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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    
115    Version 8.12 15-Jan-2011
116    ------------------------
117    
118    1.  Fixed some typos in the markup of the man pages, and wrote a script that
119        checks for such things as part of the documentation building process.
120    
121    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
122        --match-limit and --recursion-limit options (added for 8.11). In
123        particular, this made one of the standard tests fail. (The integer value
124        went into the wrong half of a long int.)
125    
126    3.  If the --colour option was given to pcregrep with -v (invert match), it
127        did strange things, either producing crazy output, or crashing. It should,
128        of course, ignore a request for colour when reporting lines that do not
129        match.
130    
131    4.  Another pcregrep bug caused similar problems if --colour was specified with
132        -M (multiline) and the pattern match finished with a line ending.
133    
134    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
135        matched in multiline mode, the following line was shown as part of the
136        match. This seems wrong, so I have changed it.
137    
138    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
139        the check for further matches in the same line (so they could be coloured)
140        to overrun the end of the current line. If another match was found, it was
141        incorrectly shown (and then shown again when found in the next line).
142    
143    7.  If pcregrep was compiled under Windows, there was a reference to the
144        function pcregrep_exit() before it was defined. I am assuming this was
145        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
146        reported by a user. I've moved the definition above the reference.
147    
148    
149    Version 8.11 10-Dec-2010
150    ------------------------
151    
152    1.  (*THEN) was not working properly if there were untried alternatives prior
153        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
154        backtracked to try for "b" instead of moving to the next alternative branch
155        at the same level (in this case, to look for "c"). The Perl documentation
156        is clear that when (*THEN) is backtracked onto, it goes to the "next
157        alternative in the innermost enclosing group".
158    
159    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
160        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
161        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
162        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
163        (*THEN).
164    
165    3.  If \s appeared in a character class, it removed the VT character from
166        the class, even if it had been included by some previous item, for example
167        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
168        of \s, but is part of the POSIX "space" class.)
169    
170    4.  A partial match never returns an empty string (because you can always
171        match an empty string at the end of the subject); however the checking for
172        an empty string was starting at the "start of match" point. This has been
173        changed to the "earliest inspected character" point, because the returned
174        data for a partial match starts at this character. This means that, for
175        example, /(?<=abc)def/ gives a partial match for the subject "abc"
176        (previously it gave "no match").
177    
178    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
179        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
180        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
181        has an implication that the given string is incomplete (because a partial
182        match is preferred over a full match). For this reason, these items now
183        give a partial match in this situation. [Aside: previously, the one case
184        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
185        match rather than a full match, which was wrong by the old rules, but is
186        now correct.]
187    
188    6.  There was a bug in the handling of #-introduced comments, recognized when
189        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
190        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
191        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
192        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
193        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
194        places in pcre_compile().
195    
196    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
197        comments when looking ahead for named forward references to subpatterns,
198        the only newline sequence it recognized was NL. It now handles newlines
199        according to the set newline convention.
200    
201    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
202        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
203        cater for a lack of strerror(). These oversights have been fixed.
204    
205    9.  Added --match-limit and --recursion-limit to pcregrep.
206    
207    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
208    
209    11. When the -o option was used, pcregrep was setting a return code of 1, even
210        when matches were found, and --line-buffered was not being honoured.
211    
212    12. Added an optional parentheses number to the -o and --only-matching options
213        of pcregrep.
214    
215    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
216        can match an empty string. The code to do it in pcretest and pcredemo
217        needed fixing:
218    
219        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
220            only one byte after an empty string match just before CRLF (this case
221            just got forgotten; "any" and "anycrlf" were OK).
222    
223        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
224            mode when an empty string match preceded an ASCII character followed by
225            a non-ASCII character. (The code for advancing by one character rather
226            than one byte was nonsense.)
227    
228        (c) The pcredemo.c sample program did not have any code at all to handle
229            the cases when CRLF is a valid newline sequence.
