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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 8.33 xx-xxxx-201x  Note that the PCRE 8.xx series (PCRE1) is now in a bugfix-only state. All
5  -------------------------  development is happening in the PCRE2 10.xx series.
6    
7    Version 8.38 xx-xxx-xxxx
8    ------------------------
9    
10    1.  If a group that contained a recursive back reference also contained a
11        forward reference subroutine call followed by a non-forward-reference
12        subroutine call, for example /.((?2)(?R)\1)()/, pcre2_compile() failed to
13        compile correct code, leading to undefined behaviour or an internally
14        detected error. This bug was discovered by the LLVM fuzzer.
15    
16    2.  Quantification of certain items (e.g. atomic back references) could cause
17        incorrect code to be compiled when recursive forward references were
18        involved. For example, in this pattern: /(?1)()((((((\1++))\x85)+)|))/.
19        This bug was discovered by the LLVM fuzzer.
20    
21    3.  A repeated conditional group whose condition was a reference by name caused
22        a buffer overflow if there was more than one group with the given name.
23        This bug was discovered by the LLVM fuzzer.
24    
25    4.  A recursive back reference by name within a group that had the same name as
26        another group caused a buffer overflow. For example:
27        /(?J)(?'d'(?'d'\g{d}))/. This bug was discovered by the LLVM fuzzer.
28    
29    5.  A forward reference by name to a group whose number is the same as the
30        current group, for example in this pattern: /(?|(\k'Pm')|(?'Pm'))/, caused
31        a buffer overflow at compile time. This bug was discovered by the LLVM
32        fuzzer.
33    
34    6.  A lookbehind assertion within a set of mutually recursive subpatterns could
35        provoke a buffer overflow. This bug was discovered by the LLVM fuzzer.
36    
37    7.  Another buffer overflow bug involved duplicate named groups with a
38        reference between their definition, with a group that reset capture
39        numbers, for example: /(?J:(?|(?'R')(\k'R')|((?'R'))))/. This has been
40        fixed by always allowing for more memory, even if not needed. (A proper fix
41        is implemented in PCRE2, but it involves more refactoring.)
42    
43    8.  There was no check for integer overflow in subroutine calls such as (?123).
44    
45    9.  The table entry for \l in EBCDIC environments was incorrect, leading to its
46        being treated as a literal 'l' instead of causing an error.
47    
48    10. There was a buffer overflow if pcre_exec() was called with an ovector of
49        size 1. This bug was found by american fuzzy lop.
50    
51    11. If a non-capturing group containing a conditional group that could match
52        an empty string was repeated, it was not identified as matching an empty
53        string itself. For example: /^(?:(?(1)x|)+)+$()/.
54    
55    12. In an EBCDIC environment, pcretest was mishandling the escape sequences
56        \a and \e in test subject lines.
57    
58    13. In an EBCDIC environment, \a in a pattern was converted to the ASCII
59        instead of the EBCDIC value.
60    
61    14. The handling of \c in an EBCDIC environment has been revised so that it is
62        now compatible with the specification in Perl's perlebcdic page.
63    
64    15. The EBCDIC character 0x41 is a non-breaking space, equivalent to 0xa0 in
65        ASCII/Unicode. This has now been added to the list of characters that are
66        recognized as white space in EBCDIC.
67    
68    16. When PCRE was compiled without UCP support, the use of \p and \P gave an
69        error (correctly) when used outside a class, but did not give an error
70        within a class.
71    
72    17. \h within a class was incorrectly compiled in EBCDIC environments.
73    
74    18. A pattern with an unmatched closing parenthesis that contained a backward
75        assertion which itself contained a forward reference caused buffer
76        overflow. And example pattern is: /(?=di(?<=(?1))|(?=(.))))/.
77    
78    19. JIT should return with error when the compiled pattern requires more stack
79        space than the maximum.
80    
81    20. A possessively repeated conditional group that could match an empty string,
82        for example, /(?(R))*+/, was incorrectly compiled.
83    
84    21. Fix infinite recursion in the JIT compiler when certain patterns such as
85        /(?:|a|){100}x/ are analysed.
86    
87    22. Some patterns with character classes involving [: and \\ were incorrectly
88        compiled and could cause reading from uninitialized memory or an incorrect
89        error diagnosis.
90    
91    
92    Version 8.37 28-April-2015
93    --------------------------
94    
95    1.  When an (*ACCEPT) is triggered inside capturing parentheses, it arranges
96        for those parentheses to be closed with whatever has been captured so far.
97        However, it was failing to mark any other groups between the hightest
98        capture so far and the currrent group as "unset". Thus, the ovector for
99        those groups contained whatever was previously there. An example is the
100        pattern /(x)|((*ACCEPT))/ when matched against "abcd".
101    
102    2.  If an assertion condition was quantified with a minimum of zero (an odd
103        thing to do, but it happened), SIGSEGV or other misbehaviour could occur.
104    
105    3.  If a pattern in pcretest input had the P (POSIX) modifier followed by an
106        unrecognized modifier, a crash could occur.
107    
108    4.  An attempt to do global matching in pcretest with a zero-length ovector
109        caused a crash.
110    
111    5.  Fixed a memory leak during matching that could occur for a subpattern
112        subroutine call (recursive or otherwise) if the number of captured groups
113        that had to be saved was greater than ten.
