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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.12 11-Jan-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.
21    Version 8.20 21-Oct-2011
22    ------------------------
24    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
25        a POSIX class. After further experiments with Perl, which convinced me that
26        Perl has bugs and confusions, a closing square bracket is no longer allowed
27        in a POSIX name. This bug also affected patterns with classes that started
28        with full stops.
30    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
31        captured substring, but while checking the failing first alternative,
32        substring 1 is temporarily captured. If the output vector supplied to
33        pcre_exec() was not big enough for this capture, the yield of the function
34        was still zero ("insufficient space for captured substrings"). This cannot
35        be totally fixed without adding another stack variable, which seems a lot
36        of expense for a edge case. However, I have improved the situation in cases
37        such as /(a)(b)x|abc/ matched against "abc", where the return code
38        indicates that fewer than the maximum number of slots in the ovector have
39        been set.
41    3.  Related to (2) above: when there are more back references in a pattern than
42        slots in the output vector, pcre_exec() uses temporary memory during
43        matching, and copies in the captures as far as possible afterwards. It was
44        using the entire output vector, but this conflicts with the specification
45        that only 2/3 is used for passing back captured substrings. Now it uses
46        only the first 2/3, for compatibility. This is, of course, another edge
47        case.
49    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
50        main code base, and can be used by building with --enable-jit. When this is
51        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
52        runtime --no-jit option is given.
54    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
55        ovector, the return from the function was zero, implying that there were
56        other matches that did not fit. The correct "exactly full" value is now
57        returned.
59    6.  If a subpattern that was called recursively or as a subroutine contained
60        (*PRUNE) or any other control that caused it to give a non-standard return,
61        invalid errors such as "Error -26 (nested recursion at the same subject
62        position)" or even infinite loops could occur.
64    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
65        computing the minimum length on reaching *ACCEPT, and so ended up with the
66        wrong value of 1 rather than 0. Further investigation indicates that
67        computing a minimum subject length in the presence of *ACCEPT is difficult
68        (think back references, subroutine calls), and so I have changed the code
69        so that no minimum is registered for a pattern that contains *ACCEPT.
71    8.  If (*THEN) was present in the first (true) branch of a conditional group,
72        it was not handled as intended. [But see 16 below.]
74    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
75        Sheri Pierce.
77    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
78        the first byte in a match must be "a".
80    11. Change 17 for 8.13 increased the recursion depth for patterns like
81        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
82        pattern contains any instances of (*THEN). If it does not, the old
83        optimizations are restored. It would be nice to do this on a per-group
84        basis, but at the moment that is not feasible.
86    12. In some environments, the output of pcretest -C is CRLF terminated. This
87        broke RunTest's code that checks for the link size. A single white space
88        character after the value is now allowed for.
90    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
91        For "fr", it uses the Windows-specific input and output files.
93    14. If (*THEN) appeared in a group that was called recursively or as a
94        subroutine, it did not work as intended. [But see next item.]
96    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
97        pattern fragments (but not containing any | characters). If A and B are
98        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
99        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
100        D. In other words, Perl considers parentheses that do not contain any |
101        characters to be part of a surrounding alternative, whereas PCRE was
102        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
103        differently. PCRE now behaves in the same way as Perl, except in the case
104        of subroutine/recursion calls such as (?1) which have in any case always
105        been different (but PCRE had them first :-).
107    16. Related to 15 above: Perl does not treat the | in a conditional group as
108        creating alternatives. Such a group is treated in the same way as an
109        ordinary group without any | characters when processing (*THEN). PCRE has
110        been changed to match Perl's behaviour.
112    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
113        RunGrepTest script failed.
115    18. Change 22 for version 13 caused atomic groups to use more stack. This is
116        inevitable for groups that contain captures, but it can lead to a lot of
117        stack use in large patterns. The old behaviour has been restored for atomic
118        groups that do not contain any capturing parentheses.
120    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
121        suppress the check for a minimum subject length at run time. (If it was
122        given to pcre_exec() or pcre_dfa_exec() it did work.)
124    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
125        fail to work when decoding hex characters in data strings in EBCDIC
126        environments.
128    21. It appears that in at least one Mac OS environment, the isxdigit() function
129        is implemented as a macro that evaluates to its argument more than once,
130        contravening the C 90 Standard (I haven't checked a later standard). There
131        was an instance in pcretest which caused it to go wrong when processing
132        \x{...} escapes in subject strings. The has been rewritten to avoid using
133        things like p++ in the argument of isxdigit().
136    Version 8.13 16-Aug-2011
137    ------------------------
139    1.  The Unicode data tables have been updated to Unicode 6.0.0.
141    2.  Two minor typos in pcre_internal.h have been fixed.
143    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
144        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
145        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
147    4.  There were a number of related bugs in the code for matching backrefences
148        caselessly in UTF-8 mode when codes for the characters concerned were
149        different numbers of bytes. For example, U+023A and U+2C65 are an upper
150        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
151        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
152        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
153        2-byte code at the end of the subject (it thought there wasn't enough data
154        left).
