diff options
Diffstat (limited to 'src/backend/utils/adt/varlena.c')
| -rw-r--r-- | src/backend/utils/adt/varlena.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c index 299d8b5790d..1587b4ed02a 100644 --- a/src/backend/utils/adt/varlena.c +++ b/src/backend/utils/adt/varlena.c @@ -1118,7 +1118,12 @@ text_position(text *t1, text *t2, Oid collid) TextPositionState state; int result; - if (VARSIZE_ANY_EXHDR(t1) < 1 || VARSIZE_ANY_EXHDR(t2) < 1) + /* Empty needle always matches at position 1 */ + if (VARSIZE_ANY_EXHDR(t2) < 1) + return 1; + + /* Otherwise, can't match if haystack is shorter than needle */ + if (VARSIZE_ANY_EXHDR(t1) < VARSIZE_ANY_EXHDR(t2)) return 0; text_position_setup(t1, t2, collid, &state); @@ -1272,6 +1277,9 @@ text_position_setup(text *t1, text *t2, Oid collid, TextPositionState *state) * Advance to the next match, starting from the end of the previous match * (or the beginning of the string, on first call). Returns true if a match * is found. + * + * Note that this refuses to match an empty-string needle. Most callers + * will have handled that case specially and we'll never see it here. */ static bool text_position_next(TextPositionState *state) |