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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.00 ??-???-??  Version 8.12 12-Jan-2011
5    ------------------------
6    
7    1.  Fixed some typos in the markup of the man pages, and wrote a script that
8        checks for such things as part of the documentation building process.
9    
10    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
11        --match-limit and --recursion-limit options (added for 8.11). In
12        particular, this made one of the standard tests crash. (The integer value
13        went into the wrong half of a long int.)
14    
15    
16    Version 8.11 10-Dec-2010
17    ------------------------
18    
19    1.  (*THEN) was not working properly if there were untried alternatives prior
20        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
21        backtracked to try for "b" instead of moving to the next alternative branch
22        at the same level (in this case, to look for "c"). The Perl documentation
23        is clear that when (*THEN) is backtracked onto, it goes to the "next
24        alternative in the innermost enclosing group".
25    
26    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
27        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
28        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
29        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
30        (*THEN).
31    
32    3.  If \s appeared in a character class, it removed the VT character from
33        the class, even if it had been included by some previous item, for example
34        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
35        of \s, but is part of the POSIX "space" class.)
36    
37    4.  A partial match never returns an empty string (because you can always
38        match an empty string at the end of the subject); however the checking for
39        an empty string was starting at the "start of match" point. This has been
40        changed to the "earliest inspected character" point, because the returned
41        data for a partial match starts at this character. This means that, for
42        example, /(?<=abc)def/ gives a partial match for the subject "abc"
43        (previously it gave "no match").
44    
45    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
46        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
47        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
48        has an implication that the given string is incomplete (because a partial
49        match is preferred over a full match). For this reason, these items now
50        give a partial match in this situation. [Aside: previously, the one case
51        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
52        match rather than a full match, which was wrong by the old rules, but is
53        now correct.]
54    
55    6.  There was a bug in the handling of #-introduced comments, recognized when
56        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
57        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
58        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
59        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
60        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
61        places in pcre_compile().
62    
63    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
64        comments when looking ahead for named forward references to subpatterns,
65        the only newline sequence it recognized was NL. It now handles newlines
66        according to the set newline convention.
67    
68    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
69        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
70        cater for a lack of strerror(). These oversights have been fixed.
71    
72    9.  Added --match-limit and --recursion-limit to pcregrep.
73    
74    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
75    
76    11. When the -o option was used, pcregrep was setting a return code of 1, even
77        when matches were found, and --line-buffered was not being honoured.
78    
79    12. Added an optional parentheses number to the -o and --only-matching options
80        of pcregrep.
81    
82    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
83        can match an empty string. The code to do it in pcretest and pcredemo
84        needed fixing:
85    
86        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
87            only one byte after an empty string match just before CRLF (this case
88            just got forgotten; "any" and "anycrlf" were OK).
89    
90        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
91            mode when an empty string match preceded an ASCII character followed by
92            a non-ASCII character. (The code for advancing by one character rather
93            than one byte was nonsense.)
94    
95        (c) The pcredemo.c sample program did not have any code at all to handle
96            the cases when CRLF is a valid newline sequence.
97    
98    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
99        as a starting offset was within the subject string. There is now a new
100        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
101        negative or greater than the length of the string. In order to test this,
102        pcretest is extended to allow the setting of negative starting offsets.
103    
104    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
105        starting offset points to the beginning of a UTF-8 character was
106        unnecessarily clumsy. I tidied it up.
107    
108    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
109        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
110    
111    17. Nobody had reported that the --include_dir option, which was added in
112        release 7.7 should have been called --include-dir (hyphen, not underscore)
113        for compatibility with GNU grep. I have changed it to --include-dir, but
114        left --include_dir as an undocumented synonym, and the same for
115        --exclude-dir, though that is not available in GNU grep, at least as of
116        release 2.5.4.
117    
118    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
119        characters from a string of bytes) have been redefined so as not to use
120        loops, in order to improve performance in some environments. At the same
121        time, I abstracted some of the common code into auxiliary macros to save
122        repetition (this should not affect the compiled code).
123    
124    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
125        compile-time error is now given if \c is not followed by an ASCII
126        character, that is, a byte less than 128. (In EBCDIC mode, the code is
127        different, and any byte value is allowed.)
128    
129    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
130        START_OPTIMIZE option, which is now allowed at compile time - but just
131        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
132        to pcregrep and other applications that have no direct access to PCRE
133        options. The new /Y option in pcretest sets this option when calling
134        pcre_compile().