114    
115    6.  Catch a bad opcode during auto-possessification after compiling a bad UTF
116        string with NO_UTF_CHECK. This is a tidyup, not a bug fix, as passing bad
117        UTF with NO_UTF_CHECK is documented as having an undefined outcome.
118    
119    7.  A UTF pattern containing a "not" match of a non-ASCII character and a
120        subroutine reference could loop at compile time. Example: /[^\xff]((?1))/.
121    
122    8. When a pattern is compiled, it remembers the highest back reference so that
123       when matching, if the ovector is too small, extra memory can be obtained to
124       use instead. A conditional subpattern whose condition is a check on a
125       capture having happened, such as, for example in the pattern
126       /^(?:(a)|b)(?(1)A|B)/, is another kind of back reference, but it was not
127       setting the highest backreference number. This mattered only if pcre_exec()
128       was called with an ovector that was too small to hold the capture, and there
129       was no other kind of back reference (a situation which is probably quite
130       rare). The effect of the bug was that the condition was always treated as
131       FALSE when the capture could not be consulted, leading to a incorrect
132       behaviour by pcre_exec(). This bug has been fixed.
133    
134    9. A reference to a duplicated named group (either a back reference or a test
135       for being set in a conditional) that occurred in a part of the pattern where
136       PCRE_DUPNAMES was not set caused the amount of memory needed for the pattern
137       to be incorrectly calculated, leading to overwriting.
138    
139    10. A mutually recursive set of back references such as (\2)(\1) caused a
140        segfault at study time (while trying to find the minimum matching length).
141        The infinite loop is now broken (with the minimum length unset, that is,
142        zero).
143    
144    11. If an assertion that was used as a condition was quantified with a minimum
145        of zero, matching went wrong. In particular, if the whole group had
146        unlimited repetition and could match an empty string, a segfault was
147        likely. The pattern (?(?=0)?)+ is an example that caused this. Perl allows
148        assertions to be quantified, but not if they are being used as conditions,
149        so the above pattern is faulted by Perl. PCRE has now been changed so that
150        it also rejects such patterns.
151    
152    12. A possessive capturing group such as (a)*+ with a minimum repeat of zero
153        failed to allow the zero-repeat case if pcre2_exec() was called with an
154        ovector too small to capture the group.
155    
156    13. Fixed two bugs in pcretest that were discovered by fuzzing and reported by
157        Red Hat Product Security:
158    
159        (a) A crash if /K and /F were both set with the option to save the compiled
160        pattern.
161    
162        (b) Another crash if the option to print captured substrings in a callout
163        was combined with setting a null ovector, for example \O\C+ as a subject
164        string.
165    
166    14. A pattern such as "((?2){0,1999}())?", which has a group containing a
167        forward reference repeated a large (but limited) number of times within a
168        repeated outer group that has a zero minimum quantifier, caused incorrect
169        code to be compiled, leading to the error "internal error:
170        previously-checked referenced subpattern not found" when an incorrect
171        memory address was read. This bug was reported as "heap overflow",
172        discovered by Kai Lu of Fortinet's FortiGuard Labs and given the CVE number
173        CVE-2015-2325.
174    
175    23. A pattern such as "((?+1)(\1))/" containing a forward reference subroutine
176        call within a group that also contained a recursive back reference caused
177        incorrect code to be compiled. This bug was reported as "heap overflow",
178        discovered by Kai Lu of Fortinet's FortiGuard Labs, and given the CVE
179        number CVE-2015-2326.
180    
181    24. Computing the size of the JIT read-only data in advance has been a source
182        of various issues, and new ones are still appear unfortunately. To fix
183        existing and future issues, size computation is eliminated from the code,
184        and replaced by on-demand memory allocation.
185    
186    25. A pattern such as /(?i)[A-`]/, where characters in the other case are
187        adjacent to the end of the range, and the range contained characters with
188        more than one other case, caused incorrect behaviour when compiled in UTF
189        mode. In that example, the range a-j was left out of the class.
190    
191    26. Fix JIT compilation of conditional blocks, which assertion
192        is converted to (*FAIL). E.g: /(?(?!))/.
193    
194    27. The pattern /(?(?!)^)/ caused references to random memory. This bug was
195        discovered by the LLVM fuzzer.
196    
197    28. The assertion (?!) is optimized to (*FAIL). This was not handled correctly
198        when this assertion was used as a condition, for example (?(?!)a|b). In
199        pcre2_match() it worked by luck; in pcre2_dfa_match() it gave an incorrect
200        error about an unsupported item.
201    
202    29. For some types of pattern, for example /Z*(|d*){216}/, the auto-
203        possessification code could take exponential time to complete. A recursion
204        depth limit of 1000 has been imposed to limit the resources used by this
205        optimization.
206    
207    30. A pattern such as /(*UTF)[\S\V\H]/, which contains a negated special class
208        such as \S in non-UCP mode, explicit wide characters (> 255) can be ignored
209        because \S ensures they are all in the class. The code for doing this was
210        interacting badly with the code for computing the amount of space needed to
211        compile the pattern, leading to a buffer overflow. This bug was discovered
212        by the LLVM fuzzer.
213    
214    31. A pattern such as /((?2)+)((?1))/ which has mutual recursion nested inside
215        other kinds of group caused stack overflow at compile time. This bug was
216        discovered by the LLVM fuzzer.
217    
218    32. A pattern such as /(?1)(?#?'){8}(a)/ which had a parenthesized comment
219        between a subroutine call and its quantifier was incorrectly compiled,
220        leading to buffer overflow or other errors. This bug was discovered by the
221        LLVM fuzzer.
222    
223    33. The illegal pattern /(?(?<E>.*!.*)?)/ was not being diagnosed as missing an
224        assertion after (?(. The code was failing to check the character after
225        (?(?< for the ! or = that would indicate a lookbehind assertion. This bug
226        was discovered by the LLVM fuzzer.