156    5.  Comprehensive information about what went wrong is now returned by
157        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
158        as the output vector has at least 2 elements. The offset of the start of
159        the failing character and a reason code are placed in the vector.
161    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
162        now returned is for the first byte of the failing character, instead of the
163        last byte inspected. This is an incompatible change, but I hope it is small
164        enough not to be a problem. It makes the returned offset consistent with
165        pcre_exec() and pcre_dfa_exec().
167    7.  pcretest now gives a text phrase as well as the error number when
168        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
169        failure, the offset and reason code are output.
171    8.  When \R was used with a maximizing quantifier it failed to skip backwards
172        over a \r\n pair if the subsequent match failed. Instead, it just skipped
173        back over a single character (\n). This seems wrong (because it treated the
174        two characters as a single entity when going forwards), conflicts with the
175        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
176        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
177        has been changed.
179    9.  Some internal refactoring has changed the processing so that the handling
180        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
181        time (the PCRE_DOTALL option was changed this way some time ago: version
182        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
183        which was always a bit of a fudge. It also means that there is one less
184        argument for the match() function, which reduces its stack requirements
185        slightly. This change also fixes an incompatibility with Perl: the pattern
186        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
188    10. More internal refactoring has drastically reduced the number of recursive
189        calls to match() for possessively repeated groups such as (abc)++ when
190        using pcre_exec().
192    11. While implementing 10, a number of bugs in the handling of groups were
193        discovered and fixed:
195        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
196        (a|)*(?1) gave a compile-time internal error.
197        ((a|)+)+  did not notice that the outer group could match an empty string.
198        (^a|^)+   was not marked as anchored.
199        (.*a|.*)+ was not marked as matching at start or after a newline.
201    12. Yet more internal refactoring has removed another argument from the match()
202        function. Special calls to this function are now indicated by setting a
203        value in a variable in the "match data" data block.
205    13. Be more explicit in pcre_study() instead of relying on "default" for
206        opcodes that mean there is no starting character; this means that when new
207        ones are added and accidentally left out of pcre_study(), testing should
208        pick them up.
210    14. The -s option of pcretest has been documented for ages as being an old
211        synonym of -m (show memory usage). I have changed it to mean "force study
212        for every regex", that is, assume /S for every regex. This is similar to -i
213        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
214        using it. It makes it easier to run collections of tests with and without
215        study enabled, and thereby test pcre_study() more easily. All the standard
216        tests are now run with and without -s (but some patterns can be marked as
217        "never study" - see 20 below).
219    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
220        restoration of the capturing data to the outer values was not happening
221        correctly.
223    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
224        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
225        pattern had matched an empty string, and so incorrectly returned a no
226        match.
228    17. There was optimizing code for the last branch of non-capturing parentheses,
229        and also for the obeyed branch of a conditional subexpression, which used
230        tail recursion to cut down on stack usage. Unfortunately, now that there is
231        the possibility of (*THEN) occurring in these branches, tail recursion is
232        no longer possible because the return has to be checked for (*THEN). These
233        two optimizations have therefore been removed. [But see 8.20/11 above.]
235    18. If a pattern containing \R was studied, it was assumed that \R always
236        matched two bytes, thus causing the minimum subject length to be
237        incorrectly computed because \R can also match just one byte.
239    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
240        was incorrectly computed.
242    20. If /S is present twice on a test pattern in pcretest input, it now
243        *disables* studying, thereby overriding the use of -s on the command line
244        (see 14 above). This is necessary for one or two tests to keep the output
245        identical in both cases.
247    21. When (*ACCEPT) was used in an assertion that matched an empty string and
248        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
250    22. When an atomic group that contained a capturing parenthesis was
251        successfully matched, but the branch in which it appeared failed, the
252        capturing was not being forgotten if a higher numbered group was later
253        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
254        group 1 to "a", when in fact it should be unset. This applied to multi-
255        branched capturing and non-capturing groups, repeated or not, and also to
256        positive assertions (capturing in negative assertions does not happen
257        in PCRE) and also to nested atomic groups.
259    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
260        subject after a captured substring, to make it easier to tell which of a
261        number of identical substrings has been captured.
263    24. The way atomic groups are processed by pcre_exec() has been changed so that
264        if they are repeated, backtracking one repetition now resets captured
265        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
266        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
267        "aaa". Previously, it would have been "a". As part of this code
268        refactoring, the way recursive calls are handled has also been changed.
270    25. If an assertion condition captured any substrings, they were not passed
271        back unless some other capturing happened later. For example, if
272        (?(?=(a))a) was matched against "a", no capturing was returned.
274    26. When studying a pattern that contained subroutine calls or assertions,
275        the code for finding the minimum length of a possible match was handling
276        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
277        group 1 called group 2 while simultaneously a separate group 2 called group
278        1). A stack overflow occurred in this case. I have fixed this by limiting
279        the recursion depth to 10.
