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revision 402 by ph10, Sat Mar 21 17:26:03 2009 UTC revision 478 by ph10, Sun Jan 3 16:05:13 2010 UTC
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1  ChangeLog for PCRE  ChangeLog for PCRE
2  ------------------  ------------------
3    
4  Version 7.9 xx-xxx-09  Version 8.01 11-Dec-09
5    ----------------------
6    
7    1.  If a pattern contained a conditional subpattern with only one branch (in
8        particular, this includes all (DEFINE) patterns), a call to pcre_study()
9        computed the wrong minimum data length (which is of course zero for such
10        subpatterns).
11    
12    2.  For patterns such as (?i)a(?-i)b|c where an option setting at the start of
13        the pattern is reset in the first branch, pcre_compile() failed with
14        "internal error: code overflow at offset...". This happened only when
15        the reset was to the original external option setting. (An optimization
16        abstracts leading options settings into an external setting, which was the
17        cause of this.)
18    
19    3.  A pattern such as ^(?!a(*SKIP)b) where a negative assertion contained one
20        of the verbs SKIP, PRUNE, or COMMIT, did not work correctly. When the
21        assertion pattern did not match (meaning that the assertion was true), it
22        was incorrectly treated as false if the SKIP had been reached during the
23        matching. This also applied to assertions used as conditions.
24    
25    4.  If an item that is not supported by pcre_dfa_exec() was encountered in an
26        assertion subpattern, including such a pattern used as a condition,
27        unpredictable results occurred, instead of the error return
28        PCRE_ERROR_DFA_UITEM.
29    
30    5.  The C++ GlobalReplace function was not working like Perl for the special
31        situation when an empty string is matched. It now does the fancy magic
32        stuff that is necessary.
33    
34    6.  In pcre_internal.h, obsolete includes to setjmp.h and stdarg.h have been
35        removed. (These were left over from very, very early versions of PCRE.)
36    
37    7.  Some cosmetic changes to the code to make life easier when compiling it
38        as part of something else:
39    
40        (a) Change DEBUG to PCRE_DEBUG.
41    
42        (b) In pcre_compile(), rename the member of the "branch_chain" structure
43            called "current" as "current_branch", to prevent a collision with the
44            Linux macro when compiled as a kernel module.
45    
46        (c) In pcre_study(), rename the function set_bit() as set_table_bit(), to
47            prevent a collision with the Linux macro when compiled as a kernel
48            module.
49    
50    8.  In pcre_compile() there are some checks for integer overflows that used to
51        cast potentially large values to (double). This has been changed to that
52        when building, a check for int64_t is made, and if it is found, it is used
53        instead, thus avoiding the use of floating point arithmetic. (There is no
54        other use of FP in PCRE.) If int64_t is not found, the fallback is to
55        double.
56    
57    9.  Added two casts to avoid signed/unsigned warnings from VS Studio Express
58        2005 (difference between two addresses compared to an unsigned value).
59    
60    10. Change the standard AC_CHECK_LIB test for libbz2 in configure.ac to a
61        custom one, because of the following reported problem in Windows:
62    
63          - libbz2 uses the Pascal calling convention (WINAPI) for the functions
64            under Win32.
65          - The standard autoconf AC_CHECK_LIB fails to include "bzlib.h",
66            therefore missing the function definition.
67          - The compiler thus generates a "C" signature for the test function.
68          - The linker fails to find the "C" function.
69          - PCRE fails to configure if asked to do so against libbz2.
70    
71    
72    Version 8.00 19-Oct-09
73    ----------------------
74    
75    1.  The table for translating pcre_compile() error codes into POSIX error codes
76        was out-of-date, and there was no check on the pcre_compile() error code
77        being within the table. This could lead to an OK return being given in
78        error.
79    
80    2.  Changed the call to open a subject file in pcregrep from fopen(pathname,
81        "r") to fopen(pathname, "rb"), which fixed a problem with some of the tests
82        in a Windows environment.
83    
84    3.  The pcregrep --count option prints the count for each file even when it is
85        zero, as does GNU grep. However, pcregrep was also printing all files when
86        --files-with-matches was added. Now, when both options are given, it prints
87        counts only for those files that have at least one match. (GNU grep just
88        prints the file name in this circumstance, but including the count seems
89        more useful - otherwise, why use --count?) Also ensured that the
90        combination -clh just lists non-zero counts, with no names.
