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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
4  Version 8.12 12-Jan-2011  Version 8.21
5    ------------
7    1.  Updating the JIT compiler.
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
12    3.  Fix cache-flush issue on PowerPC (It is still an experimental JIT port).
13        PCRE_EXTRA_TABLES is not suported by JIT, and should be checked before
14        calling _pcre_jit_exec. Some extra comments are added.
16    4.  Mark settings inside atomic groups that do not contain any capturing
17        parentheses, for example, (?>a(*:m)), were not being passed out. This bug
18        was introduced by change 18 for 8.20.
20    5.  Supporting of \x, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
41    Version 8.20 21-Oct-2011
42    ------------------------
44    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
45        a POSIX class. After further experiments with Perl, which convinced me that
46        Perl has bugs and confusions, a closing square bracket is no longer allowed
47        in a POSIX name. This bug also affected patterns with classes that started
48        with full stops.
50    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
51        captured substring, but while checking the failing first alternative,
52        substring 1 is temporarily captured. If the output vector supplied to
53        pcre_exec() was not big enough for this capture, the yield of the function
54        was still zero ("insufficient space for captured substrings"). This cannot
55        be totally fixed without adding another stack variable, which seems a lot
56        of expense for a edge case. However, I have improved the situation in cases
57        such as /(a)(b)x|abc/ matched against "abc", where the return code
58        indicates that fewer than the maximum number of slots in the ovector have
59        been set.
61    3.  Related to (2) above: when there are more back references in a pattern than
62        slots in the output vector, pcre_exec() uses temporary memory during
63        matching, and copies in the captures as far as possible afterwards. It was
64        using the entire output vector, but this conflicts with the specification
65        that only 2/3 is used for passing back captured substrings. Now it uses
66        only the first 2/3, for compatibility. This is, of course, another edge
67        case.
69    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
70        main code base, and can be used by building with --enable-jit. When this is
71        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
72        runtime --no-jit option is given.
74    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
75        ovector, the return from the function was zero, implying that there were
76        other matches that did not fit. The correct "exactly full" value is now
77        returned.
79    6.  If a subpattern that was called recursively or as a subroutine contained
80        (*PRUNE) or any other control that caused it to give a non-standard return,
81        invalid errors such as "Error -26 (nested recursion at the same subject
82        position)" or even infinite loops could occur.
84    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
85        computing the minimum length on reaching *ACCEPT, and so ended up with the
86        wrong value of 1 rather than 0. Further investigation indicates that
87        computing a minimum subject length in the presence of *ACCEPT is difficult
88        (think back references, subroutine calls), and so I have changed the code
89        so that no minimum is registered for a pattern that contains *ACCEPT.
91    8.  If (*THEN) was present in the first (true) branch of a conditional group,
92        it was not handled as intended. [But see 16 below.]
94    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
95        Sheri Pierce.
97    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
98        the first byte in a match must be "a".
100    11. Change 17 for 8.13 increased the recursion depth for patterns like
101        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
102        pattern contains any instances of (*THEN). If it does not, the old
103        optimizations are restored. It would be nice to do this on a per-group
104        basis, but at the moment that is not feasible.
106    12. In some environments, the output of pcretest -C is CRLF terminated. This
107        broke RunTest's code that checks for the link size. A single white space
108        character after the value is now allowed for.
110    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
111        For "fr", it uses the Windows-specific input and output files.
113    14. If (*THEN) appeared in a group that was called recursively or as a
114        subroutine, it did not work as intended. [But see next item.]
116    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
117        pattern fragments (but not containing any | characters). If A and B are
118        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
119        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
120        D. In other words, Perl considers parentheses that do not contain any |
121        characters to be part of a surrounding alternative, whereas PCRE was
122        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
123        differently. PCRE now behaves in the same way as Perl, except in the case
124        of subroutine/recursion calls such as (?1) which have in any case always
125        been different (but PCRE had them first :-).
