diff options
Diffstat (limited to 'src/backend/regex/regcomp.c')
| -rw-r--r-- | src/backend/regex/regcomp.c | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/src/backend/regex/regcomp.c b/src/backend/regex/regcomp.c index ae3a7b6a38c..d9840171a33 100644 --- a/src/backend/regex/regcomp.c +++ b/src/backend/regex/regcomp.c @@ -1089,11 +1089,23 @@ parseqatom(struct vars *v, /* annoying special case: {0} or {0,0} cancels everything */ if (m == 0 && n == 0) { - if (atom != NULL) - freesubre(v, atom); - if (atomtype == '(') - v->subs[subno] = NULL; - delsub(v->nfa, lp, rp); + /* + * If we had capturing subexpression(s) within the atom, we don't want + * to destroy them, because it's legal (if useless) to back-ref them + * later. Hence, just unlink the atom from lp/rp and then ignore it. + */ + if (atom != NULL && (atom->flags & CAP)) + { + delsub(v->nfa, lp, atom->begin); + delsub(v->nfa, atom->end, rp); + } + else + { + /* Otherwise, we can clean up any subre infrastructure we made */ + if (atom != NULL) + freesubre(v, atom); + delsub(v->nfa, lp, rp); + } EMPTYARC(lp, rp); return top; } |