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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.10 03 May-2010  Version 8.31
5    -----------------------------
6    
7    1.  Fixing a wrong JIT test case and some compiler warnings.
8    
9    2.  Removed a bashism from the RunTest script.
10    
11    3.  Add a cast to pcre_exec.c to fix the warning "unary minus operator applied
12        to unsigned type, result still unsigned" that was given by an MS compiler
13        on encountering the code "-sizeof(xxx)".
14    
15    4.  Partial matching support is added to the JIT compiler.
16    
17    5.  Fixed several bugs concerned with partial matching of items that consist
18        of more than one character:
19    
20        (a) /^(..)\1/ did not partially match "aba" because checking references was
21            done on an "all or nothing" basis. This also applied to repeated
22            references.
23    
24        (b) \R did not give a hard partial match if \r was found at the end of the
25            subject.
26    
27        (c) \X did not give a hard partial match after matching one or more
28            characters at the end of the subject.
29    
30        (d) When newline was set to CRLF, a pattern such as /a$/ did not recognize
31            a partial match for the string "\r".
32    
33        (e) When newline was set to CRLF, the metacharacter "." did not recognize
34            a partial match for a CR character at the end of the subject string.
35    
36    6.  When matching is performed using JIT-compiled code, the flag bit
37        PCRE_EXTRA_USED_JIT is set in the pcre_extra block and can be tested by the
38        caller. This bit is checked by pcretest if JIT is requested by /S++ or -s++
39        (instead of just /S+ or -s+) and the text "(JIT)" added to the output if
40        the bit is set.
41    
42    7.  Individual JIT compile options can be set in pcretest by following -s+[+]
43        or /S+[+] with a digit between 1 and 7.
44    
45    8.  OP_NOT now supports any UTF character not just single-byte ones.
46    
47    
48    Version 8.30 04-February-2012
49    -----------------------------
50    
51    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
52        name is defined in ctype.h.
53    
54    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
55        only in quite long subpatterns.
56    
57    3.  Removed the function pcre_info(), which has been obsolete and deprecated
58        since it was replaced by pcre_fullinfo() in February 2000.
59    
60    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
61        match a (*MARK), and the match failed at the start of the subject, a
62        reference to memory before the start of the subject could occur. This bug
63        was introduced by fix 17 of release 8.21.
64    
65    5.  A reference to an unset group with zero minimum repetition was giving
66        totally wrong answers (in non-JavaScript-compatibility mode). For example,
67        /(another)?(\1?)test/ matched against "hello world test". This bug was
68        introduced in release 8.13.
69    
70    6.  Add support for 16-bit character strings (a large amount of work involving
71        many changes and refactorings).
72    
73    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
74        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
75        from a file.
76    
77    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
78        rounding is not applied in this particular case).
79    
80    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
81        if they appear, or are escaped, in patterns.
82    
83    10. Get rid of a number of -Wunused-but-set-variable warnings.
84    
85    11. The pattern /(?=(*:x))(q|)/ matches an empty string, and returns the mark
86        "x". The similar pattern /(?=(*:x))((*:y)q|)/ did not return a mark at all.
87        Oddly, Perl behaves the same way. PCRE has been fixed so that this pattern
88        also returns the mark "x". This bug applied to capturing parentheses,
89        non-capturing parentheses, and atomic parentheses. It also applied to some
90        assertions.
91    
92    12. Stephen Kelly's patch to CMakeLists.txt allows it to parse the version
93        information out of configure.ac instead of relying on pcre.h.generic, which
94        is not stored in the repository.
95    
96    13. Applied Dmitry V. Levin's patch for a more portable method for linking with
97        -lreadline.
98    
99    14. ZH added PCRE_CONFIG_JITTARGET; added its output to pcretest -C.
100    
101    15. Applied Graycode's patch to put the top-level frame on the stack rather
102        than the heap when not using the stack for recursion. This gives a
103        performance improvement in many cases when recursion is not deep.
104    
105    16. Experimental code added to "pcretest -C" to output the stack frame size.
106    
107    
108    Version 8.21 12-Dec-2011
109    ------------------------
110    
111    1.  Updating the JIT compiler.
112    
113    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
114        are added as well.
115    
116    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
117        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
118        calling _pcre_jit_exec. Some extra comments are added.
