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

Diff of /code/trunk/ChangeLog

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

revision 583 by ph10, Tue Jan 11 16:49:55 2011 UTC revision 729 by ph10, Mon Oct 10 16:02:20 2011 UTC
# Line 1  Line 1 
1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.12 11-Jan-2011  Version 8.20 10-Oct-2011
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. This bug also affected patterns with classes that started
11        with full stops.
12    
13    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
14        captured substring, but while checking the failing first alternative,
15        substring 1 is temporarily captured. If the output vector supplied to
16        pcre_exec() was not big enough for this capture, the yield of the function
17        was still zero ("insufficient space for captured substrings"). This cannot
18        be totally fixed without adding another stack variable, which seems a lot
19        of expense for a edge case. However, I have improved the situation in cases
20        such as /(a)(b)x|abc/ matched against "abc", where the return code
21        indicates that fewer than the maximum number of slots in the ovector have
22        been set.
23    
24    3.  Related to (2) above: when there are more back references in a pattern than
25        slots in the output vector, pcre_exec() uses temporary memory during
26        matching, and copies in the captures as far as possible afterwards. It was
27        using the entire output vector, but this conflicts with the specification
28        that only 2/3 is used for passing back captured substrings. Now it uses
29        only the first 2/3, for compatibility. This is, of course, another edge
30        case.
31    
32    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
33        main code base, and can be used by building with --enable-jit. When this is
34        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
35        runtime --no-jit option is given.
36    
37    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
38        ovector, the return from the function was zero, implying that there were
39        other matches that did not fit. The correct "exactly full" value is now
40        returned.
41    
42    6.  If a subpattern that was called recursively or as a subroutine contained
43        (*PRUNE) or any other control that caused it to give a non-standard return,
44        invalid errors such as "Error -26 (nested recursion at the same subject
45        position)" or even infinite loops could occur.
46    
47    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
48        computing the minimum length on reaching *ACCEPT, and so ended up with the
49        wrong value of 1 rather than 0. Further investigation indicates that
50        computing a minimum subject length in the presence of *ACCEPT is difficult
51        (think back references, subroutine calls), and so I have changed the code
52        so that no minimum is registered for a pattern that contains *ACCEPT.
53    
54    8.  If (*THEN) was present in the first (true) branch of a conditional group,
55        it was not handled as intended. [But see 16 below.]
56    
57    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
58        Sheri Pierce.
59    
60    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
61        the first byte in a match must be "a".
62    
63    11. Change 17 for 8.13 increased the recursion depth for patterns like
64        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
65        pattern contains any instances of (*THEN). If it does not, the old
66        optimizations are restored. It would be nice to do this on a per-group
67        basis, but at the moment that is not feasible.
68    
69    12. In some environments, the output of pcretest -C is CRLF terminated. This
70        broke RunTest's code that checks for the link size. A single white space
71        after the value is now allowed for.
72    
73    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
74        For "fr", it uses the Windows-specific input and output files.
75    
76    14. If (*THEN) appeared in a group that was called recursively or as a
77        subroutine, it did not work as intended. [But see next item.]
78    
79    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
80        pattern fragments (but not containing any | characters). If A and B are
81        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
82        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
83        D. In other words, Perl considers parentheses that do not contain any |
84        characters to be part of a surrounding alternative, whereas PCRE was
85        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
86        differently. PCRE now behaves in the same way as Perl, except in the case
87        of subroutine/recursion calls such as (?1) which have in any case always
88        been different (but PCRE had them first :-).
89    
90    16. Related to 15 above: Perl does not treat the | in a conditional group as
91        creating alternatives. Such a group is treated in the same way as an
92        ordinary group without any | characters when processing (*THEN). PCRE has
93        been changed to match Perl's behaviour.
94    
95    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
96        RunGrepTest script failed.
97    
98    18. Change 22 for version 13 caused atomic groups to use more stack. This is
99        inevitable for groups that contain captures, but it can lead to a lot of
100        stack use in large patterns. The old behaviour has been restored for atomic
101        groups that do not contain any capturing parentheses.
102    
103    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
104        suppress the check for a minimum subject length at run time. (If it was
105        given to pcre_exec() or pcre_dfa_exec() it did work.)
106    
107    
108    Version 8.13 16-Aug-2011
109    ------------------------
110    
111    1.  The Unicode data tables have been updated to Unicode 6.0.0.
112    
113    2.  Two minor typos in pcre_internal.h have been fixed.
114    
115    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
116        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
117        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
118    
119    4.  There were a number of related bugs in the code for matching backrefences
120        caselessly in UTF-8 mode when codes for the characters concerned were
121        different numbers of bytes. For example, U+023A and U+2C65 are an upper
122        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
123        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
124        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
125        2-byte code at the end of the subject (it thought there wasn't enough data
126        left).
127    
128    5.  Comprehensive information about what went wrong is now returned by
129        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
130        as the output vector has at least 2 elements. The offset of the start of
131        the failing character and a reason code are placed in the vector.
132    
133    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
134        now returned is for the first byte of the failing character, instead of the
