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revision 351 by ph10, Fri Jul 4 18:27:16 2008 UTC revision 471 by ph10, Fri Dec 11 15:11:55 2009 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.0 02 Jul-08  Version 8.01 11-Dec-09
5    ----------------------
6    
7    1.  If a pattern contained a conditional subpattern with only one branch (in
8        particular, this includes all (DEFINE) patterns), a call to pcre_study()
9        computed the wrong minimum data length (which is of course zero for such
10        subpatterns).
11    
12    
13    Version 8.00 19-Oct-09
14    ----------------------
15    
16    1.  The table for translating pcre_compile() error codes into POSIX error codes
17        was out-of-date, and there was no check on the pcre_compile() error code
18        being within the table. This could lead to an OK return being given in
19        error.
20    
21    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
22        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
23        in a Windows environment.
24    
25    3.  The pcregrep --count option prints the count for each file even when it is
26        zero, as does GNU grep. However, pcregrep was also printing all files when
27        --files-with-matches was added. Now, when both options are given, it prints
28        counts only for those files that have at least one match. (GNU grep just
29        prints the file name in this circumstance, but including the count seems
30        more useful - otherwise, why use --count?) Also ensured that the
31        combination -clh just lists non-zero counts, with no names.
32    
33    4.  The long form of the pcregrep -F option was incorrectly implemented as
34        --fixed_strings instead of --fixed-strings. This is an incompatible change,
35        but it seems right to fix it, and I didn't think it was worth preserving
36        the old behaviour.
37    
38    5.  The command line items --regex=pattern and --regexp=pattern were not
39        recognized by pcregrep, which required --regex pattern or --regexp pattern
40        (with a space rather than an '='). The man page documented the '=' forms,
41        which are compatible with GNU grep; these now work.
42    
43    6.  No libpcreposix.pc file was created for pkg-config; there was just
44        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
45    
46    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
47        when UCP support is not needed, by modifying the Python script that
48        generates it from Unicode data files. This should not matter if the module
49        is correctly used as a library, but I received one complaint about 50K of
50        unwanted data. My guess is that the person linked everything into his
51        program rather than using a library. Anyway, it does no harm.
52    
53    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
54        was a minimum greater than 1 for a wide character in a possessive
55        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
56        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
57        character. Chaos in the form of incorrect output or a compiling loop could
58        result.
59    
60    9.  The restrictions on what a pattern can contain when partial matching is
61        requested for pcre_exec() have been removed. All patterns can now be
62        partially matched by this function. In addition, if there are at least two
63        slots in the offset vector, the offset of the earliest inspected character
64        for the match and the offset of the end of the subject are set in them when
65        PCRE_ERROR_PARTIAL is returned.
66    
67    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
68        synonymous with PCRE_PARTIAL, for backwards compatibility, and
69        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
70        and may be more useful for multi-segment matching.
71    
72    11. Partial matching with pcre_exec() is now more intuitive. A partial match
73        used to be given if ever the end of the subject was reached; now it is
74        given only if matching could not proceed because another character was
75        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
76        string "Z", which now yields "no match" instead of "partial match". In the
77        case of pcre_dfa_exec(), "no match" is given if every matching path for the
78        final character ended with (*FAIL).
79    
80    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
81        if the pattern had a "must contain" character that was already found in the
82        earlier partial match, unless partial matching was again requested. For
83        example, with the pattern /dog.(body)?/, the "must contain" character is
84        "g". If the first part-match was for the string "dog", restarting with
85        "sbody" failed. This bug has been fixed.
86    
87    13. The string returned by pcre_dfa_exec() after a partial match has been
88        changed so that it starts at the first inspected character rather than the
89        first character of the match. This makes a difference only if the pattern
90        starts with a lookbehind assertion or \b or \B (\K is not supported by
91        pcre_dfa_exec()). It's an incompatible change, but it makes the two
92        matching functions compatible, and I think it's the right thing to do.
