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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 7.9 xx-xxx-09  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 collection of tests with study enabled,
83        and thereby test pcre_study() more easily.
86    Version 8.12 15-Jan-2011
87    ------------------------
89    1.  Fixed some typos in the markup of the man pages, and wrote a script that
90        checks for such things as part of the documentation building process.
92    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
93        --match-limit and --recursion-limit options (added for 8.11). In
94        particular, this made one of the standard tests fail. (The integer value
95        went into the wrong half of a long int.)
97    3.  If the --colour option was given to pcregrep with -v (invert match), it
98        did strange things, either producing crazy output, or crashing. It should,
99        of course, ignore a request for colour when reporting lines that do not
100        match.
102    4.  Another pcregrep bug caused similar problems if --colour was specified with
103        -M (multiline) and the pattern match finished with a line ending.
105    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
106        matched in multiline mode, the following line was shown as part of the
107        match. This seems wrong, so I have changed it.
109    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
110        the check for further matches in the same line (so they could be coloured)
111        to overrun the end of the current line. If another match was found, it was
112        incorrectly shown (and then shown again when found in the next line).
114    7.  If pcregrep was compiled under Windows, there was a reference to the
115        function pcregrep_exit() before it was defined. I am assuming this was
116        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
117        reported by a user. I've moved the definition above the reference.
120    Version 8.11 10-Dec-2010
121    ------------------------
123    1.  (*THEN) was not working properly if there were untried alternatives prior
124        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
125        backtracked to try for "b" instead of moving to the next alternative branch
126        at the same level (in this case, to look for "c"). The Perl documentation
127        is clear that when (*THEN) is backtracked onto, it goes to the "next
128        alternative in the innermost enclosing group".
130    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
131        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
132        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
133        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
134        (*THEN).
136    3.  If \s appeared in a character class, it removed the VT character from
137        the class, even if it had been included by some previous item, for example
138        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
139        of \s, but is part of the POSIX "space" class.)
141    4.  A partial match never returns an empty string (because you can always
142        match an empty string at the end of the subject); however the checking for
143        an empty string was starting at the "start of match" point. This has been
144        changed to the "earliest inspected character" point, because the returned
145        data for a partial match starts at this character. This means that, for
146        example, /(?<=abc)def/ gives a partial match for the subject "abc"
147        (previously it gave "no match").
149    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
150        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
151        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
152        has an implication that the given string is incomplete (because a partial
153        match is preferred over a full match). For this reason, these items now
154        give a partial match in this situation. [Aside: previously, the one case
155        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
156        match rather than a full match, which was wrong by the old rules, but is
157        now correct.]
159    6.  There was a bug in the handling of #-introduced comments, recognized when
160        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
161        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
162        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
163        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
164        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
165        places in pcre_compile().
167    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
168        comments when looking ahead for named forward references to subpatterns,
169        the only newline sequence it recognized was NL. It now handles newlines
170        according to the set newline convention.
172    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
173        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
174        cater for a lack of strerror(). These oversights have been fixed.
176    9.  Added --match-limit and --recursion-limit to pcregrep.
178    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
180    11. When the -o option was used, pcregrep was setting a return code of 1, even
181        when matches were found, and --line-buffered was not being honoured.
183    12. Added an optional parentheses number to the -o and --only-matching options
184        of pcregrep.
186    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
187        can match an empty string. The code to do it in pcretest and pcredemo
188        needed fixing:
190        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
191            only one byte after an empty string match just before CRLF (this case
192            just got forgotten; "any" and "anycrlf" were OK).
194        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
195            mode when an empty string match preceded an ASCII character followed by
196            a non-ASCII character. (The code for advancing by one character rather
197            than one byte was nonsense.)
199        (c) The pcredemo.c sample program did not have any code at all to handle
200            the cases when CRLF is a valid newline sequence.
202    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
203        as a starting offset was within the subject string. There is now a new
204        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
205        negative or greater than the length of the string. In order to test this,
206        pcretest is extended to allow the setting of negative starting offsets.
208    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
209        starting offset points to the beginning of a UTF-8 character was
210        unnecessarily clumsy. I tidied it up.
