loses information:
OverflowError: regular expression code size limit exceeded
Otherwise the compiled code is gibberish, possibly leading at
least to wrong results or (as reported on c.l.py) internal
sre errors at match time.
I'm not sure how to test this. SRE_CODE is a 2-byte type on
my box, and it's easy to create a regexp that causes the new
exception to trigger here. But it may be a 4-byte type on
other boxes, and creating a regexp large enough to trigger
problems there would be pretty crazy.
Bugfix candidate.
In C++, it's an error to pass a string literal to a char* function
without a const_cast(). Rather than require every C++ extension
module to put a cast around string literals, fix the API to state the
const-ness.
I focused on parts of the API where people usually pass literals:
PyArg_ParseTuple() and friends, Py_BuildValue(), PyMethodDef, the type
slots, etc. Predictably, there were a large set of functions that
needed to be fixed as a result of these changes. The most pervasive
change was to make the keyword args list passed to
PyArg_ParseTupleAndKewords() to be a const char *kwlist[].
One cast was required as a result of the changes: A type object
mallocs the memory for its tp_doc slot and later frees it.
PyTypeObject says that tp_doc is const char *; but if the type was
created by type_new(), we know it is safe to cast to char *.
stack usage on FreeBSD, requiring the recursion limit to be lowered
further. Building with gcc 2.95 (the standard compiler on FreeBSD 4.x)
is now also affected.
The underlying issue is that FreeBSD's pthreads implementation has a
hard-coded 1MB stack size for the initial (or "primary") thread, which
can not be changed without rebuilding libc_r. Exhausting this stack
results in a bus error.
Building without pthreads (configure --without-threads), or linking
with the port of the Linux pthreads library (aka Linuxthreads) instead
of libc_r, avoids this limitation.
On OS/2, only gcc 3.2 is affected and the stack size is controllable,
so the special handling has been removed.
to use LASTMARK_SAVE()/LASTMARK_RESTORE(), based on the discussion
in patch #712900.
- Cleaned up LASTMARK_SAVE()/LASTMARK_RESTORE() usage, based on the
established rules.
- Moved the upper part of the just commited patch (relative to bug #725106)
to outside the for() loop of BRANCH OP. There's no need to mark_save()
in every loop iteration.
This problem is related to a wrong behavior from mark_save/restore(),
which don't restore the mark_stack_base before restoring the marks.
Greg's suggestion was to change the asserts, which happen to be
the only recursive ops that can continue the loop, but the problem would
happen to any operation with the same behavior. So, rather than
hardcoding this into asserts, I have changed mark_save/restore() to
always restore the stackbase before restoring the marks.
Both solutions should fix these two cases, presented by Greg:
>>> re.match('(a)(?:(?=(b)*)c)*', 'abb').groups()
('b', None)
>>> re.match('(a)((?!(b)*))*', 'abb').groups()
('b', None, None)
The rest of the bug and patch in #725149 must be discussed further.
within repeats of alternatives. The only change to the original
patch was to convert the tests to the new test_re.py file.
This patch fixes cases like:
>>> re.match('((a)|b)*', 'abc').groups()
('b', '')
Which is wrong (it's impossible to match the empty string),
and incompatible with other regex systems, like the following
examples show:
% perl -e '"abc" =~ /^((a)|b)*/; print "$1 $2\n";'
b a
% echo "abc" | sed -r -e "s/^((a)|b)*/\1 \2|/"
b a|c
I've applied a modified version of Greg Chapman's patch. I've included
the fixes without introducing the reorganization mentioned, for the sake
of stability. Also, the second fix mentioned in the patch don't fix the
mentioned problem anymore, because of the change introduced by patch
#720991 (by Greg as well). The new fix wasn't complicated though, and is
included as well.
As a note. It seems that there are other places that require the
"protection" of LASTMARK_SAVE()/LASTMARK_RESTORE(), and are just waiting
for someone to find how to break them. Particularly, I belive that every
recursion of SRE_MATCH() should be protected by these macros. I won't
do that right now since I'm not completely sure about this, and we don't
have much time for testing until the next release.
to be compliant with previous python versions, by backing out the changes
made in revision 2.84 which affected this. The bugfix for backtracking is
still maintained.
A small fix for bug #545855 and Greg Chapman's
addition of op code SRE_OP_MIN_REPEAT_ONE for
eliminating recursion on simple uses of pattern '*?' on a
long string.
This bug happened because: 1) the scanner_search and scanner_match methods
were not checking the buffer limits before increasing the current pointer;
and 2) SRE_SEARCH was using "if (ptr == end)" as a loop break, instead of
"if (ptr >= end)".
* Modules/_sre.c
(SRE_SEARCH): Check for "ptr >= end" to break loops, so that we don't
hang forever if a pointer passing the buffer limit is used.
(scanner_search,scanner_match): Don't increment the current pointer
if we're going to pass the buffer limit.
* Misc/NEWS
Mention the fix.
from Greg Chapman.
* Modules/_sre.c
(lastmark_restore): New function, implementing algorithm to restore
a state to a given lastmark. In addition to the similar algorithm used
in a few places of SRE_MATCH, restore lastindex when restoring lastmark.
(SRE_MATCH): Replace lastmark inline restoring by lastmark_restore(),
function. Also include it where missing. In SRE_OP_MARK, set lastindex
only if i > lastmark.
* Lib/test/re_tests.py
* Lib/test/test_sre.py
Included regression tests for the fixed bugs.
* Misc/NEWS
Mention fixes.
The staticforward define was needed to support certain broken C
compilers (notably SCO ODT 3.0, perhaps early AIX as well) botched the
static keyword when it was used with a forward declaration of a static
initialized structure. Standard C allows the forward declaration with
static, and we've decided to stop catering to broken C compilers. (In
fact, we expect that the compilers are all fixed eight years later.)
I'm leaving staticforward and statichere defined in object.h as
static. This is only for backwards compatibility with C extensions
that might still use it.
XXX I haven't updated the documentation.
backed out of broken minimal repeat patch from July
also fixed a couple of minor potential resource leaks in pattern_subx
(Guido had already fixed the big one)
Martin v. Löwis
Andrew M. Kuchling
Neal Norwitz
Georg Brandl
Jack Diederich
Skip Montanaro
Anthony Baxter
Tim Peters
Jeremy Hylton
Gustavo Niemeyer
Raymond Hettinger
Nicholas Bastin
Andrew MacIntyre
Guido van Rossum
Fredrik Lundh
Michael W. Hudson
Mark Hammond