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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.30
5    ------------
6    
7    1.  Renamed "isnumber" as "is_a_number" because in some Mac environments this
8        name is defined in ctype.h.
9    
10    2.  Fixed a bug in fixed-length calculation for lookbehinds that would show up
11        only in quite long subpatterns.
12    
13    3.  Removed the function pcre_info(), which has been obsolete and deprecated
14        since it was replaced by pcre_fullinfo() in February 2000.
15    
16    4.  For a non-anchored pattern, if (*SKIP) was given with a name that did not
17        match a (*MARK), and the match failed at the start of the subject, a
18        reference to memory before the start of the subject could occur. This bug
19        was introduced by fix 17 of release 8.21.
20    
21    5.  A reference to an unset group with zero minimum repetition was giving
22        totally wrong answers (in non-JavaScript-compatibility mode). For example,
23        /(another)?(\1?)test/ matched against "hello world test". This bug was
24        introduced in release 8.13.
25    
26    6.  Add support for 16-bit character strings (a large amount of work involving
27        many changes and refactorings).
28    
29    7.  RunGrepTest failed on msys because \r\n was replaced by whitespace when the
30        command "pattern=`printf 'xxx\r\njkl'`" was run. The pattern is now taken
31        from a file.
32    
33    8.  Ovector size of 2 is also supported by JIT based pcre_exec (the ovector size
34        rounding is not applied in this particular case).
35    
36    9.  The invalid Unicode surrogate codepoints U+D800 to U+DFFF are now rejected
37        if they appear, or are escaped, in patterns.
38    
39    10. Get rid of a number of -Wunused-but-set-variable warnings.
40    
41    
42    Version 8.21 12-Dec-2011
43    ------------------------
44    
45    1.  Updating the JIT compiler.
46    
47    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
48        are added as well.
49    
50    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
51        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
52        calling _pcre_jit_exec. Some extra comments are added.
53    
54    4.  (*MARK) settings inside atomic groups that do not contain any capturing
55        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
56        was introduced by change 18 for 8.20.
57    
58    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
59        ECMA-262 standard.
60    
61    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
62        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
63        This bug was probably introduced by change 9 of 8.13.
64    
65    7.  While fixing 6 above, I noticed that a number of other items were being
66        incorrectly rejected as "not fixed length". This arose partly because newer
67        opcodes had not been added to the fixed-length checking code. I have (a)
68        corrected the bug and added tests for these items, and (b) arranged for an
69        error to occur if an unknown opcode is encountered while checking for fixed
70        length instead of just assuming "not fixed length". The items that were
71        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
72        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
73        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
74    
75    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
76        being incorrectly compiled and would have given unpredicatble results.
77    
78    9.  A possessively repeated subpattern with minimum repeat count greater than
79        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
80        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
81        the first (A) could occur when it should not.
82    
83    10. Add a cast and remove a redundant test from the code.
84    
85    11. JIT should use pcre_malloc/pcre_free for allocation.
86    
87    12. Updated pcre-config so that it no longer shows -L/usr/lib, which seems
88        best practice nowadays, and helps with cross-compiling. (If the exec_prefix
89        is anything other than /usr, -L is still shown).
90    
91    13. In non-UTF-8 mode, \C is now supported in lookbehinds and DFA matching.
92    
93    14. Perl does not support \N without a following name in a [] class; PCRE now
94        also gives an error.
95    
96    15. If a forward reference was repeated with an upper limit of around 2000,
97        it caused the error "internal error: overran compiling workspace". The
98        maximum number of forward references (including repeats) was limited by the
99        internal workspace, and dependent on the LINK_SIZE. The code has been
100        rewritten so that the workspace expands (via pcre_malloc) if necessary, and
101        the default depends on LINK_SIZE. There is a new upper limit (for safety)
102        of around 200,000 forward references. While doing this, I also speeded up
103        the filling in of repeated forward references.
104    
105    16. A repeated forward reference in a pattern such as (a)(?2){2}(.) was
106        incorrectly expecting the subject to contain another "a" after the start.
107    
108    17. When (*SKIP:name) is activated without a corresponding (*MARK:name) earlier
109        in the match, the SKIP should be ignored. This was not happening; instead
110        the SKIP was being treated as NOMATCH. For patterns such as
111        /A(*MARK:A)A+(*SKIP:B)Z|AAC/ this meant that the AAC branch was never
112        tested.
