Fixing varbinary (varbinary(XX)) schema migration for mysql to map to correct spanner type with length BYTES(XX) (#1164)

* Fixing varbinary (varbinary(XX)) schema migration for mysql to map to correct spanner type with length BYTES(XX)

* Only changing varbinary type

* Updating integration test

Author: darshan-sj

sources/mysql/mysqldump_test.go

@@ -40,7 +40,7 @@ func TestProcessMySQLDump_Scalar(t *testing.T) {
 		ty       string
 		expected ddl.Type
 	}{
-		{"varbinary(100)", ddl.Type{Name: ddl.Bytes, Len: ddl.MaxLength}},
+		{"varbinary(100)", ddl.Type{Name: ddl.Bytes, Len: int64(100)}},
 		{"bigint", ddl.Type{Name: ddl.Int64}},
 		{"bool", ddl.Type{Name: ddl.Bool}},
 		{"boolean", ddl.Type{Name: ddl.Bool}},

sources/mysql/toddl.go

@@ -188,13 +188,23 @@ func toSpannerTypeInternal(srcType schema.Type, spType string) (ddl.Type, []inte
 		default:
 			return ddl.Type{Name: ddl.JSON}, nil
 		}
-	case "binary", "varbinary":
+	case "binary":
 		switch spType {
 		case ddl.String:
 			return ddl.Type{Name: ddl.String, Len: ddl.MaxLength}, nil
 		default:
 			return ddl.Type{Name: ddl.Bytes, Len: ddl.MaxLength}, nil
 		}
+	case "varbinary":
+		switch spType {
+		case ddl.String:
+			return ddl.Type{Name: ddl.String, Len: ddl.MaxLength}, nil
+		default:
+			if len(srcType.Mods) > 0 {
+				return ddl.Type{Name: ddl.Bytes, Len: srcType.Mods[0]}, nil
+			}
+			return ddl.Type{Name: ddl.Bytes, Len: ddl.MaxLength}, nil
+		}
 	case "tinyblob", "mediumblob", "blob", "longblob":
 		switch spType {
 		case ddl.String:

sources/mysql/toddl_test.go

@@ -103,6 +103,13 @@ func TestToSpannerTypeInternal(t *testing.T) {
 	if errCheck != nil {
 		t.Errorf("Error in binary to default conversion")
 	}
+	spType, errCheck := toSpannerTypeInternal(schema.Type{"varbinary", []int64{10}, []int64{}}, "BYTES")
+	if errCheck != nil {
+		t.Errorf("Error in binary to default conversion")
+	}
+	assert.Equal(t, "BYTES", spType.Name)
+	assert.Equal(t, int64(10), spType.Len)
+	assert.Equal(t, false, spType.IsArray)
 	_, errCheck = toSpannerTypeInternal(schema.Type{"blob", []int64{1, 2, 3}, []int64{1, 2, 3}}, "STRING")
 	if errCheck != nil {
 		t.Errorf("Error in blob to string conversion")