the number of opcodes).
425    
426    8.  Following on from 7, I added a similar kludge to check the length of the
427        eint vector in pcreposix.c.
428    
429    9.  Error texts for pcre_compile() are held as one long string to avoid too
430        much relocation at load time. To find a text, the string is searched,
431        counting zeros. There was no check for running off the end of the string,
432        which could happen if a new error number was added without updating the
433        string.
434    
435    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
436    
437    11. \K was not working if it appeared in an atomic group or in a group that
438        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
439        \K is "not well defined" if used in an assertion. PCRE now accepts it if
440        the assertion is positive, but not if it is negative.
441    
442    12. Change 11 fortuitously reduced the size of the stack frame used in the
443        "match()" function of pcre_exec.c by one pointer. Forthcoming
444        implementation of support for (*MARK) will need an extra pointer on the
445        stack; I have reserved it now, so that the stack frame size does not
446        decrease.
447    
448    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
449        item in branch that calls a recursion is a subroutine call - as in the
450        second branch in the above example - was incorrectly given the compile-
451        time error "recursive call could loop indefinitely" because pcre_compile()
452        was not correctly checking the subroutine for matching a non-empty string.
453    
454    14. The checks for overrunning compiling workspace could trigger after an
455        overrun had occurred. This is a "should never occur" error, but it can be
456        triggered by pathological patterns such as hundreds of nested parentheses.
457        The checks now trigger 100 bytes before the end of the workspace.
458    
459    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
460    
461    
462  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
463  ------------------------  ------------------------
464    

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