Workaround and test by treating settings as omitempty (#656)

examples/resources/grafana_contact_point/_acc_default_settings.tf

@@ -0,0 +1,8 @@
+resource "grafana_contact_point" "default_settings" {
+    name = "Default Settings"
+
+    slack {
+        token = "xoxb-token"
+        recipient = "#channel"
+    }
+}

grafana/resource_alerting_contact_point.go

@@ -208,14 +208,25 @@ func unpackContactPoints(data *schema.ResourceData) []gapi.ContactPoint {
 	for _, n := range notifiers {
 		if points, ok := data.GetOk(n.meta().field); ok {
 			for _, p := range points.([]interface{}) {
-				result = append(result, n.unpack(p, name))
+				result = append(result, unpackPointConfig(n, p, name))
 			}
 		}
 	}
 
 	return result
 }
 
+func unpackPointConfig(n notifier, data interface{}, name string) gapi.ContactPoint {
+	pt := n.unpack(data, name)
+	// Treat settings like `omitempty`. Workaround for versions affected by https://github.com/grafana/grafana/issues/55139
+	for k, v := range pt.Settings {
+		if v == "" {
+			delete(pt.Settings, k)
+		}
+	}
+	return pt
+}
+
 func packContactPoints(ps []gapi.ContactPoint, data *schema.ResourceData) error {
 	pointsPerNotifier := map[notifier][]interface{}{}
 	for _, p := range ps {

grafana/resource_alerting_contact_point_test.go

@@ -265,6 +265,35 @@ func TestAccContactPoint_notifiers(t *testing.T) {
 					resource.TestCheckResourceAttr("grafana_contact_point.receiver_types", "wecom.0.title", "title"),
 				),
 			},
+			// Test blank fields in settings should be omitted.
+			{
+				Config: testAccExample(t, "resources/grafana_contact_point/_acc_default_settings.tf"),
+				Check: resource.ComposeTestCheckFunc(
+					testContactPointCheckExists("grafana_contact_point.default_settings", &points, 1),
+					resource.TestCheckResourceAttr("grafana_contact_point.default_settings", "slack.#", "1"),
+					resource.TestCheckNoResourceAttr("grafana_contact_point.default_settings", "slack.endpoint_url"),
+					func(s *terraform.State) error {
+						rname := "grafana_contact_point.default_settings"
+						rs, ok := s.RootModule().Resources[rname]
+						if !ok {
+							return fmt.Errorf("resource not found: %s, resources: %#v", rname, s.RootModule().Resources)
+						}
+						uid := rs.Primary.ID
+
+						client := testAccProvider.Meta().(*client).gapi
+						pt, err := client.ContactPoint(uid)
+						if err != nil {
+							return fmt.Errorf("error getting resource: %w", err)
+						}
+
+						if val, ok := pt.Settings["endpointUrl"]; ok {
+							return fmt.Errorf("endpointUrl was still present in the settings when it should have been omitted. value: %#v", val)
+						}
+
+						return nil
+					},
+				),
+			},
 		},
 	})
 }