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

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