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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.10 03 May-2010  Version 8.13 30-Apr-2011
5    ------------------------
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
9    2.  Two minor typos in pcre_internal.h have been fixed.
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
110    20. If /S is present twice on a test pattern in pcretest input, it *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
141    25. When studying a pattern that contained subroutine calls or assertions,
142        the code for finding the minimum length of a possible match was handling
143        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
144        group 1 called group 2 while simultaneously a separate group 2 called group
145        1). A stack overflow occurred in this case. I have fixed this by limiting
146        the recursion depth to 10.
148    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
152    27. An instance of \X with an unlimited repeat could fail if at any point the
153        first character it looked at was a mark character.
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
158    29. Added the '=' option to pcretest to check the setting of unused capturing
159        slots at the end of the pattern, which are documented as being -1, but are
160        not included in the return count.
162    30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
163        compiled something random. Now it gives a compile-time error (as does
164        Perl).
166    31. A *MARK encountered during the processing of a positive assertion is now
167        recorded and passed back (compatible with Perl).
169    32. If --only-matching or --colour was set on a pcregrep call whose pattern
170        had alternative anchored branches, the search for a second match in a line
171        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
172        matched the line "0102" twice. The same bug affected patterns that started
173        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
174        twice.
176    33. Previously, PCRE did not allow quantification of assertions. However, Perl
177        does, and because of capturing effects, quantifying parenthesized
178        assertions may at times be useful. Quantifiers are now allowed for
179        parenthesized assertions.
181    34. A minor code tidy in pcre_compile() when checking options for \R usage.
183    35. \g was being checked for fancy things in a character class, when it should
184        just be a literal "g".
186    36. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
187        appearance of a nested POSIX class supersedes an apparent external class.
188        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
189        unescaped square brackets may also appear as part of class names. For
190        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
191        more like Perl.
193    37. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
194        was because it thought it was \N{name}, which is not supported).
196    38. Add minix to OS list not supporting the -S option in pcretest.
198    39. PCRE tries to detect cases of infinite recursion at compile time, but it
199        cannot analyze patterns in sufficient detail to catch mutual recursions
200        such as ((?1))((?2)). There is now a runtime test that gives an error if a
201        subgroup is called recursively as a subpattern for a second time at the
202        same position in the subject string. In previous releases this might have
203        been caught by the recursion limit, or it might have run out of stack.
205    40. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
206        happen only once. PCRE was, however incorrectly giving a compile time error
207        "recursive call could loop indefinitely" because it cannot analyze the
208        pattern in sufficient detail. The compile time test no longer happens when
209        PCRE is compiling a conditional subpattern, but actual runaway loops are
210        now caught at runtime (see 39 above).
212    41. It seems that Perl allows any characters other than a closing parenthesis
213        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
214        has been changed to be the same.
216    42. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
217        as not to get warnings when autogen.sh is called. Also changed
218        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
220    43. To help people who use pcregrep to scan files containing exceedingly long
221        lines, the following changes have been made:
223        (a) The default value of the buffer size parameter has been increased from
224            8K to 20K. (A buffer three times this size is actually used.)
226        (b) The default can be changed by ./configure --with-pcregrep-bufsiz when
227            PCRE is built.
229        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
230            to be set at run time.
232        (d) Numerical values in pcregrep options can be followed by K or M, for
233            example --buffer-size=50K.
235        (e) If a line being scanned overflows pcregrep's buffer, an error is now
236            given and the return code is set to 2.
238    44. Add a pointer to the latest mark to the callout data block.
241    Version 8.12 15-Jan-2011
242    ------------------------
244    1.  Fixed some typos in the markup of the man pages, and wrote a script that
245        checks for such things as part of the documentation building process.
247    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
248        --match-limit and --recursion-limit options (added for 8.11). In
249        particular, this made one of the standard tests fail. (The integer value
250        went into the wrong half of a long int.)
252    3.  If the --colour option was given to pcregrep with -v (invert match), it
253        did strange things, either producing crazy output, or crashing. It should,
254        of course, ignore a request for colour when reporting lines that do not
255        match.
257    4.  Another pcregrep bug caused similar problems if --colour was specified with
258        -M (multiline) and the pattern match finished with a line ending.
260    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
261        matched in multiline mode, the following line was shown as part of the
262        match. This seems wrong, so I have changed it.
