postgres.git / summary / log / commit / refs
commit 029dea882a7aa34f46732473eed7c917505e6481
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu Apr 06 19:52:37 2023 +0000
First released in: 16.0, 11.20, 12.15, 13.11, 14.8, 15.3
Fix ts_headline() edge cases for empty query and empty search text.
tsquery's GETQUERY() macro is only safe to apply to a tsquery
that is known non-empty; otherwise it gives a pointer to garbage.
Before commit 5a617d75d, ts_headline() avoided this pitfall, but
only in a very indirect, nonobvious way. (hlCover could not reach
its TS_execute call, because if the query contains no lexemes
then hlFirstIndex would surely return -1.) After that commit,
it fell into the trap, resulting in weird errors such as
"unrecognized operator" and/or valgrind complaints. In HEAD,
fix this by not calling TS_execute_locations() at all for an
empty query. In the back branches, add a defensive check to
hlCover() --- that's not fixing any live bug, but I judge the
code a bit too fragile as-is.
Also, both mark_hl_fragments() and mark_hl_words() were careless
about the possibility of empty search text: in the cases where
no match has been found, they'd end up telling mark_fragment() to
mark from word indexes 0 to 0 inclusive, even when there is no
word 0. This is harmless since we over-allocated the prs->words
array, but it does annoy valgrind. Fix so that the end index is -1
and thus mark_fragment() will do nothing in such cases.
Bottom line is that this fixes a live bug in HEAD, but in the
back branches it's only getting rid of a valgrind nitpick.
Back-patch anyway.
Per report from Alexander Lakhin.
Discussion: https://postgr.es/m/c27f642d-020b-01ff-ae61-086af287c4fd@gmail.com
src/backend/tsearch/wparser_def.c | 21 ++++++++++++++-------
src/test/regress/expected/tsearch.out | 21 +++++++++++++++++++++
src/test/regress/sql/tsearch.sql | 6 ++++++
3 files changed, 41 insertions(+), 7 deletions(-)
diff --git a/src/backend/tsearch/wparser_def.c b/src/backend/tsearch/wparser_def.c
index 840a44ec007..23e4e9d98a9 100644
--- a/src/backend/tsearch/wparser_def.c
+++ b/src/backend/tsearch/wparser_def.c
@@ -2417,7 +2417,8 @@ mark_hl_fragments(HeadlineParsedText *prs, TSQuery query, List *locations,
/* show the first min_words words if we have not marked anything */
if (num_f <= 0)
{
- startpos = endpos = curlen = 0;
+ startpos = curlen = 0;
+ endpos = -1;
for (i = 0; i < prs->curwords && curlen < min_words; i++)
{
if (!NONWORDTOKEN(prs->words[i].type))
@@ -2571,7 +2572,7 @@ mark_hl_words(HeadlineParsedText *prs, TSQuery query, List *locations,
if (bestlen < 0)
{
curlen = 0;
- pose = 0;
+ pose = -1;
for (i = 0; i < prs->curwords && curlen < min_words; i++)
{
if (!NONWORDTOKEN(prs->words[i].type))
@@ -2601,7 +2602,6 @@ prsd_headline(PG_FUNCTION_ARGS)
HeadlineParsedText *prs = (HeadlineParsedText *) PG_GETARG_POINTER(0);
List *prsoptions = (List *) PG_GETARG_POINTER(1);
TSQuery query = PG_GETARG_TSQUERY(2);
- hlCheck ch;
List *locations;
/* default option values: */
@@ -2671,10 +2671,17 @@ prsd_headline(PG_FUNCTION_ARGS)
}
/* Locate words and phrases matching the query */
- ch.words = prs->words;
- ch.len = prs->curwords;
- locations = TS_execute_locations(GETQUERY(query), &ch, TS_EXEC_EMPTY,
- checkcondition_HL);
+ if (query->size > 0)
+ {
+ hlCheck ch;
+
+ ch.words = prs->words;
+ ch.len = prs->curwords;
+ locations = TS_execute_locations(GETQUERY(query), &ch, TS_EXEC_EMPTY,
+ checkcondition_HL);
+ }
+ else
+ locations = NIL; /* empty query matches nothing */
/* Apply appropriate headline selector */
if (max_fragments == 0)
diff --git a/src/test/regress/expected/tsearch.out b/src/test/regress/expected/tsearch.out
index 0e682457430..6b3ad38f396 100644
--- a/src/test/regress/expected/tsearch.out
+++ b/src/test/regress/expected/tsearch.out
@@ -2127,6 +2127,27 @@ to_tsquery('english','Lorem') && phraseto_tsquery('english','ullamcorper urna'),
<b>Lorem</b> ipsum <b>urna</b>. Nullam nullam <b>ullamcorper</b> <b>urna</b>
(1 row)
+-- Edge cases with empty query
+SELECT ts_headline('english',
+'', ''::tsquery);
+NOTICE: text-search query doesn't contain lexemes: ""
+LINE 2: '', ''::tsquery);
+ ^
+ ts_headline
+-------------
+
+(1 row)
+
+SELECT ts_headline('english',
+'foo bar', ''::tsquery);
+NOTICE: text-search query doesn't contain lexemes: ""
+LINE 2: 'foo bar', ''::tsquery);
+ ^
+ ts_headline
+-------------
+ foo bar
+(1 row)
+
--Rewrite sub system
CREATE TABLE test_tsquery (txtkeyword TEXT, txtsample TEXT);
\set ECHO none
diff --git a/src/test/regress/sql/tsearch.sql b/src/test/regress/sql/tsearch.sql
index b56477a8139..f6f5fb5c270 100644
--- a/src/test/regress/sql/tsearch.sql
+++ b/src/test/regress/sql/tsearch.sql
@@ -640,6 +640,12 @@ SELECT ts_headline('english',
to_tsquery('english','Lorem') && phraseto_tsquery('english','ullamcorper urna'),
'MaxFragments=100, MaxWords=100, MinWords=1');
+-- Edge cases with empty query
+SELECT ts_headline('english',
+'', ''::tsquery);
+SELECT ts_headline('english',
+'foo bar', ''::tsquery);
+
--Rewrite sub system
CREATE TABLE test_tsquery (txtkeyword TEXT, txtsample TEXT);
[parent: 18103b7c5f1a]