281    27. Updated RunTest.bat in the distribution to the version supplied by Tom
282        Fortmann. This supports explicit test numbers on the command line, and has
283        argument validation and error reporting.
285    28. An instance of \X with an unlimited repeat could fail if at any point the
286        first character it looked at was a mark character.
288    29. Some minor code refactoring concerning Unicode properties and scripts
289        should reduce the stack requirement of match() slightly.
291    30. Added the '=' option to pcretest to check the setting of unused capturing
292        slots at the end of the pattern, which are documented as being -1, but are
293        not included in the return count.
295    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
296        compiled something random. Now it gives a compile-time error (as does
297        Perl).
299    32. A *MARK encountered during the processing of a positive assertion is now
300        recorded and passed back (compatible with Perl).
302    33. If --only-matching or --colour was set on a pcregrep call whose pattern
303        had alternative anchored branches, the search for a second match in a line
304        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
305        matched the line "0102" twice. The same bug affected patterns that started
306        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
307        twice.
309    34. Previously, PCRE did not allow quantification of assertions. However, Perl
310        does, and because of capturing effects, quantifying parenthesized
311        assertions may at times be useful. Quantifiers are now allowed for
312        parenthesized assertions.
314    35. A minor code tidy in pcre_compile() when checking options for \R usage.
316    36. \g was being checked for fancy things in a character class, when it should
317        just be a literal "g".
319    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
320        appearance of a nested POSIX class supersedes an apparent external class.
321        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
322        unescaped square brackets may also appear as part of class names. For
323        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
324        more like Perl. (But see 8.20/1 above.)
326    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
327        was because it thought it was \N{name}, which is not supported).
329    39. Add minix to OS list not supporting the -S option in pcretest.
331    40. PCRE tries to detect cases of infinite recursion at compile time, but it
332        cannot analyze patterns in sufficient detail to catch mutual recursions
333        such as ((?1))((?2)). There is now a runtime test that gives an error if a
334        subgroup is called recursively as a subpattern for a second time at the
335        same position in the subject string. In previous releases this might have
336        been caught by the recursion limit, or it might have run out of stack.
338    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
339        happen only once. PCRE was, however incorrectly giving a compile time error
340        "recursive call could loop indefinitely" because it cannot analyze the
341        pattern in sufficient detail. The compile time test no longer happens when
342        PCRE is compiling a conditional subpattern, but actual runaway loops are
343        now caught at runtime (see 40 above).
345    42. It seems that Perl allows any characters other than a closing parenthesis
346        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
347        has been changed to be the same.
349    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
350        as not to get warnings when autogen.sh is called. Also changed
351        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
353    44. To help people who use pcregrep to scan files containing exceedingly long
354        lines, the following changes have been made:
356        (a) The default value of the buffer size parameter has been increased from
357            8K to 20K. (The actual buffer used is three times this size.)
359        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
360            PCRE is built.
362        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
363            to be set at run time.
365        (d) Numerical values in pcregrep options can be followed by K or M, for
366            example --buffer-size=50K.
368        (e) If a line being scanned overflows pcregrep's buffer, an error is now
369            given and the return code is set to 2.
371    45. Add a pointer to the latest mark to the callout data block.
373    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
374        partial match of an empty string instead of no match. This was specific to
375        the use of ".".
377    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
378        complete match instead of a partial match. This bug was dependent on both
379        the PCRE_UTF8 and PCRE_DOTALL options being set.
381    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
382        starting byte set, because \b was not being ignored.
385    Version 8.12 15-Jan-2011
386  ------------------------  ------------------------
388  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
389      checks for such things as part of the documentation building process.      checks for such things as part of the documentation building process.
391    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
392        --match-limit and --recursion-limit options (added for 8.11). In
393        particular, this made one of the standard tests fail. (The integer value
394        went into the wrong half of a long int.)
396    3.  If the --colour option was given to pcregrep with -v (invert match), it
397        did strange things, either producing crazy output, or crashing. It should,
398        of course, ignore a request for colour when reporting lines that do not
399        match.
401    4.  Another pcregrep bug caused similar problems if --colour was specified with
402        -M (multiline) and the pattern match finished with a line ending.
404    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
405        matched in multiline mode, the following line was shown as part of the
406        match. This seems wrong, so I have changed it.
408    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
409        the check for further matches in the same line (so they could be coloured)
410        to overrun the end of the current line. If another match was found, it was
411        incorrectly shown (and then shown again when found in the next line).
413    7.  If pcregrep was compiled under Windows, there was a reference to the
414        function pcregrep_exit() before it was defined. I am assuming this was
415        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
416        reported by a user. I've moved the definition above the reference.
419  Version 8.11 10-Dec-2010  Version 8.11 10-Dec-2010
420  ------------------------  ------------------------

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