264    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
265        the check for further matches in the same line (so they could be coloured)
266        to overrun the end of the current line. If another match was found, it was
267        incorrectly shown (and then shown again when found in the next line).
269    7.  If pcregrep was compiled under Windows, there was a reference to the
270        function pcregrep_exit() before it was defined. I am assuming this was
271        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
272        reported by a user. I've moved the definition above the reference.
275    Version 8.11 10-Dec-2010
276    ------------------------
278    1.  (*THEN) was not working properly if there were untried alternatives prior
279        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
280        backtracked to try for "b" instead of moving to the next alternative branch
281        at the same level (in this case, to look for "c"). The Perl documentation
282        is clear that when (*THEN) is backtracked onto, it goes to the "next
283        alternative in the innermost enclosing group".
285    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
286        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
287        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
288        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
289        (*THEN).
291    3.  If \s appeared in a character class, it removed the VT character from
292        the class, even if it had been included by some previous item, for example
293        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
294        of \s, but is part of the POSIX "space" class.)
296    4.  A partial match never returns an empty string (because you can always
297        match an empty string at the end of the subject); however the checking for
298        an empty string was starting at the "start of match" point. This has been
299        changed to the "earliest inspected character" point, because the returned
300        data for a partial match starts at this character. This means that, for
301        example, /(?<=abc)def/ gives a partial match for the subject "abc"
302        (previously it gave "no match").
304    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
305        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
306        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
307        has an implication that the given string is incomplete (because a partial
308        match is preferred over a full match). For this reason, these items now
309        give a partial match in this situation. [Aside: previously, the one case
310        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
311        match rather than a full match, which was wrong by the old rules, but is
312        now correct.]
314    6.  There was a bug in the handling of #-introduced comments, recognized when
315        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
316        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
317        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
318        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
319        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
320        places in pcre_compile().
322    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
323        comments when looking ahead for named forward references to subpatterns,
324        the only newline sequence it recognized was NL. It now handles newlines
325        according to the set newline convention.
327    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
328        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
329        cater for a lack of strerror(). These oversights have been fixed.
331    9.  Added --match-limit and --recursion-limit to pcregrep.
333    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
335    11. When the -o option was used, pcregrep was setting a return code of 1, even
336        when matches were found, and --line-buffered was not being honoured.
338    12. Added an optional parentheses number to the -o and --only-matching options
339        of pcregrep.
341    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
342        can match an empty string. The code to do it in pcretest and pcredemo
343        needed fixing:
345        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
346            only one byte after an empty string match just before CRLF (this case
347            just got forgotten; "any" and "anycrlf" were OK).
349        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
350            mode when an empty string match preceded an ASCII character followed by
351            a non-ASCII character. (The code for advancing by one character rather
352            than one byte was nonsense.)
354        (c) The pcredemo.c sample program did not have any code at all to handle
355            the cases when CRLF is a valid newline sequence.
357    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
358        as a starting offset was within the subject string. There is now a new
359        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
360        negative or greater than the length of the string. In order to test this,
361        pcretest is extended to allow the setting of negative starting offsets.
363    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
364        starting offset points to the beginning of a UTF-8 character was
365        unnecessarily clumsy. I tidied it up.
367    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
368        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
370    17. Nobody had reported that the --include_dir option, which was added in
371        release 7.7 should have been called --include-dir (hyphen, not underscore)
372        for compatibility with GNU grep. I have changed it to --include-dir, but
373        left --include_dir as an undocumented synonym, and the same for
374        --exclude-dir, though that is not available in GNU grep, at least as of
375        release 2.5.4.
377    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
378        characters from a string of bytes) have been redefined so as not to use
379        loops, in order to improve performance in some environments. At the same
380        time, I abstracted some of the common code into auxiliary macros to save
381        repetition (this should not affect the compiled code).
383    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
384        compile-time error is now given if \c is not followed by an ASCII
385        character, that is, a byte less than 128. (In EBCDIC mode, the code is
386        different, and any byte value is allowed.)
388    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
389        START_OPTIMIZE option, which is now allowed at compile time - but just
390        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
391        to pcregrep and other applications that have no direct access to PCRE
392        options. The new /Y option in pcretest sets this option when calling
393        pcre_compile().