113    
114    18. The behaviour of (*MARK), (*PRUNE), and (*THEN) has been reworked and is
115        now much more compatible with Perl, in particular in cases where the result
116        is a non-match for a non-anchored pattern. For example, if
117        /b(*:m)f|a(*:n)w/ is matched against "abc", the non-match returns the name
118        "m", where previously it did not return a name. A side effect of this
119        change is that for partial matches, the last encountered mark name is
120        returned, as for non matches. A number of tests that were previously not
121        Perl-compatible have been moved into the Perl-compatible test files. The
122        refactoring has had the pleasing side effect of removing one argument from
123        the match() function, thus reducing its stack requirements.
124    
125    19. If the /S+ option was used in pcretest to study a pattern using JIT,
126        subsequent uses of /S (without +) incorrectly behaved like /S+.
127    
128    21. Retrieve executable code size support for the JIT compiler and fixing
129        some warnings.
130    
131    22. A caseless match of a UTF-8 character whose other case uses fewer bytes did
132        not work when the shorter character appeared right at the end of the
133        subject string.
134    
135    23. Added some (int) casts to non-JIT modules to reduce warnings on 64-bit
136        systems.
137    
138    24. Added PCRE_INFO_JITSIZE to pass on the value from (21) above, and also
139        output it when the /M option is used in pcretest.
140    
141    25. The CheckMan script was not being included in the distribution. Also, added
142        an explicit "perl" to run Perl scripts from the PrepareRelease script
143        because this is reportedly needed in Windows.
144    
145    26. If study data was being save in a file and studying had not found a set of
146        "starts with" bytes for the pattern, the data written to the file (though
147        never used) was taken from uninitialized memory and so caused valgrind to
148        complain.
149    
150    27. Updated RunTest.bat as provided by Sheri Pierce.
151    
152    28. Fixed a possible uninitialized memory bug in pcre_jit_compile.c.
153    
154    29. Computation of memory usage for the table of capturing group names was
155        giving an unnecessarily large value.
156    
157    
158    Version 8.20 21-Oct-2011
159    ------------------------
160    
161    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
162        a POSIX class. After further experiments with Perl, which convinced me that
163        Perl has bugs and confusions, a closing square bracket is no longer allowed
164        in a POSIX name. This bug also affected patterns with classes that started
165        with full stops.
166    
167    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
168        captured substring, but while checking the failing first alternative,
169        substring 1 is temporarily captured. If the output vector supplied to
170        pcre_exec() was not big enough for this capture, the yield of the function
171        was still zero ("insufficient space for captured substrings"). This cannot
172        be totally fixed without adding another stack variable, which seems a lot
173        of expense for a edge case. However, I have improved the situation in cases
174        such as /(a)(b)x|abc/ matched against "abc", where the return code
175        indicates that fewer than the maximum number of slots in the ovector have
176        been set.
177    
178    3.  Related to (2) above: when there are more back references in a pattern than
179        slots in the output vector, pcre_exec() uses temporary memory during
180        matching, and copies in the captures as far as possible afterwards. It was
181        using the entire output vector, but this conflicts with the specification
182        that only 2/3 is used for passing back captured substrings. Now it uses
183        only the first 2/3, for compatibility. This is, of course, another edge
184        case.
185    
186    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
187        main code base, and can be used by building with --enable-jit. When this is
188        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
189        runtime --no-jit option is given.
190    
191    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
192        ovector, the return from the function was zero, implying that there were
193        other matches that did not fit. The correct "exactly full" value is now
194        returned.
195    
196    6.  If a subpattern that was called recursively or as a subroutine contained
197        (*PRUNE) or any other control that caused it to give a non-standard return,
198        invalid errors such as "Error -26 (nested recursion at the same subject
199        position)" or even infinite loops could occur.
200    
201    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
202        computing the minimum length on reaching *ACCEPT, and so ended up with the
203        wrong value of 1 rather than 0. Further investigation indicates that
204        computing a minimum subject length in the presence of *ACCEPT is difficult
205        (think back references, subroutine calls), and so I have changed the code
206        so that no minimum is registered for a pattern that contains *ACCEPT.
207    
208    8.  If (*THEN) was present in the first (true) branch of a conditional group,
209        it was not handled as intended. [But see 16 below.]
210    
211    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
212        Sheri Pierce.
213    
214    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
215        the first byte in a match must be "a".
216    
217    11. Change 17 for 8.13 increased the recursion depth for patterns like
218        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
219        pattern contains any instances of (*THEN). If it does not, the old
220        optimizations are restored. It would be nice to do this on a per-group
221        basis, but at the moment that is not feasible.
222    
223    12. In some environments, the output of pcretest -C is CRLF terminated. This
224        broke RunTest's code that checks for the link size. A single white space
225        character after the value is now allowed for.