227    
228    34. A pattern such as /X((?2)()*+){2}+/ which has a possessive quantifier with
229        a fixed maximum following a group that contains a subroutine reference was
230        incorrectly compiled and could trigger buffer overflow. This bug was
231        discovered by the LLVM fuzzer.
232    
233    35. A mutual recursion within a lookbehind assertion such as (?<=((?2))((?1)))
234        caused a stack overflow instead of the diagnosis of a non-fixed length
235        lookbehind assertion. This bug was discovered by the LLVM fuzzer.
236    
237    36. The use of \K in a positive lookbehind assertion in a non-anchored pattern
238        (e.g. /(?<=\Ka)/) could make pcregrep loop.
239    
240    37. There was a similar problem to 36 in pcretest for global matches.
241    
242    38. If a greedy quantified \X was preceded by \C in UTF mode (e.g. \C\X*),
243        and a subsequent item in the pattern caused a non-match, backtracking over
244        the repeated \X did not stop, but carried on past the start of the subject,
245        causing reference to random memory and/or a segfault. There were also some
246        other cases where backtracking after \C could crash. This set of bugs was
247        discovered by the LLVM fuzzer.
248    
249    39. The function for finding the minimum length of a matching string could take
250        a very long time if mutual recursion was present many times in a pattern,
251        for example, /((?2){73}(?2))((?1))/. A better mutual recursion detection
252        method has been implemented. This infelicity was discovered by the LLVM
253        fuzzer.
254    
255    40. Static linking against the PCRE library using the pkg-config module was
256        failing on missing pthread symbols.
257    
258    
259    Version 8.36 26-September-2014
260    ------------------------------
261    
262    1.  Got rid of some compiler warnings in the C++ modules that were shown up by
263        -Wmissing-field-initializers and -Wunused-parameter.
264    
265    2.  The tests for quantifiers being too big (greater than 65535) were being
266        applied after reading the number, and stupidly assuming that integer
267        overflow would give a negative number. The tests are now applied as the
268        numbers are read.
269    
270    3.  Tidy code in pcre_exec.c where two branches that used to be different are
271        now the same.
272    
273    4.  The JIT compiler did not generate match limit checks for certain
274        bracketed expressions with quantifiers. This may lead to exponential
275        backtracking, instead of returning with PCRE_ERROR_MATCHLIMIT. This
276        issue should be resolved now.
277    
278    5.  Fixed an issue, which occures when nested alternatives are optimized
279        with table jumps.
280    
281    6.  Inserted two casts and changed some ints to size_t in the light of some
282        reported 64-bit compiler warnings (Bugzilla 1477).
283    
284    7.  Fixed a bug concerned with zero-minimum possessive groups that could match
285        an empty string, which sometimes were behaving incorrectly in the
286        interpreter (though correctly in the JIT matcher). This pcretest input is
287        an example:
288    
289          '\A(?:[^"]++|"(?:[^"]*+|"")*+")++'
290          NON QUOTED "QUOT""ED" AFTER "NOT MATCHED
291    
292        the interpreter was reporting a match of 'NON QUOTED ' only, whereas the
293        JIT matcher and Perl both matched 'NON QUOTED "QUOT""ED" AFTER '. The test
294        for an empty string was breaking the inner loop and carrying on at a lower
295        level, when possessive repeated groups should always return to a higher
296        level as they have no backtrack points in them. The empty string test now
297        occurs at the outer level.
298    
299    8.  Fixed a bug that was incorrectly auto-possessifying \w+ in the pattern
300        ^\w+(?>\s*)(?<=\w) which caused it not to match "test test".
301    
302    9.  Give a compile-time error for \o{} (as Perl does) and for \x{} (which Perl
303        doesn't).
304    
305    10. Change 8.34/15 introduced a bug that caused the amount of memory needed
306        to hold a pattern to be incorrectly computed (too small) when there were
307        named back references to duplicated names. This could cause "internal
308        error: code overflow" or "double free or corruption" or other memory
309        handling errors.
310    
311    11. When named subpatterns had the same prefixes, back references could be
312        confused. For example, in this pattern:
313    
314          /(?P<Name>a)?(?P<Name2>b)?(?(<Name>)c|d)*l/
315    
316        the reference to 'Name' was incorrectly treated as a reference to a
317        duplicate name.
318    
319    12. A pattern such as /^s?c/mi8 where the optional character has more than
320        one "other case" was incorrectly compiled such that it would only try to
321        match starting at "c".
322    
323    13. When a pattern starting with \s was studied, VT was not included in the
324        list of possible starting characters; this should have been part of the
325        8.34/18 patch.
326    
327    14. If a character class started [\Qx]... where x is any character, the class
328        was incorrectly terminated at the ].
329    
330    15. If a pattern that started with a caseless match for a character with more
331        than one "other case" was studied, PCRE did not set up the starting code
332        unit bit map for the list of possible characters. Now it does. This is an
333        optimization improvement, not a bug fix.
334    
335    16. The Unicode data tables have been updated to Unicode 7.0.0.
336    
337    17. Fixed a number of memory leaks in pcregrep.
338    
339    18. Avoid a compiler warning (from some compilers) for a function call with
340        a cast that removes "const" from an lvalue by using an intermediate
341        variable (to which the compiler does not object).
