grafana_folder: make uid field computed when not specified (#2314)

* grafana_folder: make uid field computed when not specified

Add Computed: true to uid field schema to allow it to be populated from API
response when not provided by user. This enables the data source to be
used in resource references that depend on the uid value.

* Add grafana version check.

Author: pstibrany

internal/resources/grafana/data_source_folder.go

@@ -30,6 +30,7 @@ func datasourceFolder() *common.DataSource {
 			"uid": {
 				Type:        schema.TypeString,
 				Optional:    true,
+				Computed:    true, // If not set by user, this will be populated by reading the folder.
 				Description: "The uid of the folder. If not set, only the title of the folder is used to find the folder.",
 			},
 			"prevent_destroy_if_not_empty": nil,

internal/resources/grafana/data_source_folder_test.go

@@ -257,3 +257,53 @@ data "grafana_folder" "f3" {
 }
 `, name)
 }
+
+func TestAccDatasourceFolderUidSetCorrectly(t *testing.T) {
+	// Test uses nested folders feature, which was introduced in Grafana 10 (behind feature-toggle) and made GA in Grafana 11.
+	testutils.CheckOSSTestsEnabled(t, ">=10.3.0")
+
+	var folder models.Folder
+	randomName := acctest.RandStringFromCharSet(6, acctest.CharSetAlpha)
+
+	resource.ParallelTest(t, resource.TestCase{
+		ProtoV5ProviderFactories: testutils.ProtoV5ProviderFactories,
+		CheckDestroy: resource.ComposeTestCheckFunc(
+			folderCheckExists.destroyed(&folder, nil),
+		),
+		Steps: []resource.TestStep{
+			{
+				// Find folder by title. We should get correct uid back.
+				Config: fmt.Sprintf(`
+					resource "grafana_folder" "folder" {
+						title = "%[1]s"
+					}
+					data "grafana_folder" "test" {
+						depends_on = ["grafana_folder.folder"]
+						title = "%[1]s"		
+					}
+					resource "grafana_folder" "nested_folder" {
+						title = "%[1]s Nested"
+						parent_folder_uid = data.grafana_folder.test.uid
+					}
+				`, randomName),
+				Check: resource.ComposeTestCheckFunc(
+					folderCheckExists.exists("grafana_folder.folder", &folder),
+					resource.TestCheckResourceAttr("grafana_folder.nested_folder", "title", randomName+" Nested"),
+					// Next line doesn't work, because resource.TestCheckResourceAttr is called too early -- before folder.UID is set.
+					//	   resource.TestCheckResourceAttr("grafana_folder.nested_folder", "parent_folder_uid", folder.UID)
+					//
+					// This works:
+					resource.TestCheckResourceAttrWith("grafana_folder.nested_folder", "parent_folder_uid", func(value string) error {
+						if folder.UID == "" {
+							return fmt.Errorf("grafana_folder.folder.uid should not be empty")
+						}
+						if value == folder.UID {
+							return nil
+						}
+						return fmt.Errorf("expected uid to be %q but got %q", folder.UID, value)
+					}),
+				),
+			},
+		},
+	})
+}