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revision 637 by ph10, Sun Jul 24 17:44:12 2011 UTC revision 681 by ph10, Tue Sep 6 09:16:32 2011 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.13 30-Apr-2011  Version 8.20
5    ------------
6    
7    1. Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
8       a POSIX class. After further experiments with Perl, which convinced me that
9       Perl has bugs and confusions, a closing square bracket is no longer allowed
10       in a POSIX name.
11    
12    2. If a pattern such as /(a)b|ac/ is matched against "ac", there is no captured
13       substring, but while checking the failing first alternative, substring 1 is
14       temporarily captured. If the output vector supplied to pcre_exec() was not
15       big enough for this capture, the yield of the function was still zero
16       ("insufficient space for captured substrings"). This cannot be totally fixed
17       without adding another stack variable, which seems a lot of expense for a
18       edge case. However, I have improved the situation in cases such as
19       /(a)(b)x|abc/ matched against "abc", where the return code indicates that
20       fewer than the maximum number of slots in the ovector have been set.
21    
22    3. Related to (2) above: when there are more back references in a pattern than
23       slots in the output vector, pcre_exec() uses temporary memory during
24       matching, and copies in the captures as far as possible afterwards. It was
25       using the entire output vector, but this conflicts with the specification
26       that only 2/3 is used for passing back captured substrings. Now it uses only
27       the first 2/3, for compatibility. This is, of course, another edge case.
28    
29    4. Zoltan Herczeg's just-in-time compiler support has been integrated into the
30       main code base, and can be used by building with --enable-jit.
31    
32    5. When the number of matches in a pcre_dfa_exec() run exactly filled the
33       ovector, the return from the function was zero, implying that there were
34       other matches that did not fit. The correct "exactly full" value is now
35       returned.
36    
37    6. If a subpattern that was called recursively or as a subroutine contained
38       (*PRUNE) or any other control that caused it to give a non-standard return,
39       invalid errors such as "Error -26 (nested recursion at the same subject
40       position)" or even infinite loops could occur.
41    
42    
43    Version 8.13 16-Aug-2011
44  ------------------------  ------------------------
45    
46  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 59  Version 8.13 30-Apr-2011
59      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
60      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
61      left).      left).
62    
63  5.  Comprehensive information about what went wrong is now returned by  5.  Comprehensive information about what went wrong is now returned by
64      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
65      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
66      the failing character and a reason code are placed in the vector.      the failing character and a reason code are placed in the vector.
67    
68  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
69      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
70      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
71      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
72      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
73    
74  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
75      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
76      failure, the offset and reason code are output.      failure, the offset and reason code are output.
77    
78  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
79      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
80      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
81      two characters as a single entity when going forwards), conflicts with the      two characters as a single entity when going forwards), conflicts with the
82      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
83      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour      behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
84      has been changed.      has been changed.
85    
86  9.  Some internal refactoring has changed the processing so that the handling  9.  Some internal refactoring has changed the processing so that the handling
87      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
88      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
89      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,
90      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
91      argument for the match() function, which reduces its stack requirements      argument for the match() function, which reduces its stack requirements
92      slightly. This change also fixes an incompatibility with Perl: the pattern      slightly. This change also fixes an incompatibility with Perl: the pattern
93      (?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.
94    
95  10. More internal refactoring has drastically reduced the number of recursive  10. More internal refactoring has drastically reduced the number of recursive
96      calls to match() for possessively repeated groups such as (abc)++ when      calls to match() for possessively repeated groups such as (abc)++ when
97      using pcre_exec().      using pcre_exec().
98    
99  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
100      discovered and fixed:      discovered and fixed:
101    
102      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).      (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
103      (a|)*(?1) gave a compile-time internal error.      (a|)*(?1) gave a compile-time internal error.
104      ((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.
105      (^a|^)+   was not marked as anchored.      (^a|^)+   was not marked as anchored.
106      (.*a|.*)+ was not marked as matching at start or after a newline.      (.*a|.*)+ was not marked as matching at start or after a newline.
107    
108  12. Yet more internal refactoring has removed another argument from the match()  12. Yet more internal refactoring has removed another argument from the match()
109      function. Special calls to this function are now indicated by setting a      function. Special calls to this function are now indicated by setting a
110      value in a variable in the "match data" data block.      value in a variable in the "match data" data block.