342    
343    19. Incorrect code was compiled if a group that contained an internal recursive
344        back reference was optional (had quantifier with a minimum of zero). This
345        example compiled incorrect code: /(((a\2)|(a*)\g<-1>))*/ and other examples
346        caused segmentation faults because of stack overflows at compile time.
347    
348    20. A pattern such as /((?(R)a|(?1)))+/, which contains a recursion within a
349        group that is quantified with an indefinite repeat, caused a compile-time
350        loop which used up all the system stack and provoked a segmentation fault.
351        This was not the same bug as 19 above.
352    
353    21. Add PCRECPP_EXP_DECL declaration to operator<< in pcre_stringpiece.h.
354        Patch by Mike Frysinger.
355    
356    
357    Version 8.35 04-April-2014
358    --------------------------
359    
360    1.  A new flag is set, when property checks are present in an XCLASS.
361        When this flag is not set, PCRE can perform certain optimizations
362        such as studying these XCLASS-es.
363    
364    2.  The auto-possessification of character sets were improved: a normal
365        and an extended character set can be compared now. Furthermore
366        the JIT compiler optimizes more character set checks.
367    
368    3.  Got rid of some compiler warnings for potentially uninitialized variables
369        that show up only when compiled with -O2.
370    
371    4.  A pattern such as (?=ab\K) that uses \K in an assertion can set the start
372        of a match later then the end of the match. The pcretest program was not
373        handling the case sensibly - it was outputting from the start to the next
374        binary zero. It now reports this situation in a message, and outputs the
375        text from the end to the start.
376    
377    5.  Fast forward search is improved in JIT. Instead of the first three
378        characters, any three characters with fixed position can be searched.
379        Search order: first, last, middle.
380    
381    6.  Improve character range checks in JIT. Characters are read by an inprecise
382        function now, which returns with an unknown value if the character code is
383        above a certain threshold (e.g: 256). The only limitation is that the value
384        must be bigger than the threshold as well. This function is useful when
385        the characters above the threshold are handled in the same way.
386    
387    7.  The macros whose names start with RAWUCHAR are placeholders for a future
388        mode in which only the bottom 21 bits of 32-bit data items are used. To
389        make this more memorable for those maintaining the code, the names have
390        been changed to start with UCHAR21, and an extensive comment has been added
391        to their definition.
392    
393    8.  Add missing (new) files sljitNativeTILEGX.c and sljitNativeTILEGX-encoder.c
394        to the export list in Makefile.am (they were accidentally omitted from the
395        8.34 tarball).
396    
397    9.  The informational output from pcretest used the phrase "starting byte set"
398        which is inappropriate for the 16-bit and 32-bit libraries. As the output
399        for "first char" and "need char" really means "non-UTF-char", I've changed
400        "byte" to "char", and slightly reworded the output. The documentation about
401        these values has also been (I hope) clarified.
402    
403    10. Another JIT related optimization: use table jumps for selecting the correct
404        backtracking path, when more than four alternatives are present inside a
405        bracket.
406    
407    11. Empty match is not possible, when the minimum length is greater than zero,
408        and there is no \K in the pattern. JIT should avoid empty match checks in
409        such cases.
410    
411    12. In a caseless character class with UCP support, when a character with more
412        than one alternative case was not the first character of a range, not all
413        the alternative cases were added to the class. For example, s and \x{17f}
414        are both alternative cases for S: the class [RST] was handled correctly,
415        but [R-T] was not.
416    
417    13. The configure.ac file always checked for pthread support when JIT was
418        enabled. This is not used in Windows, so I have put this test inside a
419        check for the presence of windows.h (which was already tested for).
420    
421    14. Improve pattern prefix search by a simplified Boyer-Moore algorithm in JIT.
422        The algorithm provides a way to skip certain starting offsets, and usually
423        faster than linear prefix searches.
424    
425    15. Change 13 for 8.20 updated RunTest to check for the 'fr' locale as well
426        as for 'fr_FR' and 'french'. For some reason, however, it then used the
427        Windows-specific input and output files, which have 'french' screwed in.
428        So this could never have worked. One of the problems with locales is that
429        they aren't always the same. I have now updated RunTest so that it checks
430        the output of the locale test (test 3) against three different output
431        files, and it allows the test to pass if any one of them matches. With luck
432        this should make the test pass on some versions of Solaris where it was
433        failing. Because of the uncertainty, the script did not used to stop if
434        test 3 failed; it now does. If further versions of a French locale ever
435        come to light, they can now easily be added.
436    
437    16. If --with-pcregrep-bufsize was given a non-integer value such as "50K",
438        there was a message during ./configure, but it did not stop. This now
439        provokes an error. The invalid example in README has been corrected.
440        If a value less than the minimum is given, the minimum value has always
441        been used, but now a warning is given.
442    
443    17. If --enable-bsr-anycrlf was set, the special 16/32-bit test failed. This
444        was a bug in the test system, which is now fixed. Also, the list of various
445        configurations that are tested for each release did not have one with both
446        16/32 bits and --enable-bar-anycrlf. It now does.
447    
448    18. pcretest was missing "-C bsr" for displaying the \R default setting.
449    
450    19. Little endian PowerPC systems are supported now by the JIT compiler.
451    
452    20. The fast forward newline mechanism could enter to an infinite loop on
453        certain invalid UTF-8 input. Although we don't support these cases
454        this issue can be fixed by a performance optimization.
455    
456    21. Change 33 of 8.34 is not sufficient to ensure stack safety because it does
457        not take account if existing stack usage. There is now a new global
458        variable called pcre_stack_guard that can be set to point to an external
459        function to check stack availability. It is called at the start of
460        processing every parenthesized group.
