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revision 567 by ph10, Sat Nov 6 17:10:00 2010 UTC revision 642 by ph10, Thu Jul 28 18:59:40 2011 UTC
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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    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
151    
152    27. An instance of \X with an unlimited repeat could fail if at any point the
153        first character it looked at was a mark character.
154    
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
157    
158    29. Added the '=' option to pcretest to check the setting of unused capturing
159        slots at the end of the pattern, which are documented as being -1, but are
160        not included in the return count.
161    
162    30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
163        compiled something random. Now it gives a compile-time error (as does
164        Perl).
165    
166    31. A *MARK encountered during the processing of a positive assertion is now
167        recorded and passed back (compatible with Perl).
168    
169    32. If --only-matching or --colour was set on a pcregrep call whose pattern
170        had alternative anchored branches, the search for a second match in a line
171        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
172        matched the line "0102" twice. The same bug affected patterns that started
173        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
174        twice.
175    
176    33. Previously, PCRE did not allow quantification of assertions. However, Perl
177        does, and because of capturing effects, quantifying parenthesized
178        assertions may at times be useful. Quantifiers are now allowed for
179        parenthesized assertions.
180    
181    34. A minor code tidy in pcre_compile() when checking options for \R usage.
182    
183    35. \g was being checked for fancy things in a character class, when it should
184        just be a literal "g".
185    
186    36. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
187        appearance of a nested POSIX class supersedes an apparent external class.
188        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
189        unescaped square brackets may also appear as part of class names. For
190        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
191        more like Perl.
192    
193    37. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
194        was because it thought it was \N{name}, which is not supported).
195    
196    38. Add minix to OS list not supporting the -S option in pcretest.
197    
198    39. PCRE tries to detect cases of infinite recursion at compile time, but it
199        cannot analyze patterns in sufficient detail to catch mutual recursions
200        such as ((?1))((?2)). There is now a runtime test that gives an error if a
201        subgroup is called recursively as a subpattern for a second time at the
202        same position in the subject string. In previous releases this might have
203        been caught by the recursion limit, or it might have run out of stack.
204    
205    40. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
206        happen only once. PCRE was, however incorrectly giving a compile time error
207        "recursive call could loop indefinitely" because it cannot analyze the
208        pattern in sufficient detail. The compile time test no longer happens when
209        PCRE is compiling a conditional subpattern, but actual runaway loops are
210        now caught at runtime (see 39 above).
211    
212    
213    Version 8.12 15-Jan-2011
214    ------------------------
215    
216    1.  Fixed some typos in the markup of the man pages, and wrote a script that
217        checks for such things as part of the documentation building process.
218    
219    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
220        --match-limit and --recursion-limit options (added for 8.11). In
221        particular, this made one of the standard tests fail. (The integer value
222        went into the wrong half of a long int.)
223    
224    3.  If the --colour option was given to pcregrep with -v (invert match), it
225        did strange things, either producing crazy output, or crashing. It should,
226        of course, ignore a request for colour when reporting lines that do not
227        match.
228    
229    4.  Another pcregrep bug caused similar problems if --colour was specified with
230        -M (multiline) and the pattern match finished with a line ending.
231    
232    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
233        matched in multiline mode, the following line was shown as part of the
234        match. This seems wrong, so I have changed it.
235    
236    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
237        the check for further matches in the same line (so they could be coloured)
238        to overrun the end of the current line. If another match was found, it was
239        incorrectly shown (and then shown again when found in the next line).
240    
241    7.  If pcregrep was compiled under Windows, there was a reference to the
242        function pcregrep_exit() before it was defined. I am assuming this was
243        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
244        reported by a user. I've moved the definition above the reference.
245    
246    
247    Version 8.11 10-Dec-2010
248  ------------------------  ------------------------
249    
250  1.  (*THEN) was not working properly if there were untried alternatives prior  1.  (*THEN) was not working properly if there were untried alternatives prior
251      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
252      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
253      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
254      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
255      alternative in the innermost enclosing group".      alternative in the innermost enclosing group".
256    
257  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
258      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
259      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
260      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
261      (*THEN).      (*THEN).
262    
263  3.  If \s appeared in a character class, it removed the VT character from  3.  If \s appeared in a character class, it removed the VT character from
264      the class, even if it had been included by some previous item, for example      the class, even if it had been included by some previous item, for example
265      in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part      in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
266      of \s, but is part of the POSIX "space" class.)      of \s, but is part of the POSIX "space" class.)
267    
268  4.  A partial match never returns an empty string (because you can always  4.  A partial match never returns an empty string (because you can always
269      match an empty string at the end of the subject); however the checking for      match an empty string at the end of the subject); however the checking for
270      an empty string was starting at the "start of match" point. This has been      an empty string was starting at the "start of match" point. This has been
# Line 31  Version 8.11 10-Oct-2010 Line 274  Version 8.11 10-Oct-2010
274      (previously it gave "no match").      (previously it gave "no match").
275    
276  5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching  5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
277      of $, \z, \Z, \b, and \B. If the match point is at the end of the string,      of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
278      previously a full match would be given. However, setting PCRE_PARTIAL_HARD      previously a full match would be given. However, setting PCRE_PARTIAL_HARD
279      has an implication that the given string is incomplete (because a partial      has an implication that the given string is incomplete (because a partial
280      match is preferred over a full match). For this reason, these items now      match is preferred over a full match). For this reason, these items now
281      give a partial match in this situation. [Aside: previously, the one case      give a partial match in this situation. [Aside: previously, the one case
282      /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial      /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
283      match rather than a full match, which was wrong by the old rules, but is      match rather than a full match, which was wrong by the old rules, but is
284      now correct.]      now correct.]
