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-revision 567 by ph10,
Sat Nov  6 17:10:00 2010 UTC
+revision 642 by ph10,
Thu Jul 28 18:59:40 2011 UTC
 Line 1
  ChangeLog for PCRE
  ------------------
- Version 8.11 10-Oct-2010
+ Version 8.13 30-Apr-2011
+ ------------------------
+.  The Unicode data tables have been updated to Unicode 6.0.0.
+.  Two minor typos in pcre_internal.h have been fixed.
+.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
+     pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
+     in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
+.  There were a number of related bugs in the code for matching backrefences
+     caselessly in UTF-8 mode when codes for the characters concerned were
+     different numbers of bytes. For example, U+023A and U+2C65 are an upper
+     and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
+     (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
+     code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
+-byte code at the end of the subject (it thought there wasn't enough data
+     left).
+.  Comprehensive information about what went wrong is now returned by
+     pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
+     as the output vector has at least 2 elements. The offset of the start of
+     the failing character and a reason code are placed in the vector.
+.  When the UTF-8 string check fails for pcre_compile(), the offset that is
+     now returned is for the first byte of the failing character, instead of the
+     last byte inspected. This is an incompatible change, but I hope it is small
+     enough not to be a problem. It makes the returned offset consistent with
+     pcre_exec() and pcre_dfa_exec().
+.  pcretest now gives a text phrase as well as the error number when
+     pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
+     failure, the offset and reason code are output.
+.  When \R was used with a maximizing quantifier it failed to skip backwards
+     over a \r\n pair if the subsequent match failed. Instead, it just skipped
+     back over a single character (\n). This seems wrong (because it treated the
+     two characters as a single entity when going forwards), conflicts with the
+     documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
+     behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
+     has been changed.
+.  Some internal refactoring has changed the processing so that the handling
+     of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
+     time (the PCRE_DOTALL option was changed this way some time ago: version
+.7 change 16). This has made it possible to abolish the OP_OPT op code,
+     which was always a bit of a fudge. It also means that there is one less
+     argument for the match() function, which reduces its stack requirements
+     slightly. This change also fixes an incompatibility with Perl: the pattern
+     (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
+. More internal refactoring has drastically reduced the number of recursive
+     calls to match() for possessively repeated groups such as (abc)++ when
+     using pcre_exec().
+. While implementing 10, a number of bugs in the handling of groups were
+     discovered and fixed:
+     (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
+     (a|)*(?1) gave a compile-time internal error.
+     ((a|)+)+  did not notice that the outer group could match an empty string.
+     (^a|^)+   was not marked as anchored.
+     (.*a|.*)+ was not marked as matching at start or after a newline.
+. Yet more internal refactoring has removed another argument from the match()
+     function. Special calls to this function are now indicated by setting a
+     value in a variable in the "match data" data block.
+. Be more explicit in pcre_study() instead of relying on "default" for
+     opcodes that mean there is no starting character; this means that when new
+     ones are added and accidentally left out of pcre_study(), testing should
+     pick them up.
+. The -s option of pcretest has been documented for ages as being an old
+     synonym of -m (show memory usage). I have changed it to mean "force study
+     for every regex", that is, assume /S for every regex. This is similar to -i
+     and -d etc. It's slightly incompatible, but I'm hoping nobody is still
+     using it. It makes it easier to run collections of tests with and without
+     study enabled, and thereby test pcre_study() more easily. All the standard
+     tests are now run with and without -s (but some patterns can be marked as
+     "never study" - see 20 below).
+. When (*ACCEPT) was used in a subpattern that was called recursively, the
+     restoration of the capturing data to the outer values was not happening
+     correctly.
+. If a recursively called subpattern ended with (*ACCEPT) and matched an
+     empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
+     pattern had matched an empty string, and so incorrectly returned a no
+     match.
+. There was optimizing code for the last branch of non-capturing parentheses,
+     and also for the obeyed branch of a conditional subexpression, which used
+     tail recursion to cut down on stack usage. Unfortunately, not that there is
+     the possibility of (*THEN) occurring in these branches, tail recursion is
+     no longer possible because the return has to be checked for (*THEN). These
+     two optimizations have therefore been removed.
