/[pcre]/code/trunk/ChangeLog
ViewVC logotype

Diff of /code/trunk/ChangeLog

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 551 by ph10, Sun Oct 10 17:33:07 2010 UTC revision 687 by ph10, Tue Sep 6 16:09:43 2011 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.11 10-Oct-2010  Version 8.20
5    ------------
6    
7    1. Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
8       a POSIX class. After further experiments with Perl, which convinced me that
9       Perl has bugs and confusions, a closing square bracket is no longer allowed
10       in a POSIX name.
11    
12    2. If a pattern such as /(a)b|ac/ is matched against "ac", there is no captured
13       substring, but while checking the failing first alternative, substring 1 is
14       temporarily captured. If the output vector supplied to pcre_exec() was not
15       big enough for this capture, the yield of the function was still zero
16       ("insufficient space for captured substrings"). This cannot be totally fixed
17       without adding another stack variable, which seems a lot of expense for a
18       edge case. However, I have improved the situation in cases such as
19       /(a)(b)x|abc/ matched against "abc", where the return code indicates that
20       fewer than the maximum number of slots in the ovector have been set.
21    
22    3. Related to (2) above: when there are more back references in a pattern than
23       slots in the output vector, pcre_exec() uses temporary memory during
24       matching, and copies in the captures as far as possible afterwards. It was
25       using the entire output vector, but this conflicts with the specification
26       that only 2/3 is used for passing back captured substrings. Now it uses only
27       the first 2/3, for compatibility. This is, of course, another edge case.
28    
29    4. Zoltan Herczeg's just-in-time compiler support has been integrated into the
30       main code base, and can be used by building with --enable-jit. When this is
31       done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
32       runtime --no-jit option is given.
33    
34    5. When the number of matches in a pcre_dfa_exec() run exactly filled the
35       ovector, the return from the function was zero, implying that there were
36       other matches that did not fit. The correct "exactly full" value is now
37       returned.
38    
39    6. If a subpattern that was called recursively or as a subroutine contained
40       (*PRUNE) or any other control that caused it to give a non-standard return,
41       invalid errors such as "Error -26 (nested recursion at the same subject
42       position)" or even infinite loops could occur.
43    
44    
45    Version 8.13 16-Aug-2011
46    ------------------------
47    
48    1.  The Unicode data tables have been updated to Unicode 6.0.0.
49    
50    2.  Two minor typos in pcre_internal.h have been fixed.
51    
52    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
53        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
54        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
55    
56    4.  There were a number of related bugs in the code for matching backrefences
57        caselessly in UTF-8 mode when codes for the characters concerned were
58        different numbers of bytes. For example, U+023A and U+2C65 are an upper
59        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
60        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
61        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
62        2-byte code at the end of the subject (it thought there wasn't enough data
63        left).
64    
65    5.  Comprehensive information about what went wrong is now returned by
66        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
67        as the output vector has at least 2 elements. The offset of the start of
68        the failing character and a reason code are placed in the vector.
69    
70    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
71        now returned is for the first byte of the failing character, instead of the
72        last byte inspected. This is an incompatible change, but I hope it is small
73        enough not to be a problem. It makes the returned offset consistent with
74        pcre_exec() and pcre_dfa_exec().
75    
76    7.  pcretest now gives a text phrase as well as the error number when
77        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
78        failure, the offset and reason code are output.
79    
80    8.  When \R was used with a maximizing quantifier it failed to skip backwards
81        over a \r\n pair if the subsequent match failed. Instead, it just skipped
82        back over a single character (\n). This seems wrong (because it treated the
83        two characters as a single entity when going forwards), conflicts with the
84        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
85        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
86        has been changed.
87    
88    9.  Some internal refactoring has changed the processing so that the handling
89        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
90        time (the PCRE_DOTALL option was changed this way some time ago: version
91        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
92        which was always a bit of a fudge. It also means that there is one less
93        argument for the match() function, which reduces its stack requirements
94        slightly. This change also fixes an incompatibility with Perl: the pattern
95        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
96    
97    10. More internal refactoring has drastically reduced the number of recursive
98        calls to match() for possessively repeated groups such as (abc)++ when
99        using pcre_exec().
100    
101    11. While implementing 10, a number of bugs in the handling of groups were
102        discovered and fixed:
103    
104        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
105        (a|)*(?1) gave a compile-time internal error.