91    
92    4.  The long form of the pcregrep -F option was incorrectly implemented as
93        --fixed_strings instead of --fixed-strings. This is an incompatible change,
94        but it seems right to fix it, and I didn't think it was worth preserving
95        the old behaviour.
96    
97    5.  The command line items --regex=pattern and --regexp=pattern were not
98        recognized by pcregrep, which required --regex pattern or --regexp pattern
99        (with a space rather than an '='). The man page documented the '=' forms,
100        which are compatible with GNU grep; these now work.
101    
102    6.  No libpcreposix.pc file was created for pkg-config; there was just
103        libpcre.pc and libpcrecpp.pc. The omission has been rectified.
104    
105    7.  Added #ifndef SUPPORT_UCP into the pcre_ucd.c module, to reduce its size
106        when UCP support is not needed, by modifying the Python script that
107        generates it from Unicode data files. This should not matter if the module
108        is correctly used as a library, but I received one complaint about 50K of
109        unwanted data. My guess is that the person linked everything into his
110        program rather than using a library. Anyway, it does no harm.
111    
112    8.  A pattern such as /\x{123}{2,2}+/8 was incorrectly compiled; the trigger
113        was a minimum greater than 1 for a wide character in a possessive
114        repetition. The same bug could also affect patterns like /(\x{ff}{0,2})*/8
115        which had an unlimited repeat of a nested, fixed maximum repeat of a wide
116        character. Chaos in the form of incorrect output or a compiling loop could
117        result.
118    
119    9.  The restrictions on what a pattern can contain when partial matching is
120        requested for pcre_exec() have been removed. All patterns can now be
121        partially matched by this function. In addition, if there are at least two
122        slots in the offset vector, the offset of the earliest inspected character
123        for the match and the offset of the end of the subject are set in them when
124        PCRE_ERROR_PARTIAL is returned.
125    
126    10. Partial matching has been split into two forms: PCRE_PARTIAL_SOFT, which is
127        synonymous with PCRE_PARTIAL, for backwards compatibility, and
128        PCRE_PARTIAL_HARD, which causes a partial match to supersede a full match,
129        and may be more useful for multi-segment matching.
130    
131    11. Partial matching with pcre_exec() is now more intuitive. A partial match
132        used to be given if ever the end of the subject was reached; now it is
133        given only if matching could not proceed because another character was
134        needed. This makes a difference in some odd cases such as Z(*FAIL) with the
135        string "Z", which now yields "no match" instead of "partial match". In the
136        case of pcre_dfa_exec(), "no match" is given if every matching path for the
137        final character ended with (*FAIL).
138    
139    12. Restarting a match using pcre_dfa_exec() after a partial match did not work
140        if the pattern had a "must contain" character that was already found in the
141        earlier partial match, unless partial matching was again requested. For
142        example, with the pattern /dog.(body)?/, the "must contain" character is
143        "g". If the first part-match was for the string "dog", restarting with
144        "sbody" failed. This bug has been fixed.
145    
146    13. The string returned by pcre_dfa_exec() after a partial match has been
147        changed so that it starts at the first inspected character rather than the
148        first character of the match. This makes a difference only if the pattern
149        starts with a lookbehind assertion or \b or \B (\K is not supported by
150        pcre_dfa_exec()). It's an incompatible change, but it makes the two
151        matching functions compatible, and I think it's the right thing to do.
152    
153    14. Added a pcredemo man page, created automatically from the pcredemo.c file,
154        so that the demonstration program is easily available in environments where
155        PCRE has not been installed from source.
156    
157    15. Arranged to add -DPCRE_STATIC to cflags in libpcre.pc, libpcreposix.cp,
158        libpcrecpp.pc and pcre-config when PCRE is not compiled as a shared
159        library.
160    
161    16. Added REG_UNGREEDY to the pcreposix interface, at the request of a user.
162        It maps to PCRE_UNGREEDY. It is not, of course, POSIX-compatible, but it
163        is not the first non-POSIX option to be added. Clearly some people find
164        these options useful.
165    
166    17. If a caller to the POSIX matching function regexec() passes a non-zero
167        value for nmatch with a NULL value for pmatch, the value of
168        nmatch is forced to zero.
169    
170    18. RunGrepTest did not have a test for the availability of the -u option of
171        the diff command, as RunTest does. It now checks in the same way as
172        RunTest, and also checks for the -b option.
173    
174    19. If an odd number of negated classes containing just a single character
175        interposed, within parentheses, between a forward reference to a named
176        subpattern and the definition of the subpattern, compilation crashed with
177        an internal error, complaining that it could not find the referenced
178        subpattern. An example of a crashing pattern is /(?&A)(([^m])(?<A>))/.