212    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
213        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
215    17. Nobody had reported that the --include_dir option, which was added in
216        release 7.7 should have been called --include-dir (hyphen, not underscore)
217        for compatibility with GNU grep. I have changed it to --include-dir, but
218        left --include_dir as an undocumented synonym, and the same for
219        --exclude-dir, though that is not available in GNU grep, at least as of
220        release 2.5.4.
222    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
223        characters from a string of bytes) have been redefined so as not to use
224        loops, in order to improve performance in some environments. At the same
225        time, I abstracted some of the common code into auxiliary macros to save
226        repetition (this should not affect the compiled code).
228    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
229        compile-time error is now given if \c is not followed by an ASCII
230        character, that is, a byte less than 128. (In EBCDIC mode, the code is
231        different, and any byte value is allowed.)
233    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
234        START_OPTIMIZE option, which is now allowed at compile time - but just
235        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
236        to pcregrep and other applications that have no direct access to PCRE
237        options. The new /Y option in pcretest sets this option when calling
238        pcre_compile().
240    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
241        back references. Groups containing recursive back references were forced to
242        be atomic by that change, but in the case of named groups, the amount of
243        memory required was incorrectly computed, leading to "Failed: internal
244        error: code overflow". This has been fixed.
246    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
247        pcretest.c, to avoid build problems in some Borland environments.
250    Version 8.10 25-Jun-2010
251    ------------------------
253    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
254        THEN.
256    2.  (*ACCEPT) was not working when inside an atomic group.
258    3.  Inside a character class, \B is treated as a literal by default, but
259        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
260        causes the error). The code is unchanged, but I tidied the documentation.
262    4.  Inside a character class, PCRE always treated \R and \X as literals,
263        whereas Perl faults them if its -w option is set. I have changed PCRE so
264        that it faults them when PCRE_EXTRA is set.
266    5.  Added support for \N, which always matches any character other than
267        newline. (It is the same as "." when PCRE_DOTALL is not set.)
269    6.  When compiling pcregrep with newer versions of gcc which may have
270        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
271        declared with attribute warn_unused_result" were given. Just casting the
272        result to (void) does not stop the warnings; a more elaborate fudge is
273        needed. I've used a macro to implement this.
275    7.  Minor change to pcretest.c to avoid a compiler warning.
277    8.  Added four artifical Unicode properties to help with an option to make
278        \s etc use properties (see next item). The new properties are: Xan
279        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
281    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
282        use Unicode properties. (*UCP) at the start of a pattern can be used to set
283        this option. Modified pcretest to add /W to test this facility. Added
284        REG_UCP to make it available via the POSIX interface.
286    10. Added --line-buffered to pcregrep.
288    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
289        studied, and the match started with a letter with a code point greater than
290        127 whose first byte was different to the first byte of the other case of
291        the letter, the other case of this starting letter was not recognized
292        (#976).
294    12. If a pattern that was studied started with a repeated Unicode property
295        test, for example, \p{Nd}+, there was the theoretical possibility of
296        setting up an incorrect bitmap of starting bytes, but fortunately it could
297        not have actually happened in practice until change 8 above was made (it
298        added property types that matched character-matching opcodes).
300    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
301        possible starting bytes for non-anchored patterns.
303    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
304        \R, and also a number of cases that involve Unicode properties, both
305        explicit and implicit when PCRE_UCP is set.
307    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
308        input, it could crash or give wrong results if characters with values
309        greater than 0xc0 were present in the subject string. (Detail: it assumed
310        UTF-8 input when processing these items.)
312    16. Added a lot of (int) casts to avoid compiler warnings in systems where
313        size_t is 64-bit (#991).
315    17. Added a check for running out of memory when PCRE is compiled with
316        --disable-stack-for-recursion (#990).
318    18. If the last data line in a file for pcretest does not have a newline on
319        the end, a newline was missing in the output.
321    19. The default pcre_chartables.c file recognizes only ASCII characters (values
322        less than 128) in its various bitmaps. However, there is a facility for
323        generating tables according to the current locale when PCRE is compiled. It
324        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
325        characters, are recognized by isspace() and therefore were getting set in
326        these tables, and indeed these tables seem to approximate to ISO 8859. This
327        caused a problem in UTF-8 mode when pcre_study() was used to create a list
328        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
329        which of course cannot start UTF-8 characters. I have changed the code so
330        that only real ASCII characters (less than 128) and the correct starting
331        bytes for UTF-8 encodings are set for characters greater than 127 when in
332        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
333        altogether.)
