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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4    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, \U and \u in JavaScript compatibility mode based on the
21        ECMA-262 standard.
22    
23    6.  Lookbehinds such as (?<=a{2}b) that contained a fixed repetition were
24        erroneously being rejected as "not fixed length" if PCRE_CASELESS was set.
25        This bug was probably introduced by change 9 of 8.13.
26    
27    7.  While fixing 6 above, I noticed that a number of other items were being
28        incorrectly rejected as "not fixed length". This arose partly because newer
29        opcodes had not been added to the fixed-length checking code. I have (a)
30        corrected the bug and added tests for these items, and (b) arranged for an
31        error to occur if an unknown opcode is encountered while checking for fixed
32        length instead of just assuming "not fixed length". The items that were
33        rejected were: (*ACCEPT), (*COMMIT), (*FAIL), (*MARK), (*PRUNE), (*SKIP),
34        (*THEN), \h, \H, \v, \V, and single character negative classes with fixed
35        repetitions, e.g. [^a]{3}, with and without PCRE_CASELESS.
36    
37    8.  A possessively repeated conditional subpattern such as (?(?=c)c|d)++ was
38        being incorrectly compiled and would have given unpredicatble results.
39    
40    9.  A possessively repeated subpattern with minimum repeat count greater than
41        one behaved incorrectly. For example, (A){2,}+ behaved as if it was
42        (A)(A)++ which meant that, after a subsequent mismatch, backtracking into
43        the first (A) could occur when it should not.
44    
45    10. Add a cast and remove a redundant test from the code.
46    
47    11. JIT should use pcre_malloc/pcre_free for allocation.
48    
49    
50    Version 8.20 21-Oct-2011
51    ------------------------
52    
53    1.  Change 37 of 8.13 broke patterns like [:a]...[b:] because it thought it had
54        a POSIX class. After further experiments with Perl, which convinced me that
55        Perl has bugs and confusions, a closing square bracket is no longer allowed
56        in a POSIX name. This bug also affected patterns with classes that started
57        with full stops.
58    
59    2.  If a pattern such as /(a)b|ac/ is matched against "ac", there is no
60        captured substring, but while checking the failing first alternative,
61        substring 1 is temporarily captured. If the output vector supplied to
62        pcre_exec() was not big enough for this capture, the yield of the function
63        was still zero ("insufficient space for captured substrings"). This cannot
64        be totally fixed without adding another stack variable, which seems a lot
65        of expense for a edge case. However, I have improved the situation in cases
66        such as /(a)(b)x|abc/ matched against "abc", where the return code
67        indicates that fewer than the maximum number of slots in the ovector have
68        been set.
69    
70    3.  Related to (2) above: when there are more back references in a pattern than
71        slots in the output vector, pcre_exec() uses temporary memory during
72        matching, and copies in the captures as far as possible afterwards. It was
73        using the entire output vector, but this conflicts with the specification
74        that only 2/3 is used for passing back captured substrings. Now it uses
75        only the first 2/3, for compatibility. This is, of course, another edge
76        case.
77    
78    4.  Zoltan Herczeg's just-in-time compiler support has been integrated into the
79        main code base, and can be used by building with --enable-jit. When this is
80        done, pcregrep automatically uses it unless --disable-pcregrep-jit or the
81        runtime --no-jit option is given.
82    
83    5.  When the number of matches in a pcre_dfa_exec() run exactly filled the
84        ovector, the return from the function was zero, implying that there were
85        other matches that did not fit. The correct "exactly full" value is now
86        returned.
87    
88    6.  If a subpattern that was called recursively or as a subroutine contained
89        (*PRUNE) or any other control that caused it to give a non-standard return,
90        invalid errors such as "Error -26 (nested recursion at the same subject
91        position)" or even infinite loops could occur.
92    
93    7.  If a pattern such as /a(*SKIP)c|b(*ACCEPT)|/ was studied, it stopped
94        computing the minimum length on reaching *ACCEPT, and so ended up with the
95        wrong value of 1 rather than 0. Further investigation indicates that
96        computing a minimum subject length in the presence of *ACCEPT is difficult
97        (think back references, subroutine calls), and so I have changed the code
98        so that no minimum is registered for a pattern that contains *ACCEPT.
99    
100    8.  If (*THEN) was present in the first (true) branch of a conditional group,
101        it was not handled as intended. [But see 16 below.]