135        last byte inspected. This is an incompatible change, but I hope it is small
136        enough not to be a problem. It makes the returned offset consistent with
137        pcre_exec() and pcre_dfa_exec().
138    
139    7.  pcretest now gives a text phrase as well as the error number when
140        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
141        failure, the offset and reason code are output.
142    
143    8.  When \R was used with a maximizing quantifier it failed to skip backwards
144        over a \r\n pair if the subsequent match failed. Instead, it just skipped
145        back over a single character (\n). This seems wrong (because it treated the
146        two characters as a single entity when going forwards), conflicts with the
147        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
148        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
149        has been changed.
150    
151    9.  Some internal refactoring has changed the processing so that the handling
152        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
153        time (the PCRE_DOTALL option was changed this way some time ago: version
154        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
155        which was always a bit of a fudge. It also means that there is one less
156        argument for the match() function, which reduces its stack requirements
157        slightly. This change also fixes an incompatibility with Perl: the pattern
158        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
159    
160    10. More internal refactoring has drastically reduced the number of recursive
161        calls to match() for possessively repeated groups such as (abc)++ when
162        using pcre_exec().
163    
164    11. While implementing 10, a number of bugs in the handling of groups were
165        discovered and fixed:
166    
167        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
168        (a|)*(?1) gave a compile-time internal error.
169        ((a|)+)+  did not notice that the outer group could match an empty string.
170        (^a|^)+   was not marked as anchored.
171        (.*a|.*)+ was not marked as matching at start or after a newline.
172    
173    12. Yet more internal refactoring has removed another argument from the match()
174        function. Special calls to this function are now indicated by setting a
175        value in a variable in the "match data" data block.
176    
177    13. Be more explicit in pcre_study() instead of relying on "default" for
178        opcodes that mean there is no starting character; this means that when new
179        ones are added and accidentally left out of pcre_study(), testing should
180        pick them up.
181    
182    14. The -s option of pcretest has been documented for ages as being an old
183        synonym of -m (show memory usage). I have changed it to mean "force study
184        for every regex", that is, assume /S for every regex. This is similar to -i
185        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
186        using it. It makes it easier to run collections of tests with and without
187        study enabled, and thereby test pcre_study() more easily. All the standard
188        tests are now run with and without -s (but some patterns can be marked as
189        "never study" - see 20 below).
190    
191    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
192        restoration of the capturing data to the outer values was not happening
193        correctly.
194    
195    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
196        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
197        pattern had matched an empty string, and so incorrectly returned a no
198        match.
199    
200    17. There was optimizing code for the last branch of non-capturing parentheses,
201        and also for the obeyed branch of a conditional subexpression, which used
202        tail recursion to cut down on stack usage. Unfortunately, now that there is
203        the possibility of (*THEN) occurring in these branches, tail recursion is
204        no longer possible because the return has to be checked for (*THEN). These
205        two optimizations have therefore been removed. [But see 8.20/11 above.]
206    
207    18. If a pattern containing \R was studied, it was assumed that \R always
208        matched two bytes, thus causing the minimum subject length to be
209        incorrectly computed because \R can also match just one byte.
210    
211    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
212        was incorrectly computed.
213    
214    20. If /S is present twice on a test pattern in pcretest input, it now
215        *disables* studying, thereby overriding the use of -s on the command line
216        (see 14 above). This is necessary for one or two tests to keep the output
217        identical in both cases.
218    
219    21. When (*ACCEPT) was used in an assertion that matched an empty string and
220        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
221    
222    22. When an atomic group that contained a capturing parenthesis was
223        successfully matched, but the branch in which it appeared failed, the
224        capturing was not being forgotten if a higher numbered group was later
225        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
226        group 1 to "a", when in fact it should be unset. This applied to multi-
227        branched capturing and non-capturing groups, repeated or not, and also to
228        positive assertions (capturing in negative assertions does not happen
229        in PCRE) and also to nested atomic groups.
230    
231    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
232        subject after a captured substring, to make it easier to tell which of a
233        number of identical substrings has been captured.
234    
235    24. The way atomic groups are processed by pcre_exec() has been changed so that
236        if they are repeated, backtracking one repetition now resets captured
237        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
238        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
239        "aaa". Previously, it would have been "a". As part of this code
240        refactoring, the way recursive calls are handled has also been changed.
241    
242    25. If an assertion condition captured any substrings, they were not passed
243        back unless some other capturing happened later. For example, if
244        (?(?=(a))a) was matched against "a", no capturing was returned.
245    
246    26. When studying a pattern that contained subroutine calls or assertions,
247        the code for finding the minimum length of a possible match was handling
248        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
249        group 1 called group 2 while simultaneously a separate group 2 called group
250        1). A stack overflow occurred in this case. I have fixed this by limiting
251        the recursion depth to 10.
252    
253    27. Updated RunTest.bat in the distribution to the version supplied by Tom
254        Fortmann. This supports explicit test numbers on the command line, and has
255        argument validation and error reporting.
256    