461    
462    22. A typo in the code meant that in ungreedy mode the max/min qualifier
463        behaved like a min-possessive qualifier, and, for example, /a{1,3}b/U did
464        not match "ab".
465    
466    23. When UTF was disabled, the JIT program reported some incorrect compile
467        errors. These messages are silenced now.
468    
469    24. Experimental support for ARM-64 and MIPS-64 has been added to the JIT
470        compiler.
471    
472    25. Change all the temporary files used in RunGrepTest to be different to those
473        used by RunTest so that the tests can be run simultaneously, for example by
474        "make -j check".
475    
476    
477    Version 8.34 15-December-2013
478    -----------------------------
479    
480    1.  Add pcre[16|32]_jit_free_unused_memory to forcibly free unused JIT
481        executable memory. Patch inspired by Carsten Klein.
482    
483    2.  ./configure --enable-coverage defined SUPPORT_GCOV in config.h, although
484        this macro is never tested and has no effect, because the work to support
485        coverage involves only compiling and linking options and special targets in
486        the Makefile. The comment in config.h implied that defining the macro would
487        enable coverage support, which is totally false. There was also support for
488        setting this macro in the CMake files (my fault, I just copied it from
489        configure). SUPPORT_GCOV has now been removed.
490    
491    3.  Make a small performance improvement in strlen16() and strlen32() in
492        pcretest.
493    
494    4.  Change 36 for 8.33 left some unreachable statements in pcre_exec.c,
495        detected by the Solaris compiler (gcc doesn't seem to be able to diagnose
496        these cases). There was also one in pcretest.c.
497    
498    5.  Cleaned up a "may be uninitialized" compiler warning in pcre_exec.c.
499    
500    6.  In UTF mode, the code for checking whether a group could match an empty
501        string (which is used for indefinitely repeated groups to allow for
502        breaking an infinite loop) was broken when the group contained a repeated
503        negated single-character class with a character that occupied more than one
504        data item and had a minimum repetition of zero (for example, [^\x{100}]* in
505        UTF-8 mode). The effect was undefined: the group might or might not be
506        deemed as matching an empty string, or the program might have crashed.
507    
508    7.  The code for checking whether a group could match an empty string was not
509        recognizing that \h, \H, \v, \V, and \R must match a character.
510    
511    8.  Implemented PCRE_INFO_MATCH_EMPTY, which yields 1 if the pattern can match
512        an empty string. If it can, pcretest shows this in its information output.
513    
514    9.  Fixed two related bugs that applied to Unicode extended grapheme clusters
515        that were repeated with a maximizing qualifier (e.g. \X* or \X{2,5}) when
516        matched by pcre_exec() without using JIT:
517    
518        (a) If the rest of the pattern did not match after a maximal run of
519            grapheme clusters, the code for backing up to try with fewer of them
520            did not always back up over a full grapheme when characters that do not
521            have the modifier quality were involved, e.g. Hangul syllables.
522    
523        (b) If the match point in a subject started with modifier character, and
524            there was no match, the code could incorrectly back up beyond the match
525            point, and potentially beyond the first character in the subject,
526            leading to a segfault or an incorrect match result.
527    
528    10. A conditional group with an assertion condition could lead to PCRE
529        recording an incorrect first data item for a match if no other first data
530        item was recorded. For example, the pattern (?(?=ab)ab) recorded "a" as a
531        first data item, and therefore matched "ca" after "c" instead of at the
532        start.
533    
534    11. Change 40 for 8.33 (allowing pcregrep to find empty strings) showed up a
535        bug that caused the command "echo a | ./pcregrep -M '|a'" to loop.
536    
537    12. The source of pcregrep now includes z/OS-specific code so that it can be
538        compiled for z/OS as part of the special z/OS distribution.
539    
540    13. Added the -T and -TM options to pcretest.
541    
542    14. The code in pcre_compile.c for creating the table of named capturing groups
543        has been refactored. Instead of creating the table dynamically during the
544        actual compiling pass, the information is remembered during the pre-compile
545        pass (on the stack unless there are more than 20 named groups, in which
546        case malloc() is used) and the whole table is created before the actual
547        compile happens. This has simplified the code (it is now nearly 150 lines
548        shorter) and prepared the way for better handling of references to groups
549        with duplicate names.
550    
551    15. A back reference to a named subpattern when there is more than one of the
552        same name now checks them in the order in which they appear in the pattern.
553        The first one that is set is used for the reference. Previously only the
554        first one was inspected. This change makes PCRE more compatible with Perl.
555    
556    16. Unicode character properties were updated from Unicode 6.3.0.
557    
558    17. The compile-time code for auto-possessification has been refactored, based
559        on a patch by Zoltan Herczeg. It now happens after instead of during
560        compilation. The code is cleaner, and more cases are handled. The option
561        PCRE_NO_AUTO_POSSESS is added for testing purposes, and the -O and /O
562        options in pcretest are provided to set it. It can also be set by
563        (*NO_AUTO_POSSESS) at the start of a pattern.
564    
565    18. The character VT has been added to the default ("C" locale) set of
566        characters that match \s and are generally treated as white space,
567        following this same change in Perl 5.18. There is now no difference between
568        "Perl space" and "POSIX space". Whether VT is treated as white space in
569        other locales depends on the locale.
570    
571    19. The code for checking named groups as conditions, either for being set or
572        for being recursed, has been refactored (this is related to 14 and 15
573        above). Processing unduplicated named groups should now be as fast at
574        numerical groups, and processing duplicated groups should be faster than
575        before.