102    
103    9.  Replaced RunTest.bat and CMakeLists.txt with improved versions provided by
104        Sheri Pierce.
105    
106    10. A pathological pattern such as /(*ACCEPT)a/ was miscompiled, thinking that
107        the first byte in a match must be "a".
108    
109    11. Change 17 for 8.13 increased the recursion depth for patterns like
110        /a(?:.)*?a/ drastically. I've improved things by remembering whether a
111        pattern contains any instances of (*THEN). If it does not, the old
112        optimizations are restored. It would be nice to do this on a per-group
113        basis, but at the moment that is not feasible.
114    
115    12. In some environments, the output of pcretest -C is CRLF terminated. This
116        broke RunTest's code that checks for the link size. A single white space
117        character after the value is now allowed for.
118    
119    13. RunTest now checks for the "fr" locale as well as for "fr_FR" and "french".
120        For "fr", it uses the Windows-specific input and output files.
121    
122    14. If (*THEN) appeared in a group that was called recursively or as a
123        subroutine, it did not work as intended. [But see next item.]
124    
125    15. Consider the pattern /A (B(*THEN)C) | D/ where A, B, C, and D are complex
126        pattern fragments (but not containing any | characters). If A and B are
127        matched, but there is a failure in C so that it backtracks to (*THEN), PCRE
128        was behaving differently to Perl. PCRE backtracked into A, but Perl goes to
129        D. In other words, Perl considers parentheses that do not contain any |
130        characters to be part of a surrounding alternative, whereas PCRE was
131        treading (B(*THEN)C) the same as (B(*THEN)C|(*FAIL)) -- which Perl handles
132        differently. PCRE now behaves in the same way as Perl, except in the case
133        of subroutine/recursion calls such as (?1) which have in any case always
134        been different (but PCRE had them first :-).
135    
136    16. Related to 15 above: Perl does not treat the | in a conditional group as
137        creating alternatives. Such a group is treated in the same way as an
138        ordinary group without any | characters when processing (*THEN). PCRE has
139        been changed to match Perl's behaviour.
140    
141    17. If a user had set PCREGREP_COLO(U)R to something other than 1:31, the
142        RunGrepTest script failed.
143    
144    18. Change 22 for version 13 caused atomic groups to use more stack. This is
145        inevitable for groups that contain captures, but it can lead to a lot of
146        stack use in large patterns. The old behaviour has been restored for atomic
147        groups that do not contain any capturing parentheses.
148    
149    19. If the PCRE_NO_START_OPTIMIZE option was set for pcre_compile(), it did not
150        suppress the check for a minimum subject length at run time. (If it was
151        given to pcre_exec() or pcre_dfa_exec() it did work.)
152    
153    20. Fixed an ASCII-dependent infelicity in pcretest that would have made it
154        fail to work when decoding hex characters in data strings in EBCDIC
155        environments.
156    
157    21. It appears that in at least one Mac OS environment, the isxdigit() function
158        is implemented as a macro that evaluates to its argument more than once,
159        contravening the C 90 Standard (I haven't checked a later standard). There
160        was an instance in pcretest which caused it to go wrong when processing
161        \x{...} escapes in subject strings. The has been rewritten to avoid using
162        things like p++ in the argument of isxdigit().
163    
164    
165    Version 8.13 16-Aug-2011
166    ------------------------
167    
168    1.  The Unicode data tables have been updated to Unicode 6.0.0.
169    
170    2.  Two minor typos in pcre_internal.h have been fixed.
171    
172    3.  Added #include <string.h> to pcre_scanner_unittest.cc, pcrecpp.cc, and
173        pcrecpp_unittest.cc. They are needed for strcmp(), memset(), and strchr()
174        in some environments (e.g. Solaris 10/SPARC using Sun Studio 12U2).
175    
176    4.  There were a number of related bugs in the code for matching backrefences
177        caselessly in UTF-8 mode when codes for the characters concerned were
178        different numbers of bytes. For example, U+023A and U+2C65 are an upper
179        and lower case pair, using 2 and 3 bytes, respectively. The main bugs were:
180        (a) A reference to 3 copies of a 2-byte code matched only 2 of a 3-byte
181        code. (b) A reference to 2 copies of a 3-byte code would not match 2 of a
182        2-byte code at the end of the subject (it thought there wasn't enough data
183        left).
