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revision 622 by ph10, Mon Jul 18 10:46:51 2011 UTC revision 744 by zherczeg, Sun Nov 13 16:31:38 2011 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.21
5    ------------
6    
7    1.  Updating the JIT compiler.
8    
9    2.  JIT compiler now supports OP_NCREF, OP_RREF and OP_NRREF. New test cases
10        are added as well.
11    
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.
15    
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.
19    
20    5.  Supporting of \x and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
22    
23    
24    Version 8.20 21-Oct-2011
25    ------------------------
26    
27    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
28        a POSIX class. After further experiments with Perl, which convinced me that
29        Perl has bugs and confusions, a closing square bracket is no longer allowed
30        in a POSIX name. This bug also affected patterns with classes that started
31        with full stops.
32    
33    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
34        captured substring, but while checking the failing first alternative,
35        substring 1 is temporarily captured. If the output vector supplied to
36        pcre_exec() was not big enough for this capture, the yield of the function
37        was still zero ("insufficient space for captured substrings"). This cannot
38        be totally fixed without adding another stack variable, which seems a lot
39        of expense for a edge case. However, I have improved the situation in cases
40        such as /(a)(b)x|abc/ matched against "abc", where the return code
41        indicates that fewer than the maximum number of slots in the ovector have
42        been set.
43    
44    3.  Related to (2) above: when there are more back references in a pattern than
45        slots in the output vector, pcre_exec() uses temporary memory during
46        matching, and copies in the captures as far as possible afterwards. It was
47        using the entire output vector, but this conflicts with the specification
48        that only 2/3 is used for passing back captured substrings. Now it uses
49        only the first 2/3, for compatibility. This is, of course, another edge
50        case.
51    
52    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
53        main code base, and can be used by building with --enable-jit. When this is
54        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
55        runtime --no-jit option is given.
56    
57    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
58        ovector, the return from the function was zero, implying that there were
59        other matches that did not fit. The correct "exactly full" value is now
60        returned.
61    
62    6.  If a subpattern that was called recursively or as a subroutine contained
63        (*PRUNE) or any other control that caused it to give a non-standard return,
64        invalid errors such as "Error -26 (nested recursion at the same subject
65        position)" or even infinite loops could occur.
66    
67    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
68        computing the minimum length on reaching *ACCEPT, and so ended up with the
69        wrong value of 1 rather than 0. Further investigation indicates that
70        computing a minimum subject length in the presence of *ACCEPT is difficult
71        (think back references, subroutine calls), and so I have changed the code
72        so that no minimum is registered for a pattern that contains *ACCEPT.
73    
74    8.  If (*THEN) was present in the first (true) branch of a conditional group,
75        it was not handled as intended. [But see 16 below.]
76    
77    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
78        Sheri Pierce.
79    
80    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
81        the first byte in a match must be "a".
82    
83    11. Change 17 for 8.13 increased the recursion depth for patterns like
84        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
85        pattern contains any instances of (*THEN). If it does not, the old
86        optimizations are restored. It would be nice to do this on a per-group
87        basis, but at the moment that is not feasible.
88    
89    12. In some environments, the output of pcretest -C is CRLF terminated. This
90        broke RunTest's code that checks for the link size. A single white space
91        character after the value is now allowed for.
92    
93    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
94        For "fr", it uses the Windows-specific input and output files.
95    
96    14. If (*THEN) appeared in a group that was called recursively or as a
97        subroutine, it did not work as intended. [But see next item.]
98    
99    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
100        pattern fragments (but not containing any | characters). If A and B are
101        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
102        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
103        D. In other words, Perl considers parentheses that do not contain any |
104        characters to be part of a surrounding alternative, whereas PCRE was
105        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
106        differently. PCRE now behaves in the same way as Perl, except in the case
107        of subroutine/recursion calls such as (?1) which have in any case always
108        been different (but PCRE had them first :-).
