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

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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 d4b667e935
commit bf9d3a5f84
1 changed files with 1 additions and 1 deletions
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2
src/backend/regex/regc_lex.c
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@ -389,7 +389,7 @@ next(struct vars *v)
{ {
v->now++; v->now++;
INTOCON(L_BRE); INTOCON(L_BRE);
RET('}'); RETV('}', 1);
} }
else else
FAILW(REG_BADBR); FAILW(REG_BADBR);