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revision 565 by ph10, Sun Oct 31 18:18:48 2010 UTC revision 649 by ph10, Mon Aug 1 11:23:52 2011 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.11 10-Oct-2010  Version 8.13 30-Apr-2011
5    ------------------------
6    
7    1.  The Unicode data tables have been updated to Unicode 6.0.0.
8    
9    2.  Two minor typos in pcre_internal.h have been fixed.
10    
11    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
12        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
13        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
14    
15    4.  There were a number of related bugs in the code for matching backrefences
16        caselessly in UTF-8 mode when codes for the characters concerned were
17        different numbers of bytes. For example, U+023A and U+2C65 are an upper
18        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
19        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
20        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
21        2-byte code at the end of the subject (it thought there wasn't enough data
22        left).
23    
24    5.  Comprehensive information about what went wrong is now returned by
25        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
26        as the output vector has at least 2 elements. The offset of the start of
27        the failing character and a reason code are placed in the vector.
28    
29    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
30        now returned is for the first byte of the failing character, instead of the
31        last byte inspected. This is an incompatible change, but I hope it is small
32        enough not to be a problem. It makes the returned offset consistent with
33        pcre_exec() and pcre_dfa_exec().
34    
35    7.  pcretest now gives a text phrase as well as the error number when
36        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
37        failure, the offset and reason code are output.
38    
39    8.  When \R was used with a maximizing quantifier it failed to skip backwards
40        over a \r\n pair if the subsequent match failed. Instead, it just skipped
41        back over a single character (\n). This seems wrong (because it treated the
42        two characters as a single entity when going forwards), conflicts with the
43        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
44        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
45        has been changed.
46    
47    9.  Some internal refactoring has changed the processing so that the handling
48        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
49        time (the PCRE_DOTALL option was changed this way some time ago: version
50        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
51        which was always a bit of a fudge. It also means that there is one less
52        argument for the match() function, which reduces its stack requirements
53        slightly. This change also fixes an incompatibility with Perl: the pattern
54        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
55    
56    10. More internal refactoring has drastically reduced the number of recursive
57        calls to match() for possessively repeated groups such as (abc)++ when
58        using pcre_exec().
59    
60    11. While implementing 10, a number of bugs in the handling of groups were
61        discovered and fixed:
62    
63        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
64        (a|)*(?1) gave a compile-time internal error.
65        ((a|)+)+  did not notice that the outer group could match an empty string.
66        (^a|^)+   was not marked as anchored.
67        (.*a|.*)+ was not marked as matching at start or after a newline.
68    
69    12. Yet more internal refactoring has removed another argument from the match()
70        function. Special calls to this function are now indicated by setting a
71        value in a variable in the "match data" data block.
72    
73    13. Be more explicit in pcre_study() instead of relying on "default" for
74        opcodes that mean there is no starting character; this means that when new
75        ones are added and accidentally left out of pcre_study(), testing should
76        pick them up.
77    
78    14. The -s option of pcretest has been documented for ages as being an old
79        synonym of -m (show memory usage). I have changed it to mean "force study
80        for every regex", that is, assume /S for every regex. This is similar to -i
81        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
82        using it. It makes it easier to run collections of tests with and without
83        study enabled, and thereby test pcre_study() more easily. All the standard
84        tests are now run with and without -s (but some patterns can be marked as
85        "never study" - see 20 below).
86    
87    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
88        restoration of the capturing data to the outer values was not happening
89        correctly.
90    
91    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
92        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
93        pattern had matched an empty string, and so incorrectly returned a no
94        match.
95    
96    17. There was optimizing code for the last branch of non-capturing parentheses,
97        and also for the obeyed branch of a conditional subexpression, which used
98        tail recursion to cut down on stack usage. Unfortunately, not that there is
99        the possibility of (*THEN) occurring in these branches, tail recursion is
100        no longer possible because the return has to be checked for (*THEN). These
101        two optimizations have therefore been removed.
102    
103    18. If a pattern containing \R was studied, it was assumed that \R always
104        matched two bytes, thus causing the minimum subject length to be
105        incorrectly computed because \R can also match just one byte.
106    
107    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
108        was incorrectly computed.
109    
110    20. If /S is present twice on a test pattern in pcretest input, it *disables*
111        studying, thereby overriding the use of -s on the command line. This is
112        necessary for one or two tests to keep the output identical in both cases.