135    
136    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
137        back references. Groups containing recursive back references were forced to
138        be atomic by that change, but in the case of named groups, the amount of
139        memory required was incorrectly computed, leading to "Failed: internal
140        error: code overflow". This has been fixed.
141    
142    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
143        pcretest.c, to avoid build problems in some Borland environments.
144    
145    
146    Version 8.10 25-Jun-2010
147    ------------------------
148    
149    1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
150        THEN.
151    
152    2.  (*ACCEPT) was not working when inside an atomic group.
153    
154    3.  Inside a character class, \B is treated as a literal by default, but
155        faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
156        causes the error). The code is unchanged, but I tidied the documentation.
157    
158    4.  Inside a character class, PCRE always treated \R and \X as literals,
159        whereas Perl faults them if its -w option is set. I have changed PCRE so
160        that it faults them when PCRE_EXTRA is set.
161    
162    5.  Added support for \N, which always matches any character other than
163        newline. (It is the same as "." when PCRE_DOTALL is not set.)
164    
165    6.  When compiling pcregrep with newer versions of gcc which may have
166        FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
167        declared with attribute warn_unused_result" were given. Just casting the
168        result to (void) does not stop the warnings; a more elaborate fudge is
169        needed. I've used a macro to implement this.
170    
171    7.  Minor change to pcretest.c to avoid a compiler warning.
172    
173    8.  Added four artifical Unicode properties to help with an option to make
174        \s etc use properties (see next item). The new properties are: Xan
175        (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
176    
177    9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
178        use Unicode properties. (*UCP) at the start of a pattern can be used to set
179        this option. Modified pcretest to add /W to test this facility. Added
180        REG_UCP to make it available via the POSIX interface.
181    
182    10. Added --line-buffered to pcregrep.
183    
184    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
185        studied, and the match started with a letter with a code point greater than
186        127 whose first byte was different to the first byte of the other case of
187        the letter, the other case of this starting letter was not recognized
188        (#976).
189    
190    12. If a pattern that was studied started with a repeated Unicode property
191        test, for example, \p{Nd}+, there was the theoretical possibility of
192        setting up an incorrect bitmap of starting bytes, but fortunately it could
193        not have actually happened in practice until change 8 above was made (it
194        added property types that matched character-matching opcodes).
195    
196    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
197        possible starting bytes for non-anchored patterns.
198    
199    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
200        \R, and also a number of cases that involve Unicode properties, both
201        explicit and implicit when PCRE_UCP is set.
202    
203    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
204        input, it could crash or give wrong results if characters with values
205        greater than 0xc0 were present in the subject string. (Detail: it assumed
206        UTF-8 input when processing these items.)
207    
208    16. Added a lot of (int) casts to avoid compiler warnings in systems where
209        size_t is 64-bit (#991).
210    
211    17. Added a check for running out of memory when PCRE is compiled with
212        --disable-stack-for-recursion (#990).
213    
214    18. If the last data line in a file for pcretest does not have a newline on
215        the end, a newline was missing in the output.
216    
217    19. The default pcre_chartables.c file recognizes only ASCII characters (values
218        less than 128) in its various bitmaps. However, there is a facility for
219        generating tables according to the current locale when PCRE is compiled. It
220        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
221        characters, are recognized by isspace() and therefore were getting set in
222        these tables, and indeed these tables seem to approximate to ISO 8859. This
223        caused a problem in UTF-8 mode when pcre_study() was used to create a list
224        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
225        which of course cannot start UTF-8 characters. I have changed the code so
226        that only real ASCII characters (less than 128) and the correct starting
227        bytes for UTF-8 encodings are set for characters greater than 127 when in
228        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
229        altogether.)
230    
231    20. Added the /T option to pcretest so as to be able to run tests with non-
232        standard character tables, thus making it possible to include the tests
233        used for 19 above in the standard set of tests.
234    
235    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
236        reference to a subpattern the other side of a comment that contains an
237        opening parenthesis caused either an internal compiling error, or a
238        reference to the wrong subpattern.
239    
240    
241    Version 8.02 19-Mar-2010
242    ------------------------
243    
244    1.  The Unicode data tables have been updated to Unicode 5.2.0.
245    
246    2.  Added the option --libs-cpp to pcre-config, but only when C++ support is
247        configured.
