ViewVC logotype

Diff of /code/trunk/ChangeLog

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

revision 594 by ph10, Sun May 1 08:22:12 2011 UTC revision 762 by ph10, Tue Nov 22 13:36:51 2011 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.13 30-Apr-2011  Version 8.21
5    ------------
7    1.  Updating the JIT compiler.
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
16    4.  Mark settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
45    10. Add a cast and remove a redundant test from the code.
47    11. JIT should use pcre_malloc/pcre_free for allocation.
49    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
50        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
51        is anything other than /usr, -L is still shown).
53    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
55    14. Perl does not support \N without a following name in a [] class; PCRE now
56        also gives an error.
58    15. If a forward reference was repeated with an upper limit of around 2000,
59        it caused the error "internal error: overran compiling workspace". This
60        is now checked, and causes "too many forward references" instead.
62    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
63        incorrectly expecting the subject to contain another "a" after the start.
66    Version 8.20 21-Oct-2011
67    ------------------------
69    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
70        a POSIX class. After further experiments with Perl, which convinced me that
71        Perl has bugs and confusions, a closing square bracket is no longer allowed
72        in a POSIX name. This bug also affected patterns with classes that started
73        with full stops.
75    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
76        captured substring, but while checking the failing first alternative,
77        substring 1 is temporarily captured. If the output vector supplied to
78        pcre_exec() was not big enough for this capture, the yield of the function
79        was still zero ("insufficient space for captured substrings"). This cannot
80        be totally fixed without adding another stack variable, which seems a lot
81        of expense for a edge case. However, I have improved the situation in cases
82        such as /(a)(b)x|abc/ matched against "abc", where the return code
83        indicates that fewer than the maximum number of slots in the ovector have
84        been set.
86    3.  Related to (2) above: when there are more back references in a pattern than
87        slots in the output vector, pcre_exec() uses temporary memory during
88        matching, and copies in the captures as far as possible afterwards. It was
89        using the entire output vector, but this conflicts with the specification
90        that only 2/3 is used for passing back captured substrings. Now it uses
91        only the first 2/3, for compatibility. This is, of course, another edge
92        case.
94    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
95        main code base, and can be used by building with --enable-jit. When this is
96        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
97        runtime --no-jit option is given.
99    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
100        ovector, the return from the function was zero, implying that there were
101        other matches that did not fit. The correct "exactly full" value is now
102        returned.
104    6.  If a subpattern that was called recursively or as a subroutine contained
105        (*PRUNE) or any other control that caused it to give a non-standard return,
106        invalid errors such as "Error -26 (nested recursion at the same subject
107        position)" or even infinite loops could occur.
109    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
110        computing the minimum length on reaching *ACCEPT, and so ended up with the
111        wrong value of 1 rather than 0. Further investigation indicates that
112        computing a minimum subject length in the presence of *ACCEPT is difficult
113        (think back references, subroutine calls), and so I have changed the code
114        so that no minimum is registered for a pattern that contains *ACCEPT.
116    8.  If (*THEN) was present in the first (true) branch of a conditional group,
117        it was not handled as intended. [But see 16 below.]
119    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
120        Sheri Pierce.
122    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
123        the first byte in a match must be "a".
125    11. Change 17 for 8.13 increased the recursion depth for patterns like
126        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
127        pattern contains any instances of (*THEN). If it does not, the old
128        optimizations are restored. It would be nice to do this on a per-group
129        basis, but at the moment that is not feasible.
131    12. In some environments, the output of pcretest -C is CRLF terminated. This
132        broke RunTest's code that checks for the link size. A single white space
133        character after the value is now allowed for.
135    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
136        For "fr", it uses the Windows-specific input and output files.
138    14. If (*THEN) appeared in a group that was called recursively or as a
139        subroutine, it did not work as intended. [But see next item.]
141    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
142        pattern fragments (but not containing any | characters). If A and B are
143        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
144        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
145        D. In other words, Perl considers parentheses that do not contain any |
146        characters to be part of a surrounding alternative, whereas PCRE was
147        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
148        differently. PCRE now behaves in the same way as Perl, except in the case
149        of subroutine/recursion calls such as (?1) which have in any case always
150        been different (but PCRE had them first :-).
152    16. Related to 15 above: Perl does not treat the | in a conditional group as
153        creating alternatives. Such a group is treated in the same way as an
154        ordinary group without any | characters when processing (*THEN). PCRE has
155        been changed to match Perl's behaviour.
157    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
158        RunGrepTest script failed.
160    18. Change 22 for version 13 caused atomic groups to use more stack. This is
161        inevitable for groups that contain captures, but it can lead to a lot of
162        stack use in large patterns. The old behaviour has been restored for atomic
163        groups that do not contain any capturing parentheses.
165    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
166        suppress the check for a minimum subject length at run time. (If it was
167        given to pcre_exec() or pcre_dfa_exec() it did work.)
169    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
170        fail to work when decoding hex characters in data strings in EBCDIC