226    
227    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
228        For "fr", it uses the Windows-specific input and output files.
229    
230    14. If (*THEN) appeared in a group that was called recursively or as a
231        subroutine, it did not work as intended. [But see next item.]
232    
233    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
234        pattern fragments (but not containing any | characters). If A and B are
235        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
236        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
237        D. In other words, Perl considers parentheses that do not contain any |
238        characters to be part of a surrounding alternative, whereas PCRE was
239        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
240        differently. PCRE now behaves in the same way as Perl, except in the case
241        of subroutine/recursion calls such as (?1) which have in any case always
242        been different (but PCRE had them first :-).
243    
244    16. Related to 15 above: Perl does not treat the | in a conditional group as
245        creating alternatives. Such a group is treated in the same way as an
246        ordinary group without any | characters when processing (*THEN). PCRE has
247        been changed to match Perl's behaviour.
248    
249    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
250        RunGrepTest script failed.
251    
252    18. Change 22 for version 13 caused atomic groups to use more stack. This is
253        inevitable for groups that contain captures, but it can lead to a lot of
254        stack use in large patterns. The old behaviour has been restored for atomic
255        groups that do not contain any capturing parentheses.
256    
257    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
258        suppress the check for a minimum subject length at run time. (If it was
259        given to pcre_exec() or pcre_dfa_exec() it did work.)
260    
261    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
262        fail to work when decoding hex characters in data strings in EBCDIC
263        environments.
264    
265    21. It appears that in at least one Mac OS environment, the isxdigit() function
266        is implemented as a macro that evaluates to its argument more than once,
267        contravening the C 90 Standard (I haven't checked a later standard). There
268        was an instance in pcretest which caused it to go wrong when processing
269        \x{...} escapes in subject strings. The has been rewritten to avoid using
270        things like p++ in the argument of isxdigit().
271    
272    
273    Version 8.13 16-Aug-2011
274  ------------------------  ------------------------
275    
276  1.  The Unicode data tables have been updated to Unicode 6.0.0.  1.  The Unicode data tables have been updated to Unicode 6.0.0.
# Line 20  Version 8.13 30-Apr-2011 Line 289  Version 8.13 30-Apr-2011
289      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a      code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
290      2-byte code at the end of the subject (it thought there wasn't enough data      2-byte code at the end of the subject (it thought there wasn't enough data
291      left).      left).
292    
293  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
294      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long      pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
295      as the output vector has at least 2 elements. The offset of the start of      as the output vector has at least 2 elements. The offset of the start of
296      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
297    
298  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is  6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
299      now returned is for the first byte of the failing character, instead of the      now returned is for the first byte of the failing character, instead of the
300      last byte inspected. This is an incompatible change, but I hope it is small      last byte inspected. This is an incompatible change, but I hope it is small
301      enough not to be a problem. It makes the returned offset consistent with      enough not to be a problem. It makes the returned offset consistent with
302      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
303    
304  7.  pcretest now gives a text phrase as well as the error number when  7.  pcretest now gives a text phrase as well as the error number when
305      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check      pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
306      failure, the offset and reason code are output.      failure, the offset and reason code are output.
307    
308  8.  When \R was used with a maximizing quantifier it failed to skip backwards  8.  When \R was used with a maximizing quantifier it failed to skip backwards
309      over a \r\n pair if the subsequent match failed. Instead, it just skipped      over a \r\n pair if the subsequent match failed. Instead, it just skipped
310      back over a single character (\n). This seems wrong (because it treated the      back over a single character (\n). This seems wrong (because it treated the
311      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
312      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the      documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
313      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
314      has been changed.      has been changed.
315    
316  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
317      of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile      of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
318      time (the PCRE_DOTALL option was changed this way some time ago: version      time (the PCRE_DOTALL option was changed this way some time ago: version
319      7.7 change 16). This has made it possible to abolish the OP_OPT op code,      7.7 change 16). This has made it possible to abolish the OP_OPT op code,
320      which was always a bit of a fudge. It also means that there is one less      which was always a bit of a fudge. It also means that there is one less
321      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
322      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
323      (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.      (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
324    
325  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
326      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
327      using pcre_exec().      using pcre_exec().
328    
329  11. While implementing 10, a number of bugs in the handling of groups were  11. While implementing 10, a number of bugs in the handling of groups were
330      discovered and fixed:      discovered and fixed:
331    
332      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
333      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
334      ((a|)+)+  did not notice that the outer group could match an empty string.      ((a|)+)+  did not notice that the outer group could match an empty string.
