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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.02 01-Mar-2010  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 collection of tests with study enabled,
83        and thereby test pcre_study() more easily.
84    
85    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
86        restoration of the capturing data to the outer values was not happening
87        correctly.
88    
89    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
90        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
91        pattern had matched an empty string, and so incorrectly returned a no
92        match.
93    
94    17. There was optimizing code for the last branch of non-capturing parentheses,
95        and also for the obeyed branch of a conditional subexpression, which used
96        tail recursion to cut down on stack usage. Unfortunately, not that there is
97        the possibility of (*THEN) occurring in these branches, tail recursion is
98        no longer possible because the return has to be checked for (*THEN). These
99        two optimizations have therefore been removed.
100    
101    18. If a pattern containing \R was studied, it was assumed that \R always
102        matched two bytes, thus causing the minimum subject length to be
103        incorrectly computed because \R can also match just one byte.
104    
105    
106    Version 8.12 15-Jan-2011
107    ------------------------
108    
109    1.  Fixed some typos in the markup of the man pages, and wrote a script that
110        checks for such things as part of the documentation building process.
111    
112    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
113        --match-limit and --recursion-limit options (added for 8.11). In
114        particular, this made one of the standard tests fail. (The integer value
115        went into the wrong half of a long int.)
116    
117    3.  If the --colour option was given to pcregrep with -v (invert match), it
118        did strange things, either producing crazy output, or crashing. It should,
119        of course, ignore a request for colour when reporting lines that do not
120        match.
121    
122    4.  Another pcregrep bug caused similar problems if --colour was specified with
123        -M (multiline) and the pattern match finished with a line ending.
124    
125    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
126        matched in multiline mode, the following line was shown as part of the
127        match. This seems wrong, so I have changed it.
128    
129    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
130        the check for further matches in the same line (so they could be coloured)
131        to overrun the end of the current line. If another match was found, it was
132        incorrectly shown (and then shown again when found in the next line).
133    
134    7.  If pcregrep was compiled under Windows, there was a reference to the
135        function pcregrep_exit() before it was defined. I am assuming this was
136        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
137        reported by a user. I've moved the definition above the reference.
138    
139    
140    Version 8.11 10-Dec-2010
141    ------------------------
142    
143    1.  (*THEN) was not working properly if there were untried alternatives prior
144        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
145        backtracked to try for "b" instead of moving to the next alternative branch
146        at the same level (in this case, to look for "c"). The Perl documentation
147        is clear that when (*THEN) is backtracked onto, it goes to the "next
148        alternative in the innermost enclosing group".
149    
150    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
151        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
152        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
153        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
154        (*THEN).
155    
156    3.  If \s appeared in a character class, it removed the VT character from
157        the class, even if it had been included by some previous item, for example
158        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
159        of \s, but is part of the POSIX "space" class.)
160    
161    4.  A partial match never returns an empty string (because you can always
162        match an empty string at the end of the subject); however the checking for
163        an empty string was starting at the "start of match" point. This has been
164        changed to the "earliest inspected character" point, because the returned
165        data for a partial match starts at this character. This means that, for
166        example, /(?<=abc)def/ gives a partial match for the subject "abc"
167        (previously it gave "no match").
168    
169    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
170        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
171        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
172        has an implication that the given string is incomplete (because a partial
173        match is preferred over a full match). For this reason, these items now
174        give a partial match in this situation. [Aside: previously, the one case
175        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
176        match rather than a full match, which was wrong by the old rules, but is
177        now correct.]
178    
179    6.  There was a bug in the handling of #-introduced comments, recognized when
180        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
181        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
182        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
183        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
184        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
185        places in pcre_compile().
186    
187    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
188        comments when looking ahead for named forward references to subpatterns,
189        the only newline sequence it recognized was NL. It now handles newlines
190        according to the set newline convention.
191    
192    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
193        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
194        cater for a lack of strerror(). These oversights have been fixed.
195    
196    9.  Added --match-limit and --recursion-limit to pcregrep.
197    
198    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
199    
200    11. When the -o option was used, pcregrep was setting a return code of 1, even
201        when matches were found, and --line-buffered was not being honoured.
202    
203    12. Added an optional parentheses number to the -o and --only-matching options
204        of pcregrep.