119    
120    4.  (*MARK) settings inside atomic groups that do not contain any capturing
121        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
122        was introduced by change 18 for 8.20.
123    
124    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
125        ECMA-262 standard.
126    
127    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
128        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
129        This bug was probably introduced by change 9 of 8.13.
130    
131    7.  While fixing 6 above, I noticed that a number of other items were being
132        incorrectly rejected as "not fixed length". This arose partly because newer
133        opcodes had not been added to the fixed-length checking code. I have (a)
134        corrected the bug and added tests for these items, and (b) arranged for an
135        error to occur if an unknown opcode is encountered while checking for fixed
136        length instead of just assuming "not fixed length". The items that were
137        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
138        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
139        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
140    
141    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
142        being incorrectly compiled and would have given unpredicatble results.
143    
144    9.  A possessively repeated subpattern with minimum repeat count greater than
145        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
146        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
147        the first (A) could occur when it should not.
148    
149    10. Add a cast and remove a redundant test from the code.
150    
151    11. JIT should use pcre_malloc/pcre_free for allocation.
152    
153    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
154        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
155        is anything other than /usr, -L is still shown).
156    
157    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
158    
159    14. Perl does not support \N without a following name in a [] class; PCRE now
160        also gives an error.
161    
162    15. If a forward reference was repeated with an upper limit of around 2000,
163        it caused the error "internal error: overran compiling workspace". The
164        maximum number of forward references (including repeats) was limited by the
165        internal workspace, and dependent on the LINK_SIZE. The code has been
166        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
167        the default depends on LINK_SIZE. There is a new upper limit (for safety)
168        of around 200,000 forward references. While doing this, I also speeded up
169        the filling in of repeated forward references.
170    
171    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
172        incorrectly expecting the subject to contain another "a" after the start.
173    
174    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
175        in the match, the SKIP should be ignored. This was not happening; instead
176        the SKIP was being treated as NOMATCH. For patterns such as
177        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
178        tested.
179    
180    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
181        now much more compatible with Perl, in particular in cases where the result
182        is a non-match for a non-anchored pattern. For example, if
183        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
184        "m", where previously it did not return a name. A side effect of this
185        change is that for partial matches, the last encountered mark name is
186        returned, as for non matches. A number of tests that were previously not
187        Perl-compatible have been moved into the Perl-compatible test files. The
188        refactoring has had the pleasing side effect of removing one argument from
189        the match() function, thus reducing its stack requirements.
190    
191    19. If the /S+ option was used in pcretest to study a pattern using JIT,
192        subsequent uses of /S (without +) incorrectly behaved like /S+.
193    
194    21. Retrieve executable code size support for the JIT compiler and fixing
195        some warnings.
196    
197    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
198        not work when the shorter character appeared right at the end of the
199        subject string.
200    
201    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
202        systems.
203    
204    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
205        output it when the /M option is used in pcretest.
206    
207    25. The CheckMan script was not being included in the distribution. Also, added
208        an explicit "perl" to run Perl scripts from the PrepareRelease script
209        because this is reportedly needed in Windows.
210    
211    26. If study data was being save in a file and studying had not found a set of
212        "starts with" bytes for the pattern, the data written to the file (though
213        never used) was taken from uninitialized memory and so caused valgrind to
214        complain.
215    
216    27. Updated RunTest.bat as provided by Sheri Pierce.
217    
218    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
219    
220    29. Computation of memory usage for the table of capturing group names was
221        giving an unnecessarily large value.
222    
223    
224    Version 8.20 21-Oct-2011
225    ------------------------
226    
227    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
228        a POSIX class. After further experiments with Perl, which convinced me that
229        Perl has bugs and confusions, a closing square bracket is no longer allowed
230        in a POSIX name. This bug also affected patterns with classes that started
231        with full stops.
232    
233    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
234        captured substring, but while checking the failing first alternative,
235        substring 1 is temporarily captured. If the output vector supplied to
236        pcre_exec() was not big enough for this capture, the yield of the function
237        was still zero ("insufficient space for captured substrings"). This cannot
238        be totally fixed without adding another stack variable, which seems a lot
239        of expense for a edge case. However, I have improved the situation in cases
240        such as /(a)(b)x|abc/ matched against "abc", where the return code
241        indicates that fewer than the maximum number of slots in the ovector have
242        been set.