+. If a pattern containing \R was studied, it was assumed that \R always
+     matched two bytes, thus causing the minimum subject length to be
+     incorrectly computed because \R can also match just one byte.
+. If a pattern containing (*ACCEPT) was studied, the minimum subject length
+     was incorrectly computed.
+. If /S is present twice on a test pattern in pcretest input, it *disables*
+     studying, thereby overriding the use of -s on the command line. This is
+     necessary for one or two tests to keep the output identical in both cases.
+. When (*ACCEPT) was used in an assertion that matched an empty string and
+     PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
+. When an atomic group that contained a capturing parenthesis was
+     successfully matched, but the branch in which it appeared failed, the
+     capturing was not being forgotten if a higher numbered group was later
+     captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
+     group 1 to "a", when in fact it should be unset. This applied to multi-
+     branched capturing and non-capturing groups, repeated or not, and also to
+     positive assertions (capturing in negative assertions is not well defined
+     in PCRE) and also to nested atomic groups.
+. Add the ++ qualifier feature to pcretest, to show the remainder of the
+     subject after a captured substring (to make it easier to tell which of a
+     number of identical substrings has been captured).
+. The way atomic groups are processed by pcre_exec() has been changed so that
+     if they are repeated, backtracking one repetition now resets captured
+     values correctly. For example, if ((?>(a+)b)+aabab) is matched against
+     "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
+     "aaa". Previously, it would have been "a". As part of this code
+     refactoring, the way recursive calls are handled has also been changed.
+. If an assertion condition captured any substrings, they were not passed
+     back unless some other capturing happened later. For example, if
+     (?(?=(a))a) was matched against "a", no capturing was returned.
+. When studying a pattern that contained subroutine calls or assertions,
+     the code for finding the minimum length of a possible match was handling
+     direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
+     group 1 called group 2 while simultaneously a separate group 2 called group
+). A stack overflow occurred in this case. I have fixed this by limiting
+     the recursion depth to 10.
+. Updated RunTest.bat in the distribution to the version supplied by Tom
+     Fortmann. This supports explicit test numbers on the command line, and has
+     argument validation and error reporting.
+. An instance of \X with an unlimited repeat could fail if at any point the
+     first character it looked at was a mark character.
+. Some minor code refactoring concerning Unicode properties and scripts
+     should reduce the stack requirement of match() slightly.
+. Added the '=' option to pcretest to check the setting of unused capturing
+     slots at the end of the pattern, which are documented as being -1, but are
+     not included in the return count.
+. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
+     compiled something random. Now it gives a compile-time error (as does
+     Perl).
+. A *MARK encountered during the processing of a positive assertion is now
+     recorded and passed back (compatible with Perl).
+. If --only-matching or --colour was set on a pcregrep call whose pattern
+     had alternative anchored branches, the search for a second match in a line
+     was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
+     matched the line "0102" twice. The same bug affected patterns that started
+     with a backwards assertion. For example /\b01|\b02/ also matched "0102"
+     twice.
+. Previously, PCRE did not allow quantification of assertions. However, Perl
+     does, and because of capturing effects, quantifying parenthesized
+     assertions may at times be useful. Quantifiers are now allowed for
+     parenthesized assertions.
+. A minor code tidy in pcre_compile() when checking options for \R usage.
+. \g was being checked for fancy things in a character class, when it should
+     just be a literal "g".
+. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
+     appearance of a nested POSIX class supersedes an apparent external class.
+     For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
+     unescaped square brackets may also appear as part of class names. For
+     example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
+     more like Perl.
+. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
+     was because it thought it was \N{name}, which is not supported).
+. Add minix to OS list not supporting the -S option in pcretest.
+. PCRE tries to detect cases of infinite recursion at compile time, but it
+     cannot analyze patterns in sufficient detail to catch mutual recursions
+     such as ((?1))((?2)). There is now a runtime test that gives an error if a
+     subgroup is called recursively as a subpattern for a second time at the
+     same position in the subject string. In previous releases this might have
+     been caught by the recursion limit, or it might have run out of stack.
+. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
+     happen only once. PCRE was, however incorrectly giving a compile time error
+     "recursive call could loop indefinitely" because it cannot analyze the
+     pattern in sufficient detail. The compile time test no longer happens when
+     PCRE is compiling a conditional subpattern, but actual runaway loops are
+     now caught at runtime (see 39 above).
+ Version 8.12 15-Jan-2011
+ ------------------------
+.  Fixed some typos in the markup of the man pages, and wrote a script that
+     checks for such things as part of the documentation building process.
+.  On a big-endian 64-bit system, pcregrep did not correctly process the
+     --match-limit and --recursion-limit options (added for 8.11). In
+     particular, this made one of the standard tests fail. (The integer value
+     went into the wrong half of a long int.)
+.  If the --colour option was given to pcregrep with -v (invert match), it
+     did strange things, either producing crazy output, or crashing. It should,
+     of course, ignore a request for colour when reporting lines that do not
+     match.
+.  Another pcregrep bug caused similar problems if --colour was specified with
+     -M (multiline) and the pattern match finished with a line ending.
+.  In pcregrep, when a pattern that ended with a literal newline sequence was
+     matched in multiline mode, the following line was shown as part of the
+     match. This seems wrong, so I have changed it.
+.  Another pcregrep bug in multiline mode, when --colour was specified, caused
+     the check for further matches in the same line (so they could be coloured)
+     to overrun the end of the current line. If another match was found, it was
+     incorrectly shown (and then shown again when found in the next line).
+.  If pcregrep was compiled under Windows, there was a reference to the
+     function pcregrep_exit() before it was defined. I am assuming this was
+     the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
+     reported by a user. I've moved the definition above the reference.
+ Version 8.11 10-Dec-2010
  ------------------------
 .  (*THEN) was not working properly if there were untried alternatives prior
      to it in the current branch. For example, in ((a|b)(*THEN)(*F)|c..) it
      backtracked to try for "b" instead of moving to the next alternative branch
      at the same level (in this case, to look for "c"). The Perl documentation
      is clear that when (*THEN) is backtracked onto, it goes to the "next
      alternative in the innermost enclosing group".
 .  (*COMMIT) was not overriding (*THEN), as it does in Perl. In a pattern
      such as   (A(*COMMIT)B(*THEN)C|D)  any failure after matching A should
      result in overall failure. Similarly, (*COMMIT) now overrides (*PRUNE) and
      (*SKIP), (*SKIP) overrides (*PRUNE) and (*THEN), and (*PRUNE) overrides
      (*THEN).
 .  If \s appeared in a character class, it removed the VT character from
      the class, even if it had been included by some previous item, for example
      in [\x00-\xff\s]. (This was a bug related to the fact that VT is not part
      of \s, but is part of the POSIX "space" class.)
 .  A partial match never returns an empty string (because you can always
      match an empty string at the end of the subject); however the checking for
      an empty string was starting at the "start of match" point. This has been
-Line 31 
 Version 8.11 10-Oct-2010
+Line 274 
 Version 8.11 10-Oct-2010
      (previously it gave "no match").
 .  Changes have been made to the way PCRE_PARTIAL_HARD affects the matching
      of $, \z, \Z, \b, and \B. If the match point is at the end of the string,
      previously a full match would be given. However, setting PCRE_PARTIAL_HARD
      has an implication that the given string is incomplete (because a partial
      match is preferred over a full match). For this reason, these items now
      give a partial match in this situation. [Aside: previously, the one case
      /t\b/ matched against "cat" with PCRE_PARTIAL_HARD set did return a partial
      match rather than a full match, which was wrong by the old rules, but is
      now correct.]
 .  There was a bug in the handling of #-introduced comments, recognized when
      PCRE_EXTENDED is set, when PCRE_NEWLINE_ANY and PCRE_UTF8 were also set.
      If a UTF-8 multi-byte character included the byte 0x85 (e.g. +U0445, whose
      UTF-8 encoding is 0xd1,0x85), this was misinterpreted as a newline when
      scanning for the end of the comment. (*Character* 0x85 is an "any" newline,
      but *byte* 0x85 is not, in UTF-8 mode). This bug was present in several
      places in pcre_compile().
