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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.11 10-Oct-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 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    
149    Version 8.12 15-Jan-2011
150    ------------------------
151    
152    1.  Fixed some typos in the markup of the man pages, and wrote a script that
153        checks for such things as part of the documentation building process.
154    
155    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
156        --match-limit and --recursion-limit options (added for 8.11). In
157        particular, this made one of the standard tests fail. (The integer value
158        went into the wrong half of a long int.)
159    
160    3.  If the --colour option was given to pcregrep with -v (invert match), it
161        did strange things, either producing crazy output, or crashing. It should,
162        of course, ignore a request for colour when reporting lines that do not
163        match.
164    
165    4.  Another pcregrep bug caused similar problems if --colour was specified with
166        -M (multiline) and the pattern match finished with a line ending.
167    
168    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
169        matched in multiline mode, the following line was shown as part of the
170        match. This seems wrong, so I have changed it.
171    
172    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
173        the check for further matches in the same line (so they could be coloured)
174        to overrun the end of the current line. If another match was found, it was
175        incorrectly shown (and then shown again when found in the next line).
176    
177    7.  If pcregrep was compiled under Windows, there was a reference to the
178        function pcregrep_exit() before it was defined. I am assuming this was
179        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
180        reported by a user. I've moved the definition above the reference.
181    
182    
183    Version 8.11 10-Dec-2010
184  ------------------------  ------------------------
185    
186  1.  (*THEN) was not working properly if there were untried alternatives prior  1.  (*THEN) was not working properly if there were untried alternatives prior
187      to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it      to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
188      backtracked to try for "b" instead of moving to the next alternative branch      backtracked to try for "b" instead of moving to the next alternative branch
189      at the same level (in this case, to look for "c"). The Perl documentation      at the same level (in this case, to look for "c"). The Perl documentation
190      is clear that when (*THEN) is backtracked onto, it goes to the "next      is clear that when (*THEN) is backtracked onto, it goes to the "next
191      alternative in the innermost enclosing group".      alternative in the innermost enclosing group".
192    
193  2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern  2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
194      such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should      such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
195      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
196      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
197      (*THEN).      (*THEN).
198    
199    3.  If \s appeared in a character class, it removed the VT character from
200        the class, even if it had been included by some previous item, for example
201        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
202        of \s, but is part of the POSIX "space" class.)
203    
204    4.  A partial match never returns an empty string (because you can always
205        match an empty string at the end of the subject); however the checking for
206        an empty string was starting at the "start of match" point. This has been
207        changed to the "earliest inspected character" point, because the returned
208        data for a partial match starts at this character. This means that, for
209        example, /(?<=abc)def/ gives a partial match for the subject "abc"
210        (previously it gave "no match").
211    
212    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
213        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
214        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
215        has an implication that the given string is incomplete (because a partial
216        match is preferred over a full match). For this reason, these items now
217        give a partial match in this situation. [Aside: previously, the one case
218        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
219        match rather than a full match, which was wrong by the old rules, but is
220        now correct.]
221    
222    6.  There was a bug in the handling of #-introduced comments, recognized when
223        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
224        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
225        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
226        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
227        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
228        places in pcre_compile().
229    
230    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
231        comments when looking ahead for named forward references to subpatterns,
232        the only newline sequence it recognized was NL. It now handles newlines
233        according to the set newline convention.
234    
235    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
236        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
237        cater for a lack of strerror(). These oversights have been fixed.
238    
239    9.  Added --match-limit and --recursion-limit to pcregrep.
240    
241    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
242    
243    11. When the -o option was used, pcregrep was setting a return code of 1, even
244        when matches were found, and --line-buffered was not being honoured.
245    
246    12. Added an optional parentheses number to the -o and --only-matching options
247        of pcregrep.
248    
249    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
250        can match an empty string. The code to do it in pcretest and pcredemo
251        needed fixing:
252    
253        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
254            only one byte after an empty string match just before CRLF (this case
255            just got forgotten; "any" and "anycrlf" were OK).
256    
257        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
258            mode when an empty string match preceded an ASCII character followed by
259            a non-ASCII character. (The code for advancing by one character rather
260            than one byte was nonsense.)
261    
262        (c) The pcredemo.c sample program did not have any code at all to handle
263            the cases when CRLF is a valid newline sequence.
264    
265    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
266        as a starting offset was within the subject string. There is now a new
267        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
268        negative or greater than the length of the string. In order to test this,
269        pcretest is extended to allow the setting of negative starting offsets.
270    
271    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
272        starting offset points to the beginning of a UTF-8 character was
273        unnecessarily clumsy. I tidied it up.
274    
275    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
276        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
277    
278    17. Nobody had reported that the --include_dir option, which was added in
279        release 7.7 should have been called --include-dir (hyphen, not underscore)
280        for compatibility with GNU grep. I have changed it to --include-dir, but
281        left --include_dir as an undocumented synonym, and the same for
282        --exclude-dir, though that is not available in GNU grep, at least as of
283        release 2.5.4.
284    
285    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
286        characters from a string of bytes) have been redefined so as not to use
287        loops, in order to improve performance in some environments. At the same
288        time, I abstracted some of the common code into auxiliary macros to save
289        repetition (this should not affect the compiled code).
290    
291    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
292        compile-time error is now given if \c is not followed by an ASCII
293        character, that is, a byte less than 128. (In EBCDIC mode, the code is
294        different, and any byte value is allowed.)
295    
296    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
297        START_OPTIMIZE option, which is now allowed at compile time - but just
298        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
299        to pcregrep and other applications that have no direct access to PCRE
300        options. The new /Y option in pcretest sets this option when calling
301        pcre_compile().
302    
303    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
304        back references. Groups containing recursive back references were forced to
305        be atomic by that change, but in the case of named groups, the amount of
306        memory required was incorrectly computed, leading to "Failed: internal
307        error: code overflow". This has been fixed.
308    
309    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
310        pcretest.c, to avoid build problems in some Borland environments.
311    
312    
313  Version 8.10 25-Jun-2010  Version 8.10 25-Jun-2010

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