285    
286  6.  There was a bug in the handling of #-introduced comments, recognized when  6.  There was a bug in the handling of #-introduced comments, recognized when
287      PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.      PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
288      If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose      If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
289      UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when      UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
290      scanning for the end of the comment. (*Character* 0x85 is an "any" newline,      scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
291      but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several      but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
292      places in pcre_compile().      places in pcre_compile().
293    
294  7.  Related to (6) above, when pcre_compile() was skipping #-introduced  7.  Related to (6) above, when pcre_compile() was skipping #-introduced
295      comments when looking ahead for named forward references to subpatterns,      comments when looking ahead for named forward references to subpatterns,
296      the only newline sequence it recognized was NL. It now handles newlines      the only newline sequence it recognized was NL. It now handles newlines
297      according to the set newline convention.      according to the set newline convention.
298    
299  8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the  8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
300      former, but used strtoul(), whereas pcretest avoided strtoul() but did not      former, but used strtoul(), whereas pcretest avoided strtoul() but did not
301      cater for a lack of strerror(). These oversights have been fixed.      cater for a lack of strerror(). These oversights have been fixed.
302    
303  9.  Added --match-limit and --recursion-limit to pcregrep.  9.  Added --match-limit and --recursion-limit to pcregrep.
304    
305  10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.  10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
306    
307  11. When the -o option was used, pcregrep was setting a return code of 1, even  11. When the -o option was used, pcregrep was setting a return code of 1, even
308      when matches were found, and --line-buffered was not being honoured.      when matches were found, and --line-buffered was not being honoured.
309    
310  12. Added an optional parentheses number to the -o and --only-matching options  12. Added an optional parentheses number to the -o and --only-matching options
311      of pcregrep.      of pcregrep.
312    
313  13. Imitating Perl's /g action for multiple matches is tricky when the pattern  13. Imitating Perl's /g action for multiple matches is tricky when the pattern
314      can match an empty string. The code to do it in pcretest and pcredemo      can match an empty string. The code to do it in pcretest and pcredemo
315      needed fixing:      needed fixing:
316    
317      (a) When the newline convention was "crlf", pcretest got it wrong, skipping      (a) When the newline convention was "crlf", pcretest got it wrong, skipping
318          only one byte after an empty string match just before CRLF (this case          only one byte after an empty string match just before CRLF (this case
319          just got forgotten; "any" and "anycrlf" were OK).          just got forgotten; "any" and "anycrlf" were OK).
320    
321      (b) The pcretest code also had a bug, causing it to loop forever in UTF-8      (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
322          mode when an empty string match preceded an ASCII character followed by          mode when an empty string match preceded an ASCII character followed by
323          a non-ASCII character. (The code for advancing by one character rather          a non-ASCII character. (The code for advancing by one character rather
324          than one byte was nonsense.)          than one byte was nonsense.)
325    
326      (c) The pcredemo.c sample program did not have any code at all to handle      (c) The pcredemo.c sample program did not have any code at all to handle
327          the cases when CRLF is a valid newline sequence.          the cases when CRLF is a valid newline sequence.
328    
329  14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given  14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
330      as a starting offset was within the subject string. There is now a new      as a starting offset was within the subject string. There is now a new
331      error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is      error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
332      negative or greater than the length of the string. In order to test this,      negative or greater than the length of the string. In order to test this,
333      pcretest is extended to allow the setting of negative starting offsets.      pcretest is extended to allow the setting of negative starting offsets.
334    
335  15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the  15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
336      starting offset points to the beginning of a UTF-8 character was      starting offset points to the beginning of a UTF-8 character was
337      unnecessarily clumsy. I tidied it up.      unnecessarily clumsy. I tidied it up.
338    
339    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
340        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
341    
342    17. Nobody had reported that the --include_dir option, which was added in
343        release 7.7 should have been called --include-dir (hyphen, not underscore)
344        for compatibility with GNU grep. I have changed it to --include-dir, but
345        left --include_dir as an undocumented synonym, and the same for
346        --exclude-dir, though that is not available in GNU grep, at least as of
347        release 2.5.4.
348    
349    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
350        characters from a string of bytes) have been redefined so as not to use
351        loops, in order to improve performance in some environments. At the same
352        time, I abstracted some of the common code into auxiliary macros to save
353        repetition (this should not affect the compiled code).
354    
355    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
356        compile-time error is now given if \c is not followed by an ASCII
357        character, that is, a byte less than 128. (In EBCDIC mode, the code is
358        different, and any byte value is allowed.)
359    
360    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
361        START_OPTIMIZE option, which is now allowed at compile time - but just
362        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
363        to pcregrep and other applications that have no direct access to PCRE
364        options. The new /Y option in pcretest sets this option when calling
365        pcre_compile().
366    
367    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
368        back references. Groups containing recursive back references were forced to
369        be atomic by that change, but in the case of named groups, the amount of
370        memory required was incorrectly computed, leading to "Failed: internal
371        error: code overflow". This has been fixed.
372    
373    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
374        pcretest.c, to avoid build problems in some Borland environments.
375    
376    
377  Version 8.10 25-Jun-2010  Version 8.10 25-Jun-2010

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