109    
110    16. Related to 15 above: Perl does not treat the | in a conditional group as
111        creating alternatives. Such a group is treated in the same way as an
112        ordinary group without any | characters when processing (*THEN). PCRE has
113        been changed to match Perl's behaviour.
114    
115    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
116        RunGrepTest script failed.
117    
118    18. Change 22 for version 13 caused atomic groups to use more stack. This is
119        inevitable for groups that contain captures, but it can lead to a lot of
120        stack use in large patterns. The old behaviour has been restored for atomic
121        groups that do not contain any capturing parentheses.
122    
123    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
124        suppress the check for a minimum subject length at run time. (If it was
125        given to pcre_exec() or pcre_dfa_exec() it did work.)
126    
127    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
128        fail to work when decoding hex characters in data strings in EBCDIC
129        environments.
130    
131    21. It appears that in at least one Mac OS environment, the isxdigit() function
132        is implemented as a macro that evaluates to its argument more than once,
133        contravening the C 90 Standard (I haven't checked a later standard). There
134        was an instance in pcretest which caused it to go wrong when processing
135        \x{...} escapes in subject strings. The has been rewritten to avoid using
136        things like p++ in the argument of isxdigit().
137    
138    
139    Version 8.13 16-Aug-2011
140  ------------------------  ------------------------
141    
142  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 155  Version 8.13 30-Apr-2011
155      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
156      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
157      left).      left).
158    
159  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
160      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
161      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
162      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
163    
164  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
165      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
166      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
167      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
168      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
169    
170  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
171      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
172      failure, the offset and reason code are output.      failure, the offset and reason code are output.
173    
174  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
175      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
176      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
177      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
178      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
179      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
180      has been changed.      has been changed.
181    
182  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
183      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
184      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
185      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,
186      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
187      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
188      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
189      (?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.
190    
191  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
192      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
193      using pcre_exec().      using pcre_exec().
194    
195  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
196      discovered and fixed:      discovered and fixed:
197    
198      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
199      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
200      ((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.
201      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
202      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
203    
204  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
205      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
206      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
207    
208  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
209      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
210      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
211      pick them up.      pick them up.
212    
213  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
214      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
215      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
216      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
217      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
218      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
219      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
220      "never study" - see 20 below).      "never study" - see 20 below).
221    
222  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
223      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
224      correctly.      correctly.
225    
226  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
227      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
228      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
229      match.      match.
230    
231  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,
232      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
233      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
234      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
235      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
236      two optimizations have therefore been removed.      two optimizations have therefore been removed. [But see 8.20/11 above.]
237    
238  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
239      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
240      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
241    
242  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
243      was incorrectly computed.      was incorrectly computed.
244    
245  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
246      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
247      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
248        identical in both cases.
249    
250  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
251      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.
252    
253  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
254      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
255      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
256      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
257      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-
258      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
259      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
260      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
261    
262  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
263      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
264      number of identical substrings has been captured).      number of identical substrings has been captured.
265    
266  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
267      if they are repeated, backtracking one repetition now resets captured      if they are repeated, backtracking one repetition now resets captured
268      values correctly. For example, if ((?>(a+)b)+aabab) is matched against      values correctly. For example, if ((?>(a+)b)+aabab) is matched against
269      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
270      "aaa". Previously, it would have been "a". As part of this code      "aaa". Previously, it would have been "a". As part of this code
271      refactoring, the way recursive calls are handled has also been changed.      refactoring, the way recursive calls are handled has also been changed.
272    
273  24. If an assertion condition captured any substrings, they were not passed  25. If an assertion condition captured any substrings, they were not passed
274      back unless some other capturing happened later. For example, if      back unless some other capturing happened later. For example, if
275      (?(?=(a))a) was matched against "a", no capturing was returned.      (?(?=(a))a) was matched against "a", no capturing was returned.