171        environments.
173    21. It appears that in at least one Mac OS environment, the isxdigit() function
174        is implemented as a macro that evaluates to its argument more than once,
175        contravening the C 90 Standard (I haven't checked a later standard). There
176        was an instance in pcretest which caused it to go wrong when processing
177        \x{...} escapes in subject strings. The has been rewritten to avoid using
178        things like p++ in the argument of isxdigit().
181    Version 8.13 16-Aug-2011
182  ------------------------  ------------------------
184  1.  The Unicode data tables have been updated to Unicode 6.0.0.  1.  The Unicode data tables have been updated to Unicode 6.0.0.
186  2.  Two minor typos in pcre_internal.h have been fixed.  2.  Two minor typos in pcre_internal.h have been fixed.
188  3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and  3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
189      pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()      pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
190      in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).      in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
192    4.  There were a number of related bugs in the code for matching backrefences
193        caselessly in UTF-8 mode when codes for the characters concerned were
194        different numbers of bytes. For example, U+023A and U+2C65 are an upper
195        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
196        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
197        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
198        2-byte code at the end of the subject (it thought there wasn't enough data
199        left).
201    5.  Comprehensive information about what went wrong is now returned by
202        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
203        as the output vector has at least 2 elements. The offset of the start of
204        the failing character and a reason code are placed in the vector.
206    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
207        now returned is for the first byte of the failing character, instead of the
208        last byte inspected. This is an incompatible change, but I hope it is small
209        enough not to be a problem. It makes the returned offset consistent with
210        pcre_exec() and pcre_dfa_exec().
212    7.  pcretest now gives a text phrase as well as the error number when
213        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
214        failure, the offset and reason code are output.
216    8.  When \R was used with a maximizing quantifier it failed to skip backwards
217        over a \r\n pair if the subsequent match failed. Instead, it just skipped
218        back over a single character (\n). This seems wrong (because it treated the
219        two characters as a single entity when going forwards), conflicts with the
220        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
221        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
222        has been changed.
224    9.  Some internal refactoring has changed the processing so that the handling
225        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
226        time (the PCRE_DOTALL option was changed this way some time ago: version
227        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
228        which was always a bit of a fudge. It also means that there is one less
229        argument for the match() function, which reduces its stack requirements
230        slightly. This change also fixes an incompatibility with Perl: the pattern
231        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
233    10. More internal refactoring has drastically reduced the number of recursive
234        calls to match() for possessively repeated groups such as (abc)++ when
235        using pcre_exec().
237    11. While implementing 10, a number of bugs in the handling of groups were
238        discovered and fixed:
240        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
241        (a|)*(?1) gave a compile-time internal error.
242        ((a|)+)+  did not notice that the outer group could match an empty string.
243        (^a|^)+   was not marked as anchored.
244        (.*a|.*)+ was not marked as matching at start or after a newline.
246    12. Yet more internal refactoring has removed another argument from the match()
247        function. Special calls to this function are now indicated by setting a
248        value in a variable in the "match data" data block.
250    13. Be more explicit in pcre_study() instead of relying on "default" for
251        opcodes that mean there is no starting character; this means that when new
252        ones are added and accidentally left out of pcre_study(), testing should
253        pick them up.
255    14. The -s option of pcretest has been documented for ages as being an old
256        synonym of -m (show memory usage). I have changed it to mean "force study
257        for every regex", that is, assume /S for every regex. This is similar to -i
258        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
259        using it. It makes it easier to run collections of tests with and without
260        study enabled, and thereby test pcre_study() more easily. All the standard
261        tests are now run with and without -s (but some patterns can be marked as
262        "never study" - see 20 below).
264    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
265        restoration of the capturing data to the outer values was not happening
266        correctly.
268    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
269        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
270        pattern had matched an empty string, and so incorrectly returned a no
271        match.
273    17. There was optimizing code for the last branch of non-capturing parentheses,
274        and also for the obeyed branch of a conditional subexpression, which used
275        tail recursion to cut down on stack usage. Unfortunately, now that there is
276        the possibility of (*THEN) occurring in these branches, tail recursion is
277        no longer possible because the return has to be checked for (*THEN). These
278        two optimizations have therefore been removed. [But see 8.20/11 above.]
280    18. If a pattern containing \R was studied, it was assumed that \R always
281        matched two bytes, thus causing the minimum subject length to be
282        incorrectly computed because \R can also match just one byte.
284    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
285        was incorrectly computed.
287    20. If /S is present twice on a test pattern in pcretest input, it now
288        *disables* studying, thereby overriding the use of -s on the command line
289        (see 14 above). This is necessary for one or two tests to keep the output
290        identical in both cases.
292    21. When (*ACCEPT) was used in an assertion that matched an empty string and
293        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
295    22. When an atomic group that contained a capturing parenthesis was
