Fix another ancient bug in parsing of BRE-mode regular expressions.

While poking at the regex code, I happened to notice that the bug
squashed in commit afcc8772e had a sibling: next() failed to return
a specific value associated with the '}' token for a "\{m,n\}"
quantifier when parsing in basic RE mode.  Again, this could result
in treating the quantifier as non-greedy, which it never should be in
basic mode.  For that to happen, the last character before "\}" that
sets "nextvalue" would have to set it to zero, or it'd have to have
accidentally been zero from the start.  The failure can be provoked
repeatably with, for example, a bound ending in digit "0".

Like the previous patch, back-patch all the way.
This commit is contained in:
Tom Lane 2021-02-18 22:38:55 -05:00
parent 614b7f18b3
commit b5a66e7353
3 changed files with 11 additions and 3 deletions

View File

@ -389,7 +389,7 @@ next(struct vars *v)
{
v->now++;
INTOCON(L_BRE);
RET('}');
RETV('}', 1);
}
else
FAILW(REG_BADBR);

View File

@ -614,7 +614,7 @@ ERROR: invalid regular expression: quantifier operand invalid
-- expectError 7.15 - a*+ BADRPT
select * from test_regex('a*+', '', '-');
ERROR: invalid regular expression: quantifier operand invalid
-- test for ancient brenext() bug; not currently in Tcl
-- tests for ancient brenext() bugs; not currently in Tcl
select * from test_regex('.*b', 'aaabbb', 'b');
test_regex
------------
@ -622,6 +622,13 @@ select * from test_regex('.*b', 'aaabbb', 'b');
{aaabbb}
(2 rows)
select * from test_regex('.\{1,10\}', 'abcdef', 'bQ');
test_regex
-----------------
{0,REG_UBOUNDS}
{abcdef}
(2 rows)
-- doing 8 "braces"
-- expectMatch 8.1 NQ "a{0,1}" "" ""
select * from test_regex('a{0,1}', '', 'NQ');

View File

@ -214,8 +214,9 @@ select * from test_regex('a?*', '', '-');
select * from test_regex('a+*', '', '-');
-- expectError 7.15 - a*+ BADRPT
select * from test_regex('a*+', '', '-');
-- test for ancient brenext() bug; not currently in Tcl
-- tests for ancient brenext() bugs; not currently in Tcl
select * from test_regex('.*b', 'aaabbb', 'b');
select * from test_regex('.\{1,10\}', 'abcdef', 'bQ');
-- doing 8 "braces"