243    
244    3.  Related to (2) above: when there are more back references in a pattern than
245        slots in the output vector, pcre_exec() uses temporary memory during
246        matching, and copies in the captures as far as possible afterwards. It was
247        using the entire output vector, but this conflicts with the specification
248        that only 2/3 is used for passing back captured substrings. Now it uses
249        only the first 2/3, for compatibility. This is, of course, another edge
250        case.
251    
252    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
253        main code base, and can be used by building with --enable-jit. When this is
254        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
255        runtime --no-jit option is given.
256    
257    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
258        ovector, the return from the function was zero, implying that there were
259        other matches that did not fit. The correct "exactly full" value is now
260        returned.
261    
262    6.  If a subpattern that was called recursively or as a subroutine contained
263        (*PRUNE) or any other control that caused it to give a non-standard return,
264        invalid errors such as "Error -26 (nested recursion at the same subject
265        position)" or even infinite loops could occur.
266    
267    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
268        computing the minimum length on reaching *ACCEPT, and so ended up with the
269        wrong value of 1 rather than 0. Further investigation indicates that
270        computing a minimum subject length in the presence of *ACCEPT is difficult
271        (think back references, subroutine calls), and so I have changed the code
272        so that no minimum is registered for a pattern that contains *ACCEPT.
273    
274    8.  If (*THEN) was present in the first (true) branch of a conditional group,
275        it was not handled as intended. [But see 16 below.]
276    
277    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
278        Sheri Pierce.
279    
280    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
281        the first byte in a match must be "a".
282    
283    11. Change 17 for 8.13 increased the recursion depth for patterns like
284        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
285        pattern contains any instances of (*THEN). If it does not, the old
286        optimizations are restored. It would be nice to do this on a per-group
287        basis, but at the moment that is not feasible.
288    
289    12. In some environments, the output of pcretest -C is CRLF terminated. This
290        broke RunTest's code that checks for the link size. A single white space
291        character after the value is now allowed for.
292    
293    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
294        For "fr", it uses the Windows-specific input and output files.
295    
296    14. If (*THEN) appeared in a group that was called recursively or as a
297        subroutine, it did not work as intended. [But see next item.]
298    
299    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
300        pattern fragments (but not containing any | characters). If A and B are
301        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
302        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
303        D. In other words, Perl considers parentheses that do not contain any |
304        characters to be part of a surrounding alternative, whereas PCRE was
305        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
306        differently. PCRE now behaves in the same way as Perl, except in the case
307        of subroutine/recursion calls such as (?1) which have in any case always
308        been different (but PCRE had them first :-).
309    
310    16. Related to 15 above: Perl does not treat the | in a conditional group as
311        creating alternatives. Such a group is treated in the same way as an
312        ordinary group without any | characters when processing (*THEN). PCRE has
313        been changed to match Perl's behaviour.
314    
315    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
316        RunGrepTest script failed.
317    
318    18. Change 22 for version 13 caused atomic groups to use more stack. This is
319        inevitable for groups that contain captures, but it can lead to a lot of
320        stack use in large patterns. The old behaviour has been restored for atomic
321        groups that do not contain any capturing parentheses.
322    
323    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
324        suppress the check for a minimum subject length at run time. (If it was
325        given to pcre_exec() or pcre_dfa_exec() it did work.)
326    
327    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
328        fail to work when decoding hex characters in data strings in EBCDIC
329        environments.
330    
331    21. It appears that in at least one Mac OS environment, the isxdigit() function
332        is implemented as a macro that evaluates to its argument more than once,
333        contravening the C 90 Standard (I haven't checked a later standard). There
334        was an instance in pcretest which caused it to go wrong when processing
335        \x{...} escapes in subject strings. The has been rewritten to avoid using
336        things like p++ in the argument of isxdigit().
337    
338    
339    Version 8.13 16-Aug-2011
340    ------------------------
341    
342    1.  The Unicode data tables have been updated to Unicode 6.0.0.
343    
344    2.  Two minor typos in pcre_internal.h have been fixed.
345    
346    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
347        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
348        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
349    
350    4.  There were a number of related bugs in the code for matching backrefences
351        caselessly in UTF-8 mode when codes for the characters concerned were
352        different numbers of bytes. For example, U+023A and U+2C65 are an upper
353        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
354        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
355        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
356        2-byte code at the end of the subject (it thought there wasn't enough data
357        left).