296        successfully matched, but the branch in which it appeared failed, the
297        capturing was not being forgotten if a higher numbered group was later
298        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
299        group 1 to "a", when in fact it should be unset. This applied to multi-
300        branched capturing and non-capturing groups, repeated or not, and also to
301        positive assertions (capturing in negative assertions does not happen
302        in PCRE) and also to nested atomic groups.
304    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
305        subject after a captured substring, to make it easier to tell which of a
306        number of identical substrings has been captured.
308    24. The way atomic groups are processed by pcre_exec() has been changed so that
309        if they are repeated, backtracking one repetition now resets captured
310        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
311        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
312        "aaa". Previously, it would have been "a". As part of this code
313        refactoring, the way recursive calls are handled has also been changed.
315    25. If an assertion condition captured any substrings, they were not passed
316        back unless some other capturing happened later. For example, if
317        (?(?=(a))a) was matched against "a", no capturing was returned.
319    26. When studying a pattern that contained subroutine calls or assertions,
320        the code for finding the minimum length of a possible match was handling
321        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
322        group 1 called group 2 while simultaneously a separate group 2 called group
323        1). A stack overflow occurred in this case. I have fixed this by limiting
324        the recursion depth to 10.
326    27. Updated RunTest.bat in the distribution to the version supplied by Tom
327        Fortmann. This supports explicit test numbers on the command line, and has
328        argument validation and error reporting.
330    28. An instance of \X with an unlimited repeat could fail if at any point the
331        first character it looked at was a mark character.
333    29. Some minor code refactoring concerning Unicode properties and scripts
334        should reduce the stack requirement of match() slightly.
336    30. Added the '=' option to pcretest to check the setting of unused capturing
337        slots at the end of the pattern, which are documented as being -1, but are
338        not included in the return count.
340    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
341        compiled something random. Now it gives a compile-time error (as does
342        Perl).
344    32. A *MARK encountered during the processing of a positive assertion is now
345        recorded and passed back (compatible with Perl).
347    33. If --only-matching or --colour was set on a pcregrep call whose pattern
348        had alternative anchored branches, the search for a second match in a line
349        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
350        matched the line "0102" twice. The same bug affected patterns that started
351        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
352        twice.
354    34. Previously, PCRE did not allow quantification of assertions. However, Perl
355        does, and because of capturing effects, quantifying parenthesized
356        assertions may at times be useful. Quantifiers are now allowed for
357        parenthesized assertions.
359    35. A minor code tidy in pcre_compile() when checking options for \R usage.
361    36. \g was being checked for fancy things in a character class, when it should
362        just be a literal "g".
364    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
365        appearance of a nested POSIX class supersedes an apparent external class.
366        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
367        unescaped square brackets may also appear as part of class names. For
368        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
369        more like Perl. (But see 8.20/1 above.)
371    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
372        was because it thought it was \N{name}, which is not supported).
374    39. Add minix to OS list not supporting the -S option in pcretest.
376    40. PCRE tries to detect cases of infinite recursion at compile time, but it
377        cannot analyze patterns in sufficient detail to catch mutual recursions
378        such as ((?1))((?2)). There is now a runtime test that gives an error if a
379        subgroup is called recursively as a subpattern for a second time at the
380        same position in the subject string. In previous releases this might have
381        been caught by the recursion limit, or it might have run out of stack.
383    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
384        happen only once. PCRE was, however incorrectly giving a compile time error
385        "recursive call could loop indefinitely" because it cannot analyze the
386        pattern in sufficient detail. The compile time test no longer happens when
387        PCRE is compiling a conditional subpattern, but actual runaway loops are
388        now caught at runtime (see 40 above).
390    42. It seems that Perl allows any characters other than a closing parenthesis
391        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
392        has been changed to be the same.
394    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
395        as not to get warnings when autogen.sh is called. Also changed
396        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
398    44. To help people who use pcregrep to scan files containing exceedingly long
399        lines, the following changes have been made:
401        (a) The default value of the buffer size parameter has been increased from
402            8K to 20K. (The actual buffer used is three times this size.)
404        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
405            PCRE is built.
407        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
408            to be set at run time.
410        (d) Numerical values in pcregrep options can be followed by K or M, for
411            example --buffer-size=50K.
413        (e) If a line being scanned overflows pcregrep's buffer, an error is now
414            given and the return code is set to 2.
416    45. Add a pointer to the latest mark to the callout data block.
418    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
419        partial match of an empty string instead of no match. This was specific to
420        the use of ".".
422    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
423        complete match instead of a partial match. This bug was dependent on both
424        the PCRE_UTF8 and PCRE_DOTALL options being set.
426    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
427        starting byte set, because \b was not being ignored.
430  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

Removed from v.594  
changed lines
  Added in v.762

  ViewVC Help
Powered by ViewVC 1.1.5