335    20. Added the /T option to pcretest so as to be able to run tests with non-
336        standard character tables, thus making it possible to include the tests
337        used for 19 above in the standard set of tests.
339    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
340        reference to a subpattern the other side of a comment that contains an
341        opening parenthesis caused either an internal compiling error, or a
342        reference to the wrong subpattern.
345    Version 8.02 19-Mar-2010
346    ------------------------
348    1.  The Unicode data tables have been updated to Unicode 5.2.0.
350    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
351        configured.
353    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
354        original author of that file, following a query about its status.
356    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
357        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
359    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
360        quantifier applied to a forward-referencing subroutine call, could compile
361        incorrect code or give the error "internal error: previously-checked
362        referenced subpattern not found".
364    6.  Both MS Visual Studio and Symbian OS have problems with initializing
365        variables to point to external functions. For these systems, therefore,
366        pcre_malloc etc. are now initialized to local functions that call the
367        relevant global functions.
369    7.  There were two entries missing in the vectors called coptable and poptable
370        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
371        I've fixed the data, and added a kludgy way of testing at compile time that
372        the lengths are correct (equal to the number of opcodes).
374    8.  Following on from 7, I added a similar kludge to check the length of the
375        eint vector in pcreposix.c.
377    9.  Error texts for pcre_compile() are held as one long string to avoid too
378        much relocation at load time. To find a text, the string is searched,
379        counting zeros. There was no check for running off the end of the string,
380        which could happen if a new error number was added without updating the
381        string.
383    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
385    11. \K was not working if it appeared in an atomic group or in a group that
386        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
387        \K is "not well defined" if used in an assertion. PCRE now accepts it if
388        the assertion is positive, but not if it is negative.
390    12. Change 11 fortuitously reduced the size of the stack frame used in the
391        "match()" function of pcre_exec.c by one pointer. Forthcoming
392        implementation of support for (*MARK) will need an extra pointer on the
393        stack; I have reserved it now, so that the stack frame size does not
394        decrease.
396    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
397        item in branch that calls a recursion is a subroutine call - as in the
398        second branch in the above example - was incorrectly given the compile-
399        time error "recursive call could loop indefinitely" because pcre_compile()
400        was not correctly checking the subroutine for matching a non-empty string.
402    14. The checks for overrunning compiling workspace could trigger after an
403        overrun had occurred. This is a "should never occur" error, but it can be
404        triggered by pathological patterns such as hundreds of nested parentheses.
405        The checks now trigger 100 bytes before the end of the workspace.
407    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
410    Version 8.01 19-Jan-2010
411    ------------------------
413    1.  If a pattern contained a conditional subpattern with only one branch (in
414        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
415        computed the wrong minimum data length (which is of course zero for such
416        subpatterns). This could cause incorrect "no match" results.
418    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
419        the pattern is reset in the first branch, pcre_compile() failed with
420        "internal error: code overflow at offset...". This happened only when
421        the reset was to the original external option setting. (An optimization
422        abstracts leading options settings into an external setting, which was the
423        cause of this.)
425    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
426        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
427        assertion pattern did not match (meaning that the assertion was true), it
428        was incorrectly treated as false if the SKIP had been reached during the
429        matching. This also applied to assertions used as conditions.
431    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
432        assertion subpattern, including such a pattern used as a condition,
433        unpredictable results occurred, instead of the error return
436    5.  The C++ GlobalReplace function was not working like Perl for the special
437        situation when an empty string is matched. It now does the fancy magic
438        stuff that is necessary.
440    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
441        removed. (These were left over from very, very early versions of PCRE.)
443    7.  Some cosmetic changes to the code to make life easier when compiling it
444        as part of something else:
446        (a) Change DEBUG to PCRE_DEBUG.
448        (b) In pcre_compile(), rename the member of the "branch_chain" structure
449            called "current" as "current_branch", to prevent a collision with the
450            Linux macro when compiled as a kernel module.
452        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
453            prevent a collision with the Linux macro when compiled as a kernel
454            module.
456    8.  In pcre_compile() there are some checks for integer overflows that used to
457        cast potentially large values to (double). This has been changed to that
458        when building, a check for int64_t is made, and if it is found, it is used
459        instead, thus avoiding the use of floating point arithmetic. (There is no
460        other use of FP in PCRE.) If int64_t is not found, the fallback is to
461        double.