358    
359    5.  Comprehensive information about what went wrong is now returned by
360        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
361        as the output vector has at least 2 elements. The offset of the start of
362        the failing character and a reason code are placed in the vector.
363    
364    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
365        now returned is for the first byte of the failing character, instead of the
366        last byte inspected. This is an incompatible change, but I hope it is small
367        enough not to be a problem. It makes the returned offset consistent with
368        pcre_exec() and pcre_dfa_exec().
369    
370    7.  pcretest now gives a text phrase as well as the error number when
371        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
372        failure, the offset and reason code are output.
373    
374    8.  When \R was used with a maximizing quantifier it failed to skip backwards
375        over a \r\n pair if the subsequent match failed. Instead, it just skipped
376        back over a single character (\n). This seems wrong (because it treated the
377        two characters as a single entity when going forwards), conflicts with the
378        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
379        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
380        has been changed.
381    
382    9.  Some internal refactoring has changed the processing so that the handling
383        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
384        time (the PCRE_DOTALL option was changed this way some time ago: version
385        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
386        which was always a bit of a fudge. It also means that there is one less
387        argument for the match() function, which reduces its stack requirements
388        slightly. This change also fixes an incompatibility with Perl: the pattern
389        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
390    
391    10. More internal refactoring has drastically reduced the number of recursive
392        calls to match() for possessively repeated groups such as (abc)++ when
393        using pcre_exec().
394    
395    11. While implementing 10, a number of bugs in the handling of groups were
396        discovered and fixed:
397    
398        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
399        (a|)*(?1) gave a compile-time internal error.
400        ((a|)+)+  did not notice that the outer group could match an empty string.
401        (^a|^)+   was not marked as anchored.
402        (.*a|.*)+ was not marked as matching at start or after a newline.
403    
404    12. Yet more internal refactoring has removed another argument from the match()
405        function. Special calls to this function are now indicated by setting a
406        value in a variable in the "match data" data block.
407    
408    13. Be more explicit in pcre_study() instead of relying on "default" for
409        opcodes that mean there is no starting character; this means that when new
410        ones are added and accidentally left out of pcre_study(), testing should
411        pick them up.
412    
413    14. The -s option of pcretest has been documented for ages as being an old
414        synonym of -m (show memory usage). I have changed it to mean "force study
415        for every regex", that is, assume /S for every regex. This is similar to -i
416        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
417        using it. It makes it easier to run collections of tests with and without
418        study enabled, and thereby test pcre_study() more easily. All the standard
419        tests are now run with and without -s (but some patterns can be marked as
420        "never study" - see 20 below).
421    
422    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
423        restoration of the capturing data to the outer values was not happening
424        correctly.
425    
426    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
427        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
428        pattern had matched an empty string, and so incorrectly returned a no
429        match.
430    
431    17. There was optimizing code for the last branch of non-capturing parentheses,
432        and also for the obeyed branch of a conditional subexpression, which used
433        tail recursion to cut down on stack usage. Unfortunately, now that there is
434        the possibility of (*THEN) occurring in these branches, tail recursion is
435        no longer possible because the return has to be checked for (*THEN). These
436        two optimizations have therefore been removed. [But see 8.20/11 above.]
437    
438    18. If a pattern containing \R was studied, it was assumed that \R always
439        matched two bytes, thus causing the minimum subject length to be
440        incorrectly computed because \R can also match just one byte.
441    
442    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
443        was incorrectly computed.
444    
445    20. If /S is present twice on a test pattern in pcretest input, it now
446        *disables* studying, thereby overriding the use of -s on the command line
447        (see 14 above). This is necessary for one or two tests to keep the output
448        identical in both cases.
449    
450    21. When (*ACCEPT) was used in an assertion that matched an empty string and
451        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
452    
453    22. When an atomic group that contained a capturing parenthesis was
454        successfully matched, but the branch in which it appeared failed, the
455        capturing was not being forgotten if a higher numbered group was later
456        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
457        group 1 to "a", when in fact it should be unset. This applied to multi-
458        branched capturing and non-capturing groups, repeated or not, and also to
459        positive assertions (capturing in negative assertions does not happen
460        in PCRE) and also to nested atomic groups.
461    
462    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
463        subject after a captured substring, to make it easier to tell which of a
464        number of identical substrings has been captured.