113    
114    21. When (*ACCEPT) was used in an assertion that matched an empty string and
115        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
116    
117    22. When an atomic group that contained a capturing parenthesis was
118        successfully matched, but the branch in which it appeared failed, the
119        capturing was not being forgotten if a higher numbered group was later
120        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
121        group 1 to "a", when in fact it should be unset. This applied to multi-
122        branched capturing and non-capturing groups, repeated or not, and also to
123        positive assertions (capturing in negative assertions is not well defined
124        in PCRE) and also to nested atomic groups.
125    
126    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
127        subject after a captured substring (to make it easier to tell which of a
128        number of identical substrings has been captured).
129    
130    24. The way atomic groups are processed by pcre_exec() has been changed so that
131        if they are repeated, backtracking one repetition now resets captured
132        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
133        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
134        "aaa". Previously, it would have been "a". As part of this code
135        refactoring, the way recursive calls are handled has also been changed.
136    
137    24. If an assertion condition captured any substrings, they were not passed
138        back unless some other capturing happened later. For example, if
139        (?(?=(a))a) was matched against "a", no capturing was returned.
140    
141    25. When studying a pattern that contained subroutine calls or assertions,
142        the code for finding the minimum length of a possible match was handling
143        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
144        group 1 called group 2 while simultaneously a separate group 2 called group
145        1). A stack overflow occurred in this case. I have fixed this by limiting
146        the recursion depth to 10.
147    
148    26. Updated RunTest.bat in the distribution to the version supplied by Tom
149        Fortmann. This supports explicit test numbers on the command line, and has
150        argument validation and error reporting.
151    
152    27. An instance of \X with an unlimited repeat could fail if at any point the
153        first character it looked at was a mark character.
154    
155    28. Some minor code refactoring concerning Unicode properties and scripts
156        should reduce the stack requirement of match() slightly.
157    
158    29. Added the '=' option to pcretest to check the setting of unused capturing
159        slots at the end of the pattern, which are documented as being -1, but are
160        not included in the return count.
161    
162    30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
163        compiled something random. Now it gives a compile-time error (as does
164        Perl).
165    
166    31. A *MARK encountered during the processing of a positive assertion is now
167        recorded and passed back (compatible with Perl).
168    
169    32. If --only-matching or --colour was set on a pcregrep call whose pattern
170        had alternative anchored branches, the search for a second match in a line
171        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
172        matched the line "0102" twice. The same bug affected patterns that started
173        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
174        twice.
175    
176    33. Previously, PCRE did not allow quantification of assertions. However, Perl
177        does, and because of capturing effects, quantifying parenthesized
178        assertions may at times be useful. Quantifiers are now allowed for
179        parenthesized assertions.
180    
181    34. A minor code tidy in pcre_compile() when checking options for \R usage.
182    
183    35. \g was being checked for fancy things in a character class, when it should
184        just be a literal "g".
185    
186    36. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
187        appearance of a nested POSIX class supersedes an apparent external class.
188        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
189        unescaped square brackets may also appear as part of class names. For
190        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
191        more like Perl.
192    
193    37. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
194        was because it thought it was \N{name}, which is not supported).
195    
196    38. Add minix to OS list not supporting the -S option in pcretest.
197    
198    39. PCRE tries to detect cases of infinite recursion at compile time, but it
199        cannot analyze patterns in sufficient detail to catch mutual recursions
200        such as ((?1))((?2)). There is now a runtime test that gives an error if a
201        subgroup is called recursively as a subpattern for a second time at the
202        same position in the subject string. In previous releases this might have
203        been caught by the recursion limit, or it might have run out of stack.
204    
205    40. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
206        happen only once. PCRE was, however incorrectly giving a compile time error
207        "recursive call could loop indefinitely" because it cannot analyze the
208        pattern in sufficient detail. The compile time test no longer happens when
209        PCRE is compiling a conditional subpattern, but actual runaway loops are
210        now caught at runtime (see 39 above).
211    
212    41. It seems that Perl allows any characters other than a closing parenthesis
213        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
214        has been changed to be the same.
215    
216    42. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
217        as not to get warnings when autogen.sh is called. Also changed
218        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
219    
220    43. To help people who use pcregrep to scan files containing exceedingly long
221        lines, the following changes have been made:
222    
223        (a) The default value of the buffer size parameter has been increased from
224            8K to 20K. (A buffer three times this size is actually used.)
225    
226        (b) The default can be changed by ./configure --with-pcregrep-bufsiz when
227            PCRE is built.
228    
229        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
230            to be set at run time.
