Fixed bug #470582, using a modified version of patch #527371,
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.
diff --git a/Lib/test/re_tests.py b/Lib/test/re_tests.py
index 953e4fd..d6f04f0 100755
--- a/Lib/test/re_tests.py
+++ b/Lib/test/re_tests.py
@@ -646,6 +646,8 @@
(r'a[^>]*?b', 'a>b', FAIL),
# bug 490573: minimizing repeat problem
(r'^a*?$', 'foo', FAIL),
+ # bug 470582: nested groups problem
+ (r'^((a)c)?(ab)$', 'ab', SUCCEED, 'g1+"-"+g2+"-"+g3', 'None-None-ab'),
]
try:
diff --git a/Lib/test/test_sre.py b/Lib/test/test_sre.py
index 284212c..6a00aff 100644
--- a/Lib/test/test_sre.py
+++ b/Lib/test/test_sre.py
@@ -78,6 +78,11 @@
test(r"""sre.match(r'(a)|(b)', 'b').end(1)""", -1)
test(r"""sre.match(r'(a)|(b)', 'b').span(1)""", (-1, -1))
+# bug described in patch 527371
+test(r"""sre.match(r'(a)?a','a').lastindex""", None)
+test(r"""sre.match(r'(a)(b)?b','ab').lastindex""", 1)
+test(r"""sre.match(r'(?P<a>a)(?P<b>b)?b','ab').lastgroup""", 'a')
+
if verbose:
print 'Running tests on sre.sub'
diff --git a/Misc/NEWS b/Misc/NEWS
index c57ca1d..cccaff5 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -352,6 +352,13 @@
to the value of the PYTHON_API_VERSION macro with which the
interpreter was compiled.
+- Fixed bug #470582: sre module would return a tuple (None, 'a', 'ab')
+ when applying the regular expression '^((a)c)?(ab)$' on 'ab'. It now
+ returns (None, None, 'ab'), as expected. Also fixed handling of
+ lastindex/lastgroup match attributes in a similar cases. For example,
+ when running the expression r'(a)(b)?b' over 'ab', lastindex must be
+ 1, not 2.
+
Library
-------
diff --git a/Modules/_sre.c b/Modules/_sre.c
index f4dbef0..4440a6e 100644
--- a/Modules/_sre.c
+++ b/Modules/_sre.c
@@ -353,6 +353,18 @@
return 0;
}
+void lastmark_restore(SRE_STATE *state, int lastmark)
+{
+ if (state->lastmark > lastmark) {
+ memset(
+ state->mark + lastmark + 1, 0,
+ (state->lastmark - lastmark) * sizeof(void*)
+ );
+ state->lastmark = lastmark;
+ state->lastindex = (lastmark == 0) ? -1 : (lastmark-1)/2+1;
+ }
+}
+
/* generate 8-bit version */
#define SRE_CHAR unsigned char
@@ -860,10 +872,11 @@
/* <MARK> <gid> */
TRACE(("|%p|%p|MARK %d\n", pattern, ptr, pattern[0]));
i = pattern[0];
- if (i & 1)
- state->lastindex = i/2 + 1;
- if (i > state->lastmark)
+ if (i > state->lastmark) {
state->lastmark = i;
+ if (i & 1)
+ state->lastindex = i/2 + 1;
+ }
state->mark[i] = ptr;
pattern++;
break;
@@ -920,13 +933,7 @@
i = SRE_MATCH(state, pattern + 1, level + 1);
if (i)
return i;
- if (state->lastmark > lastmark) {
- memset(
- state->mark + lastmark + 1, 0,
- (state->lastmark - lastmark) * sizeof(void*)
- );
- state->lastmark = lastmark;
- }
+ lastmark_restore(state, lastmark);
}
return 0;
@@ -997,13 +1004,7 @@
return i;
ptr--;
count--;
- if (state->lastmark > lastmark) {
- memset(
- state->mark + lastmark + 1, 0,
- (state->lastmark - lastmark) * sizeof(void*)
- );
- state->lastmark = lastmark;
- }
+ lastmark_restore(state, lastmark);
}
}
return 0;
@@ -1071,9 +1072,9 @@
if (i)
return i;
i = mark_restore(state, 0, lastmark);
- state->lastmark = lastmark;
if (i < 0)
return i;
+ lastmark_restore(state, lastmark);
rp->count = count - 1;
state->ptr = ptr;
}