465    
466    24. The way atomic groups are processed by pcre_exec() has been changed so that
467        if they are repeated, backtracking one repetition now resets captured
468        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
469        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
470        "aaa". Previously, it would have been "a". As part of this code
471        refactoring, the way recursive calls are handled has also been changed.
472    
473    25. If an assertion condition captured any substrings, they were not passed
474        back unless some other capturing happened later. For example, if
475        (?(?=(a))a) was matched against "a", no capturing was returned.
476    
477    26. When studying a pattern that contained subroutine calls or assertions,
478        the code for finding the minimum length of a possible match was handling
479        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
480        group 1 called group 2 while simultaneously a separate group 2 called group
481        1). A stack overflow occurred in this case. I have fixed this by limiting
482        the recursion depth to 10.
483    
484    27. Updated RunTest.bat in the distribution to the version supplied by Tom
485        Fortmann. This supports explicit test numbers on the command line, and has
486        argument validation and error reporting.
487    
488    28. An instance of \X with an unlimited repeat could fail if at any point the
489        first character it looked at was a mark character.
490    
491    29. Some minor code refactoring concerning Unicode properties and scripts
492        should reduce the stack requirement of match() slightly.
493    
494    30. Added the '=' option to pcretest to check the setting of unused capturing
495        slots at the end of the pattern, which are documented as being -1, but are
496        not included in the return count.
497    
498    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
499        compiled something random. Now it gives a compile-time error (as does
500        Perl).
501    
502    32. A *MARK encountered during the processing of a positive assertion is now
503        recorded and passed back (compatible with Perl).
504    
505    33. If --only-matching or --colour was set on a pcregrep call whose pattern
506        had alternative anchored branches, the search for a second match in a line
507        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
508        matched the line "0102" twice. The same bug affected patterns that started
509        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
510        twice.
511    
512    34. Previously, PCRE did not allow quantification of assertions. However, Perl
513        does, and because of capturing effects, quantifying parenthesized
514        assertions may at times be useful. Quantifiers are now allowed for
515        parenthesized assertions.
516    
517    35. A minor code tidy in pcre_compile() when checking options for \R usage.
518    
519    36. \g was being checked for fancy things in a character class, when it should
520        just be a literal "g".
521    
522    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
523        appearance of a nested POSIX class supersedes an apparent external class.
524        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
525        unescaped square brackets may also appear as part of class names. For
526        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
527        more like Perl. (But see 8.20/1 above.)
528    
529    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
530        was because it thought it was \N{name}, which is not supported).
531    
532    39. Add minix to OS list not supporting the -S option in pcretest.
533    
534    40. PCRE tries to detect cases of infinite recursion at compile time, but it
535        cannot analyze patterns in sufficient detail to catch mutual recursions
536        such as ((?1))((?2)). There is now a runtime test that gives an error if a
537        subgroup is called recursively as a subpattern for a second time at the
538        same position in the subject string. In previous releases this might have
539        been caught by the recursion limit, or it might have run out of stack.
540    
541    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
542        happen only once. PCRE was, however incorrectly giving a compile time error
543        "recursive call could loop indefinitely" because it cannot analyze the
544        pattern in sufficient detail. The compile time test no longer happens when
545        PCRE is compiling a conditional subpattern, but actual runaway loops are
546        now caught at runtime (see 40 above).
547    
548    42. It seems that Perl allows any characters other than a closing parenthesis
549        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
550        has been changed to be the same.
551    
552    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
553        as not to get warnings when autogen.sh is called. Also changed
554        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
555    
556    44. To help people who use pcregrep to scan files containing exceedingly long
557        lines, the following changes have been made:
558    
559        (a) The default value of the buffer size parameter has been increased from
560            8K to 20K. (The actual buffer used is three times this size.)
561    
562        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
563            PCRE is built.
564    
565        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
566            to be set at run time.
567    
568        (d) Numerical values in pcregrep options can be followed by K or M, for
569            example --buffer-size=50K.
570    
571        (e) If a line being scanned overflows pcregrep's buffer, an error is now
572            given and the return code is set to 2.
573    
574    45. Add a pointer to the latest mark to the callout data block.
575    
576    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
577        partial match of an empty string instead of no match. This was specific to
578        the use of ".".
