MDEV-20800 Server crashes in Field_inet6::store_warning upon updating table statistics

Suppress warnings when Field_inet6::store() is called from
read_statistics_for_table() and other optimizer related routines.

This patch does for Field_inet6 the same thing with what Monty's
patch previously did for other Field_xxx:

> commit 1bbe8c5e0f
> Author: Michael Widenius <monty@mariadb.org>
> Date:   Sun Sep 22 04:08:48 2019 +0300
>
>    Proper fix for disabling warnings in read_statistics_for_table().
>    MDEV-20589: Server still crashes in Field::set_warning_truncated_wrong_value

Alas, some meaningful warnings disappeared.

plugin/type_inet/mysql-test/type_inet/type_inet6_innodb.result

@@ -30,13 +30,11 @@ SELECT * FROM t1 WHERE a='garbage';
 a
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 EXPLAIN SELECT * FROM t1 WHERE a='garbage';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 SELECT * FROM t1 WHERE a>='::fe';
 a
 ::fe
@@ -46,13 +44,9 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	a	a	17	NULL	2	Using where; Using index
 SELECT * FROM t1 WHERE a>='garbage';
 a
-Warnings:
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 EXPLAIN SELECT * FROM t1 WHERE a>='garbage';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 SELECT * FROM t1 WHERE a IN ('::80','::a0','::f0');
 a
 ::80
@@ -67,13 +61,11 @@ a
 ::a0
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 EXPLAIN SELECT * FROM t1 WHERE a IN ('::80','::a0','garbage');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	a	a	17	NULL	2	Using where; Using index
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 SELECT * FROM t1 WHERE a BETWEEN '::80' AND '::81';
 a
 ::80
@@ -83,13 +75,9 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	a	a	17	NULL	2	Using where; Using index
 SELECT * FROM t1 WHERE a BETWEEN '::80' AND 'garbage';
 a
-Warnings:
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 EXPLAIN SELECT * FROM t1 WHERE a BETWEEN '::80' AND 'garbage';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 SELECT * FROM t1 WHERE a=CAST('::ff' AS INET6);
 a
 ::ff

plugin/type_inet/mysql-test/type_inet/type_inet6_memory.result

@@ -30,13 +30,11 @@ SELECT * FROM t1 WHERE a='garbage';
 a
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 EXPLAIN SELECT * FROM t1 WHERE a='garbage';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 SELECT * FROM t1 WHERE a>='::fe';
 a
 ::fe
@@ -65,13 +63,11 @@ a
 ::a0
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 EXPLAIN SELECT * FROM t1 WHERE a IN ('::80','::a0','garbage');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	a	a	17	NULL	4	Using where
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 SELECT * FROM t1 WHERE a BETWEEN '::80' AND '::81';
 a
 ::80

plugin/type_inet/mysql-test/type_inet/type_inet6_myisam.result

@@ -30,13 +30,11 @@ SELECT * FROM t1 WHERE a='garbage';
 a
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 EXPLAIN SELECT * FROM t1 WHERE a='garbage';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 SELECT * FROM t1 WHERE a>='::fe';
 a
 ::fe
@@ -46,13 +44,9 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	a	a	17	NULL	2	Using where; Using index
 SELECT * FROM t1 WHERE a>='garbage';
 a
-Warnings:
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 EXPLAIN SELECT * FROM t1 WHERE a>='garbage';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 SELECT * FROM t1 WHERE a IN ('::80','::a0','::f0');
 a
 ::80
@@ -67,13 +61,11 @@ a
 ::a0
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 EXPLAIN SELECT * FROM t1 WHERE a IN ('::80','::a0','garbage');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	a	a	17	NULL	2	Using where; Using index
 Warnings:
 Warning	1292	Incorrect inet6 value: 'garbage'
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 SELECT * FROM t1 WHERE a BETWEEN '::80' AND '::81';
 a
 ::80
@@ -83,13 +75,9 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	a	a	17	NULL	2	Using where; Using index
 SELECT * FROM t1 WHERE a BETWEEN '::80' AND 'garbage';
 a
-Warnings:
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 EXPLAIN SELECT * FROM t1 WHERE a BETWEEN '::80' AND 'garbage';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
-Warnings:
-Warning	1292	Incorrect inet6 value: 'garbage' for column `test`.`t1`.`a` at row 1
 SELECT * FROM t1 WHERE a=CAST('::ff' AS INET6);
 a
 ::ff

plugin/type_inet/mysql-test/type_inet/type_inet6_stat_tables.result

@@ -0,0 +1,17 @@
+#
+# Start of 10.5 tests
+#
+#
+# MDEV-20800 Server crashes in Field_inet6::store_warning upon updating table statistics
+#
+CREATE TABLE t1 (a INET6);
+INSERT INTO t1 VALUES ('1::1'),('2::2');
+ANALYZE TABLE t1 PERSISTENT FOR ALL;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+INSERT INTO t1 VALUES ('3::3');
+DROP TABLE t1;
+#
+# End of 10.5 tests
+#

plugin/type_inet/mysql-test/type_inet/type_inet6_stat_tables.test

@@ -0,0 +1,19 @@
+--source include/have_stat_tables.inc
+
+--echo #
+--echo # Start of 10.5 tests
+--echo #
+
+--echo #
+--echo # MDEV-20800 Server crashes in Field_inet6::store_warning upon updating table statistics
+--echo #
+
+CREATE TABLE t1 (a INET6);
+INSERT INTO t1 VALUES ('1::1'),('2::2');
+ANALYZE TABLE t1 PERSISTENT FOR ALL;
+INSERT INTO t1 VALUES ('3::3');
+DROP TABLE t1;
+
+--echo #
+--echo # End of 10.5 tests
+--echo #

plugin/type_inet/sql_type_inet.cc

@@ -609,9 +609,10 @@ class Field_inet6: public Field
                      Sql_condition::enum_warning_level level)
   {
     static const Name type_name= type_handler_inet6.name();
-    get_thd()->push_warning_truncated_value_for_field(level, type_name.ptr(),
-                                                      str.ptr(), table->s,
-                                                      field_name.str);
+    if (get_thd()->count_cuted_fields > CHECK_FIELD_EXPRESSION)
+      get_thd()->push_warning_truncated_value_for_field(level, type_name.ptr(),
+                                                        str.ptr(), table->s,
+                                                        field_name.str);
   }
   int set_null_with_warn(const ErrConv &str)
   {