93    
94    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
95        so that the demonstration program is easily available in environments where
96        PCRE has not been installed from source.
97    
98    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
99        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
100        library.
101    
102    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
103        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
104        is not the first non-POSIX option to be added. Clearly some people find
105        these options useful.
106    
107    17. If a caller to the POSIX matching function regexec() passes a non-zero
108        value for nmatch with a NULL value for pmatch, the value of
109        nmatch is forced to zero.
110    
111    18. RunGrepTest did not have a test for the availability of the -u option of
112        the diff command, as RunTest does. It now checks in the same way as
113        RunTest, and also checks for the -b option.
114    
115    19. If an odd number of negated classes containing just a single character
116        interposed, within parentheses, between a forward reference to a named
117        subpattern and the definition of the subpattern, compilation crashed with
118        an internal error, complaining that it could not find the referenced
119        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
120        [The bug was that it was starting one character too far in when skipping
121        over the character class, thus treating the ] as data rather than
122        terminating the class. This meant it could skip too much.]
123    
124    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
125        /g option in pcretest when the pattern contains \K, which makes it possible
126        to have an empty string match not at the start, even when the pattern is
127        anchored. Updated pcretest and pcredemo to use this option.
128    
129    21. If the maximum number of capturing subpatterns in a recursion was greater
130        than the maximum at the outer level, the higher number was returned, but
131        with unset values at the outer level. The correct (outer level) value is
132        now given.
133    
134    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
135        PCRE did not set those parentheses (unlike Perl). I have now found a way to
136        make it do so. The string so far is captured, making this feature
137        compatible with Perl.
138    
139    23. The tests have been re-organized, adding tests 11 and 12, to make it
140        possible to check the Perl 5.10 features against Perl 5.10.
141    
142    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
143        pattern matches a fixed length string. PCRE did not allow this; now it
144        does. Neither allows recursion.
145    
146    25. I finally figured out how to implement a request to provide the minimum
147        length of subject string that was needed in order to match a given pattern.
148        (It was back references and recursion that I had previously got hung up
149        on.) This code has now been added to pcre_study(); it finds a lower bound
150        to the length of subject needed. It is not necessarily the greatest lower
151        bound, but using it to avoid searching strings that are too short does give
152        some useful speed-ups. The value is available to calling programs via
153        pcre_fullinfo().
154    
155    26. While implementing 25, I discovered to my embarrassment that pcretest had
156        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
157        study optimizations had never been tested with that matching function.
158        Oops. What is worse, even when it was passed study data, there was a bug in
159        pcre_dfa_exec() that meant it never actually used it. Double oops. There
160        were also very few tests of studied patterns with pcre_dfa_exec().
161    
162    27. If (?| is used to create subpatterns with duplicate numbers, they are now
163        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
164        on the other side of the coin, they are no longer allowed to have different
165        names, because these cannot be distinguished in PCRE, and this has caused
166        confusion. (This is a difference from Perl.)
167    
168    28. When duplicate subpattern names are present (necessarily with different
169        numbers, as required by 27 above), and a test is made by name in a
170        conditional pattern, either for a subpattern having been matched, or for
171        recursion in such a pattern, all the associated numbered subpatterns are
172        tested, and the overall condition is true if the condition is true for any
173        one of them. This is the way Perl works, and is also more like the way
174        testing by number works.
175    
176    
177    Version 7.9 11-Apr-09
178    ---------------------
179    
180    1.  When building with support for bzlib/zlib (pcregrep) and/or readline
181        (pcretest), all targets were linked against these libraries. This included
182        libpcre, libpcreposix, and libpcrecpp, even though they do not use these
183        libraries. This caused unwanted dependencies to be created. This problem
184        has been fixed, and now only pcregrep is linked with bzlib/zlib and only
185        pcretest is linked with readline.