230    
231    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
232        as a starting offset was within the subject string. There is now a new
233        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
234        negative or greater than the length of the string. In order to test this,
235        pcretest is extended to allow the setting of negative starting offsets.
236    
237    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
238        starting offset points to the beginning of a UTF-8 character was
239        unnecessarily clumsy. I tidied it up.
240    
241    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
242        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
243    
244    17. Nobody had reported that the --include_dir option, which was added in
245        release 7.7 should have been called --include-dir (hyphen, not underscore)
246        for compatibility with GNU grep. I have changed it to --include-dir, but
247        left --include_dir as an undocumented synonym, and the same for
248        --exclude-dir, though that is not available in GNU grep, at least as of
249        release 2.5.4.
250    
251    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
252        characters from a string of bytes) have been redefined so as not to use
253        loops, in order to improve performance in some environments. At the same
254        time, I abstracted some of the common code into auxiliary macros to save
255        repetition (this should not affect the compiled code).
256    
257    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
258        compile-time error is now given if \c is not followed by an ASCII
259        character, that is, a byte less than 128. (In EBCDIC mode, the code is
260        different, and any byte value is allowed.)
261    
262    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
263        START_OPTIMIZE option, which is now allowed at compile time - but just
264        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
265        to pcregrep and other applications that have no direct access to PCRE
266        options. The new /Y option in pcretest sets this option when calling
267        pcre_compile().
268    
269    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
270        back references. Groups containing recursive back references were forced to
271        be atomic by that change, but in the case of named groups, the amount of
272        memory required was incorrectly computed, leading to "Failed: internal
273        error: code overflow". This has been fixed.
274    
275    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
276        pcretest.c, to avoid build problems in some Borland environments.
277    
278    
279    Version 8.10 25-Jun-2010
280    ------------------------
281    
282    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
283        THEN.
284    
285    2.  (*ACCEPT) was not working when inside an atomic group.
286    
287    3.  Inside a character class, \B is treated as a literal by default, but
288        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
289        causes the error). The code is unchanged, but I tidied the documentation.
290    
291    4.  Inside a character class, PCRE always treated \R and \X as literals,
292        whereas Perl faults them if its -w option is set. I have changed PCRE so
293        that it faults them when PCRE_EXTRA is set.
294    
295    5.  Added support for \N, which always matches any character other than
296        newline. (It is the same as "." when PCRE_DOTALL is not set.)
297    
298    6.  When compiling pcregrep with newer versions of gcc which may have
299        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
300        declared with attribute warn_unused_result" were given. Just casting the
301        result to (void) does not stop the warnings; a more elaborate fudge is
302        needed. I've used a macro to implement this.
303    
304    7.  Minor change to pcretest.c to avoid a compiler warning.
305    
306    8.  Added four artifical Unicode properties to help with an option to make
307        \s etc use properties (see next item). The new properties are: Xan
308        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
309    
310    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
311        use Unicode properties. (*UCP) at the start of a pattern can be used to set
312        this option. Modified pcretest to add /W to test this facility. Added
313        REG_UCP to make it available via the POSIX interface.
314    
315    10. Added --line-buffered to pcregrep.
316    
317    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
318        studied, and the match started with a letter with a code point greater than
319        127 whose first byte was different to the first byte of the other case of
320        the letter, the other case of this starting letter was not recognized
321        (#976).
322    
323    12. If a pattern that was studied started with a repeated Unicode property
324        test, for example, \p{Nd}+, there was the theoretical possibility of
325        setting up an incorrect bitmap of starting bytes, but fortunately it could
326        not have actually happened in practice until change 8 above was made (it
327        added property types that matched character-matching opcodes).
328    
329    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
330        possible starting bytes for non-anchored patterns.
331    
332    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
333        \R, and also a number of cases that involve Unicode properties, both
334        explicit and implicit when PCRE_UCP is set.
