Bug#45100: Incomplete DROP USER in case of SQL_MODE = 'PAD_CHAR_TO_FULL_LENGTH'

The SQL-mode PAD_CHAR_TO_FULL_LENGTH could prevent a DROP USER
statement from privileges associated with the user being dropped.
What ocurred was that reading from the User and Host fields of
the tables tables_priv or columns_priv would yield values padded
with spaces, causing a failure to match a specified user or host 
('user' != 'user     ');

The solution is to disregard the PAD_CHAR_TO_FULL_LENGTH mode
when iterating over and matching values in the privileges tables
for a DROP USER statement.

mysql-test/r/sql_mode.result:
  Add test case result for Bug#45100.
mysql-test/t/sql_mode.test:
  Add test case for Bug#45100.
sql/sql_acl.cc:
  Clear MODE_PAD_CHAR_TO_FULL_LENGTH before dropping privileges.

1 files changed, 36 insertions, 0 deletions

diff --git a/mysql-test/t/sql_mode.test b/mysql-test/t/sql_mode.test
index acc9cc7979e..4a9f34443cb 100644
--- a/mysql-test/t/sql_mode.test
+++ b/mysql-test/t/sql_mode.test
@@ -308,3 +308,39 @@ flush privileges;
 
 --connection default
 drop user mysqltest_32753@localhost;
+
+#
+# Bug#45100: Incomplete DROP USER in case of SQL_MODE = 'PAD_CHAR_TO_FULL_LENGTH'
+#
+
+--disable_warnings
+DROP TABLE IF EXISTS t1,t2;
+--enable_warnings
+
+# Generate some prerequisites
+CREATE USER 'user_PCTFL'@'localhost' identified by 'PWD';
+CREATE USER 'user_no_PCTFL'@'localhost' identified by 'PWD';
+
+CREATE TABLE t1 (f1 BIGINT);
+CREATE TABLE t2 (f1 CHAR(3) NOT NULL, f2 CHAR(20));
+
+# Grant privilege on a TABLE
+GRANT ALL ON t1 TO 'user_PCTFL'@'localhost','user_no_PCTFL'@'localhost';
+# Grant privilege on some COLUMN of a table
+GRANT SELECT(f1) ON t2 TO 'user_PCTFL'@'localhost','user_no_PCTFL'@'localhost';
+
+SET @OLD_SQL_MODE = @@SESSION.SQL_MODE;
+SET SESSION SQL_MODE = 'PAD_CHAR_TO_FULL_LENGTH';
+DROP USER 'user_PCTFL'@'localhost';
+SET SESSION SQL_MODE = @OLD_SQL_MODE;
+DROP USER 'user_no_PCTFL'@'localhost';
+
+FLUSH PRIVILEGES;
+
+SELECT * FROM mysql.db WHERE Host = 'localhost' AND User LIKE 'user_%PCTFL';
+SELECT * FROM mysql.tables_priv WHERE Host = 'localhost' AND User LIKE 'user_%PCTFL';
+SELECT * FROM mysql.columns_priv WHERE Host = 'localhost' AND User LIKE 'user_%PCTFL';
+
+# Cleanup
+DROP TABLE t1;
+DROP TABLE t2;