179        [The bug was that it was starting one character too far in when skipping
180        over the character class, thus treating the ] as data rather than
181        terminating the class. This meant it could skip too much.]
182    
183    20. Added PCRE_NOTEMPTY_ATSTART in order to be able to correctly implement the
184        /g option in pcretest when the pattern contains \K, which makes it possible
185        to have an empty string match not at the start, even when the pattern is
186        anchored. Updated pcretest and pcredemo to use this option.
187    
188    21. If the maximum number of capturing subpatterns in a recursion was greater
189        than the maximum at the outer level, the higher number was returned, but
190        with unset values at the outer level. The correct (outer level) value is
191        now given.
192    
193    22. If (*ACCEPT) appeared inside capturing parentheses, previous releases of
194        PCRE did not set those parentheses (unlike Perl). I have now found a way to
195        make it do so. The string so far is captured, making this feature
196        compatible with Perl.
197    
198    23. The tests have been re-organized, adding tests 11 and 12, to make it
199        possible to check the Perl 5.10 features against Perl 5.10.
200    
201    24. Perl 5.10 allows subroutine calls in lookbehinds, as long as the subroutine
202        pattern matches a fixed length string. PCRE did not allow this; now it
203        does. Neither allows recursion.
204    
205    25. I finally figured out how to implement a request to provide the minimum
206        length of subject string that was needed in order to match a given pattern.
207        (It was back references and recursion that I had previously got hung up
208        on.) This code has now been added to pcre_study(); it finds a lower bound
209        to the length of subject needed. It is not necessarily the greatest lower
210        bound, but using it to avoid searching strings that are too short does give
211        some useful speed-ups. The value is available to calling programs via
212        pcre_fullinfo().
213    
214    26. While implementing 25, I discovered to my embarrassment that pcretest had
215        not been passing the result of pcre_study() to pcre_dfa_exec(), so the
216        study optimizations had never been tested with that matching function.
217        Oops. What is worse, even when it was passed study data, there was a bug in
218        pcre_dfa_exec() that meant it never actually used it. Double oops. There
219        were also very few tests of studied patterns with pcre_dfa_exec().
220    
221    27. If (?| is used to create subpatterns with duplicate numbers, they are now
222        allowed to have the same name, even if PCRE_DUPNAMES is not set. However,
223        on the other side of the coin, they are no longer allowed to have different
224        names, because these cannot be distinguished in PCRE, and this has caused
225        confusion. (This is a difference from Perl.)
226    
227    28. When duplicate subpattern names are present (necessarily with different
228        numbers, as required by 27 above), and a test is made by name in a
229        conditional pattern, either for a subpattern having been matched, or for
230        recursion in such a pattern, all the associated numbered subpatterns are
231        tested, and the overall condition is true if the condition is true for any
232        one of them. This is the way Perl works, and is also more like the way
233        testing by number works.
234    
235    
236    Version 7.9 11-Apr-09
237  ---------------------  ---------------------
238    
239  1.  When building with support for bzlib/zlib (pcregrep) and/or readline  1.  When building with support for bzlib/zlib (pcregrep) and/or readline
# Line 17  Version 7.9 xx-xxx-09 Line 249  Version 7.9 xx-xxx-09
249      but BOOL is not.      but BOOL is not.
250    
251  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and  3.  The pcre_config() function was treating the PCRE_MATCH_LIMIT and
252      PCRE_MATCH_LIMIT_RETURSION values as ints, when they should be long ints.      PCRE_MATCH_LIMIT_RECURSION values as ints, when they should be long ints.
253    
254  4.  The pcregrep documentation said spaces were inserted as well as colons (or  4.  The pcregrep documentation said spaces were inserted as well as colons (or
255      hyphens) following file names and line numbers when outputting matching      hyphens) following file names and line numbers when outputting matching
# Line 42  Version 7.9 xx-xxx-09 Line 274  Version 7.9 xx-xxx-09
274      correctly handled. The rule now is that both the assertion and what follows      correctly handled. The rule now is that both the assertion and what follows
275      in the first alternative must satisfy the test.      in the first alternative must satisfy the test.