395    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
396        back references. Groups containing recursive back references were forced to
397        be atomic by that change, but in the case of named groups, the amount of
398        memory required was incorrectly computed, leading to "Failed: internal
399        error: code overflow". This has been fixed.
401    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
402        pcretest.c, to avoid build problems in some Borland environments.
405    Version 8.10 25-Jun-2010
406  ------------------------  ------------------------
408  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
# Line 9  Version 8.10 03 May-2010 Line 410  Version 8.10 03 May-2010
411  2.  (*ACCEPT) was not working when inside an atomic group.  2.  (*ACCEPT) was not working when inside an atomic group.
413  3.  Inside a character class, \B is treated as a literal by default, but  3.  Inside a character class, \B is treated as a literal by default, but
414      faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option      faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
415      causes the error). The code is unchanged, but I tidied the documentation.      causes the error). The code is unchanged, but I tidied the documentation.
417  4.  Inside a character class, PCRE always treated \R and \X as literals,  4.  Inside a character class, PCRE always treated \R and \X as literals,
418      whereas Perl faults them if its -w option is set. I have changed PCRE so      whereas Perl faults them if its -w option is set. I have changed PCRE so
419      that it faults them when PCRE_EXTRA is set.      that it faults them when PCRE_EXTRA is set.
421    5.  Added support for \N, which always matches any character other than
422        newline. (It is the same as "." when PCRE_DOTALL is not set.)
424    6.  When compiling pcregrep with newer versions of gcc which may have
425        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
426        declared with attribute warn_unused_result" were given. Just casting the
427        result to (void) does not stop the warnings; a more elaborate fudge is
428        needed. I've used a macro to implement this.
430    7.  Minor change to pcretest.c to avoid a compiler warning.
432    8.  Added four artifical Unicode properties to help with an option to make
433        \s etc use properties (see next item). The new properties are: Xan
434        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
436    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
437        use Unicode properties. (*UCP) at the start of a pattern can be used to set
438        this option. Modified pcretest to add /W to test this facility. Added
439        REG_UCP to make it available via the POSIX interface.
441    10. Added --line-buffered to pcregrep.
443    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
444        studied, and the match started with a letter with a code point greater than
445        127 whose first byte was different to the first byte of the other case of
446        the letter, the other case of this starting letter was not recognized
447        (#976).
449    12. If a pattern that was studied started with a repeated Unicode property
450        test, for example, \p{Nd}+, there was the theoretical possibility of
451        setting up an incorrect bitmap of starting bytes, but fortunately it could
452        not have actually happened in practice until change 8 above was made (it
453        added property types that matched character-matching opcodes).
455    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
456        possible starting bytes for non-anchored patterns.
458    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
459        \R, and also a number of cases that involve Unicode properties, both
460        explicit and implicit when PCRE_UCP is set.
462    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
463        input, it could crash or give wrong results if characters with values
464        greater than 0xc0 were present in the subject string. (Detail: it assumed
465        UTF-8 input when processing these items.)
467    16. Added a lot of (int) casts to avoid compiler warnings in systems where
468        size_t is 64-bit (#991).
470    17. Added a check for running out of memory when PCRE is compiled with
471        --disable-stack-for-recursion (#990).
473    18. If the last data line in a file for pcretest does not have a newline on
474        the end, a newline was missing in the output.
476    19. The default pcre_chartables.c file recognizes only ASCII characters (values
477        less than 128) in its various bitmaps. However, there is a facility for
478        generating tables according to the current locale when PCRE is compiled. It
479        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
480        characters, are recognized by isspace() and therefore were getting set in
481        these tables, and indeed these tables seem to approximate to ISO 8859. This
482        caused a problem in UTF-8 mode when pcre_study() was used to create a list
483        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
484        which of course cannot start UTF-8 characters. I have changed the code so
485        that only real ASCII characters (less than 128) and the correct starting
486        bytes for UTF-8 encodings are set for characters greater than 127 when in
487        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
488        altogether.)
490    20. Added the /T option to pcretest so as to be able to run tests with non-
491        standard character tables, thus making it possible to include the tests
492        used for 19 above in the standard set of tests.
494    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
495        reference to a subpattern the other side of a comment that contains an
496        opening parenthesis caused either an internal compiling error, or a
497        reference to the wrong subpattern.
500  Version 8.02 19-Mar-2010  Version 8.02 19-Mar-2010
501  ------------------------  ------------------------

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