184    
185    5.  Comprehensive information about what went wrong is now returned by
186        pcre_exec() and pcre_dfa_exec() when the UTF-8 string check fails, as long
187        as the output vector has at least 2 elements. The offset of the start of
188        the failing character and a reason code are placed in the vector.
189    
190    6.  When the UTF-8 string check fails for pcre_compile(), the offset that is
191        now returned is for the first byte of the failing character, instead of the
192        last byte inspected. This is an incompatible change, but I hope it is small
193        enough not to be a problem. It makes the returned offset consistent with
194        pcre_exec() and pcre_dfa_exec().
195    
196    7.  pcretest now gives a text phrase as well as the error number when
197        pcre_exec() or pcre_dfa_exec() fails; if the error is a UTF-8 check
198        failure, the offset and reason code are output.
199    
200    8.  When \R was used with a maximizing quantifier it failed to skip backwards
201        over a \r\n pair if the subsequent match failed. Instead, it just skipped
202        back over a single character (\n). This seems wrong (because it treated the
203        two characters as a single entity when going forwards), conflicts with the
204        documentation that \R is equivalent to (?>\r\n|\n|...etc), and makes the
205        behaviour of \R* different to (\R)*, which also seems wrong. The behaviour
206        has been changed.
207    
208    9.  Some internal refactoring has changed the processing so that the handling
209        of the PCRE_CASELESS and PCRE_MULTILINE options is done entirely at compile
210        time (the PCRE_DOTALL option was changed this way some time ago: version
211        7.7 change 16). This has made it possible to abolish the OP_OPT op code,
212        which was always a bit of a fudge. It also means that there is one less
213        argument for the match() function, which reduces its stack requirements
214        slightly. This change also fixes an incompatibility with Perl: the pattern
215        (?i:([^b]))(?1) should not match "ab", but previously PCRE gave a match.
216    
217    10. More internal refactoring has drastically reduced the number of recursive
218        calls to match() for possessively repeated groups such as (abc)++ when
219        using pcre_exec().
220    
221    11. While implementing 10, a number of bugs in the handling of groups were
222        discovered and fixed:
223    
224        (?<=(a)+) was not diagnosed as invalid (non-fixed-length lookbehind).
225        (a|)*(?1) gave a compile-time internal error.
226        ((a|)+)+  did not notice that the outer group could match an empty string.
227        (^a|^)+   was not marked as anchored.
228        (.*a|.*)+ was not marked as matching at start or after a newline.
229    
230    12. Yet more internal refactoring has removed another argument from the match()
231        function. Special calls to this function are now indicated by setting a
232        value in a variable in the "match data" data block.
233    
234    13. Be more explicit in pcre_study() instead of relying on "default" for
235        opcodes that mean there is no starting character; this means that when new
236        ones are added and accidentally left out of pcre_study(), testing should
237        pick them up.
238    
239    14. The -s option of pcretest has been documented for ages as being an old
240        synonym of -m (show memory usage). I have changed it to mean "force study
241        for every regex", that is, assume /S for every regex. This is similar to -i
242        and -d etc. It's slightly incompatible, but I'm hoping nobody is still
243        using it. It makes it easier to run collections of tests with and without
244        study enabled, and thereby test pcre_study() more easily. All the standard
245        tests are now run with and without -s (but some patterns can be marked as
246        "never study" - see 20 below).
247    
248    15. When (*ACCEPT) was used in a subpattern that was called recursively, the
249        restoration of the capturing data to the outer values was not happening
250        correctly.
251    
252    16. If a recursively called subpattern ended with (*ACCEPT) and matched an
253        empty string, and PCRE_NOTEMPTY was set, pcre_exec() thought the whole
254        pattern had matched an empty string, and so incorrectly returned a no
255        match.
256    
257    17. There was optimizing code for the last branch of non-capturing parentheses,
258        and also for the obeyed branch of a conditional subexpression, which used
259        tail recursion to cut down on stack usage. Unfortunately, now that there is
260        the possibility of (*THEN) occurring in these branches, tail recursion is
261        no longer possible because the return has to be checked for (*THEN). These
262        two optimizations have therefore been removed. [But see 8.20/11 above.]
263    
264    18. If a pattern containing \R was studied, it was assumed that \R always
265        matched two bytes, thus causing the minimum subject length to be
266        incorrectly computed because \R can also match just one byte.
267    
268    19. If a pattern containing (*ACCEPT) was studied, the minimum subject length
269        was incorrectly computed.
