From 57372b7f47afc328ffc6e507a36f87ed43e02aed Mon Sep 17 00:00:00 2001
From: Dave Stubbs <dave.stubbs@countingup.com>
Date: Thu, 16 Nov 2017 15:28:07 +0000
Subject: [PATCH] Fix Valuers by returning driver.ErrSkip if couldn't convert
 type internally

Added a test that Valuer types are handled correctly. This test fails without the fix.

CheckNamedValue code was included recently and breaks existing applications:
https://github.com/go-sql-driver/mysql/pull/690

Reported in:
https://github.com/go-sql-driver/mysql/issues/708
---
 AUTHORS            |  1 +
 connection_go18.go |  6 +++++-
 driver_test.go     | 30 ++++++++++++++++++++++++++++++
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/AUTHORS b/AUTHORS
index c405b8912..1ace1fa45 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -71,6 +71,7 @@ Zhenye Xie <xiezhenye at gmail.com>
 # Organizations
 
 Barracuda Networks, Inc.
+Counting Ltd.
 Google Inc.
 Keybase Inc.
 Pivotal Inc.
diff --git a/connection_go18.go b/connection_go18.go
index 1306b70b7..65cc63ef2 100644
--- a/connection_go18.go
+++ b/connection_go18.go
@@ -197,6 +197,10 @@ func (mc *mysqlConn) startWatcher() {
 }
 
 func (mc *mysqlConn) CheckNamedValue(nv *driver.NamedValue) (err error) {
-	nv.Value, err = converter{}.ConvertValue(nv.Value)
+	value, err := converter{}.ConvertValue(nv.Value)
+	if err != nil {
+		return driver.ErrSkip
+	}
+	nv.Value = value
 	return
 }
diff --git a/driver_test.go b/driver_test.go
index f6965b191..392e752a3 100644
--- a/driver_test.go
+++ b/driver_test.go
@@ -499,6 +499,36 @@ func TestString(t *testing.T) {
 	})
 }
 
+type testValuer struct {
+	value string
+}
+
+func (tv testValuer) Value() (driver.Value, error) {
+	return tv.value, nil
+}
+
+func TestValuer(t *testing.T) {
+	runTests(t, dsn, func(dbt *DBTest) {
+		in := testValuer{"a_value"}
+		var out string
+		var rows *sql.Rows
+
+		dbt.mustExec("CREATE TABLE test (value VARCHAR(255)) CHARACTER SET utf8")
+		dbt.mustExec("INSERT INTO test VALUES (?)", in)
+		rows = dbt.mustQuery("SELECT value FROM test")
+		if rows.Next() {
+			rows.Scan(&out)
+			if in.value != out {
+				dbt.Errorf("Valuer: %v != %s", in, out)
+			}
+		} else {
+			dbt.Errorf("Valuer: no data")
+		}
+
+		dbt.mustExec("DROP TABLE IF EXISTS test")
+	})
+}
+
 type timeTests struct {
 	dbtype  string
 	tlayout string