186    
187    2.  The "typedef int BOOL" in pcre_internal.h that was included inside the
188        "#ifndef FALSE" condition by an earlier change (probably 7.8/18) has been
189        moved outside it again, because FALSE and TRUE are already defined in AIX,
190        but BOOL is not.
191    
192    3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
193        PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
194    
195    4.  The pcregrep documentation said spaces were inserted as well as colons (or
196        hyphens) following file names and line numbers when outputting matching
197        lines. This is not true; no spaces are inserted. I have also clarified the
198        wording for the --colour (or --color) option.
199    
200    5.  In pcregrep, when --colour was used with -o, the list of matching strings
201        was not coloured; this is different to GNU grep, so I have changed it to be
202        the same.
203    
204    6.  When --colo(u)r was used in pcregrep, only the first matching substring in
205        each matching line was coloured. Now it goes on to look for further matches
206        of any of the test patterns, which is the same behaviour as GNU grep.
207    
208    7.  A pattern that could match an empty string could cause pcregrep to loop; it
209        doesn't make sense to accept an empty string match in pcregrep, so I have
210        locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
211        seems to be how GNU grep behaves.
212    
213    8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
214        start or after a newline", because the conditional assertion was not being
215        correctly handled. The rule now is that both the assertion and what follows
216        in the first alternative must satisfy the test.
217    
218    9.  If auto-callout was enabled in a pattern with a conditional group whose
219        condition was an assertion, PCRE could crash during matching, both with
220        pcre_exec() and pcre_dfa_exec().
221    
222    10. The PCRE_DOLLAR_ENDONLY option was not working when pcre_dfa_exec() was
223        used for matching.
224    
225    11. Unicode property support in character classes was not working for
226        characters (bytes) greater than 127 when not in UTF-8 mode.
227    
228    12. Added the -M command line option to pcretest.
229    
230    14. Added the non-standard REG_NOTEMPTY option to the POSIX interface.
231    
232    15. Added the PCRE_NO_START_OPTIMIZE match-time option.
233    
234    16. Added comments and documentation about mis-use of no_arg in the C++
235        wrapper.
236    
237    17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
238        from Martin Jerabek that uses macro names for all relevant character and
239        string constants.
240    
241    18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
242        SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
243        SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
244        these, but not everybody uses configure.
245    
246    19. A conditional group that had only one branch was not being correctly
247        recognized as an item that could match an empty string. This meant that an
248        enclosing group might also not be so recognized, causing infinite looping
249        (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
250        with the subject "ab", where knowledge that the repeated group can match
251        nothing is needed in order to break the loop.
252    
253    20. If a pattern that was compiled with callouts was matched using pcre_dfa_
254        exec(), but without supplying a callout function, matching went wrong.
255    
256    21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
257        leak if the size of the offset vector was greater than 30. When the vector
258        is smaller, the saved offsets during recursion go onto a local stack
259        vector, but for larger vectors malloc() is used. It was failing to free
260        when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
261        error, in fact).
262    
263    22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
264        heapframe that is used only when UTF-8 support is enabled. This caused no
265        problem, but was untidy.
266    
267    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
268        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
269        included within another project.
270    
271    24. Steven Van Ingelgem's patches to add more options to the CMake support,
272        slightly modified by me:
273    
274          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
275              not building pcregrep.
276    
277          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
278              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
279    
280    25. Forward references, both numeric and by name, in patterns that made use of
281        duplicate group numbers, could behave incorrectly or give incorrect errors,
282        because when scanning forward to find the reference group, PCRE was not
283        taking into account the duplicate group numbers. A pattern such as
284        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
285    
286    26. Changed a few more instances of "const unsigned char *" to USPTR, making
287        the feature of a custom pointer more persuasive (as requested by a user).
288    
289    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
290        pcretest.c, inside #ifndefs, because it seems they are sometimes already
291        pre-defined.
292    
293    28. Added support for (*UTF8) at the start of a pattern.
