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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". The
60        maximum number of forward references (including repeats) was limited by the
61        internal workspace, and dependent on the LINK_SIZE. The code has been
62        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
63        the default depends on LINK_SIZE. There is a new upper limit (for safety)
64        of around 200,000 forward references. While doing this, I also speeded up
65        the filling in of repeated forward references.
67    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
68        incorrectly expecting the subject to contain another "a" after the start.
70    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
71        in the match, the SKIP should be ignored. This was not happening; instead
72        the SKIP was being treated as NOMATCH. For patterns such as
73        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
74        tested.
76    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
77        now much more compatible with Perl, in particular in cases where the result
78        is a non-match for a non-anchored pattern. For example, if
79        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
80        "m", where previously it did not return a name. A side effect of this
81        change is that for partial matches, the last encountered mark name is
82        returned, as for non matches. A number of tests that were previously not
83        Perl-compatible have been moved into the Perl-compatible test files. The
84        refactoring has had the pleasing side effect of removing one argument from
85        the match() function, thus reducing its stack requirements.
87    19. If the /S+ option was used in pcretest to study a pattern using JIT,
88        subsequent uses of /S (without +) incorrectly behaved like /S+.
90    21. Retrieve executable code size support for the JIT compiler and fixing
91        some warnings.
93    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
94        not work when the shorter character appeared right at the end of the
95        subject string.
98    Version 8.20 21-Oct-2011
99    ------------------------
101    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
102        a POSIX class. After further experiments with Perl, which convinced me that
103        Perl has bugs and confusions, a closing square bracket is no longer allowed
104        in a POSIX name. This bug also affected patterns with classes that started
105        with full stops.
107    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
108        captured substring, but while checking the failing first alternative,
109        substring 1 is temporarily captured. If the output vector supplied to
110        pcre_exec() was not big enough for this capture, the yield of the function
111        was still zero ("insufficient space for captured substrings"). This cannot
112        be totally fixed without adding another stack variable, which seems a lot
113        of expense for a edge case. However, I have improved the situation in cases
114        such as /(a)(b)x|abc/ matched against "abc", where the return code
115        indicates that fewer than the maximum number of slots in the ovector have
116        been set.
118    3.  Related to (2) above: when there are more back references in a pattern than
119        slots in the output vector, pcre_exec() uses temporary memory during
120        matching, and copies in the captures as far as possible afterwards. It was
121        using the entire output vector, but this conflicts with the specification
122        that only 2/3 is used for passing back captured substrings. Now it uses
123        only the first 2/3, for compatibility. This is, of course, another edge
124        case.
126    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
127        main code base, and can be used by building with --enable-jit. When this is
128        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
129        runtime --no-jit option is given.
131    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
132        ovector, the return from the function was zero, implying that there were
133        other matches that did not fit. The correct "exactly full" value is now
134        returned.
136    6.  If a subpattern that was called recursively or as a subroutine contained
137        (*PRUNE) or any other control that caused it to give a non-standard return,
138        invalid errors such as "Error -26 (nested recursion at the same subject
139        position)" or even infinite loops could occur.
141    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
142        computing the minimum length on reaching *ACCEPT, and so ended up with the
143        wrong value of 1 rather than 0. Further investigation indicates that
144        computing a minimum subject length in the presence of *ACCEPT is difficult
145        (think back references, subroutine calls), and so I have changed the code
146        so that no minimum is registered for a pattern that contains *ACCEPT.
148    8.  If (*THEN) was present in the first (true) branch of a conditional group,
149        it was not handled as intended. [But see 16 below.]
151    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
152        Sheri Pierce.
154    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
155        the first byte in a match must be "a".
157    11. Change 17 for 8.13 increased the recursion depth for patterns like
158        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
159        pattern contains any instances of (*THEN). If it does not, the old
160        optimizations are restored. It would be nice to do this on a per-group
161        basis, but at the moment that is not feasible.
163    12. In some environments, the output of pcretest -C is CRLF terminated. This
164        broke RunTest's code that checks for the link size. A single white space
165        character after the value is now allowed for.
167    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
168        For "fr", it uses the Windows-specific input and output files.
170    14. If (*THEN) appeared in a group that was called recursively or as a
171        subroutine, it did not work as intended. [But see next item.]
173    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
174        pattern fragments (but not containing any | characters). If A and B are
175        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
176        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
177        D. In other words, Perl considers parentheses that do not contain any |
178        characters to be part of a surrounding alternative, whereas PCRE was
179        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
180        differently. PCRE now behaves in the same way as Perl, except in the case
181        of subroutine/recursion calls such as (?1) which have in any case always
182        been different (but PCRE had them first :-).
184    16. Related to 15 above: Perl does not treat the | in a conditional group as
185        creating alternatives. Such a group is treated in the same way as an
186        ordinary group without any | characters when processing (*THEN). PCRE has
187        been changed to match Perl's behaviour.