579    
580    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
581        complete match instead of a partial match. This bug was dependent on both
582        the PCRE_UTF8 and PCRE_DOTALL options being set.
583    
584    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
585        starting byte set, because \b was not being ignored.
586    
587    
588    Version 8.12 15-Jan-2011
589    ------------------------
590    
591    1.  Fixed some typos in the markup of the man pages, and wrote a script that
592        checks for such things as part of the documentation building process.
593    
594    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
595        --match-limit and --recursion-limit options (added for 8.11). In
596        particular, this made one of the standard tests fail. (The integer value
597        went into the wrong half of a long int.)
598    
599    3.  If the --colour option was given to pcregrep with -v (invert match), it
600        did strange things, either producing crazy output, or crashing. It should,
601        of course, ignore a request for colour when reporting lines that do not
602        match.
603    
604    4.  Another pcregrep bug caused similar problems if --colour was specified with
605        -M (multiline) and the pattern match finished with a line ending.
606    
607    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
608        matched in multiline mode, the following line was shown as part of the
609        match. This seems wrong, so I have changed it.
610    
611    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
612        the check for further matches in the same line (so they could be coloured)
613        to overrun the end of the current line. If another match was found, it was
614        incorrectly shown (and then shown again when found in the next line).
615    
616    7.  If pcregrep was compiled under Windows, there was a reference to the
617        function pcregrep_exit() before it was defined. I am assuming this was
618        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
619        reported by a user. I've moved the definition above the reference.
620    
621    
622    Version 8.11 10-Dec-2010
623    ------------------------
624    
625    1.  (*THEN) was not working properly if there were untried alternatives prior
626        to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
627        backtracked to try for "b" instead of moving to the next alternative branch
628        at the same level (in this case, to look for "c"). The Perl documentation
629        is clear that when (*THEN) is backtracked onto, it goes to the "next
630        alternative in the innermost enclosing group".
631    
632    2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
633        such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
634        result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
635        (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
636        (*THEN).
637    
638    3.  If \s appeared in a character class, it removed the VT character from
639        the class, even if it had been included by some previous item, for example
640        in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
641        of \s, but is part of the POSIX "space" class.)
642    
643    4.  A partial match never returns an empty string (because you can always
644        match an empty string at the end of the subject); however the checking for
645        an empty string was starting at the "start of match" point. This has been
646        changed to the "earliest inspected character" point, because the returned
647        data for a partial match starts at this character. This means that, for
648        example, /(?<=abc)def/ gives a partial match for the subject "abc"
649        (previously it gave "no match").
650    
651    5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
652        of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
653        previously a full match would be given. However, setting PCRE_PARTIAL_HARD
654        has an implication that the given string is incomplete (because a partial
655        match is preferred over a full match). For this reason, these items now
656        give a partial match in this situation. [Aside: previously, the one case
657        /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
658        match rather than a full match, which was wrong by the old rules, but is
659        now correct.]
660    
661    6.  There was a bug in the handling of #-introduced comments, recognized when
662        PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
663        If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
664        UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
665        scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
666        but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
667        places in pcre_compile().
668    
669    7.  Related to (6) above, when pcre_compile() was skipping #-introduced
670        comments when looking ahead for named forward references to subpatterns,
671        the only newline sequence it recognized was NL. It now handles newlines
672        according to the set newline convention.
673    
674    8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
675        former, but used strtoul(), whereas pcretest avoided strtoul() but did not
676        cater for a lack of strerror(). These oversights have been fixed.
677    
678    9.  Added --match-limit and --recursion-limit to pcregrep.
679    
680    10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
681    
682    11. When the -o option was used, pcregrep was setting a return code of 1, even
683        when matches were found, and --line-buffered was not being honoured.
684    
685    12. Added an optional parentheses number to the -o and --only-matching options
686        of pcregrep.
687    
688    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
689        can match an empty string. The code to do it in pcretest and pcredemo
690        needed fixing:
691    
692        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
693            only one byte after an empty string match just before CRLF (this case
694            just got forgotten; "any" and "anycrlf" were OK).
695    
696        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
697            mode when an empty string match preceded an ASCII character followed by
698            a non-ASCII character. (The code for advancing by one character rather
699            than one byte was nonsense.)
700    
701        (c) The pcredemo.c sample program did not have any code at all to handle
702            the cases when CRLF is a valid newline sequence.