 .  Related to (6) above, when pcre_compile() was skipping #-introduced
      comments when looking ahead for named forward references to subpatterns,
      the only newline sequence it recognized was NL. It now handles newlines
      according to the set newline convention.
 .  SunOS4 doesn't have strerror() or strtoul(); pcregrep dealt with the
      former, but used strtoul(), whereas pcretest avoided strtoul() but did not
      cater for a lack of strerror(). These oversights have been fixed.
 .  Added --match-limit and --recursion-limit to pcregrep.
 . Added two casts needed to build with Visual Studio when NO_RECURSE is set.
 . When the -o option was used, pcregrep was setting a return code of 1, even
      when matches were found, and --line-buffered was not being honoured.
 . Added an optional parentheses number to the -o and --only-matching options
      of pcregrep.
 . Imitating Perl's /g action for multiple matches is tricky when the pattern
      can match an empty string. The code to do it in pcretest and pcredemo
      needed fixing:
      (a) When the newline convention was "crlf", pcretest got it wrong, skipping
          only one byte after an empty string match just before CRLF (this case
          just got forgotten; "any" and "anycrlf" were OK).
      (b) The pcretest code also had a bug, causing it to loop forever in UTF-8
          mode when an empty string match preceded an ASCII character followed by
          a non-ASCII character. (The code for advancing by one character rather
          than one byte was nonsense.)
      (c) The pcredemo.c sample program did not have any code at all to handle
          the cases when CRLF is a valid newline sequence.
 . Neither pcre_exec() nor pcre_dfa_exec() was checking that the value given
      as a starting offset was within the subject string. There is now a new
      error, PCRE_ERROR_BADOFFSET, which is returned if the starting offset is
      negative or greater than the length of the string. In order to test this,
      pcretest is extended to allow the setting of negative starting offsets.
 . In both pcre_exec() and pcre_dfa_exec() the code for checking that the
      starting offset points to the beginning of a UTF-8 character was
      unnecessarily clumsy. I tidied it up.
+. Added PCRE_ERROR_SHORTUTF8 to make it possible to distinguish between a
+     bad UTF-8 sequence and one that is incomplete when using PCRE_PARTIAL_HARD.
+. Nobody had reported that the --include_dir option, which was added in
+     release 7.7 should have been called --include-dir (hyphen, not underscore)
+     for compatibility with GNU grep. I have changed it to --include-dir, but
+     left --include_dir as an undocumented synonym, and the same for
+     --exclude-dir, though that is not available in GNU grep, at least as of
+     release 2.5.4.
+. At a user's suggestion, the macros GETCHAR and friends (which pick up UTF-8
+     characters from a string of bytes) have been redefined so as not to use
+     loops, in order to improve performance in some environments. At the same
+     time, I abstracted some of the common code into auxiliary macros to save
+     repetition (this should not affect the compiled code).
+. If \c was followed by a multibyte UTF-8 character, bad things happened. A
+     compile-time error is now given if \c is not followed by an ASCII
+     character, that is, a byte less than 128. (In EBCDIC mode, the code is
+     different, and any byte value is allowed.)
+. Recognize (*NO_START_OPT) at the start of a pattern to set the PCRE_NO_
+     START_OPTIMIZE option, which is now allowed at compile time - but just
+     passed through to pcre_exec() or pcre_dfa_exec(). This makes it available
+     to pcregrep and other applications that have no direct access to PCRE
+     options. The new /Y option in pcretest sets this option when calling
+     pcre_compile().
+. Change 18 of release 8.01 broke the use of named subpatterns for recursive
+     back references. Groups containing recursive back references were forced to
+     be atomic by that change, but in the case of named groups, the amount of
+     memory required was incorrectly computed, leading to "Failed: internal
+     error: code overflow". This has been fixed.
+. Some patches to pcre_stringpiece.h, pcre_stringpiece_unittest.cc, and
+     pcretest.c, to avoid build problems in some Borland environments.
  Version 8.10 25-Jun-2010

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