248    
249    3.  Updated the licensing terms in the pcregexp.pas file, as agreed with the
250        original author of that file, following a query about its status.
251    
252    4.  On systems that do not have stdint.h (e.g. Solaris), check for and include
253        inttypes.h instead. This fixes a bug that was introduced by change 8.01/8.
254    
255    5.  A pattern such as (?&t)*+(?(DEFINE)(?<t>.)) which has a possessive
256        quantifier applied to a forward-referencing subroutine call, could compile
257        incorrect code or give the error "internal error: previously-checked
258        referenced subpattern not found".
259    
260    6.  Both MS Visual Studio and Symbian OS have problems with initializing
261        variables to point to external functions. For these systems, therefore,
262        pcre_malloc etc. are now initialized to local functions that call the
263        relevant global functions.
264    
265    7.  There were two entries missing in the vectors called coptable and poptable
266        in pcre_dfa_exec.c. This could lead to memory accesses outsize the vectors.
267        I've fixed the data, and added a kludgy way of testing at compile time that
268        the lengths are correct (equal to the number of opcodes).
269    
270    8.  Following on from 7, I added a similar kludge to check the length of the
271        eint vector in pcreposix.c.
272    
273    9.  Error texts for pcre_compile() are held as one long string to avoid too
274        much relocation at load time. To find a text, the string is searched,
275        counting zeros. There was no check for running off the end of the string,
276        which could happen if a new error number was added without updating the
277        string.
278    
279    10. \K gave a compile-time error if it appeared in a lookbehind assersion.
280    
281    11. \K was not working if it appeared in an atomic group or in a group that
282        was called as a "subroutine", or in an assertion. Perl 5.11 documents that
283        \K is "not well defined" if used in an assertion. PCRE now accepts it if
284        the assertion is positive, but not if it is negative.
285    
286    12. Change 11 fortuitously reduced the size of the stack frame used in the
287        "match()" function of pcre_exec.c by one pointer. Forthcoming
288        implementation of support for (*MARK) will need an extra pointer on the
289        stack; I have reserved it now, so that the stack frame size does not
290        decrease.
291    
292    13. A pattern such as (?P<L1>(?P<L2>0)|(?P>L2)(?P>L1)) in which the only other
293        item in branch that calls a recursion is a subroutine call - as in the
294        second branch in the above example - was incorrectly given the compile-
295        time error "recursive call could loop indefinitely" because pcre_compile()
296        was not correctly checking the subroutine for matching a non-empty string.
297    
298    14. The checks for overrunning compiling workspace could trigger after an
299        overrun had occurred. This is a "should never occur" error, but it can be
300        triggered by pathological patterns such as hundreds of nested parentheses.
301        The checks now trigger 100 bytes before the end of the workspace.
302    
303    15. Fix typo in configure.ac: "srtoq" should be "strtoq".
304    
305    
306    Version 8.01 19-Jan-2010
307    ------------------------
308    
309    1.  If a pattern contained a conditional subpattern with only one branch (in
310        particular, this includes all (*DEFINE) patterns), a call to pcre_study()
311        computed the wrong minimum data length (which is of course zero for such
312        subpatterns). This could cause incorrect "no match" results.
313    
314    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
315        the pattern is reset in the first branch, pcre_compile() failed with
316        "internal error: code overflow at offset...". This happened only when
317        the reset was to the original external option setting. (An optimization
318        abstracts leading options settings into an external setting, which was the
319        cause of this.)
320    
321    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
322        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
323        assertion pattern did not match (meaning that the assertion was true), it
324        was incorrectly treated as false if the SKIP had been reached during the
325        matching. This also applied to assertions used as conditions.
326    
327    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
328        assertion subpattern, including such a pattern used as a condition,
329        unpredictable results occurred, instead of the error return
330        PCRE_ERROR_DFA_UITEM.
331    
332    5.  The C++ GlobalReplace function was not working like Perl for the special
333        situation when an empty string is matched. It now does the fancy magic
334        stuff that is necessary.
335    
336    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
337        removed. (These were left over from very, very early versions of PCRE.)
338    
339    7.  Some cosmetic changes to the code to make life easier when compiling it
340        as part of something else:
341    
342        (a) Change DEBUG to PCRE_DEBUG.
