MDEV-9524 Cannot load from mysql.event when sql_mode is set to PAD_CHAR_TO_FULL_LENGTH

The patch fixes the problem with loading information from system tables
(e.g. event and help related tables) when PAD_CHAR_TO_FULL_LENGTH is enabled,
as well as includes some additional minor improvements:
- refactoring in get_field() to return an error rather than success
  if strmake_root() failed
- removing of duplicate code in similar functions:
  char *get_field(MEM_ROOT *mem, Field *field)
  bool get_field(MEM_ROOT *mem, Field *field, String *res)

1 files changed, 15 insertions, 0 deletions

diff --git a/mysql-test/r/help.result b/mysql-test/r/help.result
index 16719cc8193..319a1ba3e85 100644
--- a/mysql-test/r/help.result
+++ b/mysql-test/r/help.result
@@ -148,6 +148,21 @@ help 'impossible_category_1';
 source_category_name	name	is_it_category
 impossible_category_1	impossible_function_1	N
 impossible_category_1	impossible_function_2	N
+# MDEV-9524 Cannot load from mysql.event when sql_mode is set to PAD_CHAR_TO_FULL_LENGTH
+help 'impossible_function_1';
+name	description	example
+impossible_function_1	description of 
+ impossible_function1
+	example of 
+ impossible_function1
+SET sql_mode=PAD_CHAR_TO_FULL_LENGTH;
+help 'impossible_function_1';
+name	description	example
+impossible_function_1	description of 
+ impossible_function1
+	example of 
+ impossible_function1
+SET sql_mode=DEFAULT;
 alter table mysql.help_relation engine=innodb;
 alter table mysql.help_keyword engine=innodb;
 alter table mysql.help_topic engine=innodb;