MDEV-29778 Having Unique index interference with MATCH from a FULLTEXT

InnoDB fails to fetch FTS_DOC_ID if the select query uses secondary
index. So always do extra lookup on clustered index in case of fts
query

mysql-test/suite/innodb_fts/r/fulltext.result

@@ -774,4 +774,15 @@ UNLOCK TABLES;
 ALTER TABLE t1 DISCARD TABLESPACE;
 ALTER TABLE t2 IMPORT TABLESPACE;
 DROP TABLE t2, t1;
+#
+#  MDEV-29778  Having Unique index interference with MATCH
+#		from a FULLTEXT
+#
+CREATE TABLE t1(f1 VARCHAR(100), FULLTEXT(f1),
+UNIQUE INDEX(f1))ENGINE=InnoDB;
+INSERT INTO t1 VALUES("test");
+SELECT f1, MATCH(f1) AGAINST ("test" IN BOOLEAN MODE) FROM t1;
+f1	MATCH(f1) AGAINST ("test" IN BOOLEAN MODE)
+test	0.000000001885928302414186
+DROP TABLE t1;
 # End of 10.3 tests

mysql-test/suite/innodb_fts/t/fulltext.test

@@ -790,4 +790,14 @@ ALTER TABLE t2 IMPORT TABLESPACE;
 --enable_warnings
 DROP TABLE t2, t1;
 
+--echo #
+--echo #  MDEV-29778  Having Unique index interference with MATCH
+--echo #		from a FULLTEXT
+--echo #
+CREATE TABLE t1(f1 VARCHAR(100), FULLTEXT(f1),
+		UNIQUE INDEX(f1))ENGINE=InnoDB;
+INSERT INTO t1 VALUES("test");
+SELECT f1, MATCH(f1) AGAINST ("test" IN BOOLEAN MODE) FROM t1;
+DROP TABLE t1;
+
 --echo # End of 10.3 tests

storage/innobase/handler/ha_innodb.cc

@@ -7703,6 +7703,11 @@ ha_innobase::build_template(
 	m_prebuilt->versioned_write = table->versioned_write(VERS_TRX_ID);
 	m_prebuilt->need_to_access_clustered = (index == clust_index);
 
+	if (m_prebuilt->in_fts_query) {
+		/* Do clustered index lookup to fetch the FTS_DOC_ID */
+		m_prebuilt->need_to_access_clustered = true;
+	}
+
 	/* Either m_prebuilt->index should be a secondary index, or it
 	should be the clustered index. */
 	ut_ad(dict_index_is_clust(index) == (index == clust_index));