257    28. An instance of \X with an unlimited repeat could fail if at any point the
258        first character it looked at was a mark character.
259    
260    29. Some minor code refactoring concerning Unicode properties and scripts
261        should reduce the stack requirement of match() slightly.
262    
263    30. Added the '=' option to pcretest to check the setting of unused capturing
264        slots at the end of the pattern, which are documented as being -1, but are
265        not included in the return count.
266    
267    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
268        compiled something random. Now it gives a compile-time error (as does
269        Perl).
270    
271    32. A *MARK encountered during the processing of a positive assertion is now
272        recorded and passed back (compatible with Perl).
273    
274    33. If --only-matching or --colour was set on a pcregrep call whose pattern
275        had alternative anchored branches, the search for a second match in a line
276        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
277        matched the line "0102" twice. The same bug affected patterns that started
278        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
279        twice.
280    
281    34. Previously, PCRE did not allow quantification of assertions. However, Perl
282        does, and because of capturing effects, quantifying parenthesized
283        assertions may at times be useful. Quantifiers are now allowed for
284        parenthesized assertions.
285    
286    35. A minor code tidy in pcre_compile() when checking options for \R usage.
287    
288    36. \g was being checked for fancy things in a character class, when it should
289        just be a literal "g".
290    
291    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
292        appearance of a nested POSIX class supersedes an apparent external class.
293        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
294        unescaped square brackets may also appear as part of class names. For
295        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
296        more like Perl. (But see 8.20/1 above.)
297    
298    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
299        was because it thought it was \N{name}, which is not supported).
300    
301    39. Add minix to OS list not supporting the -S option in pcretest.
302    
303    40. PCRE tries to detect cases of infinite recursion at compile time, but it
304        cannot analyze patterns in sufficient detail to catch mutual recursions
305        such as ((?1))((?2)). There is now a runtime test that gives an error if a
306        subgroup is called recursively as a subpattern for a second time at the
307        same position in the subject string. In previous releases this might have
308        been caught by the recursion limit, or it might have run out of stack.
309    
310    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
311        happen only once. PCRE was, however incorrectly giving a compile time error
312        "recursive call could loop indefinitely" because it cannot analyze the
313        pattern in sufficient detail. The compile time test no longer happens when
314        PCRE is compiling a conditional subpattern, but actual runaway loops are
315        now caught at runtime (see 40 above).
316    
317    42. It seems that Perl allows any characters other than a closing parenthesis
318        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
319        has been changed to be the same.
320    
321    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
322        as not to get warnings when autogen.sh is called. Also changed
323        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
324    
325    44. To help people who use pcregrep to scan files containing exceedingly long
326        lines, the following changes have been made:
327    
328        (a) The default value of the buffer size parameter has been increased from
329            8K to 20K. (The actual buffer used is three times this size.)
330    
331        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
332            PCRE is built.
333    
334        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
335            to be set at run time.
336    
337        (d) Numerical values in pcregrep options can be followed by K or M, for
338            example --buffer-size=50K.
339    
340        (e) If a line being scanned overflows pcregrep's buffer, an error is now
341            given and the return code is set to 2.
342    
343    45. Add a pointer to the latest mark to the callout data block.
344    
345    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
346        partial match of an empty string instead of no match. This was specific to
347        the use of ".".
348    
349    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
350        complete match instead of a partial match. This bug was dependent on both
351        the PCRE_UTF8 and PCRE_DOTALL options being set.
352    
353    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
354        starting byte set, because \b was not being ignored.
355    
356    
357    Version 8.12 15-Jan-2011
358  ------------------------  ------------------------
359    
360  1.  Fixed some typos in the markup of the man pages, and wrote a script that  1.  Fixed some typos in the markup of the man pages, and wrote a script that
361      checks for such things as part of the documentation building process.      checks for such things as part of the documentation building process.
362    
363    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
364        --match-limit and --recursion-limit options (added for 8.11). In
365        particular, this made one of the standard tests fail. (The integer value
366        went into the wrong half of a long int.)
367    
368    3.  If the --colour option was given to pcregrep with -v (invert match), it
369        did strange things, either producing crazy output, or crashing. It should,
370        of course, ignore a request for colour when reporting lines that do not
371        match.
372    
373    4.  Another pcregrep bug caused similar problems if --colour was specified with
374        -M (multiline) and the pattern match finished with a line ending.
375    
376    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
377        matched in multiline mode, the following line was shown as part of the
378        match. This seems wrong, so I have changed it.
379    
380    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
381        the check for further matches in the same line (so they could be coloured)
382        to overrun the end of the current line. If another match was found, it was
383        incorrectly shown (and then shown again when found in the next line).
384    
385    7.  If pcregrep was compiled under Windows, there was a reference to the
386        function pcregrep_exit() before it was defined. I am assuming this was
387        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
388        reported by a user. I've moved the definition above the reference.
389    
390    
391  Version 8.11 10-Dec-2010  Version 8.11 10-Dec-2010
392  ------------------------  ------------------------

Legend:
Removed from v.583  
changed lines
  Added in v.729

  ViewVC Help
Powered by ViewVC 1.1.5