Bug #54106 assert in Protocol::end_statement,

           INSERT IGNORE ... SELECT ... UNION SELECT ...

This assert was triggered by INSERT IGNORE ... SELECT. The assert checks that a
statement either sends OK or an error to the client. If the bug was triggered
on release builds, it caused OK to be sent to the client instead of the correct
error message (in this case ER_FIELD_SPECIFIED_TWICE).

The reason the assert was triggered, was that lex->no_error was set to TRUE
during JOIN::optimize() because of IGNORE. This causes all errors to be ignored.
However, not all errors can be ignored. Some, such as ER_FIELD_SPECIFIED_TWICE
will cause the INSERT to fail no matter what. But since lex->no_error was set,
the critical errors were ignored, the INSERT failed and neither OK nor the
error message was sent to the client.

This patch fixes the problem by temporarily turning off lex->no_error in
places where errors cannot be ignored during processing of INSERT ... SELECT.

Test case added to insert.test.

1 files changed, 25 insertions, 0 deletions

diff --git a/mysql-test/t/insert.test b/mysql-test/t/insert.test
index 8f9ed6c7d06..152f43a671d 100644
--- a/mysql-test/t/insert.test
+++ b/mysql-test/t/insert.test
@@ -499,3 +499,28 @@ DROP TABLE t1, t2;
 
 --echo End of 5.0 tests.
 
+
+--echo #
+--echo # Bug#54106 assert in Protocol::end_statement,
+--echo #           INSERT IGNORE ... SELECT ... UNION SELECT ...
+--echo #
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+--enable_warnings
+
+CREATE TABLE t1 (a INT);
+
+--error ER_FIELD_SPECIFIED_TWICE
+INSERT INTO t1 (a, a) VALUES (1, 1);
+# Verify that ER_FIELD_SPECIFIED_TWICE is not ignorable
+--error ER_FIELD_SPECIFIED_TWICE
+INSERT IGNORE t1 (a, a) VALUES (1, 1);
+
+--error ER_FIELD_SPECIFIED_TWICE
+INSERT IGNORE t1 (a, a) SELECT 1,1;
+# Used to cause an assert
+--error ER_FIELD_SPECIFIED_TWICE
+INSERT IGNORE t1 (a, a) SELECT 1,1 UNION SELECT 2,2;
+
+DROP TABLE t1;