276    
277  9.  If auto-callout was enabled in a pattern with a conditional group whose  9.  If auto-callout was enabled in a pattern with a conditional group whose
278      condition was an assertion, PCRE could crash during matching, both with      condition was an assertion, PCRE could crash during matching, both with
279      pcre_exec() and pcre_dfa_exec().      pcre_exec() and pcre_dfa_exec().
280    
# Line 64  Version 7.9 xx-xxx-09 Line 296  Version 7.9 xx-xxx-09
296  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch  17. Implemented support for UTF-8 encoding in EBCDIC environments, a patch
297      from Martin Jerabek that uses macro names for all relevant character and      from Martin Jerabek that uses macro names for all relevant character and
298      string constants.      string constants.
299    
300  18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and  18. Added to pcre_internal.h two configuration checks: (a) If both EBCDIC and
301      SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without      SUPPORT_UTF8 are set, give an error; (b) If SUPPORT_UCP is set without
302      SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of      SUPPORT_UTF8, define SUPPORT_UTF8. The "configure" script handles both of
303      these, but not everybody uses configure.      these, but not everybody uses configure.
304    
305  19. A conditional group that had only one branch was not being correctly  19. A conditional group that had only one branch was not being correctly
306      recognized as an item that could match an empty string. This meant that an      recognized as an item that could match an empty string. This meant that an
307      enclosing group might also not be so recognized, causing infinite looping      enclosing group might also not be so recognized, causing infinite looping
308      (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$      (and probably a segfault) for patterns such as ^"((?(?=[a])[^"])|b)*"$
309      with the subject "ab", where knowledge that the repeated group can match      with the subject "ab", where knowledge that the repeated group can match
310      nothing is needed in order to break the loop.      nothing is needed in order to break the loop.
311    
312  20. If a pattern that was compiled with callouts was matched using pcre_dfa_  20. If a pattern that was compiled with callouts was matched using pcre_dfa_
313      exec(), but without supplying a callout function, matching went wrong.      exec(), but without supplying a callout function, matching went wrong.
314    
315  21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory  21. If PCRE_ERROR_MATCHLIMIT occurred during a recursion, there was a memory
316      leak if the size of the offset vector was greater than 30. When the vector      leak if the size of the offset vector was greater than 30. When the vector
317      is smaller, the saved offsets during recursion go onto a local stack      is smaller, the saved offsets during recursion go onto a local stack
318      vector, but for larger vectors malloc() is used. It was failing to free      vector, but for larger vectors malloc() is used. It was failing to free
319      when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"      when the recursion yielded PCRE_ERROR_MATCH_LIMIT (or any other "abnormal"
320      error, in fact).      error, in fact).
321    
322  22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the  22. There was a missing #ifdef SUPPORT_UTF8 round one of the variables in the
323      heapframe that is used only when UTF-8 support is enabled. This caused no      heapframe that is used only when UTF-8 support is enabled. This caused no
324      problem, but was untidy.      problem, but was untidy.
325    
326    23. Steven Van Ingelgem's patch to CMakeLists.txt to change the name
327        CMAKE_BINARY_DIR to PROJECT_BINARY_DIR so that it works when PCRE is
328        included within another project.
329    
330    24. Steven Van Ingelgem's patches to add more options to the CMake support,
331        slightly modified by me:
332    
333          (a) PCRE_BUILD_TESTS can be set OFF not to build the tests, including
334              not building pcregrep.
335    
336          (b) PCRE_BUILD_PCREGREP can be see OFF not to build pcregrep, but only
337              if PCRE_BUILD_TESTS is also set OFF, because the tests use pcregrep.
338    
339    25. Forward references, both numeric and by name, in patterns that made use of
340        duplicate group numbers, could behave incorrectly or give incorrect errors,
341        because when scanning forward to find the reference group, PCRE was not
342        taking into account the duplicate group numbers. A pattern such as
343        ^X(?3)(a)(?|(b)|(q))(Y) is an example.
344    
345    26. Changed a few more instances of "const unsigned char *" to USPTR, making
346        the feature of a custom pointer more persuasive (as requested by a user).
347    
348    27. Wrapped the definitions of fileno and isatty for Windows, which appear in
349        pcretest.c, inside #ifndefs, because it seems they are sometimes already
350        pre-defined.
351    
352    28. Added support for (*UTF8) at the start of a pattern.
353    
354    29. Arrange for flags added by the "release type" setting in CMake to be shown
355        in the configuration summary.
356    
357    
358  Version 7.8 05-Sep-08  Version 7.8 05-Sep-08
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