111    
112  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
113      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
114      ones are added and accidentally left out of pcre_study(), testing should      ones are added and accidentally left out of pcre_study(), testing should
115      pick them up.      pick them up.
116    
117  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
118      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
119      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
120      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
121      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
122      study enabled, and thereby test pcre_study() more easily. All the standard      study enabled, and thereby test pcre_study() more easily. All the standard
123      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
124      "never study" - see 20 below).      "never study" - see 20 below).
125    
126  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
127      restoration of the capturing data to the outer values was not happening      restoration of the capturing data to the outer values was not happening
128      correctly.      correctly.
129    
130  16. If a recursively called subpattern ended with (*ACCEPT) and matched an  16. If a recursively called subpattern ended with (*ACCEPT) and matched an
131      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole      empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
132      pattern had matched an empty string, and so incorrectly returned a no      pattern had matched an empty string, and so incorrectly returned a no
133      match.      match.
134    
135  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,
136      and also for the obeyed branch of a conditional subexpression, which used      and also for the obeyed branch of a conditional subexpression, which used
137      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
138      the possibility of (*THEN) occurring in these branches, tail recursion is      the possibility of (*THEN) occurring in these branches, tail recursion is
139      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
140      two optimizations have therefore been removed.      two optimizations have therefore been removed.
141    
142  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
143      matched two bytes, thus causing the minimum subject length to be      matched two bytes, thus causing the minimum subject length to be
144      incorrectly computed because \R can also match just one byte.      incorrectly computed because \R can also match just one byte.
145    
146  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length  19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
147      was incorrectly computed.      was incorrectly computed.
148    
149  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
150      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
151      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
152        identical in both cases.
153    
154  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
155      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.
156    
157  22. When an atomic group that contained a capturing parenthesis was  22. When an atomic group that contained a capturing parenthesis was
158      successfully matched, but the branch in which it appeared failed, the      successfully matched, but the branch in which it appeared failed, the
159      capturing was not being forgotten if a higher numbered group was later      capturing was not being forgotten if a higher numbered group was later
160      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing      captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
161      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-
162      branched capturing and non-capturing groups, repeated or not, and also to      branched capturing and non-capturing groups, repeated or not, and also to
163      positive assertions (capturing in negative assertions is not well defined      positive assertions (capturing in negative assertions does not happen
164      in PCRE) and also to nested atomic groups.      in PCRE) and also to nested atomic groups.
165    
166  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
167      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
168      number of identical substrings has been captured).      number of identical substrings has been captured.
169    
170  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
171      if they are repeated, backtracking one repetition now resets captured      if they are repeated, backtracking one repetition now resets captured
172      values correctly. For example, if ((?>(a+)b)+aabab) is matched against      values correctly. For example, if ((?>(a+)b)+aabab) is matched against
173      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as      "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
174      "aaa". Previously, it would have been "a". As part of this code      "aaa". Previously, it would have been "a". As part of this code
175      refactoring, the way recursive calls are handled has also been changed.      refactoring, the way recursive calls are handled has also been changed.
176    
177  24. If an assertion condition captured any substrings, they were not passed  25. If an assertion condition captured any substrings, they were not passed
178      back unless some other capturing happened later. For example, if      back unless some other capturing happened later. For example, if
179      (?(?=(a))a) was matched against "a", no capturing was returned.      (?(?=(a))a) was matched against "a", no capturing was returned.
180    
181  25. When studying a pattern that contained subroutine calls or assertions,  26. When studying a pattern that contained subroutine calls or assertions,
182      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
183      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where      direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
184      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
185      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
186      the recursion depth to 10.      the recursion depth to 10.
187    
188  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
189      Fortmann. This supports explicit test numbers on the command line, and has      Fortmann. This supports explicit test numbers on the command line, and has
190      argument validation and error reporting.      argument validation and error reporting.
191    
192  27. An instance of \X with an unlimited repeat could fail if at any point the  28. An instance of \X with an unlimited repeat could fail if at any point the
193      first character it looked at was a mark character.      first character it looked at was a mark character.
194    
195  28. Some minor code refactoring concerning Unicode properties and scripts  29. Some minor code refactoring concerning Unicode properties and scripts
196      should reduce the stack requirement of match() slightly.      should reduce the stack requirement of match() slightly.