231    
232        (d) Numerical values in pcregrep options can be followed by K or M, for
233            example --buffer-size=50K.
234    
235        (e) If a line being scanned overflows pcregrep's buffer, an error is now
236            given and the return code is set to 2.
237    
238    44. Add a pointer to the latest mark to the callout data block.
239    
240    45. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
241        partial match of an empty string instead of no match. This was specific to
242        the use of ".".
243    
244    46. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
245        complete match instead of a partial match. This bug was dependent on both
246        the PCRE_UTF8 and PCRE_DOTALL options being set.
247    
248    
249    Version 8.12 15-Jan-2011
250    ------------------------
251    
252    1.  Fixed some typos in the markup of the man pages, and wrote a script that
253        checks for such things as part of the documentation building process.
254    
255    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
256        --match-limit and --recursion-limit options (added for 8.11). In
257        particular, this made one of the standard tests fail. (The integer value
258        went into the wrong half of a long int.)
259    
260    3.  If the --colour option was given to pcregrep with -v (invert match), it
261        did strange things, either producing crazy output, or crashing. It should,
262        of course, ignore a request for colour when reporting lines that do not
263        match.
264    
265    4.  Another pcregrep bug caused similar problems if --colour was specified with
266        -M (multiline) and the pattern match finished with a line ending.
267    
268    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
269        matched in multiline mode, the following line was shown as part of the
270        match. This seems wrong, so I have changed it.
271    
272    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
273        the check for further matches in the same line (so they could be coloured)
274        to overrun the end of the current line. If another match was found, it was
275        incorrectly shown (and then shown again when found in the next line).
276    
277    7.  If pcregrep was compiled under Windows, there was a reference to the
278        function pcregrep_exit() before it was defined. I am assuming this was
279        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
280        reported by a user. I've moved the definition above the reference.
281    
282    
283    Version 8.11 10-Dec-2010
284  ------------------------  ------------------------
285    
286  1.  (*THEN) was not working properly if there were untried alternatives prior  1.  (*THEN) was not working properly if there were untried alternatives prior
287      to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it      to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
288      backtracked to try for "b" instead of moving to the next alternative branch      backtracked to try for "b" instead of moving to the next alternative branch
289      at the same level (in this case, to look for "c"). The Perl documentation      at the same level (in this case, to look for "c"). The Perl documentation
290      is clear that when (*THEN) is backtracked onto, it goes to the "next      is clear that when (*THEN) is backtracked onto, it goes to the "next
291      alternative in the innermost enclosing group".      alternative in the innermost enclosing group".
292    
293  2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern  2.  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
294      such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should      such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
295      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
296      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
297      (*THEN).      (*THEN).
298    
299  3.  If \s appeared in a character class, it removed the VT character from  3.  If \s appeared in a character class, it removed the VT character from
300      the class, even if it had been included by some previous item, for example      the class, even if it had been included by some previous item, for example
301      in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part      in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
302      of \s, but is part of the POSIX "space" class.)      of \s, but is part of the POSIX "space" class.)
303    
304  4.  A partial match never returns an empty string (because you can always  4.  A partial match never returns an empty string (because you can always
305      match an empty string at the end of the subject); however the checking for      match an empty string at the end of the subject); however the checking for
306      an empty string was starting at the "start of match" point. This has been      an empty string was starting at the "start of match" point. This has been
# Line 31  Version 8.11 10-Oct-2010 Line 310  Version 8.11 10-Oct-2010
310      (previously it gave "no match").      (previously it gave "no match").
311    
312  5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching  5.  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
313      of $, \z, \Z, \b, and \B. If the match point is at the end of the string,      of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
314      previously a full match would be given. However, setting PCRE_PARTIAL_HARD      previously a full match would be given. However, setting PCRE_PARTIAL_HARD
315      has an implication that the given string is incomplete (because a partial      has an implication that the given string is incomplete (because a partial
316      match is preferred over a full match). For this reason, these items now      match is preferred over a full match). For this reason, these items now
317      give a partial match in this situation. [Aside: previously, the one case      give a partial match in this situation. [Aside: previously, the one case
318      /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial      /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
319      match rather than a full match, which was wrong by the old rules, but is      match rather than a full match, which was wrong by the old rules, but is
320      now correct.]      now correct.]