106        ((a|)+)+  did not notice that the outer group could match an empty string.
107        (^a|^)+   was not marked as anchored.
108        (.*a|.*)+ was not marked as matching at start or after a newline.
109    
110    12. Yet more internal refactoring has removed another argument from the match()
111        function. Special calls to this function are now indicated by setting a
112        value in a variable in the "match data" data block.
113    
114    13. Be more explicit in pcre_study() instead of relying on "default" for
115        opcodes that mean there is no starting character; this means that when new
116        ones are added and accidentally left out of pcre_study(), testing should
117        pick them up.
118    
119    14. The -s option of pcretest has been documented for ages as being an old
120        synonym of -m (show memory usage). I have changed it to mean "force study
121        for every regex", that is, assume /S for every regex. This is similar to -i
122        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
123        using it. It makes it easier to run collections of tests with and without
124        study enabled, and thereby test pcre_study() more easily. All the standard
125        tests are now run with and without -s (but some patterns can be marked as
126        "never study" - see 20 below).
127    
128    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
129        restoration of the capturing data to the outer values was not happening
130        correctly.
131    
132    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
133        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
134        pattern had matched an empty string, and so incorrectly returned a no
135        match.
136    
137    17. There was optimizing code for the last branch of non-capturing parentheses,
138        and also for the obeyed branch of a conditional subexpression, which used
139        tail recursion to cut down on stack usage. Unfortunately, now that there is
140        the possibility of (*THEN) occurring in these branches, tail recursion is
141        no longer possible because the return has to be checked for (*THEN). These
142        two optimizations have therefore been removed.
143    
144    18. If a pattern containing \R was studied, it was assumed that \R always
145        matched two bytes, thus causing the minimum subject length to be
146        incorrectly computed because \R can also match just one byte.
147    
148    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
149        was incorrectly computed.
150    
151    20. If /S is present twice on a test pattern in pcretest input, it now
152        *disables* studying, thereby overriding the use of -s on the command line
153        (see 14 above). This is necessary for one or two tests to keep the output
154        identical in both cases.
155    
156    21. When (*ACCEPT) was used in an assertion that matched an empty string and
157        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
158    
159    22. When an atomic group that contained a capturing parenthesis was
160        successfully matched, but the branch in which it appeared failed, the
161        capturing was not being forgotten if a higher numbered group was later
162        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
163        group 1 to "a", when in fact it should be unset. This applied to multi-
164        branched capturing and non-capturing groups, repeated or not, and also to
165        positive assertions (capturing in negative assertions does not happen
166        in PCRE) and also to nested atomic groups.
167    
168    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
169        subject after a captured substring, to make it easier to tell which of a
170        number of identical substrings has been captured.
171    
172    24. The way atomic groups are processed by pcre_exec() has been changed so that
173        if they are repeated, backtracking one repetition now resets captured
174        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
175        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
176        "aaa". Previously, it would have been "a". As part of this code
177        refactoring, the way recursive calls are handled has also been changed.
178    
179    25. If an assertion condition captured any substrings, they were not passed
180        back unless some other capturing happened later. For example, if
181        (?(?=(a))a) was matched against "a", no capturing was returned.
182    
183    26. When studying a pattern that contained subroutine calls or assertions,
184        the code for finding the minimum length of a possible match was handling
185        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
186        group 1 called group 2 while simultaneously a separate group 2 called group
187        1). A stack overflow occurred in this case. I have fixed this by limiting
188        the recursion depth to 10.
189    
190    27. Updated RunTest.bat in the distribution to the version supplied by Tom
191        Fortmann. This supports explicit test numbers on the command line, and has
192        argument validation and error reporting.
193    
194    28. An instance of \X with an unlimited repeat could fail if at any point the
195        first character it looked at was a mark character.
196    
197    29. Some minor code refactoring concerning Unicode properties and scripts
198        should reduce the stack requirement of match() slightly.
199    
200    30. Added the '=' option to pcretest to check the setting of unused capturing
201        slots at the end of the pattern, which are documented as being -1, but are
202        not included in the return count.
203    
204    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
205        compiled something random. Now it gives a compile-time error (as does
206        Perl).
207    
208    32. A *MARK encountered during the processing of a positive assertion is now
209        recorded and passed back (compatible with Perl).