463    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
464        2005 (difference between two addresses compared to an unsigned value).
466    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
467        custom one, because of the following reported problem in Windows:
469          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
470              under Win32.
471          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
472              therefore missing the function definition.
473          - The compiler thus generates a "C" signature for the test function.
474          - The linker fails to find the "C" function.
475          - PCRE fails to configure if asked to do so against libbz2.
477    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
478        messages were output:
480          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
481          rerunning libtoolize, to keep the correct libtool macros in-tree.
482          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
484        I have done both of these things.
486    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
487        most of the time, it *can* run out if it is given a pattern that contains a
488        runaway infinite recursion. I updated the discussion in the pcrestack man
489        page.
491    13. Now that we have gone to the x.xx style of version numbers, the minor
492        version may start with zero. Using 08 or 09 is a bad idea because users
493        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
494        interpreted as invalid octal numbers. I've updated the previous comment in
495        configure.ac, and also added a check that gives an error if 08 or 09 are
496        used.
498    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
499        causing partial matching to fail when the end of the subject matched \W
500        in a UTF-8 pattern where \W was quantified with a minimum of 3.
502    15. There were some discrepancies between the declarations in pcre_internal.h
503        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
504        their definitions. The declarations used "const uschar *" and the
505        definitions used USPTR. Even though USPTR is normally defined as "const
506        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
507        reported that: "This difference in casting confuses some C++ compilers, for
508        example, SunCC recognizes above declarations as different functions and
509        generates broken code for hbpcre." I have changed the declarations to use
510        USPTR.
512    16. GNU libtool is named differently on some systems. The autogen.sh script now
513        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
514        (FreeBSD).
516    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
517        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
518        comment: "Figure out how to create a longlong from a string: strtoll and
519        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
520        instance, but it only takes 2 args instead of 3!"
522    18. A subtle bug concerned with back references has been fixed by a change of
523        specification, with a corresponding code fix. A pattern such as
524        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
525        refers, was giving matches when it shouldn't. For example, xa=xaaa would
526        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
527        same bug. Such groups have to be quantified to be useful, or contained
528        inside another quantified group. (If there's no repetition, the reference
529        can never match.) The problem arises because, having left the group and
530        moved on to the rest of the pattern, a later failure that backtracks into
531        the group uses the captured value from the final iteration of the group
532        rather than the correct earlier one. I have fixed this in PCRE by forcing
533        any group that contains a reference to itself to be an atomic group; that
534        is, there cannot be any backtracking into it once it has completed. This is
535        similar to recursive and subroutine calls.
538    Version 8.00 19-Oct-09
539    ----------------------
541    1.  The table for translating pcre_compile() error codes into POSIX error codes
542        was out-of-date, and there was no check on the pcre_compile() error code
543        being within the table. This could lead to an OK return being given in
544        error.
546    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
547        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
548        in a Windows environment.
550    3.  The pcregrep --count option prints the count for each file even when it is
551        zero, as does GNU grep. However, pcregrep was also printing all files when
552        --files-with-matches was added. Now, when both options are given, it prints
553        counts only for those files that have at least one match. (GNU grep just
554        prints the file name in this circumstance, but including the count seems
555        more useful - otherwise, why use --count?) Also ensured that the
556        combination -clh just lists non-zero counts, with no names.
558    4.  The long form of the pcregrep -F option was incorrectly implemented as
559        --fixed_strings instead of --fixed-strings. This is an incompatible change,
560        but it seems right to fix it, and I didn't think it was worth preserving
561        the old behaviour.
563    5.  The command line items --regex=pattern and --regexp=pattern were not
564        recognized by pcregrep, which required --regex pattern or --regexp pattern
565        (with a space rather than an '='). The man page documented the '=' forms,
566        which are compatible with GNU grep; these now work.
568    6.  No libpcreposix.pc file was created for pkg-config; there was just
569        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
571    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
572        when UCP support is not needed, by modifying the Python script that
573        generates it from Unicode data files. This should not matter if the module
574        is correctly used as a library, but I received one complaint about 50K of
575        unwanted data. My guess is that the person linked everything into his
576        program rather than using a library. Anyway, it does no harm.