321    
322  6.  There was a bug in the handling of #-introduced comments, recognized when  6.  There was a bug in the handling of #-introduced comments, recognized when
323      PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.      PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
324      If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose      If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
325      UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when      UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
326      scanning for the end of the comment. (*Character* 0x85 is an "any" newline,      scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
327      but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several      but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
328      places in pcre_compile().      places in pcre_compile().
329    
330  7.  Related to (6) above, when pcre_compile() was skipping #-introduced  7.  Related to (6) above, when pcre_compile() was skipping #-introduced
331      comments when looking ahead for named forward references to subpatterns,      comments when looking ahead for named forward references to subpatterns,
332      the only newline sequence it recognized was NL. It now handles newlines      the only newline sequence it recognized was NL. It now handles newlines
333      according to the set newline convention.      according to the set newline convention.
334    
335  8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the  8.  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
336      former, but used strtoul(), whereas pcretest avoided strtoul() but did not      former, but used strtoul(), whereas pcretest avoided strtoul() but did not
337      cater for a lack of strerror(). These oversights have been fixed.      cater for a lack of strerror(). These oversights have been fixed.
338    
339  9.  Added --match-limit and --recursion-limit to pcregrep.  9.  Added --match-limit and --recursion-limit to pcregrep.
340    
341  10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.  10. Added two casts needed to build with Visual Studio when NO_RECURSE is set.
342    
343  11. When the -o option was used, pcregrep was setting a return code of 1, even  11. When the -o option was used, pcregrep was setting a return code of 1, even
344      when matches were found, and --line-buffered was not being honoured.      when matches were found, and --line-buffered was not being honoured.
345    
346  12. Added an optional parentheses number to the -o and --only-matching options  12. Added an optional parentheses number to the -o and --only-matching options
347      of pcregrep.      of pcregrep.
348    
349    13. Imitating Perl's /g action for multiple matches is tricky when the pattern
350        can match an empty string. The code to do it in pcretest and pcredemo
351        needed fixing:
352    
353        (a) When the newline convention was "crlf", pcretest got it wrong, skipping
354            only one byte after an empty string match just before CRLF (this case
355            just got forgotten; "any" and "anycrlf" were OK).
356    
357        (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
358            mode when an empty string match preceded an ASCII character followed by
359            a non-ASCII character. (The code for advancing by one character rather
360            than one byte was nonsense.)
361    
362        (c) The pcredemo.c sample program did not have any code at all to handle
363            the cases when CRLF is a valid newline sequence.
364    
365    14. Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
366        as a starting offset was within the subject string. There is now a new
367        error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
368        negative or greater than the length of the string. In order to test this,
369        pcretest is extended to allow the setting of negative starting offsets.
370    
371    15. In both pcre_exec() and pcre_dfa_exec() the code for checking that the
372        starting offset points to the beginning of a UTF-8 character was
373        unnecessarily clumsy. I tidied it up.
374    
375    16. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
376        bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
377    
378    17. Nobody had reported that the --include_dir option, which was added in
379        release 7.7 should have been called --include-dir (hyphen, not underscore)
380        for compatibility with GNU grep. I have changed it to --include-dir, but
381        left --include_dir as an undocumented synonym, and the same for
382        --exclude-dir, though that is not available in GNU grep, at least as of
383        release 2.5.4.
384    
385    18. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
386        characters from a string of bytes) have been redefined so as not to use
387        loops, in order to improve performance in some environments. At the same
388        time, I abstracted some of the common code into auxiliary macros to save
389        repetition (this should not affect the compiled code).
390    
391    19. If \c was followed by a multibyte UTF-8 character, bad things happened. A
392        compile-time error is now given if \c is not followed by an ASCII
393        character, that is, a byte less than 128. (In EBCDIC mode, the code is
394        different, and any byte value is allowed.)
395    
396    20. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
397        START_OPTIMIZE option, which is now allowed at compile time - but just
398        passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
399        to pcregrep and other applications that have no direct access to PCRE
400        options. The new /Y option in pcretest sets this option when calling
401        pcre_compile().
402    
403    21. Change 18 of release 8.01 broke the use of named subpatterns for recursive
404        back references. Groups containing recursive back references were forced to
405        be atomic by that change, but in the case of named groups, the amount of
406        memory required was incorrectly computed, leading to "Failed: internal
407        error: code overflow". This has been fixed.
408    
409    22. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
410        pcretest.c, to avoid build problems in some Borland environments.
411    
412    
413  Version 8.10 25-Jun-2010  Version 8.10 25-Jun-2010

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