270    
271    20. If /S is present twice on a test pattern in pcretest input, it now
272        *disables* studying, thereby overriding the use of -s on the command line
273        (see 14 above). This is necessary for one or two tests to keep the output
274        identical in both cases.
275    
276    21. When (*ACCEPT) was used in an assertion that matched an empty string and
277        PCRE_NOTEMPTY was set, PCRE applied the non-empty test to the assertion.
278    
279    22. When an atomic group that contained a capturing parenthesis was
280        successfully matched, but the branch in which it appeared failed, the
281        capturing was not being forgotten if a higher numbered group was later
282        captured. For example, /(?>(a))b|(a)c/ when matching "ac" set capturing
283        group 1 to "a", when in fact it should be unset. This applied to multi-
284        branched capturing and non-capturing groups, repeated or not, and also to
285        positive assertions (capturing in negative assertions does not happen
286        in PCRE) and also to nested atomic groups.
287    
288    23. Add the ++ qualifier feature to pcretest, to show the remainder of the
289        subject after a captured substring, to make it easier to tell which of a
290        number of identical substrings has been captured.
291    
292    24. The way atomic groups are processed by pcre_exec() has been changed so that
293        if they are repeated, backtracking one repetition now resets captured
294        values correctly. For example, if ((?>(a+)b)+aabab) is matched against
295        "aaaabaaabaabab" the value of captured group 2 is now correctly recorded as
296        "aaa". Previously, it would have been "a". As part of this code
297        refactoring, the way recursive calls are handled has also been changed.
298    
299    25. If an assertion condition captured any substrings, they were not passed
300        back unless some other capturing happened later. For example, if
301        (?(?=(a))a) was matched against "a", no capturing was returned.
302    
303    26. When studying a pattern that contained subroutine calls or assertions,
304        the code for finding the minimum length of a possible match was handling
305        direct recursions such as (xxx(?1)|yyy) but not mutual recursions (where
306        group 1 called group 2 while simultaneously a separate group 2 called group
307        1). A stack overflow occurred in this case. I have fixed this by limiting
308        the recursion depth to 10.
309    
310    27. Updated RunTest.bat in the distribution to the version supplied by Tom
311        Fortmann. This supports explicit test numbers on the command line, and has
312        argument validation and error reporting.
313    
314    28. An instance of \X with an unlimited repeat could fail if at any point the
315        first character it looked at was a mark character.
316    
317    29. Some minor code refactoring concerning Unicode properties and scripts
318        should reduce the stack requirement of match() slightly.
319    
320    30. Added the '=' option to pcretest to check the setting of unused capturing
321        slots at the end of the pattern, which are documented as being -1, but are
322        not included in the return count.
323    
324    31. If \k was not followed by a braced, angle-bracketed, or quoted name, PCRE
325        compiled something random. Now it gives a compile-time error (as does
326        Perl).
327    
328    32. A *MARK encountered during the processing of a positive assertion is now
329        recorded and passed back (compatible with Perl).
330    
331    33. If --only-matching or --colour was set on a pcregrep call whose pattern
332        had alternative anchored branches, the search for a second match in a line
333        was done as if at the line start. Thus, for example, /^01|^02/ incorrectly
334        matched the line "0102" twice. The same bug affected patterns that started
335        with a backwards assertion. For example /\b01|\b02/ also matched "0102"
336        twice.
337    
338    34. Previously, PCRE did not allow quantification of assertions. However, Perl
339        does, and because of capturing effects, quantifying parenthesized
340        assertions may at times be useful. Quantifiers are now allowed for
341        parenthesized assertions.
342    
343    35. A minor code tidy in pcre_compile() when checking options for \R usage.
344    
345    36. \g was being checked for fancy things in a character class, when it should
346        just be a literal "g".
347    
348    37. PCRE was rejecting [:a[:digit:]] whereas Perl was not. It seems that the
349        appearance of a nested POSIX class supersedes an apparent external class.
350        For example, [:a[:digit:]b:] matches "a", "b", ":", or a digit. Also,
351        unescaped square brackets may also appear as part of class names. For
352        example, [:a[:abc]b:] gives unknown class "[:abc]b:]". PCRE now behaves
353        more like Perl. (But see 8.20/1 above.)
354    
355    38. PCRE was giving an error for \N with a braced quantifier such as {1,} (this
356        was because it thought it was \N{name}, which is not supported).
