MDEV-21539 Assertion ...prtype... failed in row_log_table_apply_convert_mrec

This bug is a cousin of MDEV-18719 and MDEV-20190, which failed to
relax a debug assertion in one more code path.

row_log_table_apply_convert_mrec(): Use dict_col_t::same_format()
and ignore all format-agnostic flags in the assertions.

mysql-test/suite/innodb/r/alter_not_null_debug.result

@@ -74,5 +74,27 @@ c1	c2	c3
 1	2	3
 2	0	4
 DROP TABLE t1;
-disconnect con1;
 SET DEBUG_SYNC='RESET';
+#
+# MDEV-21539 Assertion ...prtype... in row_log_table_apply_convert_mrec
+#
+CREATE TABLE t1 (f VARCHAR(8) CHARACTER SET latin1 COLLATE latin1_swedish_ci)
+ENGINE=InnoDB;
+connection con1;
+SET DEBUG_SYNC = 'row_log_table_apply1_before SIGNAL scanned WAIT_FOR insert_done';
+ALTER TABLE t1 MODIFY f VARCHAR(256) COLLATE latin1_german2_ci NOT NULL;
+# session default
+connection default;
+SET DEBUG_SYNC = 'now WAIT_FOR scanned';
+INSERT INTO t1 VALUES('one');
+SET DEBUG_SYNC = 'now SIGNAL insert_done';
+connection con1;
+disconnect con1;
+connection default;
+SET DEBUG_SYNC=RESET;
+ALTER TABLE t1 CHANGE f eins VARCHAR(257) COLLATE latin1_german1_ci NOT NULL,
+ALGORITHM=INSTANT;
+SELECT * FROM t1;
+eins
+one
+DROP TABLE t1;

mysql-test/suite/innodb/t/alter_not_null_debug.test

@@ -68,5 +68,32 @@ reap;
 --disable_info
 SELECT * FROM t1;
 DROP TABLE t1;
-disconnect con1;
 SET DEBUG_SYNC='RESET';
+
+--echo #
+--echo # MDEV-21539 Assertion ...prtype... in row_log_table_apply_convert_mrec
+--echo #
+CREATE TABLE t1 (f VARCHAR(8) CHARACTER SET latin1 COLLATE latin1_swedish_ci)
+ENGINE=InnoDB;
+
+connection con1;
+SET DEBUG_SYNC = 'row_log_table_apply1_before SIGNAL scanned WAIT_FOR insert_done';
+send ALTER TABLE t1 MODIFY f VARCHAR(256) COLLATE latin1_german2_ci NOT NULL;
+
+--echo # session default
+connection default;
+SET DEBUG_SYNC = 'now WAIT_FOR scanned';
+INSERT INTO t1 VALUES('one');
+SET DEBUG_SYNC = 'now SIGNAL insert_done';
+
+connection con1;
+reap;
+disconnect con1;
+connection default;
+SET DEBUG_SYNC=RESET;
+
+ALTER TABLE t1 CHANGE f eins VARCHAR(257) COLLATE latin1_german1_ci NOT NULL,
+ALGORITHM=INSTANT;
+
+SELECT * FROM t1;
+DROP TABLE t1;

storage/innobase/row/row0log.cc

@@ -1648,12 +1648,12 @@ blob_done:
 		/* See if any columns were changed to NULL or NOT NULL. */
 		const dict_col_t*	new_col
 			= dict_table_get_nth_col(log->table, col_no);
-		ut_ad(new_col->mtype == col->mtype);
+		ut_ad(new_col->same_format(*col));
 
 		/* Assert that prtype matches except for nullability. */
-		ut_ad(!((new_col->prtype ^ col->prtype) & ~DATA_NOT_NULL));
 		ut_ad(!((new_col->prtype ^ dfield_get_type(dfield)->prtype)
-			& ~DATA_NOT_NULL));
+			& ~(DATA_NOT_NULL | DATA_VERSIONED
+			    | CHAR_COLL_MASK << 16 | DATA_LONG_TRUE_VARCHAR)));
 
 		if (new_col->prtype == col->prtype) {
 			continue;