127    16. Related to 15 above: Perl does not treat the | in a conditional group as
128        creating alternatives. Such a group is treated in the same way as an
129        ordinary group without any | characters when processing (*THEN). PCRE has
130        been changed to match Perl's behaviour.
132    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
133        RunGrepTest script failed.
135    18. Change 22 for version 13 caused atomic groups to use more stack. This is
136        inevitable for groups that contain captures, but it can lead to a lot of
137        stack use in large patterns. The old behaviour has been restored for atomic
138        groups that do not contain any capturing parentheses.
140    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
141        suppress the check for a minimum subject length at run time. (If it was
142        given to pcre_exec() or pcre_dfa_exec() it did work.)
144    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
145        fail to work when decoding hex characters in data strings in EBCDIC
146        environments.
148    21. It appears that in at least one Mac OS environment, the isxdigit() function
149        is implemented as a macro that evaluates to its argument more than once,
150        contravening the C 90 Standard (I haven't checked a later standard). There
151        was an instance in pcretest which caused it to go wrong when processing
152        \x{...} escapes in subject strings. The has been rewritten to avoid using
153        things like p++ in the argument of isxdigit().
156    Version 8.13 16-Aug-2011
157    ------------------------
159    1.  The Unicode data tables have been updated to Unicode 6.0.0.
161    2.  Two minor typos in pcre_internal.h have been fixed.
163    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
164        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
165        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
167    4.  There were a number of related bugs in the code for matching backrefences
168        caselessly in UTF-8 mode when codes for the characters concerned were
169        different numbers of bytes. For example, U+023A and U+2C65 are an upper
170        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
171        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
172        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
173        2-byte code at the end of the subject (it thought there wasn't enough data
174        left).
176    5.  Comprehensive information about what went wrong is now returned by
177        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
178        as the output vector has at least 2 elements. The offset of the start of
179        the failing character and a reason code are placed in the vector.
181    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
182        now returned is for the first byte of the failing character, instead of the
183        last byte inspected. This is an incompatible change, but I hope it is small
184        enough not to be a problem. It makes the returned offset consistent with
185        pcre_exec() and pcre_dfa_exec().
187    7.  pcretest now gives a text phrase as well as the error number when
188        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
189        failure, the offset and reason code are output.
191    8.  When \R was used with a maximizing quantifier it failed to skip backwards
192        over a \r\n pair if the subsequent match failed. Instead, it just skipped
193        back over a single character (\n). This seems wrong (because it treated the
194        two characters as a single entity when going forwards), conflicts with the
195        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
196        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
197        has been changed.
199    9.  Some internal refactoring has changed the processing so that the handling
200        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
201        time (the PCRE_DOTALL option was changed this way some time ago: version
202        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
203        which was always a bit of a fudge. It also means that there is one less
204        argument for the match() function, which reduces its stack requirements
205        slightly. This change also fixes an incompatibility with Perl: the pattern
206        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
208    10. More internal refactoring has drastically reduced the number of recursive
209        calls to match() for possessively repeated groups such as (abc)++ when
210        using pcre_exec().
212    11. While implementing 10, a number of bugs in the handling of groups were
213        discovered and fixed:
215        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
216        (a|)*(?1) gave a compile-time internal error.
217        ((a|)+)+  did not notice that the outer group could match an empty string.
218        (^a|^)+   was not marked as anchored.
219        (.*a|.*)+ was not marked as matching at start or after a newline.
221    12. Yet more internal refactoring has removed another argument from the match()
222        function. Special calls to this function are now indicated by setting a
223        value in a variable in the "match data" data block.
225    13. Be more explicit in pcre_study() instead of relying on "default" for
226        opcodes that mean there is no starting character; this means that when new
227        ones are added and accidentally left out of pcre_study(), testing should
228        pick them up.