335      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
336      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
337    
338  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
339      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
340      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
341    
342  13. Be more explicit in pcre_study() instead of relying on "default" for  13. Be more explicit in pcre_study() instead of relying on "default" for
343      opcodes that mean there is no starting character; this means that when new      opcodes that mean there is no starting character; this means that when new
344      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
345      pick them up.      pick them up.
346    
347  14. The -s option of pcretest has been documented for ages as being an old  14. The -s option of pcretest has been documented for ages as being an old
348      synonym of -m (show memory usage). I have changed it to mean "force study      synonym of -m (show memory usage). I have changed it to mean "force study
349      for every regex", that is, assume /S for every regex. This is similar to -i      for every regex", that is, assume /S for every regex. This is similar to -i
350      and -d etc. It's slightly incompatible, but I'm hoping nobody is still      and -d etc. It's slightly incompatible, but I'm hoping nobody is still
351      using it. It makes it easier to run collections of tests with and without      using it. It makes it easier to run collections of tests with and without
352      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
353      tests are now run with and without -s (but some patterns can be marked as      tests are now run with and without -s (but some patterns can be marked as
354      "never study" - see 20 below).      "never study" - see 20 below).
355    
356  15. When (*ACCEPT) was used in a subpattern that was called recursively, the  15. When (*ACCEPT) was used in a subpattern that was called recursively, the
357      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
358      correctly.      correctly.
359    
360  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
361      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
362      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
363      match.      match.
364    
365  17. There was optimizing code for the last branch of non-capturing parentheses,  17. There was optimizing code for the last branch of non-capturing parentheses,
366      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
367      tail recursion to cut down on stack usage. Unfortunately, not that there is      tail recursion to cut down on stack usage. Unfortunately, now that there is
368      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
369      no longer possible because the return has to be checked for (*THEN). These      no longer possible because the return has to be checked for (*THEN). These
370      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
371    
372  18. If a pattern containing \R was studied, it was assumed that \R always  18. If a pattern containing \R was studied, it was assumed that \R always
373      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
374      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
375    
376  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
377      was incorrectly computed.      was incorrectly computed.
378    
379  20. If /S is present twice on a test pattern in pcretest input, it *disables*  20. If /S is present twice on a test pattern in pcretest input, it now
380      studying, thereby overriding the use of -s on the command line. This is      *disables* studying, thereby overriding the use of -s on the command line
381      necessary for one or two tests to keep the output identical in both cases.      (see 14 above). This is necessary for one or two tests to keep the output
382        identical in both cases.
383    
384  21. When (*ACCEPT) was used in an assertion that matched an empty string and  21. When (*ACCEPT) was used in an assertion that matched an empty string and
385      PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.      PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
386    
387  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
388      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
389      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
390      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
391      group 1 to "a", when in fact it should be unset. This applied to multi-      group 1 to "a", when in fact it should be unset. This applied to multi-
392      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
393      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
394      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
395    
396  23. Add the ++ qualifier feature to pcretest, to show the remainder of the  23. Add the ++ qualifier feature to pcretest, to show the remainder of the
397      subject after a captured substring (to make it easier to tell which of a      subject after a captured substring, to make it easier to tell which of a
398      number of identical substrings has been captured).      number of identical substrings has been captured.
399    
400  24. The way atomic groups are processed by pcre_exec() has been changed so that  24. The way atomic groups are processed by pcre_exec() has been changed so that
401      if they are repeated, backtracking one repetition now resets captured      if they are repeated, backtracking one repetition now resets captured
402      values correctly. For example, if ((?>(a+)b)+aabab) is matched against      values correctly. For example, if ((?>(a+)b)+aabab) is matched against
403      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
404      "aaa". Previously, it would have been "a". As part of this code      "aaa". Previously, it would have been "a". As part of this code
405      refactoring, the way recursive calls are handled has also been changed.      refactoring, the way recursive calls are handled has also been changed.
406    
407  24. If an assertion condition captured any substrings, they were not passed  25. If an assertion condition captured any substrings, they were not passed
408      back unless some other capturing happened later. For example, if      back unless some other capturing happened later. For example, if
409      (?(?=(a))a) was matched against "a", no capturing was returned.      (?(?=(a))a) was matched against "a", no capturing was returned.