294    
295    29. Arrange for flags added by the "release type" setting in CMake to be shown
296        in the configuration summary.
297    
298    
299    Version 7.8 05-Sep-08
300  ---------------------  ---------------------
301    
302  1.  Replaced UCP searching code with optimized version as implemented for Ad  1.  Replaced UCP searching code with optimized version as implemented for Ad
# Line 14  Version 8.0 02 Jul-08 Line 309  Version 8.0 02 Jul-08
309  2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more  2.  Updated the Unicode datatables to Unicode 5.1.0. This adds yet more
310      scripts.      scripts.
311    
312    3.  Change 12 for 7.7 introduced a bug in pcre_study() when a pattern contained
313        a group with a zero qualifier. The result of the study could be incorrect,
314        or the function might crash, depending on the pattern.
315    
316    4.  Caseless matching was not working for non-ASCII characters in back
317        references. For example, /(\x{de})\1/8i was not matching \x{de}\x{fe}.
318        It now works when Unicode Property Support is available.
319    
320    5.  In pcretest, an escape such as \x{de} in the data was always generating
321        a UTF-8 string, even in non-UTF-8 mode. Now it generates a single byte in
322        non-UTF-8 mode. If the value is greater than 255, it gives a warning about
323        truncation.
324    
325    6.  Minor bugfix in pcrecpp.cc (change "" == ... to NULL == ...).
326    
327    7.  Added two (int) casts to pcregrep when printing the difference of two
328        pointers, in case they are 64-bit values.
329    
330    8.  Added comments about Mac OS X stack usage to the pcrestack man page and to
331        test 2 if it fails.
332    
333    9.  Added PCRE_CALL_CONVENTION just before the names of all exported functions,
334        and a #define of that name to empty if it is not externally set. This is to
335        allow users of MSVC to set it if necessary.
336    
337    10. The PCRE_EXP_DEFN macro which precedes exported functions was missing from
338        the convenience functions in the pcre_get.c source file.
339    
340    11. An option change at the start of a pattern that had top-level alternatives
341        could cause overwriting and/or a crash. This command provoked a crash in
342        some environments:
343    
344          printf "/(?i)[\xc3\xa9\xc3\xbd]|[\xc3\xa9\xc3\xbdA]/8\n" | pcretest
345    
346        This potential security problem was recorded as CVE-2008-2371.
347    
348    12. For a pattern where the match had to start at the beginning or immediately
349        after a newline (e.g /.*anything/ without the DOTALL flag), pcre_exec() and
350        pcre_dfa_exec() could read past the end of the passed subject if there was
351        no match. To help with detecting such bugs (e.g. with valgrind), I modified
352        pcretest so that it places the subject at the end of its malloc-ed buffer.
353    
354    13. The change to pcretest in 12 above threw up a couple more cases when pcre_
355        exec() might read past the end of the data buffer in UTF-8 mode.
356    
357    14. A similar bug to 7.3/2 existed when the PCRE_FIRSTLINE option was set and
358        the data contained the byte 0x85 as part of a UTF-8 character within its
359        first line. This applied both to normal and DFA matching.
360    
361    15. Lazy qualifiers were not working in some cases in UTF-8 mode. For example,
362        /^[^d]*?$/8 failed to match "abc".
363    
364    16. Added a missing copyright notice to pcrecpp_internal.h.
365    
366    17. Make it more clear in the documentation that values returned from
367        pcre_exec() in ovector are byte offsets, not character counts.
368    
369    18. Tidied a few places to stop certain compilers from issuing warnings.
370    
371    19. Updated the Virtual Pascal + BCC files to compile the latest v7.7, as
372        supplied by Stefan Weber. I made a further small update for 7.8 because
373        there is a change of source arrangements: the pcre_searchfuncs.c module is
374        replaced by pcre_ucd.c.
375    
376    
377  Version 7.7 07-May-08  Version 7.7 07-May-08
378  ---------------------  ---------------------

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