703    
704    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
705        as a starting offset was within the subject string. There is now a new
706        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
707        negative or greater than the length of the string. In order to test this,
708        pcretest is extended to allow the setting of negative starting offsets.
709    
710    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
711        starting offset points to the beginning of a UTF-8 character was
712        unnecessarily clumsy. I tidied it up.
713    
714    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
715        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
716    
717    17. Nobody had reported that the --include_dir option, which was added in
718        release 7.7 should have been called --include-dir (hyphen, not underscore)
719        for compatibility with GNU grep. I have changed it to --include-dir, but
720        left --include_dir as an undocumented synonym, and the same for
721        --exclude-dir, though that is not available in GNU grep, at least as of
722        release 2.5.4.
723    
724    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
725        characters from a string of bytes) have been redefined so as not to use
726        loops, in order to improve performance in some environments. At the same
727        time, I abstracted some of the common code into auxiliary macros to save
728        repetition (this should not affect the compiled code).
729    
730    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
731        compile-time error is now given if \c is not followed by an ASCII
732        character, that is, a byte less than 128. (In EBCDIC mode, the code is
733        different, and any byte value is allowed.)
734    
735    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
736        START_OPTIMIZE option, which is now allowed at compile time - but just
737        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
738        to pcregrep and other applications that have no direct access to PCRE
739        options. The new /Y option in pcretest sets this option when calling
740        pcre_compile().
741    
742    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
743        back references. Groups containing recursive back references were forced to
744        be atomic by that change, but in the case of named groups, the amount of
745        memory required was incorrectly computed, leading to "Failed: internal
746        error: code overflow". This has been fixed.
747    
748    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
749        pcretest.c, to avoid build problems in some Borland environments.
750    
751    
752    Version 8.10 25-Jun-2010
753  ------------------------  ------------------------
754    
755  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and  1.  Added support for (*MARK:ARG) and for ARG additions to PRUNE, SKIP, and
# Line 9  Version 8.10 03 May-2010 Line 757  Version 8.10 03 May-2010
757    
758  2.  (*ACCEPT) was not working when inside an atomic group.  2.  (*ACCEPT) was not working when inside an atomic group.
759    
760  3.  Inside a character class, \B is treated as a literal by default, but  3.  Inside a character class, \B is treated as a literal by default, but
761      faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option      faulted if PCRE_EXTRA is set. This mimics Perl's behaviour (the -w option
762      causes the error). The code is unchanged, but I tidied the documentation.      causes the error). The code is unchanged, but I tidied the documentation.
763    
764  4.  Inside a character class, PCRE always treated \R and \X as literals,  4.  Inside a character class, PCRE always treated \R and \X as literals,
765      whereas Perl faults them if its -w option is set. I have changed PCRE so      whereas Perl faults them if its -w option is set. I have changed PCRE so
766      that it faults them when PCRE_EXTRA is set.      that it faults them when PCRE_EXTRA is set.
767    
768  5.  Added support for \N, which always matches any character other than  5.  Added support for \N, which always matches any character other than
769      newline. (It is the same as "." when PCRE_DOTALL is not set.)      newline. (It is the same as "." when PCRE_DOTALL is not set.)
770    
771  6.  When compiling pcregrep with newer versions of gcc which may have  6.  When compiling pcregrep with newer versions of gcc which may have
772      FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',      FORTIFY_SOURCE set, several warnings "ignoring return value of 'fwrite',
773      declared with attribute warn_unused_result" were given. Just casting the      declared with attribute warn_unused_result" were given. Just casting the
774      result to (void) does not stop the warnings; a more elaborate fudge is      result to (void) does not stop the warnings; a more elaborate fudge is
775      needed. I've used a macro to implement this.      needed. I've used a macro to implement this.
776    
777  7.  Minor change to pcretest.c to avoid a compiler warning.  7.  Minor change to pcretest.c to avoid a compiler warning.
778    
779  8.  Added four artifical Unicode properties to help with an option to make  8.  Added four artifical Unicode properties to help with an option to make
780      \s etc use properties (see next item). The new properties are: Xan      \s etc use properties (see next item). The new properties are: Xan
781      (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).      (alphanumeric), Xsp (Perl space), Xps (POSIX space), and Xwd (word).