357    
358    39. Add minix to OS list not supporting the -S option in pcretest.
359    
360    40. PCRE tries to detect cases of infinite recursion at compile time, but it
361        cannot analyze patterns in sufficient detail to catch mutual recursions
362        such as ((?1))((?2)). There is now a runtime test that gives an error if a
363        subgroup is called recursively as a subpattern for a second time at the
364        same position in the subject string. In previous releases this might have
365        been caught by the recursion limit, or it might have run out of stack.
366    
367    41. A pattern such as /(?(R)a+|(?R)b)/ is quite safe, as the recursion can
368        happen only once. PCRE was, however incorrectly giving a compile time error
369        "recursive call could loop indefinitely" because it cannot analyze the
370        pattern in sufficient detail. The compile time test no longer happens when
371        PCRE is compiling a conditional subpattern, but actual runaway loops are
372        now caught at runtime (see 40 above).
373    
374    42. It seems that Perl allows any characters other than a closing parenthesis
375        to be part of the NAME in (*MARK:NAME) and other backtracking verbs. PCRE
376        has been changed to be the same.
377    
378    43. Updated configure.ac to put in more quoting round AC_LANG_PROGRAM etc. so
379        as not to get warnings when autogen.sh is called. Also changed
380        AC_PROG_LIBTOOL (deprecated) to LT_INIT (the current macro).
381    
382    44. To help people who use pcregrep to scan files containing exceedingly long
383        lines, the following changes have been made:
384    
385        (a) The default value of the buffer size parameter has been increased from
386            8K to 20K. (The actual buffer used is three times this size.)
387    
388        (b) The default can be changed by ./configure --with-pcregrep-bufsize when
389            PCRE is built.
390    
391        (c) A --buffer-size=n option has been added to pcregrep, to allow the size
392            to be set at run time.
393    
394        (d) Numerical values in pcregrep options can be followed by K or M, for
395            example --buffer-size=50K.
396    
397        (e) If a line being scanned overflows pcregrep's buffer, an error is now
398            given and the return code is set to 2.
399    
400    45. Add a pointer to the latest mark to the callout data block.
401    
402    46. The pattern /.(*F)/, when applied to "abc" with PCRE_PARTIAL_HARD, gave a
403        partial match of an empty string instead of no match. This was specific to
404        the use of ".".
405    
406    47. The pattern /f.*/8s, when applied to "for" with PCRE_PARTIAL_HARD, gave a
407        complete match instead of a partial match. This bug was dependent on both
408        the PCRE_UTF8 and PCRE_DOTALL options being set.
409    
410    48. For a pattern such as /\babc|\bdef/ pcre_study() was failing to set up the
411        starting byte set, because \b was not being ignored.
412    
413    
414    Version 8.12 15-Jan-2011
415    ------------------------
416    
417    1.  Fixed some typos in the markup of the man pages, and wrote a script that
418        checks for such things as part of the documentation building process.
419    
420    2.  On a big-endian 64-bit system, pcregrep did not correctly process the
421        --match-limit and --recursion-limit options (added for 8.11). In
422        particular, this made one of the standard tests fail. (The integer value
423        went into the wrong half of a long int.)
424    
425    3.  If the --colour option was given to pcregrep with -v (invert match), it
426        did strange things, either producing crazy output, or crashing. It should,
427        of course, ignore a request for colour when reporting lines that do not
428        match.
429    
430    4.  Another pcregrep bug caused similar problems if --colour was specified with
431        -M (multiline) and the pattern match finished with a line ending.
432    
433    5.  In pcregrep, when a pattern that ended with a literal newline sequence was
434        matched in multiline mode, the following line was shown as part of the
435        match. This seems wrong, so I have changed it.
436    
437    6.  Another pcregrep bug in multiline mode, when --colour was specified, caused
438        the check for further matches in the same line (so they could be coloured)
439        to overrun the end of the current line. If another match was found, it was
440        incorrectly shown (and then shown again when found in the next line).
441    
442    7.  If pcregrep was compiled under Windows, there was a reference to the
443        function pcregrep_exit() before it was defined. I am assuming this was
444        the cause of the "error C2371: 'pcregrep_exit' : redefinition;" that was
445        reported by a user. I've moved the definition above the reference.
446    
447    
448  Version 8.11 10-Dec-2010  Version 8.11 10-Dec-2010
449  ------------------------  ------------------------
450    

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