576    
577    20. Two patches to the CMake build system, by Alexander Barkov:
578    
579          (1) Replace the "source" command by "." in CMakeLists.txt because
580              "source" is a bash-ism.
581    
582          (2) Add missing HAVE_STDINT_H and HAVE_INTTYPES_H to config-cmake.h.in;
583              without these the CMake build does not work on Solaris.
584    
585    21. Perl has changed its handling of \8 and \9. If there is no previously
586        encountered capturing group of those numbers, they are treated as the
587        literal characters 8 and 9 instead of a binary zero followed by the
588        literals. PCRE now does the same.
589    
590    22. Following Perl, added \o{} to specify codepoints in octal, making it
591        possible to specify values greater than 0777 and also making them
592        unambiguous.
593    
594    23. Perl now gives an error for missing closing braces after \x{... instead of
595        treating the string as literal. PCRE now does the same.
596    
597    24. RunTest used to grumble if an inappropriate test was selected explicitly,
598        but just skip it when running all tests. This make it awkward to run ranges
599        of tests when one of them was inappropriate. Now it just skips any
600        inappropriate tests, as it always did when running all tests.
601    
602    25. If PCRE_AUTO_CALLOUT and PCRE_UCP were set for a pattern that contained
603        character types such as \d or \w, too many callouts were inserted, and the
604        data that they returned was rubbish.
605    
606    26. In UCP mode, \s was not matching two of the characters that Perl matches,
607        namely NEL (U+0085) and MONGOLIAN VOWEL SEPARATOR (U+180E), though they
608        were matched by \h. The code has now been refactored so that the lists of
609        the horizontal and vertical whitespace characters used for \h and \v (which
610        are defined only in one place) are now also used for \s.
611    
612    27. Add JIT support for the 64 bit TileGX architecture.
613        Patch by Jiong Wang (Tilera Corporation).
614    
615    28. Possessive quantifiers for classes (both explicit and automatically
616        generated) now use special opcodes instead of wrapping in ONCE brackets.
617    
618    29. Whereas an item such as A{4}+ ignored the possessivenes of the quantifier
619        (because it's meaningless), this was not happening when PCRE_CASELESS was
620        set. Not wrong, but inefficient.
621    
622    30. Updated perltest.pl to add /u (force Unicode mode) when /W (use Unicode
623        properties for \w, \d, etc) is present in a test regex. Otherwise if the
624        test contains no characters greater than 255, Perl doesn't realise it
625        should be using Unicode semantics.
626    
627    31. Upgraded the handling of the POSIX classes [:graph:], [:print:], and
628        [:punct:] when PCRE_UCP is set so as to include the same characters as Perl
629        does in Unicode mode.
630    
631    32. Added the "forbid" facility to pcretest so that putting tests into the
632        wrong test files can sometimes be quickly detected.
633    
634    33. There is now a limit (default 250) on the depth of nesting of parentheses.
635        This limit is imposed to control the amount of system stack used at compile
636        time. It can be changed at build time by --with-parens-nest-limit=xxx or
637        the equivalent in CMake.
638    
639    34. Character classes such as [A-\d] or [a-[:digit:]] now cause compile-time
640        errors. Perl warns for these when in warning mode, but PCRE has no facility
641        for giving warnings.
642    
643    35. Change 34 for 8.13 allowed quantifiers on assertions, because Perl does.
644        However, this was not working for (?!) because it is optimized to (*FAIL),
645        for which PCRE does not allow quantifiers. The optimization is now disabled
646        when a quantifier follows (?!). I can't see any use for this, but it makes
647        things uniform.
648    
649    36. Perl no longer allows group names to start with digits, so I have made this
650        change also in PCRE. It simplifies the code a bit.
651    
652    37. In extended mode, Perl ignores spaces before a + that indicates a
653        possessive quantifier. PCRE allowed a space before the quantifier, but not
654        before the possessive +. It now does.
655    
656    38. The use of \K (reset reported match start) within a repeated possessive
657        group such as (a\Kb)*+ was not working.
658    
659    40. Document that the same character tables must be used at compile time and
660        run time, and that the facility to pass tables to pcre_exec() and
661        pcre_dfa_exec() is for use only with saved/restored patterns.
662    
663    41. Applied Jeff Trawick's patch CMakeLists.txt, which "provides two new
664        features for Builds with MSVC:
665    
666        1. Support pcre.rc and/or pcreposix.rc (as is already done for MinGW
667           builds). The .rc files can be used to set FileDescription and many other
668           attributes.
669    
670        2. Add an option (-DINSTALL_MSVC_PDB) to enable installation of .pdb files.
671           This allows higher-level build scripts which want .pdb files to avoid
672           hard-coding the exact files needed."
673    
674    42. Added support for [[:<:]] and [[:>:]] as used in the BSD POSIX library to
675        mean "start of word" and "end of word", respectively, as a transition aid.
676    
677    43. A minimizing repeat of a class containing codepoints greater than 255 in
678        non-UTF 16-bit or 32-bit modes caused an internal error when PCRE was
679        compiled to use the heap for recursion.
680    
681    44. Got rid of some compiler warnings for unused variables when UTF but not UCP
682        is configured.
