Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commitafcc877

Browse files
committed
Fix ancient bug in parsing of BRE-mode regular expressions.
brenext(), when parsing a '*' quantifier, forgot to return any "value"for the token; per the equivalent case in next(), it should returnvalue 1 to indicate that greedy rather than non-greedy behavior iswanted. The result is that the compiled regexp could behave like 'x*?'rather than the intended 'x*', if we were unlucky enough to havea zero in v->nextvalue at this point. That seems to happen with somereliability if we have '.*' at the beginning of a BRE-mode regexp,although that depends on the initial contents of a stack-allocatedstruct, so it's not guaranteed to fail.Found by Alexander Lakhin using valgrind testing. This bug seemsto be aboriginal in Spencer's code, so back-patch all the way.Discussion:https://postgr.es/m/16814-6c5e3edd2bdf0d50@postgresql.org
1 parent15b824d commitafcc877

File tree

3 files changed

+11
-1
lines changed

3 files changed

+11
-1
lines changed

‎src/backend/regex/regc_lex.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -994,7 +994,7 @@ brenext(struct vars *v,
994994
caseCHR('*'):
995995
if (LASTTYPE(EMPTY)||LASTTYPE('(')||LASTTYPE('^'))
996996
RETV(PLAIN,c);
997-
RET('*');
997+
RETV('*',1);
998998
break;
999999
caseCHR('['):
10001000
if (HAVE(6)&&*(v->now+0)==CHR('[')&&

‎src/test/modules/test_regex/expected/test_regex.out‎

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -614,6 +614,14 @@ ERROR: invalid regular expression: quantifier operand invalid
614614
-- expectError7.15 -a*+BADRPT
615615
select * from test_regex('a*+', '', '-');
616616
ERROR: invalid regular expression: quantifier operand invalid
617+
-- test for ancient brenext() bug; not currently in Tcl
618+
select * from test_regex('.*b', 'aaabbb', 'b');
619+
test_regex
620+
------------
621+
{0}
622+
{aaabbb}
623+
(2 rows)
624+
617625
-- doing 8 "braces"
618626
-- expectMatch8.1 NQ"a{0,1}"""""
619627
select * from test_regex('a{0,1}', '', 'NQ');

‎src/test/modules/test_regex/sql/test_regex.sql‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -214,6 +214,8 @@ select * from test_regex('a?*', '', '-');
214214
select*from test_regex('a+*','','-');
215215
-- expectError7.15 -a*+BADRPT
216216
select*from test_regex('a*+','','-');
217+
-- test for ancient brenext() bug; not currently in Tcl
218+
select*from test_regex('.*b','aaabbb','b');
217219

218220
-- doing 8 "braces"
219221

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp