MDEV-14655 Assertion `!fts_index' failed in prepare_inplace_alter_table_dict

MariaDB inherits the MySQL limitation that ALGORITHM=INPLACE cannot
create more than one FULLTEXT INDEX at a time. As part of the MDEV-11369
Instant ADD COLUMN refactoring, MariaDB 10.3.2 accidentally stopped
enforcing the restriction.

Actually, it is a bug in MySQL 5.6 and MariaDB 10.0 that an ALTER TABLE
statement with multiple ADD FULLTEXT INDEX but without explicit
ALGORITHM=INPLACE would return in an error message, rather than
executing the operation with ALGORITHM=COPY.

ha_innobase::check_if_supported_inplace_alter(): Enforce the restriction
on multiple FULLTEXT INDEX.

prepare_inplace_alter_table_dict(): Replace some code with debug
assertions. A "goto error_handled" at this point would result in
another error, because the reference count of ctx->new_table would be 0.

2 files changed, 16 insertions, 11 deletions

diff --git a/mysql-test/suite/innodb_fts/r/innodb-fts-ddl.result b/mysql-test/suite/innodb_fts/r/innodb-fts-ddl.result
index 983f254cf90..cd7d8f03923 100644
--- a/mysql-test/suite/innodb_fts/r/innodb-fts-ddl.result
+++ b/mysql-test/suite/innodb_fts/r/innodb-fts-ddl.result
@@ -162,11 +162,15 @@ INSERT INTO articles (FTS_DOC_ID, title, body) VALUES
 (14,'1001 MySQL Tricks','1. Never run mysqld as root. 2. ...'),
 (19, 'MySQL vs. YourSQL','In the following database comparison ...'),
 (20, 'MySQL Security','When configured properly, MySQL ...');
-ALTER TABLE articles ADD FULLTEXT INDEX idx3 (title),
-ADD FULLTEXT INDEX idx5 (title);
-ERROR HY000: InnoDB presently supports one FULLTEXT index creation at a time
-CREATE FULLTEXT INDEX idx on articles (title);
-ALTER TABLE articles ADD FULLTEXT INDEX idx3 (title);
+ALTER TABLE articles ADD FULLTEXT INDEX idx (title),
+ADD FULLTEXT INDEX idx3 (title), ALGORITHM=INPLACE;
+ERROR 0A000: ALGORITHM=INPLACE is not supported. Reason: InnoDB presently supports one FULLTEXT index creation at a time. Try ALGORITHM=COPY
+ALTER TABLE articles ADD FULLTEXT INDEX idx (title),
+ADD FULLTEXT INDEX idx3 (title);
+affected rows: 6
+info: Records: 6  Duplicates: 0  Warnings: 1
+Warnings:
+Note	1831	Duplicate index `idx3`. This is deprecated and will be disallowed in a future release
 ALTER TABLE articles ADD INDEX t20 (title(20)), LOCK=NONE;
 ALTER TABLE articles DROP INDEX t20;
 INSERT INTO articles (FTS_DOC_ID, title, body) VALUES
diff --git a/mysql-test/suite/innodb_fts/t/innodb-fts-ddl.test b/mysql-test/suite/innodb_fts/t/innodb-fts-ddl.test
index 10dc1462c98..23065a97002 100644
--- a/mysql-test/suite/innodb_fts/t/innodb-fts-ddl.test
+++ b/mysql-test/suite/innodb_fts/t/innodb-fts-ddl.test
@@ -195,12 +195,13 @@ INSERT INTO articles (FTS_DOC_ID, title, body) VALUES
         (19, 'MySQL vs. YourSQL','In the following database comparison ...'),
         (20, 'MySQL Security','When configured properly, MySQL ...');
 
---error ER_INNODB_FT_LIMIT
-ALTER TABLE articles ADD FULLTEXT INDEX idx3 (title),
-		     ADD FULLTEXT INDEX idx5 (title);
-
-CREATE FULLTEXT INDEX idx on articles (title);
-ALTER TABLE articles ADD FULLTEXT INDEX idx3 (title);
+--error ER_ALTER_OPERATION_NOT_SUPPORTED_REASON
+ALTER TABLE articles ADD FULLTEXT INDEX idx (title),
+		     ADD FULLTEXT INDEX idx3 (title), ALGORITHM=INPLACE;
+--enable_info
+ALTER TABLE articles ADD FULLTEXT INDEX idx (title),
+		     ADD FULLTEXT INDEX idx3 (title);
+--disable_info
 
 ALTER TABLE articles ADD INDEX t20 (title(20)), LOCK=NONE;
 ALTER TABLE articles DROP INDEX t20;