683    
684    
685    Version 8.33 28-May-2013
686    ------------------------
687    
688  1.  Added 'U' to some constants that are compared to unsigned integers, to  1.  Added 'U' to some constants that are compared to unsigned integers, to
689      avoid compiler signed/unsigned warnings. Added (int) casts to unsigned      avoid compiler signed/unsigned warnings. Added (int) casts to unsigned
# Line 14  Version 8.33 xx-xxxx-201x Line 695  Version 8.33 xx-xxxx-201x
695    
696  3.  Revise the creation of config.h.generic so that all boolean macros are  3.  Revise the creation of config.h.generic so that all boolean macros are
697      #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes      #undefined, whereas non-boolean macros are #ifndef/#endif-ed. This makes
698      overriding via -D on the command line possible.      overriding via -D on the command line possible.
699    
700  4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar  4.  Changing the definition of the variable "op" in pcre_exec.c from pcre_uchar
701      to unsigned int is reported to make a quite noticeable speed difference in      to unsigned int is reported to make a quite noticeable speed difference in
702      a specific Windows environment. Testing on Linux did also appear to show      a specific Windows environment. Testing on Linux did also appear to show
703      some benefit (and it is clearly not harmful). Also fixed the definition of      some benefit (and it is clearly not harmful). Also fixed the definition of
704      Xop which should be unsigned.      Xop which should be unsigned.
705    
706  5.  Related to (4), changing the definition of the intermediate variable cc  5.  Related to (4), changing the definition of the intermediate variable cc
707      in repeated character loops from pcre_uchar to pcre_uint32 also gave speed      in repeated character loops from pcre_uchar to pcre_uint32 also gave speed
# Line 28  Version 8.33 xx-xxxx-201x Line 709  Version 8.33 xx-xxxx-201x
709    
710  6.  Fix forward search in JIT when link size is 3 or greater. Also removed some  6.  Fix forward search in JIT when link size is 3 or greater. Also removed some
711      unnecessary spaces.      unnecessary spaces.
712    
713  7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12  7.  Adjust autogen.sh and configure.ac to lose warnings given by automake 1.12
714      and later.      and later.
715    
716  8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.  8.  Fix two buffer over read issues in 16 and 32 bit modes. Affects JIT only.
717    
718  9.  Optimizing fast_forward_start_bits in JIT.  9.  Optimizing fast_forward_start_bits in JIT.
719    
720  10. Adding experimental support for callouts in JIT, and fixing some  10. Adding support for callouts in JIT, and fixing some issues revealed
721      issues revealed during this work. Namely:      during this work. Namely:
722    
723      (a) Unoptimized capturing brackets incorrectly reset on backtrack.      (a) Unoptimized capturing brackets incorrectly reset on backtrack.
724    
725      (b) Minimum length was not checked before the matching is started.      (b) Minimum length was not checked before the matching is started.
726    
727  11. The value of capture_last that is passed to callouts was incorrect in some  11. The value of capture_last that is passed to callouts was incorrect in some
728      cases when there was a capture on one path that was subsequently abandoned      cases when there was a capture on one path that was subsequently abandoned
729      after a backtrack. Also, the capture_last value is now reset after a      after a backtrack. Also, the capture_last value is now reset after a
730      recursion, since all captures are also reset in this case.      recursion, since all captures are also reset in this case.
731    
732  12. The interpreter no longer returns the "too many substrings" error in the  12. The interpreter no longer returns the "too many substrings" error in the
733      case when an overflowing capture is in a branch that is subsequently      case when an overflowing capture is in a branch that is subsequently
734      abandoned after a backtrack.      abandoned after a backtrack.
735    
736  13. In the pathological case when an offset vector of size 2 is used, pcretest  13. In the pathological case when an offset vector of size 2 is used, pcretest
737      now prints out the matched string after a yield of 0 or 1.      now prints out the matched string after a yield of 0 or 1.
738    
739  14. Inlining subpatterns in recursions, when certain conditions are fulfilled.  14. Inlining subpatterns in recursions, when certain conditions are fulfilled.
# Line 61  Version 8.33 xx-xxxx-201x Line 742  Version 8.33 xx-xxxx-201x
742  15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.  15. JIT compiler now supports 32 bit Macs thanks to Lawrence Velazquez.
743    
744  16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the  16. Partial matches now set offsets[2] to the "bumpalong" value, that is, the
745      offset of the starting point of the matching process, provided the offsets      offset of the starting point of the matching process, provided the offsets
746      vector is large enough.      vector is large enough.
747    
748  17. The \A escape now records a lookbehind value of 1, though its execution  17. The \A escape now records a lookbehind value of 1, though its execution
749      does not actually inspect the previous character. This is to ensure that,      does not actually inspect the previous character. This is to ensure that,
750      in partial multi-segment matching, at least one character from the old      in partial multi-segment matching, at least one character from the old
# Line 71  Version 8.33 xx-xxxx-201x Line 752  Version 8.33 xx-xxxx-201x
752      are no lookbehinds in the pattern, \A might match incorrectly at the start      are no lookbehinds in the pattern, \A might match incorrectly at the start
753      of a new segment.      of a new segment.
754    
755    18. Added some #ifdef __VMS code into pcretest.c to help VMS implementations.
756    
757    19. Redefined some pcre_uchar variables in pcre_exec.c as pcre_uint32; this
758        gives some modest performance improvement in 8-bit mode.
759    
760    20. Added the PCRE-specific property \p{Xuc} for matching characters that can
761        be expressed in certain programming languages using Universal Character
762        Names.
763    
764    21. Unicode validation has been updated in the light of Unicode Corrigendum #9,
765        which points out that "non characters" are not "characters that may not
766        appear in Unicode strings" but rather "characters that are reserved for
767        internal use and have only local meaning".