343    
344        (b) In pcre_compile(), rename the member of the "branch_chain" structure
345            called "current" as "current_branch", to prevent a collision with the
346            Linux macro when compiled as a kernel module.
347    
348        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
349            prevent a collision with the Linux macro when compiled as a kernel
350            module.
351    
352    8.  In pcre_compile() there are some checks for integer overflows that used to
353        cast potentially large values to (double). This has been changed to that
354        when building, a check for int64_t is made, and if it is found, it is used
355        instead, thus avoiding the use of floating point arithmetic. (There is no
356        other use of FP in PCRE.) If int64_t is not found, the fallback is to
357        double.
358    
359    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
360        2005 (difference between two addresses compared to an unsigned value).
361    
362    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
363        custom one, because of the following reported problem in Windows:
364    
365          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
366              under Win32.
367          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
368              therefore missing the function definition.
369          - The compiler thus generates a "C" signature for the test function.
370          - The linker fails to find the "C" function.
371          - PCRE fails to configure if asked to do so against libbz2.
372    
373    11. When running libtoolize from libtool-2.2.6b as part of autogen.sh, these
374        messages were output:
375    
376          Consider adding `AC_CONFIG_MACRO_DIR([m4])' to configure.ac and
377          rerunning libtoolize, to keep the correct libtool macros in-tree.
378          Consider adding `-I m4' to ACLOCAL_AMFLAGS in Makefile.am.
379    
380        I have done both of these things.
381    
382    12. Although pcre_dfa_exec() does not use nearly as much stack as pcre_exec()
383        most of the time, it *can* run out if it is given a pattern that contains a
384        runaway infinite recursion. I updated the discussion in the pcrestack man
385        page.
386    
387    13. Now that we have gone to the x.xx style of version numbers, the minor
388        version may start with zero. Using 08 or 09 is a bad idea because users
389        might check the value of PCRE_MINOR in their code, and 08 or 09 may be
390        interpreted as invalid octal numbers. I've updated the previous comment in
391        configure.ac, and also added a check that gives an error if 08 or 09 are
392        used.
393    
394    14. Change 8.00/11 was not quite complete: code had been accidentally omitted,
395        causing partial matching to fail when the end of the subject matched \W
396        in a UTF-8 pattern where \W was quantified with a minimum of 3.
397    
398    15. There were some discrepancies between the declarations in pcre_internal.h
399        of _pcre_is_newline(), _pcre_was_newline(), and _pcre_valid_utf8() and
400        their definitions. The declarations used "const uschar *" and the
401        definitions used USPTR. Even though USPTR is normally defined as "const
402        unsigned char *" (and uschar is typedeffed as "unsigned char"), it was
403        reported that: "This difference in casting confuses some C++ compilers, for
404        example, SunCC recognizes above declarations as different functions and
405        generates broken code for hbpcre." I have changed the declarations to use
406        USPTR.
407    
408    16. GNU libtool is named differently on some systems. The autogen.sh script now
409        tries several variants such as glibtoolize (MacOSX) and libtoolize1x
410        (FreeBSD).
411    
412    17. Applied Craig's patch that fixes an HP aCC compile error in pcre 8.00
413        (strtoXX undefined when compiling pcrecpp.cc). The patch contains this
414        comment: "Figure out how to create a longlong from a string: strtoll and
415        equivalent. It's not enough to call AC_CHECK_FUNCS: hpux has a strtoll, for
416        instance, but it only takes 2 args instead of 3!"
417    
418    18. A subtle bug concerned with back references has been fixed by a change of
419        specification, with a corresponding code fix. A pattern such as
420        ^(xa|=?\1a)+$ which contains a back reference inside the group to which it
421        refers, was giving matches when it shouldn't. For example, xa=xaaa would
422        match that pattern. Interestingly, Perl (at least up to 5.11.3) has the
423        same bug. Such groups have to be quantified to be useful, or contained
424        inside another quantified group. (If there's no repetition, the reference
425        can never match.) The problem arises because, having left the group and
426        moved on to the rest of the pattern, a later failure that backtracks into
427        the group uses the captured value from the final iteration of the group
428        rather than the correct earlier one. I have fixed this in PCRE by forcing
429        any group that contains a reference to itself to be an atomic group; that
430        is, there cannot be any backtracking into it once it has completed. This is
431        similar to recursive and subroutine calls.