197    
198  29. Added the '=' option to pcretest to check the setting of unused capturing  30. Added the '=' option to pcretest to check the setting of unused capturing
199      slots at the end of the pattern, which are documented as being -1, but are      slots at the end of the pattern, which are documented as being -1, but are
200      not included in the return count.      not included in the return count.
201    
202  30. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE  31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
203      compiled something random. Now it gives a compile-time error (as does      compiled something random. Now it gives a compile-time error (as does
204      Perl).      Perl).
205    
206  31. A *MARK encountered during the processing of a positive assertion is now  32. A *MARK encountered during the processing of a positive assertion is now
207      recorded and passed back (compatible with Perl).      recorded and passed back (compatible with Perl).
208    
209  32. If --only-matching or --colour was set on a pcregrep call whose pattern  33. If --only-matching or --colour was set on a pcregrep call whose pattern
210      had alternative anchored branches, the search for a second match in a line      had alternative anchored branches, the search for a second match in a line
211      was done as if at the line start. Thus, for example, /^01|^02/ incorrectly      was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
212      matched the line "0102" twice. The same bug affected patterns that started      matched the line "0102" twice. The same bug affected patterns that started
213      with a backwards assertion. For example /\b01|\b02/ also matched "0102"      with a backwards assertion. For example /\b01|\b02/ also matched "0102"
214      twice.      twice.
215    
216  33. Previously, PCRE did not allow quantification of assertions. However, Perl  34. Previously, PCRE did not allow quantification of assertions. However, Perl
217      does, and because of capturing effects, quantifying parenthesized      does, and because of capturing effects, quantifying parenthesized
218      assertions may at times be useful. Quantifiers are now allowed for      assertions may at times be useful. Quantifiers are now allowed for
219      parenthesized assertions.      parenthesized assertions.
220    
221    35. A minor code tidy in pcre_compile() when checking options for \R usage.
222    
223    36. \g was being checked for fancy things in a character class, when it should
224        just be a literal "g".
225    
226    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
227        appearance of a nested POSIX class supersedes an apparent external class.
228        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
229        unescaped square brackets may also appear as part of class names. For
230        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
231        more like Perl. (But see 8.20/1 above.)
232    
233    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
234        was because it thought it was \N{name}, which is not supported).
235    
236    39. Add minix to OS list not supporting the -S option in pcretest.
237    
238    40. PCRE tries to detect cases of infinite recursion at compile time, but it
239        cannot analyze patterns in sufficient detail to catch mutual recursions
240        such as ((?1))((?2)). There is now a runtime test that gives an error if a
241        subgroup is called recursively as a subpattern for a second time at the
242        same position in the subject string. In previous releases this might have
243        been caught by the recursion limit, or it might have run out of stack.
244    
245    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
246        happen only once. PCRE was, however incorrectly giving a compile time error
247        "recursive call could loop indefinitely" because it cannot analyze the
248        pattern in sufficient detail. The compile time test no longer happens when
249        PCRE is compiling a conditional subpattern, but actual runaway loops are
250        now caught at runtime (see 40 above).
251    
252    42. It seems that Perl allows any characters other than a closing parenthesis
253        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
254        has been changed to be the same.
255    
256    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
257        as not to get warnings when autogen.sh is called. Also changed
258        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
259    
260    44. To help people who use pcregrep to scan files containing exceedingly long
261        lines, the following changes have been made:
262    
263        (a) The default value of the buffer size parameter has been increased from
264            8K to 20K. (The actual buffer used is three times this size.)
265    
266        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
267            PCRE is built.
268    
269        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
270            to be set at run time.
271    
272        (d) Numerical values in pcregrep options can be followed by K or M, for
273            example --buffer-size=50K.
274    
275        (e) If a line being scanned overflows pcregrep's buffer, an error is now
276            given and the return code is set to 2.
277    
278    45. Add a pointer to the latest mark to the callout data block.
279    
280    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
281        partial match of an empty string instead of no match. This was specific to
282        the use of ".".
283    
284    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
285        complete match instead of a partial match. This bug was dependent on both
286        the PCRE_UTF8 and PCRE_DOTALL options being set.
287    
288    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
289        starting byte set, because \b was not being ignored.
290    
291    
292  Version 8.12 15-Jan-2011  Version 8.12 15-Jan-2011
293  ------------------------  ------------------------

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