MDEV-32439 INSERT IGNORE on constraints result in ERROR rather than warning

INSERT IGNORE had a pecular undocumented case that when one row was
inserted, there was an error rather than a warning.

As LOAD DATA IGNORE, UPDATE IGNORE, INSERT IGNORE SELECT, and INSERT
IGNORE VALUES (single row, for foreign key violation) all behave the same
way with a warning lets keep the behaviour normalized.

In compatibility, previously a error was generated, now a warning is
generated.

This behaviour is now consistent with MySQL-8.0 too.

mysql-test/main/check_constraint.result

@@ -308,5 +308,61 @@ t1	CREATE TABLE `t1` (
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
 drop table t1;
 #
-# End of 10.4 tests
+# MDEV-32439 INSERT IGNORE VALUES (one row) errors on constraint
+#
+CREATE TABLE t1 (v1 varchar(10), v2 varchar(10), constraint unequal check (v1 != v2));
+INSERT IGNORE INTO t1 VALUES (1,1);
+Warnings:
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+SHOW WARNINGS;
+Level	Code	Message
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+INSERT IGNORE INTO t1 VALUES (1,2),(2,2);
+Warnings:
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+SHOW WARNINGS;
+Level	Code	Message
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+INSERT IGNORE INTO t1 VALUES (3,3),(4,4);
+Warnings:
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+SHOW WARNINGS;
+Level	Code	Message
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+SELECT * FROM t1;
+v1	v2
+1	2
+DROP TABLE t1;
+#
+# MDEV-32439 INSERT IGNORE VALUES (one row) errors on constraint
+#
+CREATE TABLE t1 (v1 varchar(10), v2 varchar(10), constraint unequal check (v1 != v2));
+INSERT IGNORE INTO t1 VALUES (1,1);
+Warnings:
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+SHOW WARNINGS;
+Level	Code	Message
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+INSERT IGNORE INTO t1 VALUES (1,2),(2,2);
+Warnings:
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+SHOW WARNINGS;
+Level	Code	Message
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+INSERT IGNORE INTO t1 VALUES (3,3),(4,4);
+Warnings:
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+SHOW WARNINGS;
+Level	Code	Message
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+Warning	4025	CONSTRAINT `unequal` failed for `test`.`t1`
+SELECT * FROM t1;
+v1	v2
+1	2
+DROP TABLE t1;
+#
+# End of 11.4 tests
 #

mysql-test/main/check_constraint.test

@@ -232,5 +232,33 @@ show create table t1;
 drop table t1;
 
 --echo #
---echo # End of 10.4 tests
+--echo # MDEV-32439 INSERT IGNORE VALUES (one row) errors on constraint
+--echo #
+
+CREATE TABLE t1 (v1 varchar(10), v2 varchar(10), constraint unequal check (v1 != v2));
+INSERT IGNORE INTO t1 VALUES (1,1);
+SHOW WARNINGS;
+INSERT IGNORE INTO t1 VALUES (1,2),(2,2);
+SHOW WARNINGS;
+INSERT IGNORE INTO t1 VALUES (3,3),(4,4);
+SHOW WARNINGS;
+SELECT * FROM t1;
+DROP TABLE t1;
+
+--echo #
+--echo # MDEV-32439 INSERT IGNORE VALUES (one row) errors on constraint
+--echo #
+
+CREATE TABLE t1 (v1 varchar(10), v2 varchar(10), constraint unequal check (v1 != v2));
+INSERT IGNORE INTO t1 VALUES (1,1);
+SHOW WARNINGS;
+INSERT IGNORE INTO t1 VALUES (1,2),(2,2);
+SHOW WARNINGS;
+INSERT IGNORE INTO t1 VALUES (3,3),(4,4);
+SHOW WARNINGS;
+SELECT * FROM t1;
+DROP TABLE t1;
+
+--echo #
+--echo # End of 11.4 tests
 --echo #

mysql-test/main/view.result

@@ -1228,10 +1228,17 @@ drop table t1;
 create table t1 (s1 int);
 create view v1 as select * from t1 where s1 < 5 with check option;
 insert ignore into v1 values (6);
-ERROR 44000: CHECK OPTION failed `test`.`v1`
+Warnings:
+Warning	1369	CHECK OPTION failed `test`.`v1`
+SHOW WARNINGS;
+Level	Code	Message
+Warning	1369	CHECK OPTION failed `test`.`v1`
 insert ignore into v1 values (6),(3);
 Warnings:
 Warning	1369	CHECK OPTION failed `test`.`v1`
+SHOW WARNINGS;
+Level	Code	Message
+Warning	1369	CHECK OPTION failed `test`.`v1`
 select * from t1;
 s1
 3

mysql-test/main/view.test

@@ -1126,15 +1126,16 @@ drop view v2, v1;
 drop table t1;
 
 #
-# inserting single value with check option failed always get error
+# inserting single value with check option warns like 2 values
 #
 create table t1 (s1 int);
 create view v1 as select * from t1 where s1 < 5 with check option;
 #single value
--- error ER_VIEW_CHECK_FAILED
 insert ignore into v1 values (6);
+SHOW WARNINGS;
 #several values
 insert ignore into v1 values (6),(3);
+SHOW WARNINGS;
 select * from t1;
 drop view v1;
 drop table t1;

sql/sql_insert.cc

@@ -1129,11 +1129,7 @@ bool mysql_insert(THD *thd, TABLE_LIST *table_list,
         }
       }
 
-      if ((res= table_list->view_check_option(thd,
-                                              (values_list.elements == 1 ?
-                                               0 :
-                                               ignore))) ==
-          VIEW_CHECK_SKIP)
+      if ((res= table_list->view_check_option(thd, ignore)) == VIEW_CHECK_SKIP)
         continue;
       else if (res == VIEW_CHECK_ERROR)
       {