432    
433    
434    Version 8.00 19-Oct-09
435  ----------------------  ----------------------
436    
437  1.  The table for translating pcre_compile() error codes into POSIX error codes  1.  The table for translating pcre_compile() error codes into POSIX error codes
438      was out-of-date, and there was no check on the pcre_compile() error code      was out-of-date, and there was no check on the pcre_compile() error code
439      being within the table. This could lead to an OK return being given in      being within the table. This could lead to an OK return being given in
440      error.      error.
441    
442  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,  2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
443      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests      "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
444      in a Windows environment.      in a Windows environment.
445    
446  3.  The pcregrep --count option prints the count for each file even when it is  3.  The pcregrep --count option prints the count for each file even when it is
447      zero, as does GNU grep. However, pcregrep was also printing all files when      zero, as does GNU grep. However, pcregrep was also printing all files when
448      --files-with-matches was added. Now, when both options are given, it prints      --files-with-matches was added. Now, when both options are given, it prints
449      counts only for those files that have at least one match. (GNU grep just      counts only for those files that have at least one match. (GNU grep just
450      prints the file name in this circumstance, but including the count seems      prints the file name in this circumstance, but including the count seems
451      more useful - otherwise, why use --count?) Also ensured that the      more useful - otherwise, why use --count?) Also ensured that the
452      combination -clh just lists non-zero counts, with no names.      combination -clh just lists non-zero counts, with no names.
453    
454  4.  The long form of the pcregrep -F option was incorrectly implemented as  4.  The long form of the pcregrep -F option was incorrectly implemented as
455      --fixed_strings instead of --fixed-strings. This is an incompatible change,      --fixed_strings instead of --fixed-strings. This is an incompatible change,
456      but it seems right to fix it, and I didn't think it was worth preserving      but it seems right to fix it, and I didn't think it was worth preserving
457      the old behaviour.      the old behaviour.
458    
459  5.  The command line items --regex=pattern and --regexp=pattern were not  5.  The command line items --regex=pattern and --regexp=pattern were not
460      recognized by pcregrep, which required --regex pattern or --regexp pattern      recognized by pcregrep, which required --regex pattern or --regexp pattern
461      (with a space rather than an '='). The man page documented the '=' forms,      (with a space rather than an '='). The man page documented the '=' forms,
462      which are compatible with GNU grep; these now work.      which are compatible with GNU grep; these now work.
463    
464  6.  No libpcreposix.pc file was created for pkg-config; there was just  6.  No libpcreposix.pc file was created for pkg-config; there was just
465      libpcre.pc and libpcrecpp.pc. The omission has been rectified.      libpcre.pc and libpcrecpp.pc. The omission has been rectified.
466    
467  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size  7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
468      when UCP support is not needed, by modifying the Python script that      when UCP support is not needed, by modifying the Python script that
469      generates it from Unicode data files. This should not matter if the module      generates it from Unicode data files. This should not matter if the module
470      is correctly used as a library, but I received one complaint about 50K of      is correctly used as a library, but I received one complaint about 50K of
471      unwanted data. My guess is that the person linked everything into his      unwanted data. My guess is that the person linked everything into his
472      program rather than using a library. Anyway, it does no harm.      program rather than using a library. Anyway, it does no harm.
473    
474  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger  8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
475      was a minimum greater than 1 for a wide character in a possessive      was a minimum greater than 1 for a wide character in a possessive
476      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8      repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
477      which had an unlimited repeat of a nested, fixed maximum repeat of a wide      which had an unlimited repeat of a nested, fixed maximum repeat of a wide
478      character. Chaos in the form of incorrect output or a compiling loop could      character. Chaos in the form of incorrect output or a compiling loop could
479      result.      result.
480    
481  9.  The restrictions on what a pattern can contain when partial matching is  9.  The restrictions on what a pattern can contain when partial matching is
482      requested for pcre_exec() have been removed. All patterns can now be      requested for pcre_exec() have been removed. All patterns can now be
483      partially matched by this function. In addition, if there are at least two      partially matched by this function. In addition, if there are at least two
484      slots in the offset vector, the offset of the earliest inspected character      slots in the offset vector, the offset of the earliest inspected character
485      for the match and the offset of the end of the subject are set in them when      for the match and the offset of the end of the subject are set in them when
486      PCRE_ERROR_PARTIAL is returned.      PCRE_ERROR_PARTIAL is returned.
487    
488  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is  10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
489      synonymous with PCRE_PARTIAL, for backwards compatibility, and      synonymous with PCRE_PARTIAL, for backwards compatibility, and
490      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,      PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
491      and may be more useful for multi-segment matching, especially with      and may be more useful for multi-segment matching.