189    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
190        RunGrepTest script failed.
192    18. Change 22 for version 13 caused atomic groups to use more stack. This is
193        inevitable for groups that contain captures, but it can lead to a lot of
194        stack use in large patterns. The old behaviour has been restored for atomic
195        groups that do not contain any capturing parentheses.
197    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
198        suppress the check for a minimum subject length at run time. (If it was
199        given to pcre_exec() or pcre_dfa_exec() it did work.)
201    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
202        fail to work when decoding hex characters in data strings in EBCDIC
203        environments.
205    21. It appears that in at least one Mac OS environment, the isxdigit() function
206        is implemented as a macro that evaluates to its argument more than once,
207        contravening the C 90 Standard (I haven't checked a later standard). There
208        was an instance in pcretest which caused it to go wrong when processing
209        \x{...} escapes in subject strings. The has been rewritten to avoid using
210        things like p++ in the argument of isxdigit().
213    Version 8.13 16-Aug-2011
214  ------------------------  ------------------------
216  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.
# Line 21  Version 8.13 30-Apr-2011 Line 230  Version 8.13 30-Apr-2011
230      2-byte code at the end of the subject (it thought there wasn't enough data      2-byte code at the end of the subject (it thought there wasn't enough data
231      left).      left).
233    5.  Comprehensive information about what went wrong is now returned by
234        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
235        as the output vector has at least 2 elements. The offset of the start of
236        the failing character and a reason code are placed in the vector.
238    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
239        now returned is for the first byte of the failing character, instead of the
240        last byte inspected. This is an incompatible change, but I hope it is small
241        enough not to be a problem. It makes the returned offset consistent with
242        pcre_exec() and pcre_dfa_exec().
244    7.  pcretest now gives a text phrase as well as the error number when
245        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
246        failure, the offset and reason code are output.
248    8.  When \R was used with a maximizing quantifier it failed to skip backwards
249        over a \r\n pair if the subsequent match failed. Instead, it just skipped
250        back over a single character (\n). This seems wrong (because it treated the
251        two characters as a single entity when going forwards), conflicts with the
252        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
253        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
254        has been changed.
256    9.  Some internal refactoring has changed the processing so that the handling
257        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
258        time (the PCRE_DOTALL option was changed this way some time ago: version
259        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
260        which was always a bit of a fudge. It also means that there is one less
261        argument for the match() function, which reduces its stack requirements
262        slightly. This change also fixes an incompatibility with Perl: the pattern
263        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
265    10. More internal refactoring has drastically reduced the number of recursive
266        calls to match() for possessively repeated groups such as (abc)++ when
267        using pcre_exec().
269    11. While implementing 10, a number of bugs in the handling of groups were
270        discovered and fixed:
272        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
273        (a|)*(?1) gave a compile-time internal error.
274        ((a|)+)+  did not notice that the outer group could match an empty string.
275        (^a|^)+   was not marked as anchored.
276        (.*a|.*)+ was not marked as matching at start or after a newline.
278    12. Yet more internal refactoring has removed another argument from the match()
279        function. Special calls to this function are now indicated by setting a
280        value in a variable in the "match data" data block.
282    13. Be more explicit in pcre_study() instead of relying on "default" for
283        opcodes that mean there is no starting character; this means that when new
284        ones are added and accidentally left out of pcre_study(), testing should
285        pick them up.
287    14. The -s option of pcretest has been documented for ages as being an old
288        synonym of -m (show memory usage). I have changed it to mean "force study
289        for every regex", that is, assume /S for every regex. This is similar to -i
290        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
291        using it. It makes it easier to run collections of tests with and without
292        study enabled, and thereby test pcre_study() more easily. All the standard
293        tests are now run with and without -s (but some patterns can be marked as
294        "never study" - see 20 below).
296    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
297        restoration of the capturing data to the outer values was not happening
298        correctly.
300    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
301        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
302        pattern had matched an empty string, and so incorrectly returned a no
303        match.
305    17. There was optimizing code for the last branch of non-capturing parentheses,
306        and also for the obeyed branch of a conditional subexpression, which used
307        tail recursion to cut down on stack usage. Unfortunately, now that there is
308        the possibility of (*THEN) occurring in these branches, tail recursion is
309        no longer possible because the return has to be checked for (*THEN). These
310        two optimizations have therefore been removed. [But see 8.20/11 above.]
312    18. If a pattern containing \R was studied, it was assumed that \R always
313        matched two bytes, thus causing the minimum subject length to be
314        incorrectly computed because \R can also match just one byte.
316    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
317        was incorrectly computed.
319    20. If /S is present twice on a test pattern in pcretest input, it now
320        *disables* studying, thereby overriding the use of -s on the command line
321        (see 14 above). This is necessary for one or two tests to keep the output
322        identical in both cases.
