using string builder

Signed-off-by: Shlomi Noach <[email protected]>

go/vt/schemadiff/errors.go

@@ -394,11 +394,15 @@ type ViewDependencyUnresolvedError struct {
 }
 
 func (e *ViewDependencyUnresolvedError) Error() string {
-	s := make([]string, len(e.MissingReferencedEntities))
+	var b strings.Builder
+	b.WriteString(fmt.Sprintf("view %s has unresolved/loop dependencies: ", sqlescape.EscapeID(e.View)))
 	for i, entity := range e.MissingReferencedEntities {
-		s[i] = sqlescape.EscapeID(entity)
+		if i > 0 {
+			b.WriteString(", ")
+		}
+		sqlescape.WriteEscapeID(&b, entity)
 	}
-	return fmt.Sprintf("view %s has unresolved/loop dependencies: %s", sqlescape.EscapeID(e.View), strings.Join(s, ", "))
+	return b.String()
 }
 
 type InvalidColumnReferencedInViewError struct {

go/vt/schemadiff/schema_test.go

@@ -133,6 +133,7 @@ func TestNewSchemaFromQueriesUnresolvedMulti(t *testing.T) {
 	schema, err := NewSchemaFromQueries(NewTestEnv(), queries)
 	assert.Error(t, err)
 	assert.EqualError(t, err, (&ViewDependencyUnresolvedError{View: "v7", MissingReferencedEntities: []string{"v8", "t20", "v21"}}).Error())
+	assert.Equal(t, "view `v7` has unresolved/loop dependencies: `v8`, `t20`, `v21`", err.Error())
 	v := schema.sorted[len(schema.sorted)-1]
 	assert.IsType(t, &CreateViewEntity{}, v)
 	assert.Equal(t, "CREATE VIEW `v7` AS SELECT * FROM `v8`, `t2`, `t20`, `v21`", v.Create().CanonicalStatementString())