492      pcre_exec().  
493    11. Partial matching with pcre_exec() is now more intuitive. A partial match
494  11. Partial matching with pcre_exec() is now more intuitive. A partial match      used to be given if ever the end of the subject was reached; now it is
495      used to be given if ever the end of the subject was reached; now it is      given only if matching could not proceed because another character was
496      given only if matching could not proceed because another character was      needed. This makes a difference in some odd cases such as Z(*FAIL) with the
497      needed. This makes a difference in some odd cases such as Z(*FAIL) with the      string "Z", which now yields "no match" instead of "partial match". In the
498      string "Z", which now yields "no match" instead of "partial match". In the      case of pcre_dfa_exec(), "no match" is given if every matching path for the
499      case of pcre_dfa_exec(), "no match" is given if every matching path for the      final character ended with (*FAIL).
500      final character ended with (*FAIL).  
   
501  12. Restarting a match using pcre_dfa_exec() after a partial match did not work  12. Restarting a match using pcre_dfa_exec() after a partial match did not work
502      if the pattern had a "must contain" character that was already found in the      if the pattern had a "must contain" character that was already found in the
503      earlier partial match, unless partial matching was again requested. For      earlier partial match, unless partial matching was again requested. For
504      example, with the pattern /dog.(body)?/, the "must contain" character is      example, with the pattern /dog.(body)?/, the "must contain" character is
505      "g". If the first part-match was for the string "dog", restarting with      "g". If the first part-match was for the string "dog", restarting with
506      "sbody" failed. This bug has been fixed.      "sbody" failed. This bug has been fixed.
507    
508  13. The string returned by pcre_dfa_exec() after a partial match has been  13. The string returned by pcre_dfa_exec() after a partial match has been
509      changed so that it starts at the first inspected character rather than the      changed so that it starts at the first inspected character rather than the
510      first character of the match. This makes a difference only if the pattern      first character of the match. This makes a difference only if the pattern
511      starts with a lookbehind assertion or \b or \B (\K is not supported by      starts with a lookbehind assertion or \b or \B (\K is not supported by
512      pcre_dfa_exec()). It's an incompatible change, but it makes the two      pcre_dfa_exec()). It's an incompatible change, but it makes the two
513      matching functions compatible, and I think it's the right thing to do.      matching functions compatible, and I think it's the right thing to do.
514    
515  14. Added a pcredemo man page, created automatically from the pcredemo.c file,  14. Added a pcredemo man page, created automatically from the pcredemo.c file,
516      so that the demonstration program is easily available in environments where      so that the demonstration program is easily available in environments where
517      PCRE has not been installed from source.      PCRE has not been installed from source.
518    
519  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,  15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
520      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared      libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
521      library.      library.
522    
523  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.  16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
524      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it      It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
525      is not the first non-POSIX option to be added. Clearly some people find      is not the first non-POSIX option to be added. Clearly some people find
526      these options useful.      these options useful.
527    
528  17. If a caller to the POSIX matching function regexec() passes a non-zero  17. If a caller to the POSIX matching function regexec() passes a non-zero
529      value for nmatch with a NULL value for pmatch, the value of      value for nmatch with a NULL value for pmatch, the value of
530      nmatch is forced to zero.      nmatch is forced to zero.
531    
532  18. RunGrepTest did not have a test for the availability of the -u option of  18. RunGrepTest did not have a test for the availability of the -u option of
533      the diff command, as RunTest does. It now checks in the same way as      the diff command, as RunTest does. It now checks in the same way as
534      RunTest, and also checks for the -b option.      RunTest, and also checks for the -b option.
535    
536  19. If an odd number of negated classes containing just a single character  19. If an odd number of negated classes containing just a single character
537      interposed, within parentheses, between a forward reference to a named      interposed, within parentheses, between a forward reference to a named
538      subpattern and the definition of the subpattern, compilation crashed with      subpattern and the definition of the subpattern, compilation crashed with
539      an internal error, complaining that it could not find the referenced      an internal error, complaining that it could not find the referenced
540      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.      subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
541      [The bug was that it was starting one character too far in when skipping      [The bug was that it was starting one character too far in when skipping
542      over the character class, thus treating the ] as data rather than      over the character class, thus treating the ] as data rather than
543      terminating the class. This meant it could skip too much.]      terminating the class. This meant it could skip too much.]