230    14. The -s option of pcretest has been documented for ages as being an old
231        synonym of -m (show memory usage). I have changed it to mean "force study
232        for every regex", that is, assume /S for every regex. This is similar to -i
233        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
234        using it. It makes it easier to run collections of tests with and without
235        study enabled, and thereby test pcre_study() more easily. All the standard
236        tests are now run with and without -s (but some patterns can be marked as
237        "never study" - see 20 below).
239    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
240        restoration of the capturing data to the outer values was not happening
241        correctly.
243    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
244        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
245        pattern had matched an empty string, and so incorrectly returned a no
246        match.
248    17. There was optimizing code for the last branch of non-capturing parentheses,
249        and also for the obeyed branch of a conditional subexpression, which used
250        tail recursion to cut down on stack usage. Unfortunately, now that there is
251        the possibility of (*THEN) occurring in these branches, tail recursion is
252        no longer possible because the return has to be checked for (*THEN). These
253        two optimizations have therefore been removed. [But see 8.20/11 above.]
255    18. If a pattern containing \R was studied, it was assumed that \R always
256        matched two bytes, thus causing the minimum subject length to be
257        incorrectly computed because \R can also match just one byte.
259    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
260        was incorrectly computed.
262    20. If /S is present twice on a test pattern in pcretest input, it now
263        *disables* studying, thereby overriding the use of -s on the command line
264        (see 14 above). This is necessary for one or two tests to keep the output
265        identical in both cases.
267    21. When (*ACCEPT) was used in an assertion that matched an empty string and
268        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
270    22. When an atomic group that contained a capturing parenthesis was
271        successfully matched, but the branch in which it appeared failed, the
272        capturing was not being forgotten if a higher numbered group was later
273        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
274        group 1 to "a", when in fact it should be unset. This applied to multi-
275        branched capturing and non-capturing groups, repeated or not, and also to
276        positive assertions (capturing in negative assertions does not happen
277        in PCRE) and also to nested atomic groups.
279    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
280        subject after a captured substring, to make it easier to tell which of a
281        number of identical substrings has been captured.
283    24. The way atomic groups are processed by pcre_exec() has been changed so that
284        if they are repeated, backtracking one repetition now resets captured
285        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
286        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
287        "aaa". Previously, it would have been "a". As part of this code
288        refactoring, the way recursive calls are handled has also been changed.
290    25. If an assertion condition captured any substrings, they were not passed
291        back unless some other capturing happened later. For example, if
292        (?(?=(a))a) was matched against "a", no capturing was returned.
294    26. When studying a pattern that contained subroutine calls or assertions,
295        the code for finding the minimum length of a possible match was handling
296        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
297        group 1 called group 2 while simultaneously a separate group 2 called group
298        1). A stack overflow occurred in this case. I have fixed this by limiting
299        the recursion depth to 10.
301    27. Updated RunTest.bat in the distribution to the version supplied by Tom
302        Fortmann. This supports explicit test numbers on the command line, and has
303        argument validation and error reporting.
305    28. An instance of \X with an unlimited repeat could fail if at any point the
306        first character it looked at was a mark character.
308    29. Some minor code refactoring concerning Unicode properties and scripts
309        should reduce the stack requirement of match() slightly.
311    30. Added the '=' option to pcretest to check the setting of unused capturing
312        slots at the end of the pattern, which are documented as being -1, but are
313        not included in the return count.
315    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
316        compiled something random. Now it gives a compile-time error (as does
317        Perl).
319    32. A *MARK encountered during the processing of a positive assertion is now
320        recorded and passed back (compatible with Perl).
322    33. If --only-matching or --colour was set on a pcregrep call whose pattern
323        had alternative anchored branches, the search for a second match in a line
324        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
325        matched the line "0102" twice. The same bug affected patterns that started
326        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
327        twice.
329    34. Previously, PCRE did not allow quantification of assertions. However, Perl
330        does, and because of capturing effects, quantifying parenthesized
331        assertions may at times be useful. Quantifiers are now allowed for
332        parenthesized assertions.
334    35. A minor code tidy in pcre_compile() when checking options for \R usage.