210    
211    33. If --only-matching or --colour was set on a pcregrep call whose pattern
212        had alternative anchored branches, the search for a second match in a line
213        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
214        matched the line "0102" twice. The same bug affected patterns that started
215        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
216        twice.
217    
218    34. Previously, PCRE did not allow quantification of assertions. However, Perl
219        does, and because of capturing effects, quantifying parenthesized
220        assertions may at times be useful. Quantifiers are now allowed for
221        parenthesized assertions.
222    
223    35. A minor code tidy in pcre_compile() when checking options for \R usage.
224    
225    36. \g was being checked for fancy things in a character class, when it should
226        just be a literal "g".
227    
228    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
229        appearance of a nested POSIX class supersedes an apparent external class.
230        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
231        unescaped square brackets may also appear as part of class names. For
232        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
233        more like Perl. (But see 8.20/1 above.)
234    
235    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
236        was because it thought it was \N{name}, which is not supported).
237    
238    39. Add minix to OS list not supporting the -S option in pcretest.
239    
240    40. PCRE tries to detect cases of infinite recursion at compile time, but it
241        cannot analyze patterns in sufficient detail to catch mutual recursions
242        such as ((?1))((?2)). There is now a runtime test that gives an error if a
243        subgroup is called recursively as a subpattern for a second time at the
244        same position in the subject string. In previous releases this might have
245        been caught by the recursion limit, or it might have run out of stack.
246    
247    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
248        happen only once. PCRE was, however incorrectly giving a compile time error
249        "recursive call could loop indefinitely" because it cannot analyze the
250        pattern in sufficient detail. The compile time test no longer happens when
251        PCRE is compiling a conditional subpattern, but actual runaway loops are
252        now caught at runtime (see 40 above).
253    
254    42. It seems that Perl allows any characters other than a closing parenthesis
255        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
256        has been changed to be the same.
257    
258    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
259        as not to get warnings when autogen.sh is called. Also changed
260        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
261    
262    44. To help people who use pcregrep to scan files containing exceedingly long
263        lines, the following changes have been made:
264    
265        (a) The default value of the buffer size parameter has been increased from
266            8K to 20K. (The actual buffer used is three times this size.)
267    
268        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
269            PCRE is built.
270    
271        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
272            to be set at run time.
273    
274        (d) Numerical values in pcregrep options can be followed by K or M, for
275            example --buffer-size=50K.
276    
277        (e) If a line being scanned overflows pcregrep's buffer, an error is now
278            given and the return code is set to 2.
279    
280    45. Add a pointer to the latest mark to the callout data block.
281    
282    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
283        partial match of an empty string instead of no match. This was specific to
284        the use of ".".
285    
286    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
287        complete match instead of a partial match. This bug was dependent on both
288        the PCRE_UTF8 and PCRE_DOTALL options being set.
289    
290    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
291        starting byte set, because \b was not being ignored.
292    
293    
294    Version 8.12 15-Jan-2011
295    ------------------------
296    
297    1.  Fixed some typos in the markup of the man pages, and wrote a script that
298        checks for such things as part of the documentation building process.
299    
300    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
301        --match-limit and --recursion-limit options (added for 8.11). In
302        particular, this made one of the standard tests fail. (The integer value
303        went into the wrong half of a long int.)
304    
305    3.  If the --colour option was given to pcregrep with -v (invert match), it
306        did strange things, either producing crazy output, or crashing. It should,
307        of course, ignore a request for colour when reporting lines that do not
308        match.
309    
310    4.  Another pcregrep bug caused similar problems if --colour was specified with
311        -M (multiline) and the pattern match finished with a line ending.
312    
313    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
314        matched in multiline mode, the following line was shown as part of the
315        match. This seems wrong, so I have changed it.
316    
317    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
318        the check for further matches in the same line (so they could be coloured)
319        to overrun the end of the current line. If another match was found, it was
320        incorrectly shown (and then shown again when found in the next line).
321    
322    7.  If pcregrep was compiled under Windows, there was a reference to the
323        function pcregrep_exit() before it was defined. I am assuming this was
324        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
325        reported by a user. I've moved the definition above the reference.
326    
327    
328    Version 8.11 10-Dec-2010
329  ------------------------  ------------------------
330    
331  1.  (*THEN) was not working properly if there were untried alternatives prior  1.  (*THEN) was not working properly if there were untried alternatives prior
332      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
333      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
334      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
335      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
336      alternative in the innermost enclosing group".      alternative in the innermost enclosing group".