578    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
579        was a minimum greater than 1 for a wide character in a possessive
580        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
581        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
582        character. Chaos in the form of incorrect output or a compiling loop could
583        result.
585    9.  The restrictions on what a pattern can contain when partial matching is
586        requested for pcre_exec() have been removed. All patterns can now be
587        partially matched by this function. In addition, if there are at least two
588        slots in the offset vector, the offset of the earliest inspected character
589        for the match and the offset of the end of the subject are set in them when
590        PCRE_ERROR_PARTIAL is returned.
592    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
593        synonymous with PCRE_PARTIAL, for backwards compatibility, and
594        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
595        and may be more useful for multi-segment matching.
597    11. Partial matching with pcre_exec() is now more intuitive. A partial match
598        used to be given if ever the end of the subject was reached; now it is
599        given only if matching could not proceed because another character was
600        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
601        string "Z", which now yields "no match" instead of "partial match". In the
602        case of pcre_dfa_exec(), "no match" is given if every matching path for the
603        final character ended with (*FAIL).
605    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
606        if the pattern had a "must contain" character that was already found in the
607        earlier partial match, unless partial matching was again requested. For
608        example, with the pattern /dog.(body)?/, the "must contain" character is
609        "g". If the first part-match was for the string "dog", restarting with
610        "sbody" failed. This bug has been fixed.
612    13. The string returned by pcre_dfa_exec() after a partial match has been
613        changed so that it starts at the first inspected character rather than the
614        first character of the match. This makes a difference only if the pattern
615        starts with a lookbehind assertion or \b or \B (\K is not supported by
616        pcre_dfa_exec()). It's an incompatible change, but it makes the two
617        matching functions compatible, and I think it's the right thing to do.
619    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
620        so that the demonstration program is easily available in environments where
621        PCRE has not been installed from source.
623    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
624        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
625        library.
627    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
628        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
629        is not the first non-POSIX option to be added. Clearly some people find
630        these options useful.
632    17. If a caller to the POSIX matching function regexec() passes a non-zero
633        value for nmatch with a NULL value for pmatch, the value of
634        nmatch is forced to zero.
636    18. RunGrepTest did not have a test for the availability of the -u option of
637        the diff command, as RunTest does. It now checks in the same way as
638        RunTest, and also checks for the -b option.
640    19. If an odd number of negated classes containing just a single character
641        interposed, within parentheses, between a forward reference to a named
642        subpattern and the definition of the subpattern, compilation crashed with
643        an internal error, complaining that it could not find the referenced
644        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
645        [The bug was that it was starting one character too far in when skipping
646        over the character class, thus treating the ] as data rather than
647        terminating the class. This meant it could skip too much.]
649    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
650        /g option in pcretest when the pattern contains \K, which makes it possible
651        to have an empty string match not at the start, even when the pattern is
652        anchored. Updated pcretest and pcredemo to use this option.
654    21. If the maximum number of capturing subpatterns in a recursion was greater
655        than the maximum at the outer level, the higher number was returned, but
656        with unset values at the outer level. The correct (outer level) value is
657        now given.
659    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
660        PCRE did not set those parentheses (unlike Perl). I have now found a way to
661        make it do so. The string so far is captured, making this feature
662        compatible with Perl.
664    23. The tests have been re-organized, adding tests 11 and 12, to make it
665        possible to check the Perl 5.10 features against Perl 5.10.
667    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
668        pattern matches a fixed length string. PCRE did not allow this; now it
669        does. Neither allows recursion.
671    25. I finally figured out how to implement a request to provide the minimum
672        length of subject string that was needed in order to match a given pattern.
673        (It was back references and recursion that I had previously got hung up
674        on.) This code has now been added to pcre_study(); it finds a lower bound
675        to the length of subject needed. It is not necessarily the greatest lower
676        bound, but using it to avoid searching strings that are too short does give
677        some useful speed-ups. The value is available to calling programs via
678        pcre_fullinfo().
680    26. While implementing 25, I discovered to my embarrassment that pcretest had
681        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
682        study optimizations had never been tested with that matching function.
683        Oops. What is worse, even when it was passed study data, there was a bug in
684        pcre_dfa_exec() that meant it never actually used it. Double oops. There
685        were also very few tests of studied patterns with pcre_dfa_exec().