276    
277  25. When studying a pattern that contained subroutine calls or assertions,  26. When studying a pattern that contained subroutine calls or assertions,
278      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
279      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
280      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
281      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
282      the recursion depth to 10.      the recursion depth to 10.
283    
284  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
285      Fortmann. This supports explicit test numbers on the command line, and has      Fortmann. This supports explicit test numbers on the command line, and has
286      argument validation and error reporting.      argument validation and error reporting.
287    
288    28. An instance of \X with an unlimited repeat could fail if at any point the
289        first character it looked at was a mark character.
290    
291    29. Some minor code refactoring concerning Unicode properties and scripts
292        should reduce the stack requirement of match() slightly.
293    
294    30. Added the '=' option to pcretest to check the setting of unused capturing
295        slots at the end of the pattern, which are documented as being -1, but are
296        not included in the return count.
297    
298    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
299        compiled something random. Now it gives a compile-time error (as does
300        Perl).
301    
302    32. A *MARK encountered during the processing of a positive assertion is now
303        recorded and passed back (compatible with Perl).
304    
305    33. If --only-matching or --colour was set on a pcregrep call whose pattern
306        had alternative anchored branches, the search for a second match in a line
307        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
308        matched the line "0102" twice. The same bug affected patterns that started
309        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
310        twice.
311    
312    34. Previously, PCRE did not allow quantification of assertions. However, Perl
313        does, and because of capturing effects, quantifying parenthesized
314        assertions may at times be useful. Quantifiers are now allowed for
315        parenthesized assertions.
316    
317    35. A minor code tidy in pcre_compile() when checking options for \R usage.
318    
319    36. \g was being checked for fancy things in a character class, when it should
320        just be a literal "g".
321    
322    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
323        appearance of a nested POSIX class supersedes an apparent external class.
324        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
325        unescaped square brackets may also appear as part of class names. For
326        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
327        more like Perl. (But see 8.20/1 above.)
328    
329    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
330        was because it thought it was \N{name}, which is not supported).
331    
332    39. Add minix to OS list not supporting the -S option in pcretest.
333    
334    40. PCRE tries to detect cases of infinite recursion at compile time, but it
335        cannot analyze patterns in sufficient detail to catch mutual recursions
336        such as ((?1))((?2)). There is now a runtime test that gives an error if a
337        subgroup is called recursively as a subpattern for a second time at the
338        same position in the subject string. In previous releases this might have
339        been caught by the recursion limit, or it might have run out of stack.
340    
341    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
342        happen only once. PCRE was, however incorrectly giving a compile time error
343        "recursive call could loop indefinitely" because it cannot analyze the
344        pattern in sufficient detail. The compile time test no longer happens when
345        PCRE is compiling a conditional subpattern, but actual runaway loops are
346        now caught at runtime (see 40 above).
347    
348    42. It seems that Perl allows any characters other than a closing parenthesis
349        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
350        has been changed to be the same.
351    
352    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
353        as not to get warnings when autogen.sh is called. Also changed
354        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
355    
356    44. To help people who use pcregrep to scan files containing exceedingly long
357        lines, the following changes have been made:
358    
359        (a) The default value of the buffer size parameter has been increased from
360            8K to 20K. (The actual buffer used is three times this size.)
361    
362        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
363            PCRE is built.
364    
365        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
366            to be set at run time.
367    
368        (d) Numerical values in pcregrep options can be followed by K or M, for
369            example --buffer-size=50K.
370    
371        (e) If a line being scanned overflows pcregrep's buffer, an error is now
372            given and the return code is set to 2.
373    
374    45. Add a pointer to the latest mark to the callout data block.
375    
376    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
377        partial match of an empty string instead of no match. This was specific to
378        the use of ".".
379    
380    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
381        complete match instead of a partial match. This bug was dependent on both
382        the PCRE_UTF8 and PCRE_DOTALL options being set.
383    
384    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
385        starting byte set, because \b was not being ignored.
386    
387    
388  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011

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