PS-10383 [8.4]: ensure performs phrase search in BOOLEAN MODE with Mecab plugin

[kakao-jenna-me]

Background

In the MeCab full-text parser documentation, it is described that:

• In NATURAL LANGUAGE MODE, the search term is converted into a union of tokens.
• In BOOLEAN MODE, the search term is converted into a search phrase.

However, when using the MeCab plugin, phrase search behavior in BOOLEAN MODE was not enforced correctly: rows were returned even when extra tokens existed between phrase tokens.

--boolean mode
select * from issue_test where match (content) against ('서울날씨' in boolean mode);
+----+-----------------+
| id | content         |
+----+-----------------+
|  1 | 서울날씨        |
|  2 | 서울봄날씨      |
+----+-----------------+

select * from issue_test where match (content) against ('"서울날씨"' in boolean mode);
+----+-----------------+
| id | content         |
+----+-----------------+
|  1 | 서울날씨        |
|  2 | 서울봄날씨      |
+----+-----------------+

--natural mode
select * from issue_test where match (content) against ('서울날씨');
+----+-----------------+
| id | content         |
+----+-----------------+
|  1 | 서울날씨        |
|  2 | 서울봄날씨      |
+----+-----------------+

CAUSE

fts_query_match_phrase_add_word_for_parser() returns a non-zero value when phrase token matching fails.
However, as-is code ignored this return values.

AFTER FIX

--boolean mode
select * from issue_test where match (content) against ('서울날씨' in boolean mode);
+----+--------------+
| id | content      |
+----+--------------+
|  1 | 서울날씨     |
+----+--------------+

select * from issue_test where match (content) against ('"서울날씨"' in boolean mode);
+----+--------------+
| id | content      |
+----+--------------+
|  1 | 서울날씨     |
+----+--------------+

-- natural mode
select * from issue_test where match (content) against ('서울날씨');
+----+-----------------+
| id | content         |
+----+-----------------+
|  1 | 서울날씨        |
|  2 | 서울봄날씨      |
+----+-----------------+