205    
206    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
207        can match an empty string. The code to do it in pcretest and pcredemo
208        needed fixing:
209    
210        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
211            only one byte after an empty string match just before CRLF (this case
212            just got forgotten; "any" and "anycrlf" were OK).
213    
214        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
215            mode when an empty string match preceded an ASCII character followed by
216            a non-ASCII character. (The code for advancing by one character rather
217            than one byte was nonsense.)
218    
219        (c) The pcredemo.c sample program did not have any code at all to handle
220            the cases when CRLF is a valid newline sequence.
221    
222    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
223        as a starting offset was within the subject string. There is now a new
224        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
225        negative or greater than the length of the string. In order to test this,
226        pcretest is extended to allow the setting of negative starting offsets.
227    
228    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
229        starting offset points to the beginning of a UTF-8 character was
230        unnecessarily clumsy. I tidied it up.
231    
232    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
233        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
234    
235    17. Nobody had reported that the --include_dir option, which was added in
236        release 7.7 should have been called --include-dir (hyphen, not underscore)
237        for compatibility with GNU grep. I have changed it to --include-dir, but
238        left --include_dir as an undocumented synonym, and the same for
239        --exclude-dir, though that is not available in GNU grep, at least as of
240        release 2.5.4.
241    
242    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
243        characters from a string of bytes) have been redefined so as not to use
244        loops, in order to improve performance in some environments. At the same
245        time, I abstracted some of the common code into auxiliary macros to save
246        repetition (this should not affect the compiled code).
247    
248    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
249        compile-time error is now given if \c is not followed by an ASCII
250        character, that is, a byte less than 128. (In EBCDIC mode, the code is
251        different, and any byte value is allowed.)
252    
253    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
254        START_OPTIMIZE option, which is now allowed at compile time - but just
255        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
256        to pcregrep and other applications that have no direct access to PCRE
257        options. The new /Y option in pcretest sets this option when calling
258        pcre_compile().
259    
260    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
261        back references. Groups containing recursive back references were forced to
262        be atomic by that change, but in the case of named groups, the amount of
263        memory required was incorrectly computed, leading to "Failed: internal
264        error: code overflow". This has been fixed.
265    
266    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
267        pcretest.c, to avoid build problems in some Borland environments.
268    
269    
270    Version 8.10 25-Jun-2010
271    ------------------------
272    
273    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
274        THEN.
275    
276    2.  (*ACCEPT) was not working when inside an atomic group.
277    
278    3.  Inside a character class, \B is treated as a literal by default, but
279        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
280        causes the error). The code is unchanged, but I tidied the documentation.
281    
282    4.  Inside a character class, PCRE always treated \R and \X as literals,
283        whereas Perl faults them if its -w option is set. I have changed PCRE so
284        that it faults them when PCRE_EXTRA is set.
285    
286    5.  Added support for \N, which always matches any character other than
287        newline. (It is the same as "." when PCRE_DOTALL is not set.)
288    
289    6.  When compiling pcregrep with newer versions of gcc which may have
290        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
291        declared with attribute warn_unused_result" were given. Just casting the
292        result to (void) does not stop the warnings; a more elaborate fudge is
293        needed. I've used a macro to implement this.
294    
295    7.  Minor change to pcretest.c to avoid a compiler warning.
296    
297    8.  Added four artifical Unicode properties to help with an option to make
298        \s etc use properties (see next item). The new properties are: Xan
299        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
300    
301    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
302        use Unicode properties. (*UCP) at the start of a pattern can be used to set
303        this option. Modified pcretest to add /W to test this facility. Added
304        REG_UCP to make it available via the POSIX interface.
305    
306    10. Added --line-buffered to pcregrep.
307    
308    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
309        studied, and the match started with a letter with a code point greater than
310        127 whose first byte was different to the first byte of the other case of
311        the letter, the other case of this starting letter was not recognized
312        (#976).
313    
314    12. If a pattern that was studied started with a repeated Unicode property
315        test, for example, \p{Nd}+, there was the theoretical possibility of
316        setting up an incorrect bitmap of starting bytes, but fortunately it could
317        not have actually happened in practice until change 8 above was made (it
318        added property types that matched character-matching opcodes).
319    
320    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
321        possible starting bytes for non-anchored patterns.