336    36. \g was being checked for fancy things in a character class, when it should
337        just be a literal "g".
339    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
340        appearance of a nested POSIX class supersedes an apparent external class.
341        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
342        unescaped square brackets may also appear as part of class names. For
343        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
344        more like Perl. (But see 8.20/1 above.)
346    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
347        was because it thought it was \N{name}, which is not supported).
349    39. Add minix to OS list not supporting the -S option in pcretest.
351    40. PCRE tries to detect cases of infinite recursion at compile time, but it
352        cannot analyze patterns in sufficient detail to catch mutual recursions
353        such as ((?1))((?2)). There is now a runtime test that gives an error if a
354        subgroup is called recursively as a subpattern for a second time at the
355        same position in the subject string. In previous releases this might have
356        been caught by the recursion limit, or it might have run out of stack.
358    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
359        happen only once. PCRE was, however incorrectly giving a compile time error
360        "recursive call could loop indefinitely" because it cannot analyze the
361        pattern in sufficient detail. The compile time test no longer happens when
362        PCRE is compiling a conditional subpattern, but actual runaway loops are
363        now caught at runtime (see 40 above).
365    42. It seems that Perl allows any characters other than a closing parenthesis
366        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
367        has been changed to be the same.
369    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
370        as not to get warnings when autogen.sh is called. Also changed
371        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
373    44. To help people who use pcregrep to scan files containing exceedingly long
374        lines, the following changes have been made:
376        (a) The default value of the buffer size parameter has been increased from
377            8K to 20K. (The actual buffer used is three times this size.)
379        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
380            PCRE is built.
382        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
383            to be set at run time.
385        (d) Numerical values in pcregrep options can be followed by K or M, for
386            example --buffer-size=50K.
388        (e) If a line being scanned overflows pcregrep's buffer, an error is now
389            given and the return code is set to 2.
391    45. Add a pointer to the latest mark to the callout data block.
393    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
394        partial match of an empty string instead of no match. This was specific to
395        the use of ".".
397    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
398        complete match instead of a partial match. This bug was dependent on both
399        the PCRE_UTF8 and PCRE_DOTALL options being set.
401    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
402        starting byte set, because \b was not being ignored.
405    Version 8.12 15-Jan-2011
406  ------------------------  ------------------------
408  1.  Fixed some typos in the markup of the man pages, and wrote a script that  1.  Fixed some typos in the markup of the man pages, and wrote a script that
409      checks for such things as part of the documentation building process.      checks for such things as part of the documentation building process.
411  2.  On a big-endian 64-bit system, pcregrep did not correctly process the  2.  On a big-endian 64-bit system, pcregrep did not correctly process the
412      --match-limit and --recursion-limit options (added for 8.11). In      --match-limit and --recursion-limit options (added for 8.11). In
413      particular, this made one of the standard tests crash. (The integer value      particular, this made one of the standard tests fail. (The integer value
414      went into the wrong half of a long int.)      went into the wrong half of a long int.)
416    3.  If the --colour option was given to pcregrep with -v (invert match), it
417        did strange things, either producing crazy output, or crashing. It should,
418        of course, ignore a request for colour when reporting lines that do not
419        match.
421    4.  Another pcregrep bug caused similar problems if --colour was specified with
422        -M (multiline) and the pattern match finished with a line ending.
424    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
425        matched in multiline mode, the following line was shown as part of the
426        match. This seems wrong, so I have changed it.
428    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
429        the check for further matches in the same line (so they could be coloured)
430        to overrun the end of the current line. If another match was found, it was
431        incorrectly shown (and then shown again when found in the next line).
433    7.  If pcregrep was compiled under Windows, there was a reference to the
434        function pcregrep_exit() before it was defined. I am assuming this was
435        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
436        reported by a user. I've moved the definition above the reference.
439  Version 8.11 10-Dec-2010  Version 8.11 10-Dec-2010
440  ------------------------  ------------------------

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