337    
338  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
339      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
340      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
341      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
342      (*THEN).      (*THEN).
343    
344    3.  If \s appeared in a character class, it removed the VT character from
345        the class, even if it had been included by some previous item, for example
346        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
347        of \s, but is part of the POSIX "space" class.)
348    
349    4.  A partial match never returns an empty string (because you can always
350        match an empty string at the end of the subject); however the checking for
351        an empty string was starting at the "start of match" point. This has been
352        changed to the "earliest inspected character" point, because the returned
353        data for a partial match starts at this character. This means that, for
354        example, /(?<=abc)def/ gives a partial match for the subject "abc"
355        (previously it gave "no match").
356    
357    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
358        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
359        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
360        has an implication that the given string is incomplete (because a partial
361        match is preferred over a full match). For this reason, these items now
362        give a partial match in this situation. [Aside: previously, the one case
363        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
364        match rather than a full match, which was wrong by the old rules, but is
365        now correct.]
366    
367    6.  There was a bug in the handling of #-introduced comments, recognized when
368        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
369        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
370        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
371        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
372        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
373        places in pcre_compile().
374    
375    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
376        comments when looking ahead for named forward references to subpatterns,
377        the only newline sequence it recognized was NL. It now handles newlines
378        according to the set newline convention.
379    
380    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
381        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
382        cater for a lack of strerror(). These oversights have been fixed.
383    
384    9.  Added --match-limit and --recursion-limit to pcregrep.
385    
386    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
387    
388    11. When the -o option was used, pcregrep was setting a return code of 1, even
389        when matches were found, and --line-buffered was not being honoured.
390    
391    12. Added an optional parentheses number to the -o and --only-matching options
392        of pcregrep.
393    
394    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
395        can match an empty string. The code to do it in pcretest and pcredemo
396        needed fixing:
397    
398        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
399            only one byte after an empty string match just before CRLF (this case
400            just got forgotten; "any" and "anycrlf" were OK).
401    
402        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
403            mode when an empty string match preceded an ASCII character followed by
404            a non-ASCII character. (The code for advancing by one character rather
405            than one byte was nonsense.)
406    
407        (c) The pcredemo.c sample program did not have any code at all to handle
408            the cases when CRLF is a valid newline sequence.
409    
410    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
411        as a starting offset was within the subject string. There is now a new
412        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
413        negative or greater than the length of the string. In order to test this,
414        pcretest is extended to allow the setting of negative starting offsets.
415    
416    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
417        starting offset points to the beginning of a UTF-8 character was
418        unnecessarily clumsy. I tidied it up.
419    
420    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
421        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
422    
423    17. Nobody had reported that the --include_dir option, which was added in
424        release 7.7 should have been called --include-dir (hyphen, not underscore)
425        for compatibility with GNU grep. I have changed it to --include-dir, but
426        left --include_dir as an undocumented synonym, and the same for
427        --exclude-dir, though that is not available in GNU grep, at least as of
428        release 2.5.4.
429    
430    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
431        characters from a string of bytes) have been redefined so as not to use
432        loops, in order to improve performance in some environments. At the same
433        time, I abstracted some of the common code into auxiliary macros to save
434        repetition (this should not affect the compiled code).
435    
436    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
437        compile-time error is now given if \c is not followed by an ASCII
438        character, that is, a byte less than 128. (In EBCDIC mode, the code is
439        different, and any byte value is allowed.)
440    
441    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
442        START_OPTIMIZE option, which is now allowed at compile time - but just
443        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
444        to pcregrep and other applications that have no direct access to PCRE
445        options. The new /Y option in pcretest sets this option when calling
446        pcre_compile().
447    
448    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
449        back references. Groups containing recursive back references were forced to
450        be atomic by that change, but in the case of named groups, the amount of
451        memory required was incorrectly computed, leading to "Failed: internal
452        error: code overflow". This has been fixed.
453    
454    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
455        pcretest.c, to avoid build problems in some Borland environments.
456    
457    
458  Version 8.10 25-Jun-2010  Version 8.10 25-Jun-2010

Legend:
Removed from v.551  
changed lines
  Added in v.687

webmaster@exim.org
ViewVC Help
Powered by ViewVC 1.1.12