322    
323    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
324        \R, and also a number of cases that involve Unicode properties, both
325        explicit and implicit when PCRE_UCP is set.
326    
327    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
328        input, it could crash or give wrong results if characters with values
329        greater than 0xc0 were present in the subject string. (Detail: it assumed
330        UTF-8 input when processing these items.)
331    
332    16. Added a lot of (int) casts to avoid compiler warnings in systems where
333        size_t is 64-bit (#991).
334    
335    17. Added a check for running out of memory when PCRE is compiled with
336        --disable-stack-for-recursion (#990).
337    
338    18. If the last data line in a file for pcretest does not have a newline on
339        the end, a newline was missing in the output.
340    
341    19. The default pcre_chartables.c file recognizes only ASCII characters (values
342        less than 128) in its various bitmaps. However, there is a facility for
343        generating tables according to the current locale when PCRE is compiled. It
344        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
345        characters, are recognized by isspace() and therefore were getting set in
346        these tables, and indeed these tables seem to approximate to ISO 8859. This
347        caused a problem in UTF-8 mode when pcre_study() was used to create a list
348        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
349        which of course cannot start UTF-8 characters. I have changed the code so
350        that only real ASCII characters (less than 128) and the correct starting
351        bytes for UTF-8 encodings are set for characters greater than 127 when in
352        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
353        altogether.)
354    
355    20. Added the /T option to pcretest so as to be able to run tests with non-
356        standard character tables, thus making it possible to include the tests
357        used for 19 above in the standard set of tests.
358    
359    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
360        reference to a subpattern the other side of a comment that contains an
361        opening parenthesis caused either an internal compiling error, or a
362        reference to the wrong subpattern.
363    
364    
365    Version 8.02 19-Mar-2010
366  ------------------------  ------------------------
367    
368  1.  The Unicode data tables have been updated to Unicode 5.2.0.  1.  The Unicode data tables have been updated to Unicode 5.2.0.
369    
370  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is  2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
371      configured.      configured.
372    
373  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the  3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
374      original author of that file, following a query about its status.      original author of that file, following a query about its status.
375    
376    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
377        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
378    
379    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
380        quantifier applied to a forward-referencing subroutine call, could compile
381        incorrect code or give the error "internal error: previously-checked
382        referenced subpattern not found".
383    
384    6.  Both MS Visual Studio and Symbian OS have problems with initializing
385        variables to point to external functions. For these systems, therefore,
386        pcre_malloc etc. are now initialized to local functions that call the
387        relevant global functions.
388    
389    7.  There were two entries missing in the vectors called coptable and poptable
390        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
391        I've fixed the data, and added a kludgy way of testing at compile time that
392        the lengths are correct (equal to the number of opcodes).
393    
394    8.  Following on from 7, I added a similar kludge to check the length of the
395        eint vector in pcreposix.c.
396    
397    9.  Error texts for pcre_compile() are held as one long string to avoid too
398        much relocation at load time. To find a text, the string is searched,
399        counting zeros. There was no check for running off the end of the string,
400        which could happen if a new error number was added without updating the
401        string.
402    
403    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
404    
405    11. \K was not working if it appeared in an atomic group or in a group that
406        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
407        \K is "not well defined" if used in an assertion. PCRE now accepts it if
408        the assertion is positive, but not if it is negative.
409    
410    12. Change 11 fortuitously reduced the size of the stack frame used in the
411        "match()" function of pcre_exec.c by one pointer. Forthcoming
412        implementation of support for (*MARK) will need an extra pointer on the
413        stack; I have reserved it now, so that the stack frame size does not
414        decrease.
415    
416    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
417        item in branch that calls a recursion is a subroutine call - as in the
418        second branch in the above example - was incorrectly given the compile-
419        time error "recursive call could loop indefinitely" because pcre_compile()
420        was not correctly checking the subroutine for matching a non-empty string.
421    
422    14. The checks for overrunning compiling workspace could trigger after an
423        overrun had occurred. This is a "should never occur" error, but it can be
424        triggered by pathological patterns such as hundreds of nested parentheses.
425        The checks now trigger 100 bytes before the end of the workspace.
426    
427    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
428    
429    
430  Version 8.01 19-Jan-2010  Version 8.01 19-Jan-2010

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