335    
336    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
337        input, it could crash or give wrong results if characters with values
338        greater than 0xc0 were present in the subject string. (Detail: it assumed
339        UTF-8 input when processing these items.)
340    
341    16. Added a lot of (int) casts to avoid compiler warnings in systems where
342        size_t is 64-bit (#991).
343    
344    17. Added a check for running out of memory when PCRE is compiled with
345        --disable-stack-for-recursion (#990).
346    
347    18. If the last data line in a file for pcretest does not have a newline on
348        the end, a newline was missing in the output.
349    
350    19. The default pcre_chartables.c file recognizes only ASCII characters (values
351        less than 128) in its various bitmaps. However, there is a facility for
352        generating tables according to the current locale when PCRE is compiled. It
353        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
354        characters, are recognized by isspace() and therefore were getting set in
355        these tables, and indeed these tables seem to approximate to ISO 8859. This
356        caused a problem in UTF-8 mode when pcre_study() was used to create a list
357        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
358        which of course cannot start UTF-8 characters. I have changed the code so
359        that only real ASCII characters (less than 128) and the correct starting
360        bytes for UTF-8 encodings are set for characters greater than 127 when in
361        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
362        altogether.)
363    
364    20. Added the /T option to pcretest so as to be able to run tests with non-
365        standard character tables, thus making it possible to include the tests
366        used for 19 above in the standard set of tests.
367    
368    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
369        reference to a subpattern the other side of a comment that contains an
370        opening parenthesis caused either an internal compiling error, or a
371        reference to the wrong subpattern.
372    
373    
374    Version 8.02 19-Mar-2010
375    ------------------------
376    
377    1.  The Unicode data tables have been updated to Unicode 5.2.0.
378    
379    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
380        configured.
381    
382    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
383        original author of that file, following a query about its status.
384    
385    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
386        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
387    
388    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
389        quantifier applied to a forward-referencing subroutine call, could compile
390        incorrect code or give the error "internal error: previously-checked
391        referenced subpattern not found".
392    
393    6.  Both MS Visual Studio and Symbian OS have problems with initializing
394        variables to point to external functions. For these systems, therefore,
395        pcre_malloc etc. are now initialized to local functions that call the
396        relevant global functions.
397    
398    7.  There were two entries missing in the vectors called coptable and poptable
399        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
400        I've fixed the data, and added a kludgy way of testing at compile time that
401        the lengths are correct (equal to the number of opcodes).
402    
403    8.  Following on from 7, I added a similar kludge to check the length of the
404        eint vector in pcreposix.c.
405    
406    9.  Error texts for pcre_compile() are held as one long string to avoid too
407        much relocation at load time. To find a text, the string is searched,
408        counting zeros. There was no check for running off the end of the string,
409        which could happen if a new error number was added without updating the
410        string.
411    
412    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
413    
414    11. \K was not working if it appeared in an atomic group or in a group that
415        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
416        \K is "not well defined" if used in an assertion. PCRE now accepts it if
417        the assertion is positive, but not if it is negative.
418    
419    12. Change 11 fortuitously reduced the size of the stack frame used in the
420        "match()" function of pcre_exec.c by one pointer. Forthcoming
421        implementation of support for (*MARK) will need an extra pointer on the
422        stack; I have reserved it now, so that the stack frame size does not
423        decrease.
424    
425    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
426        item in branch that calls a recursion is a subroutine call - as in the
427        second branch in the above example - was incorrectly given the compile-
428        time error "recursive call could loop indefinitely" because pcre_compile()
429        was not correctly checking the subroutine for matching a non-empty string.
430    
431    14. The checks for overrunning compiling workspace could trigger after an
432        overrun had occurred. This is a "should never occur" error, but it can be
433        triggered by pathological patterns such as hundreds of nested parentheses.
434        The checks now trigger 100 bytes before the end of the workspace.
435    
436    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
437    
438    
439  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010
440  ------------------------  ------------------------
441    

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