782    
783  9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes  9.  Added PCRE_UCP to make \b, \d, \s, \w, and certain POSIX character classes
784      use Unicode properties. (*UCP) at the start of a pattern can be used to set      use Unicode properties. (*UCP) at the start of a pattern can be used to set
785      this option. Modified pcretest to add /W to test this facility. Added      this option. Modified pcretest to add /W to test this facility. Added
786      REG_UCP to make it available via the POSIX interface.      REG_UCP to make it available via the POSIX interface.
   
 10. Added --line-buffered to pcregrep.  
787    
788  11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was  10. Added --line-buffered to pcregrep.
789      studied, and the match started with a letter with a code point greater than  
790    11. In UTF-8 mode, if a pattern that was compiled with PCRE_CASELESS was
791        studied, and the match started with a letter with a code point greater than
792      127 whose first byte was different to the first byte of the other case of      127 whose first byte was different to the first byte of the other case of
793      the letter, the other case of this starting letter was not recognized.      the letter, the other case of this starting letter was not recognized
794        (#976).
795  12. pcreposix.c included pcre.h before including pcre_internal.h. This caused a  
796      conflict in the definition of PCRE_EXP_DECL. I have removed the include of  12. If a pattern that was studied started with a repeated Unicode property
     pcre.h as pcre_internal.h includes pcre.h itself. (This may be a bit of  
     historical tidying that never got done.)  
   
 13. If a pattern that was studied started with a repeated Unicode property  
797      test, for example, \p{Nd}+, there was the theoretical possibility of      test, for example, \p{Nd}+, there was the theoretical possibility of
798      setting up an incorrect bitmap of starting bytes, but fortunately it could      setting up an incorrect bitmap of starting bytes, but fortunately it could
799      not have actually happened in practice until change 8 above was made (it      not have actually happened in practice until change 8 above was made (it
800      added property types that matched character-matching opcodes).      added property types that matched character-matching opcodes).
801    
802    13. pcre_study() now recognizes \h, \v, and \R when constructing a bit map of
803        possible starting bytes for non-anchored patterns.
804    
805    14. Extended the "auto-possessify" feature of pcre_compile(). It now recognizes
806        \R, and also a number of cases that involve Unicode properties, both
807        explicit and implicit when PCRE_UCP is set.
808    
809    15. If a repeated Unicode property match (e.g. \p{Lu}*) was used with non-UTF-8
810        input, it could crash or give wrong results if characters with values
811        greater than 0xc0 were present in the subject string. (Detail: it assumed
812        UTF-8 input when processing these items.)
813    
814    16. Added a lot of (int) casts to avoid compiler warnings in systems where
815        size_t is 64-bit (#991).
816    
817    17. Added a check for running out of memory when PCRE is compiled with
818        --disable-stack-for-recursion (#990).
819    
820    18. If the last data line in a file for pcretest does not have a newline on
821        the end, a newline was missing in the output.
822    
823    19. The default pcre_chartables.c file recognizes only ASCII characters (values
824        less than 128) in its various bitmaps. However, there is a facility for
825        generating tables according to the current locale when PCRE is compiled. It
826        turns out that in some environments, 0x85 and 0xa0, which are Unicode space
827        characters, are recognized by isspace() and therefore were getting set in
828        these tables, and indeed these tables seem to approximate to ISO 8859. This
829        caused a problem in UTF-8 mode when pcre_study() was used to create a list
830        of bytes that can start a match. For \s, it was including 0x85 and 0xa0,
831        which of course cannot start UTF-8 characters. I have changed the code so
832        that only real ASCII characters (less than 128) and the correct starting
833        bytes for UTF-8 encodings are set for characters greater than 127 when in
834        UTF-8 mode. (When PCRE_UCP is set - see 9 above - the code is different
835        altogether.)
836    
837    20. Added the /T option to pcretest so as to be able to run tests with non-
838        standard character tables, thus making it possible to include the tests
839        used for 19 above in the standard set of tests.
840    
841    21. A pattern such as (?&t)(?#()(?(DEFINE)(?<t>a)) which has a forward
842        reference to a subpattern the other side of a comment that contains an
843        opening parenthesis caused either an internal compiling error, or a
844        reference to the wrong subpattern.
845    
846    
847  Version 8.02 19-Mar-2010  Version 8.02 19-Mar-2010

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