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revision 661 by ph10, Sun Aug 21 09:00:54 2011 UTC revision 931 by ph10, Fri Feb 24 13:21:02 2012 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.20  Version 8.31
5  ------------  -----------------------------
7  1. Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had  1.  Fixing a wrong JIT test case and some compiler warnings.
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 in  2.  Removed a bashism from the RunTest script.
10  a POSIX name.  
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
15    4.  Partial matching support is added to the JIT compiler.
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
36    6.  If JIT is requested using /S++ or -s++ (instead of just /S+ or -s+) when
37        running pcretest, the text "(JIT)" added to the output whenever JIT is
38        actually used to run the match.
40    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
41        or /S+[+] with a digit between 1 and 7.
43    8.  OP_NOT now supports any UTF character not just single-byte ones.
45    9.  (*MARK) control verb is now supported by the JIT compiler.
47    10. The command "./RunTest list" lists the available tests without actually
48        running any of them. (Because I keep forgetting what they all are.)
51    Version 8.30 04-February-2012
52    -----------------------------
54    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
55        name is defined in ctype.h.
57    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
58        only in quite long subpatterns.
60    3.  Removed the function pcre_info(), which has been obsolete and deprecated
61        since it was replaced by pcre_fullinfo() in February 2000.
63    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
64        match a (*MARK), and the match failed at the start of the subject, a
65        reference to memory before the start of the subject could occur. This bug
66        was introduced by fix 17 of release 8.21.
68    5.  A reference to an unset group with zero minimum repetition was giving
69        totally wrong answers (in non-JavaScript-compatibility mode). For example,
70        /(another)?(\1?)test/ matched against "hello world test". This bug was
71        introduced in release 8.13.
73    6.  Add support for 16-bit character strings (a large amount of work involving
74        many changes and refactorings).
76    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
77        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
78        from a file.
80    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
81        rounding is not applied in this particular case).
83    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
84        if they appear, or are escaped, in patterns.
86    10. Get rid of a number of -Wunused-but-set-variable warnings.
88    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
89        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
90        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
91        also returns the mark "x". This bug applied to capturing parentheses,
92        non-capturing parentheses, and atomic parentheses. It also applied to some
93        assertions.
95    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
96        information out of configure.ac instead of relying on pcre.h.generic, which
97        is not stored in the repository.
99    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
100        -lreadline.
102    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
104    15. Applied Graycode's patch to put the top-level frame on the stack rather
105        than the heap when not using the stack for recursion. This gives a
106        performance improvement in many cases when recursion is not deep.
108    16. Experimental code added to "pcretest -C" to output the stack frame size.
111    Version 8.21 12-Dec-2011
112    ------------------------
114    1.  Updating the JIT compiler.
116    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
117        are added as well.
119    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
120        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
121        calling _pcre_jit_exec. Some extra comments are added.
123    4.  (*MARK) settings inside atomic groups that do not contain any capturing
124        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
125        was introduced by change 18 for 8.20.
127    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
128        ECMA-262 standard.
130    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
131        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
132        This bug was probably introduced by change 9 of 8.13.
134    7.  While fixing 6 above, I noticed that a number of other items were being
135        incorrectly rejected as "not fixed length". This arose partly because newer
136        opcodes had not been added to the fixed-length checking code. I have (a)
137        corrected the bug and added tests for these items, and (b) arranged for an
138        error to occur if an unknown opcode is encountered while checking for fixed
139        length instead of just assuming "not fixed length". The items that were
140        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
141        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
142        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
144    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
145        being incorrectly compiled and would have given unpredicatble results.
147    9.  A possessively repeated subpattern with minimum repeat count greater than
148        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
149        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
150        the first (A) could occur when it should not.
152    10. Add a cast and remove a redundant test from the code.
154    11. JIT should use pcre_malloc/pcre_free for allocation.
156    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
157        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
158        is anything other than /usr, -L is still shown).
160    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
162    14. Perl does not support \N without a following name in a [] class; PCRE now
163        also gives an error.
165    15. If a forward reference was repeated with an upper limit of around 2000,
166        it caused the error "internal error: overran compiling workspace". The
167        maximum number of forward references (including repeats) was limited by the
168        internal workspace, and dependent on the LINK_SIZE. The code has been
169        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
170        the default depends on LINK_SIZE. There is a new upper limit (for safety)
171        of around 200,000 forward references. While doing this, I also speeded up
172        the filling in of repeated forward references.
174    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
175        incorrectly expecting the subject to contain another "a" after the start.
177    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
178        in the match, the SKIP should be ignored. This was not happening; instead
179        the SKIP was being treated as NOMATCH. For patterns such as
180        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
181        tested.
183    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
184        now much more compatible with Perl, in particular in cases where the result
185        is a non-match for a non-anchored pattern. For example, if
186        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
187        "m", where previously it did not return a name. A side effect of this
188        change is that for partial matches, the last encountered mark name is
189        returned, as for non matches. A number of tests that were previously not
190        Perl-compatible have been moved into the Perl-compatible test files. The
191        refactoring has had the pleasing side effect of removing one argument from
192        the match() function, thus reducing its stack requirements.
194    19. If the /S+ option was used in pcretest to study a pattern using JIT,
195        subsequent uses of /S (without +) incorrectly behaved like /S+.
197    21. Retrieve executable code size support for the JIT compiler and fixing
198        some warnings.
200    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
201        not work when the shorter character appeared right at the end of the
202        subject string.
204    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
205        systems.
207    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
208        output it when the /M option is used in pcretest.
