storagezone: use d.Partial in Update instead of revertUpdateValues

internal/provider/resource_storagezone.go

@@ -272,14 +272,11 @@ func resourceStorageZoneUpdate(ctx context.Context, d *schema.ResourceData, meta
 
 	updateErr := clt.StorageZone.Update(ctx, id, storageZone)
 	if updateErr != nil {
-		// if our update failed then revert our values to their original
-		// state so that we can run an apply again.
-		revertErr := revertUpdateValues(d)
-
-		if revertErr != nil {
-			return diagsErrFromErr("updating storage zone via API failed", revertErr)
-		}
-
+		// The storagezone contains fields /custom_404_file_path) that are only updated by the
+		// provider and not retrieved via ReadContext(). This causes that we run into the bug
+		// https://github.com/hashicorp/terraform-plugin-sdk/issues/476.
+		// As workaround d.Partial(true) is called.
+		d.Partial(true)
 		return diagsErrFromErr("updating storage zone via API failed", updateErr)
 	}
 
@@ -370,23 +367,6 @@ func storageZoneToResource(sz *bunny.StorageZone, d *schema.ResourceData) error
 	return nil
 }
 
-func revertUpdateValues(d *schema.ResourceData) error {
-	o, _ := d.GetChange(keyOriginURL)
-	if err := d.Set(keyOriginURL, o); err != nil {
-		return err
-	}
-	o, _ = d.GetChange(keyCustom404FilePath)
-	if err := d.Set(keyCustom404FilePath, o); err != nil {
-		return err
-	}
-	o, _ = d.GetChange(keyRewrite404To200)
-	if err := d.Set(keyRewrite404To200, o); err != nil {
-		return err
-	}
-
-	return nil
-}
-
 // storageZoneFromResource returns a StorageZoneUpdateOptions API type that
 // has fields set to the values in d.
 func storageZoneFromResource(d *schema.ResourceData) *bunny.StorageZoneUpdateOptions {

internal/provider/resource_storagezone_test.go

@@ -295,6 +295,61 @@ func checkSzState(t *testing.T, resourceName string, wanted *bunny.StorageZone)
 	}
 }
 
+// TestAccFailedUpdateDoesNotApplychanges tests the scenario described in
+// https://github.com/5-stones/terraform-provider-bunny/pull/1#discussion_r898134629
+func TestAccFailedUpdateDoesNotApplychanges(t *testing.T) {
+	attrs := storageZoneWanted{
+		TerraformResourceName: "bunny_storagezone.mytest1",
+		Name:                  randResourceName(),
+		Region:                "DE",
+	}
+
+	resource.Test(t, resource.TestCase{
+		Providers: testProviders,
+		Steps: []resource.TestStep{
+			{
+				Config: fmt.Sprintf(`
+resource "bunny_storagezone" "mytest1" {
+	name = "%s"
+	region = "%s"
+	custom_404_file_path = "/error.html"
+}`,
+					attrs.Name,
+					attrs.Region,
+				),
+				Check: checkBasicStorageZoneAPIState(&attrs),
+			},
+			// change custom_404_file_path to a value that spawns a generation error on bunny side
+			{
+				Config: fmt.Sprintf(`
+resource "bunny_storagezone" "mytest1" {
+	name = "%s"
+	region = "%s"
+	custom_404_file_path = "abc"
+}`,
+					attrs.Name,
+					attrs.Region,
+				),
+				Check:       checkBasicStorageZoneAPIState(&attrs),
+				ExpectError: regexp.MustCompile(".*updating storage zone via API failed.*"),
+			},
+			{
+				Config: fmt.Sprintf(`
+resource "bunny_storagezone" "mytest1" {
+	name = "%s"
+	region = "%s"
+	custom_404_file_path = "/error.html"
+}`,
+					attrs.Name,
+					attrs.Region,
+				),
+				PlanOnly: true,
+			},
+		},
+		CheckDestroy: checkStorageZoneNotExists(attrs.Name),
+	})
+}
+
 // storageZoneDiffIgnoredFields contains a list of fieldsnames in a bunny.StorageZone struct that are ignored by szDiff.
 var storageZoneDiffIgnoredFields = map[string]struct{}{
 	"ID":               {}, // computed field