Broken connection is returned to pool after context has been canceled

[JakobJoonas]

Description

When context is canceled during the query, then it's not cleaned properly as its using go-sql-driver v1.5.0 instead of v1.6.0 (v1.6.0 supports IsValid(), which validates the connection before returning it to pool) go-sql-driver PR

Currently this step is skipped and pool gets canceled connections.

Steps to Reproduce

		dsn := fmt.Sprintf("root:root@tcp(%s:%d)/", address, port)

		// open connection with new relic wrapper
		db, err := sql.Open("nrmysql", dsn)
		assert.NoError(t, err)

		// Setup timeout of a query
		ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*50)
		defer cancel()

		// Get the connection
		conn, err := db.Conn(ctx)
		assert.NoError(t, err)

		// Execute the request, context will be canceled before this query manages to execute
		_, err = conn.ExecContext(ctx, "SELECT SLEEP(1)")
		assert.Error(t, err)

		// Close the connection
		// This only releases the connection, however does not validate if the connection is valid
		err = conn.Close()
		assert.NoError(t, err)

		// Pick a new connection from the pool (as connections are reused, then the previous one is picked)
		conn, err = db.Conn(context.Background())
		assert.NoError(t, err)

		// As we are reusing the broken connection, then this ping will fail.
		err = conn.PingContext(context.Background())
		assert.NoError(t, err)

		// Now change the driver from `nrmysql` to `mysql`
		// Make sure that go-sql-driver version is v1.6.0 and rerun the test, it should pass.

Expected Behavior

Before connection is passed back to the pool, it should be validated if it has been canceled

Your Environment

Go 1.17
github.com/go-sql-driver/mysql v1.6.0
github.com/newrelic/go-agent/v3/integrations/nrmysql v1.2.1

[iamemilio]

Thanks for filing this bug @JakobJoonas. It's always super helpful when there is a good reproducer attached. We will take a look at this and patch it up as soon as we can.

[iamemilio]

@JakobJoonas we totally lost sight of this. If I understand correctly, upgrading to github.com/go-sql-driver/mysql v1.6.0 should resolve this problem, right?