687    27. If (?| is used to create subpatterns with duplicate numbers, they are now
688        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
689        on the other side of the coin, they are no longer allowed to have different
690        names, because these cannot be distinguished in PCRE, and this has caused
691        confusion. (This is a difference from Perl.)
693    28. When duplicate subpattern names are present (necessarily with different
694        numbers, as required by 27 above), and a test is made by name in a
695        conditional pattern, either for a subpattern having been matched, or for
696        recursion in such a pattern, all the associated numbered subpatterns are
697        tested, and the overall condition is true if the condition is true for any
698        one of them. This is the way Perl works, and is also more like the way
699        testing by number works.
702    Version 7.9 11-Apr-09
703  ---------------------  ---------------------
705  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 17  Version 7.9 xx-xxx-09 Line 715  Version 7.9 xx-xxx-09
715      but BOOL is not.      but BOOL is not.
717  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
718      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
720  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
721      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 42  Version 7.9 xx-xxx-09 Line 740  Version 7.9 xx-xxx-09
740      correctly handled. The rule now is that both the assertion and what follows      correctly handled. The rule now is that both the assertion and what follows
741      in the first alternative must satisfy the test.      in the first alternative must satisfy the test.
743  9.  If auto-callout was enabled in a pattern with a conditional group whose  9.  If auto-callout was enabled in a pattern with a conditional group whose
744      condition was an assertion, PCRE could crash during matching, both with      condition was an assertion, PCRE could crash during matching, both with
745      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
# Line 64  Version 7.9 xx-xxx-09 Line 762  Version 7.9 xx-xxx-09
762  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
763      from Martin Jerabek that uses macro names for all relevant character and      from Martin Jerabek that uses macro names for all relevant character and
764      string constants.      string constants.
766  18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and  18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
767      SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without      SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
768      SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of      SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
769      these, but not everybody uses configure.      these, but not everybody uses configure.
771  19. A conditional group that had only one branch was not being correctly  19. A conditional group that had only one branch was not being correctly
772      recognized as an item that could match an empty string. This meant that an      recognized as an item that could match an empty string. This meant that an
773      enclosing group might also not be so recognized, causing infinite looping      enclosing group might also not be so recognized, causing infinite looping
774      (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$      (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
775      with the subject "ab", where knowledge that the repeated group can match      with the subject "ab", where knowledge that the repeated group can match
776      nothing is needed in order to break the loop.      nothing is needed in order to break the loop.
778  20. If a pattern that was compiled with callouts was matched using pcre_dfa_  20. If a pattern that was compiled with callouts was matched using pcre_dfa_
779      exec(), but without supplying a callout function, matching went wrong.      exec(), but without supplying a callout function, matching went wrong.
781  21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory  21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
782      leak if the size of the offset vector was greater than 30. When the vector      leak if the size of the offset vector was greater than 30. When the vector
783      is smaller, the saved offsets during recursion go onto a local stack      is smaller, the saved offsets during recursion go onto a local stack
784      vector, but for larger vectors malloc() is used. It was failing to free      vector, but for larger vectors malloc() is used. It was failing to free
785      when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"      when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
786      error, in fact).      error, in fact).
788  22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the  22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
789      heapframe that is used only when UTF-8 support is enabled. This caused no      heapframe that is used only when UTF-8 support is enabled. This caused no
790      problem, but was untidy.      problem, but was untidy.
792    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
793        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
794        included within another project.
796    24. Steven Van Ingelgem's patches to add more options to the CMake support,
797        slightly modified by me:
799          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
800              not building pcregrep.
802          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
803              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
805    25. Forward references, both numeric and by name, in patterns that made use of
806        duplicate group numbers, could behave incorrectly or give incorrect errors,
807        because when scanning forward to find the reference group, PCRE was not
808        taking into account the duplicate group numbers. A pattern such as
809        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
811    26. Changed a few more instances of "const unsigned char *" to USPTR, making
812        the feature of a custom pointer more persuasive (as requested by a user).
814    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
815        pcretest.c, inside #ifndefs, because it seems they are sometimes already
816        pre-defined.
818    28. Added support for (*UTF8) at the start of a pattern.
820    29. Arrange for flags added by the "release type" setting in CMake to be shown
821        in the configuration summary.
824  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08

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