324    21. When (*ACCEPT) was used in an assertion that matched an empty string and
325        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
327    22. When an atomic group that contained a capturing parenthesis was
328        successfully matched, but the branch in which it appeared failed, the
329        capturing was not being forgotten if a higher numbered group was later
330        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
331        group 1 to "a", when in fact it should be unset. This applied to multi-
332        branched capturing and non-capturing groups, repeated or not, and also to
333        positive assertions (capturing in negative assertions does not happen
334        in PCRE) and also to nested atomic groups.
336    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
337        subject after a captured substring, to make it easier to tell which of a
338        number of identical substrings has been captured.
340    24. The way atomic groups are processed by pcre_exec() has been changed so that
341        if they are repeated, backtracking one repetition now resets captured
342        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
343        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
344        "aaa". Previously, it would have been "a". As part of this code
345        refactoring, the way recursive calls are handled has also been changed.
347    25. If an assertion condition captured any substrings, they were not passed
348        back unless some other capturing happened later. For example, if
349        (?(?=(a))a) was matched against "a", no capturing was returned.
351    26. When studying a pattern that contained subroutine calls or assertions,
352        the code for finding the minimum length of a possible match was handling
353        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
354        group 1 called group 2 while simultaneously a separate group 2 called group
355        1). A stack overflow occurred in this case. I have fixed this by limiting
356        the recursion depth to 10.
358    27. Updated RunTest.bat in the distribution to the version supplied by Tom
359        Fortmann. This supports explicit test numbers on the command line, and has
360        argument validation and error reporting.
362    28. An instance of \X with an unlimited repeat could fail if at any point the
363        first character it looked at was a mark character.
365    29. Some minor code refactoring concerning Unicode properties and scripts
366        should reduce the stack requirement of match() slightly.
368    30. Added the '=' option to pcretest to check the setting of unused capturing
369        slots at the end of the pattern, which are documented as being -1, but are
370        not included in the return count.
372    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
373        compiled something random. Now it gives a compile-time error (as does
374        Perl).
376    32. A *MARK encountered during the processing of a positive assertion is now
377        recorded and passed back (compatible with Perl).
379    33. If --only-matching or --colour was set on a pcregrep call whose pattern
380        had alternative anchored branches, the search for a second match in a line
381        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
382        matched the line "0102" twice. The same bug affected patterns that started
383        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
384        twice.
386    34. Previously, PCRE did not allow quantification of assertions. However, Perl
387        does, and because of capturing effects, quantifying parenthesized
388        assertions may at times be useful. Quantifiers are now allowed for
389        parenthesized assertions.
391    35. A minor code tidy in pcre_compile() when checking options for \R usage.
393    36. \g was being checked for fancy things in a character class, when it should
394        just be a literal "g".
396    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
397        appearance of a nested POSIX class supersedes an apparent external class.
398        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
399        unescaped square brackets may also appear as part of class names. For
400        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
401        more like Perl. (But see 8.20/1 above.)
403    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
404        was because it thought it was \N{name}, which is not supported).
406    39. Add minix to OS list not supporting the -S option in pcretest.
408    40. PCRE tries to detect cases of infinite recursion at compile time, but it
409        cannot analyze patterns in sufficient detail to catch mutual recursions
410        such as ((?1))((?2)). There is now a runtime test that gives an error if a
411        subgroup is called recursively as a subpattern for a second time at the
412        same position in the subject string. In previous releases this might have
413        been caught by the recursion limit, or it might have run out of stack.
415    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
416        happen only once. PCRE was, however incorrectly giving a compile time error
417        "recursive call could loop indefinitely" because it cannot analyze the
418        pattern in sufficient detail. The compile time test no longer happens when
419        PCRE is compiling a conditional subpattern, but actual runaway loops are
420        now caught at runtime (see 40 above).
422    42. It seems that Perl allows any characters other than a closing parenthesis
423        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
424        has been changed to be the same.
426    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
427        as not to get warnings when autogen.sh is called. Also changed
428        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
430    44. To help people who use pcregrep to scan files containing exceedingly long
431        lines, the following changes have been made:
433        (a) The default value of the buffer size parameter has been increased from
434            8K to 20K. (The actual buffer used is three times this size.)
436        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
437            PCRE is built.
439        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
440            to be set at run time.
442        (d) Numerical values in pcregrep options can be followed by K or M, for
443            example --buffer-size=50K.
445        (e) If a line being scanned overflows pcregrep's buffer, an error is now
446            given and the return code is set to 2.
448    45. Add a pointer to the latest mark to the callout data block.
450    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
451        partial match of an empty string instead of no match. This was specific to
452        the use of ".".
454    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
455        complete match instead of a partial match. This bug was dependent on both
456        the PCRE_UTF8 and PCRE_DOTALL options being set.
458    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
459        starting byte set, because \b was not being ignored.
462  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
463  ------------------------  ------------------------

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