210    25. The CheckMan script was not being included in the distribution. Also, added
211        an explicit "perl" to run Perl scripts from the PrepareRelease script
212        because this is reportedly needed in Windows.
214    26. If study data was being save in a file and studying had not found a set of
215        "starts with" bytes for the pattern, the data written to the file (though
216        never used) was taken from uninitialized memory and so caused valgrind to
217        complain.
219    27. Updated RunTest.bat as provided by Sheri Pierce.
221    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
223    29. Computation of memory usage for the table of capturing group names was
224        giving an unnecessarily large value.
227    Version 8.20 21-Oct-2011
228    ------------------------
230    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
231        a POSIX class. After further experiments with Perl, which convinced me that
232        Perl has bugs and confusions, a closing square bracket is no longer allowed
233        in a POSIX name. This bug also affected patterns with classes that started
234        with full stops.
236    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
237        captured substring, but while checking the failing first alternative,
238        substring 1 is temporarily captured. If the output vector supplied to
239        pcre_exec() was not big enough for this capture, the yield of the function
240        was still zero ("insufficient space for captured substrings"). This cannot
241        be totally fixed without adding another stack variable, which seems a lot
242        of expense for a edge case. However, I have improved the situation in cases
243        such as /(a)(b)x|abc/ matched against "abc", where the return code
244        indicates that fewer than the maximum number of slots in the ovector have
245        been set.
247    3.  Related to (2) above: when there are more back references in a pattern than
248        slots in the output vector, pcre_exec() uses temporary memory during
249        matching, and copies in the captures as far as possible afterwards. It was
250        using the entire output vector, but this conflicts with the specification
251        that only 2/3 is used for passing back captured substrings. Now it uses
252        only the first 2/3, for compatibility. This is, of course, another edge
253        case.
255    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
256        main code base, and can be used by building with --enable-jit. When this is
257        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
258        runtime --no-jit option is given.
260    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
261        ovector, the return from the function was zero, implying that there were
262        other matches that did not fit. The correct "exactly full" value is now
263        returned.
265    6.  If a subpattern that was called recursively or as a subroutine contained
266        (*PRUNE) or any other control that caused it to give a non-standard return,
267        invalid errors such as "Error -26 (nested recursion at the same subject
268        position)" or even infinite loops could occur.
270    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
271        computing the minimum length on reaching *ACCEPT, and so ended up with the
272        wrong value of 1 rather than 0. Further investigation indicates that
273        computing a minimum subject length in the presence of *ACCEPT is difficult
274        (think back references, subroutine calls), and so I have changed the code
275        so that no minimum is registered for a pattern that contains *ACCEPT.
277    8.  If (*THEN) was present in the first (true) branch of a conditional group,
278        it was not handled as intended. [But see 16 below.]
280    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
281        Sheri Pierce.
283    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
284        the first byte in a match must be "a".
286    11. Change 17 for 8.13 increased the recursion depth for patterns like
287        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
288        pattern contains any instances of (*THEN). If it does not, the old
289        optimizations are restored. It would be nice to do this on a per-group
290        basis, but at the moment that is not feasible.
292    12. In some environments, the output of pcretest -C is CRLF terminated. This
293        broke RunTest's code that checks for the link size. A single white space
294        character after the value is now allowed for.
296    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
297        For "fr", it uses the Windows-specific input and output files.
299    14. If (*THEN) appeared in a group that was called recursively or as a
300        subroutine, it did not work as intended. [But see next item.]
302    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
303        pattern fragments (but not containing any | characters). If A and B are
304        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
305        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
306        D. In other words, Perl considers parentheses that do not contain any |
307        characters to be part of a surrounding alternative, whereas PCRE was
308        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
309        differently. PCRE now behaves in the same way as Perl, except in the case
310        of subroutine/recursion calls such as (?1) which have in any case always
311        been different (but PCRE had them first :-).
313    16. Related to 15 above: Perl does not treat the | in a conditional group as
314        creating alternatives. Such a group is treated in the same way as an
315        ordinary group without any | characters when processing (*THEN). PCRE has
316        been changed to match Perl's behaviour.
318    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
319        RunGrepTest script failed.
321    18. Change 22 for version 13 caused atomic groups to use more stack. This is
322        inevitable for groups that contain captures, but it can lead to a lot of
323        stack use in large patterns. The old behaviour has been restored for atomic
324        groups that do not contain any capturing parentheses.
326    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
327        suppress the check for a minimum subject length at run time. (If it was
328        given to pcre_exec() or pcre_dfa_exec() it did work.)
330    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
331        fail to work when decoding hex characters in data strings in EBCDIC
332        environments.
334    21. It appears that in at least one Mac OS environment, the isxdigit() function
335        is implemented as a macro that evaluates to its argument more than once,
336        contravening the C 90 Standard (I haven't checked a later standard). There
337        was an instance in pcretest which caused it to go wrong when processing
338        \x{...} escapes in subject strings. The has been rewritten to avoid using
339        things like p++ in the argument of isxdigit().
342  Version 8.13 16-Aug-2011  Version 8.13 16-Aug-2011
# Line 107  Version 8.13 16-Aug-2011 Line 436  Version 8.13 16-Aug-2011
436      tail recursion to cut down on stack usage. Unfortunately, now that there is      tail recursion to cut down on stack usage. Unfortunately, now that there is
437      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
438      no longer possible because the return has to be checked for (*THEN). These      no longer possible because the return has to be checked for (*THEN). These
439      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
441  18. If a pattern containing \R was studied, it was assumed that \R always  18. If a pattern containing \R was studied, it was assumed that \R always
442      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be

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