544    
545  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the  20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
546      /g option in pcretest when the pattern contains \K, which makes it possible      /g option in pcretest when the pattern contains \K, which makes it possible
547      to have an empty string match not at the start, even when the pattern is      to have an empty string match not at the start, even when the pattern is
548      anchored. Updated pcretest and pcredemo to use this option.      anchored. Updated pcretest and pcredemo to use this option.
549    
550  21. If the maximum number of capturing subpatterns in a recursion was greater  21. If the maximum number of capturing subpatterns in a recursion was greater
551      than the maximum at the outer level, the higher number was returned, but      than the maximum at the outer level, the higher number was returned, but
552      with unset values at the outer level. The correct (outer level) value is      with unset values at the outer level. The correct (outer level) value is
553      now given.      now given.
554    
555  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of  22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
556      PCRE did not set those parentheses (unlike Perl). I have now found a way to      PCRE did not set those parentheses (unlike Perl). I have now found a way to
557      make it do so. The string so far is captured, making this feature      make it do so. The string so far is captured, making this feature
558      compatible with Perl.      compatible with Perl.
559    
560  23. The tests have been re-organized, adding tests 11 and 12, to make it  23. The tests have been re-organized, adding tests 11 and 12, to make it
561      possible to check the Perl 5.10 features against Perl 5.10.      possible to check the Perl 5.10 features against Perl 5.10.
562    
563  24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine  24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
564      pattern matches a fixed length string. PCRE did not allow this; now it      pattern matches a fixed length string. PCRE did not allow this; now it
565      does. Neither allows recursion.      does. Neither allows recursion.
566    
567  25. I finally figured out how to implement a request to provide the minimum  25. I finally figured out how to implement a request to provide the minimum
568      length of subject string that was needed in order to match a given pattern.      length of subject string that was needed in order to match a given pattern.
569      (It was back references and recursion that I had previously got hung up      (It was back references and recursion that I had previously got hung up
570      on.) This code has now been added to pcre_study(); it finds a lower bound      on.) This code has now been added to pcre_study(); it finds a lower bound
571      to the length of subject needed. It is not necessarily the greatest lower      to the length of subject needed. It is not necessarily the greatest lower
572      bound, but using it to avoid searching strings that are too short does give      bound, but using it to avoid searching strings that are too short does give
573      some useful speed-ups. The value is available to calling programs via      some useful speed-ups. The value is available to calling programs via
574      pcre_fullinfo().      pcre_fullinfo().
575    
576  26. While implementing 25, I discovered to my embarrassment that pcretest had  26. While implementing 25, I discovered to my embarrassment that pcretest had
577      not been passing the result of pcre_study() to pcre_dfa_exec(), so the      not been passing the result of pcre_study() to pcre_dfa_exec(), so the
578      study optimizations had never been tested with that matching function.      study optimizations had never been tested with that matching function.
579      Oops. What is worse, even when it was passed study data, there was a bug in      Oops. What is worse, even when it was passed study data, there was a bug in
580      pcre_dfa_exec() that meant it never actually used it. Double oops. There      pcre_dfa_exec() that meant it never actually used it. Double oops. There
581      were also very few tests of studied patterns with pcre_dfa_exec().      were also very few tests of studied patterns with pcre_dfa_exec().
582    
583    27. If (?| is used to create subpatterns with duplicate numbers, they are now
584        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
585        on the other side of the coin, they are no longer allowed to have different
586        names, because these cannot be distinguished in PCRE, and this has caused
587        confusion. (This is a difference from Perl.)
588    
589    28. When duplicate subpattern names are present (necessarily with different
590        numbers, as required by 27 above), and a test is made by name in a
591        conditional pattern, either for a subpattern having been matched, or for
592        recursion in such a pattern, all the associated numbered subpatterns are
593        tested, and the overall condition is true if the condition is true for any
594        one of them. This is the way Perl works, and is also more like the way
595        testing by number works.
596    
597    
598  Version 7.9 11-Apr-09  Version 7.9 11-Apr-09
599  ---------------------  ---------------------

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