410    
411  25. When studying a pattern that contained subroutine calls or assertions,  26. When studying a pattern that contained subroutine calls or assertions,
412      the code for finding the minimum length of a possible match was handling      the code for finding the minimum length of a possible match was handling
413      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
414      group 1 called group 2 while simultaneously a separate group 2 called group      group 1 called group 2 while simultaneously a separate group 2 called group
415      1). A stack overflow occurred in this case. I have fixed this by limiting      1). A stack overflow occurred in this case. I have fixed this by limiting
416      the recursion depth to 10.      the recursion depth to 10.
417    
418  26. Updated RunTest.bat in the distribution to the version supplied by Tom  27. Updated RunTest.bat in the distribution to the version supplied by Tom
419      Fortmann. This supports explicit test numbers on the command line, and has      Fortmann. This supports explicit test numbers on the command line, and has
420      argument validation and error reporting.      argument validation and error reporting.
421    
422  27. An instance of \X with an unlimited repeat could fail if at any point the  28. An instance of \X with an unlimited repeat could fail if at any point the
423      first character it looked at was a mark character.      first character it looked at was a mark character.
424    
425  28. Some minor code refactoring concerning Unicode properties and scripts  29. Some minor code refactoring concerning Unicode properties and scripts
426      should reduce the stack requirement of match() slightly.      should reduce the stack requirement of match() slightly.
427    
428  29. Added the '=' option to pcretest to check the setting of unused capturing  30. Added the '=' option to pcretest to check the setting of unused capturing
429      slots at the end of the pattern, which are documented as being -1, but are      slots at the end of the pattern, which are documented as being -1, but are
430      not included in the return count.      not included in the return count.
431    
432    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
433        compiled something random. Now it gives a compile-time error (as does
434        Perl).
435    
436    32. A *MARK encountered during the processing of a positive assertion is now
437        recorded and passed back (compatible with Perl).
438    
439    33. If --only-matching or --colour was set on a pcregrep call whose pattern
440        had alternative anchored branches, the search for a second match in a line
441        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
442        matched the line "0102" twice. The same bug affected patterns that started
443        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
444        twice.
445    
446    34. Previously, PCRE did not allow quantification of assertions. However, Perl
447        does, and because of capturing effects, quantifying parenthesized
448        assertions may at times be useful. Quantifiers are now allowed for
449        parenthesized assertions.
450    
451    35. A minor code tidy in pcre_compile() when checking options for \R usage.
452    
453    36. \g was being checked for fancy things in a character class, when it should
454        just be a literal "g".
455    
456    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
457        appearance of a nested POSIX class supersedes an apparent external class.
458        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
459        unescaped square brackets may also appear as part of class names. For
460        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
461        more like Perl. (But see 8.20/1 above.)
462    
463    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
464        was because it thought it was \N{name}, which is not supported).
465    
466    39. Add minix to OS list not supporting the -S option in pcretest.
467    
468    40. PCRE tries to detect cases of infinite recursion at compile time, but it
469        cannot analyze patterns in sufficient detail to catch mutual recursions
470        such as ((?1))((?2)). There is now a runtime test that gives an error if a
471        subgroup is called recursively as a subpattern for a second time at the
472        same position in the subject string. In previous releases this might have
473        been caught by the recursion limit, or it might have run out of stack.
474    
475    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
476        happen only once. PCRE was, however incorrectly giving a compile time error
477        "recursive call could loop indefinitely" because it cannot analyze the
478        pattern in sufficient detail. The compile time test no longer happens when
479        PCRE is compiling a conditional subpattern, but actual runaway loops are
480        now caught at runtime (see 40 above).
481    
482    42. It seems that Perl allows any characters other than a closing parenthesis
483        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
484        has been changed to be the same.
485    
486    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
487        as not to get warnings when autogen.sh is called. Also changed
488        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
489    
490    44. To help people who use pcregrep to scan files containing exceedingly long
491        lines, the following changes have been made:
492    
493        (a) The default value of the buffer size parameter has been increased from
494            8K to 20K. (The actual buffer used is three times this size.)
495    
496        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
497            PCRE is built.
498    
499        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
500            to be set at run time.
501    
502        (d) Numerical values in pcregrep options can be followed by K or M, for
503            example --buffer-size=50K.
504    
505        (e) If a line being scanned overflows pcregrep's buffer, an error is now
506            given and the return code is set to 2.
507    
508    45. Add a pointer to the latest mark to the callout data block.
509    
510    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
511        partial match of an empty string instead of no match. This was specific to
512        the use of ".".
513    
514    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
515        complete match instead of a partial match. This bug was dependent on both
516        the PCRE_UTF8 and PCRE_DOTALL options being set.
517    
518    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
519        starting byte set, because \b was not being ignored.
520    
521    
522  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

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