768    
769    22. When a pattern was compiled with automatic callouts (PCRE_AUTO_CALLOUT) and
770        there was a conditional group that depended on an assertion, if the
771        assertion was false, the callout that immediately followed the alternation
772        in the condition was skipped when pcre_exec() was used for matching.
773    
774    23. Allow an explicit callout to be inserted before an assertion that is the
775        condition for a conditional group, for compatibility with automatic
776        callouts, which always insert a callout at this point.
777    
778    24. In 8.31, (*COMMIT) was confined to within a recursive subpattern. Perl also
779        confines (*SKIP) and (*PRUNE) in the same way, and this has now been done.
780    
781    25. (*PRUNE) is now supported by the JIT compiler.
782    
783    26. Fix infinite loop when /(?<=(*SKIP)ac)a/ is matched against aa.
784    
785    27. Fix the case where there are two or more SKIPs with arguments that may be
786        ignored.
787    
788    28. (*SKIP) is now supported by the JIT compiler.
789    
790    29. (*THEN) is now supported by the JIT compiler.
791    
792    30. Update RunTest with additional test selector options.
793    
794    31. The way PCRE handles backtracking verbs has been changed in two ways.
795    
796        (1) Previously, in something like (*COMMIT)(*SKIP), COMMIT would override
797        SKIP. Now, PCRE acts on whichever backtracking verb is reached first by
798        backtracking. In some cases this makes it more Perl-compatible, but Perl's
799        rather obscure rules do not always do the same thing.
800    
801        (2) Previously, backtracking verbs were confined within assertions. This is
802        no longer the case for positive assertions, except for (*ACCEPT). Again,
803        this sometimes improves Perl compatibility, and sometimes does not.
804    
805    32. A number of tests that were in test 2 because Perl did things differently
806        have been moved to test 1, because either Perl or PCRE has changed, and
807        these tests are now compatible.
808    
809    32. Backtracking control verbs are now handled in the same way in JIT and
810        interpreter.
811    
812    33. An opening parenthesis in a MARK/PRUNE/SKIP/THEN name in a pattern that
813        contained a forward subroutine reference caused a compile error.
814    
815    34. Auto-detect and optimize limited repetitions in JIT.
816    
817    35. Implement PCRE_NEVER_UTF to lock out the use of UTF, in particular,
818        blocking (*UTF) etc.
819    
820    36. In the interpreter, maximizing pattern repetitions for characters and
821        character types now use tail recursion, which reduces stack usage.
822    
823    37. The value of the max lookbehind was not correctly preserved if a compiled
824        and saved regex was reloaded on a host of different endianness.
825    
826    38. Implemented (*LIMIT_MATCH) and (*LIMIT_RECURSION). As part of the extension
827        of the compiled pattern block, expand the flags field from 16 to 32 bits
828        because it was almost full.
829    
830    39. Try madvise first before posix_madvise.
831    
832    40. Change 7 for PCRE 7.9 made it impossible for pcregrep to find empty lines
833        with a pattern such as ^$. It has taken 4 years for anybody to notice! The
834        original change locked out all matches of empty strings. This has been
835        changed so that one match of an empty string per line is recognized.
836        Subsequent searches on the same line (for colouring or for --only-matching,
837        for example) do not recognize empty strings.
838    
839    41. Applied a user patch to fix a number of spelling mistakes in comments.
840    
841    42. Data lines longer than 65536 caused pcretest to crash.
842    
843    43. Clarified the data type for length and startoffset arguments for pcre_exec
844        and pcre_dfa_exec in the function-specific man pages, where they were
845        explicitly stated to be in bytes, never having been updated. I also added
846        some clarification to the pcreapi man page.
847    
848    44. A call to pcre_dfa_exec() with an output vector size less than 2 caused
849        a segmentation fault.
850    
851    
852  Version 8.32 30-November-2012  Version 8.32 30-November-2012
853  -----------------------------  -----------------------------
# Line 1579  Version 7.9 11-Apr-09 Line 2356  Version 7.9 11-Apr-09
2356  7.  A pattern that could match an empty string could cause pcregrep to loop; it  7.  A pattern that could match an empty string could cause pcregrep to loop; it
2357      doesn't make sense to accept an empty string match in pcregrep, so I have      doesn't make sense to accept an empty string match in pcregrep, so I have
2358      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this      locked it out (using PCRE's PCRE_NOTEMPTY option). By experiment, this
2359      seems to be how GNU grep behaves.      seems to be how GNU grep behaves. [But see later change 40 for release
2360        8.33.]
2361    
2362  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at  8.  The pattern (?(?=.*b)b|^) was incorrectly compiled as "match must be at
2363      start or after a newline", because the conditional assertion was not being      start or after a newline", because the conditional assertion was not being
# Line 1822  Version 7.7 07-May-08 Line 2600  Version 7.7 07-May-08
2600      containing () gave an internal compiling error instead of "reference to      containing () gave an internal compiling error instead of "reference to
2601      non-existent subpattern". Fortunately, when the pattern did exist, the      non-existent subpattern". Fortunately, when the pattern did exist, the
2602      compiled code was correct. (When scanning forwards to check for the      compiled code was correct. (When scanning forwards to check for the
2603      existencd of the subpattern, it was treating the data ']' as terminating      existence of the subpattern, it was treating the data ']' as terminating
2604      the class, so got the count wrong. When actually compiling, the reference      the class, so got the count wrong. When actually compiling, the reference
2605      was subsequently set up correctly.)      was subsequently set up correctly.)
2606    

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