Folders: Return `409 Conflict` status when folder already exists (#36429)

* Return 409 Conflict when trying to post folder that already exists

* Fix tests

* Update documentation for new error message in folders api

docs/sources/http_api/folder.md

@@ -154,6 +154,7 @@ Status Codes:
 - **400** – Errors (invalid json, missing or invalid fields, etc)
 - **401** – Unauthorized
 - **403** – Access Denied
+- **409** - Folder already exists
 
 ## Update folder
 

pkg/api/folder.go

@@ -147,8 +147,6 @@ func ToFolderErrorResponse(err error) response.Response {
 	}
 
 	if errors.Is(err, models.ErrFolderTitleEmpty) ||
-		errors.Is(err, models.ErrFolderSameNameExists) ||
-		errors.Is(err, models.ErrFolderWithSameUIDExists) ||
 		errors.Is(err, models.ErrDashboardTypeMismatch) ||
 		errors.Is(err, models.ErrDashboardInvalidUid) ||
 		errors.Is(err, models.ErrDashboardUidTooLong) {
@@ -163,6 +161,11 @@ func ToFolderErrorResponse(err error) response.Response {
 		return response.JSON(404, util.DynMap{"status": "not-found", "message": models.ErrFolderNotFound.Error()})
 	}
 
+	if errors.Is(err, models.ErrFolderSameNameExists) ||
+		errors.Is(err, models.ErrFolderWithSameUIDExists) {
+		return response.Error(409, err.Error(), nil)
+	}
+
 	if errors.Is(err, models.ErrFolderVersionMismatch) {
 		return response.JSON(412, util.DynMap{"status": "version-mismatch", "message": models.ErrFolderVersionMismatch.Error()})
 	}

pkg/api/folder_test.go

@@ -46,9 +46,9 @@ func TestFoldersAPIEndpoint(t *testing.T) {
 			Error              error
 			ExpectedStatusCode int
 		}{
-			{Error: models.ErrFolderWithSameUIDExists, ExpectedStatusCode: 400},
+			{Error: models.ErrFolderWithSameUIDExists, ExpectedStatusCode: 409},
 			{Error: models.ErrFolderTitleEmpty, ExpectedStatusCode: 400},
-			{Error: models.ErrFolderSameNameExists, ExpectedStatusCode: 400},
+			{Error: models.ErrFolderSameNameExists, ExpectedStatusCode: 409},
 			{Error: models.ErrDashboardInvalidUid, ExpectedStatusCode: 400},
 			{Error: models.ErrDashboardUidTooLong, ExpectedStatusCode: 400},
 			{Error: models.ErrFolderAccessDenied, ExpectedStatusCode: 403},
@@ -102,9 +102,9 @@ func TestFoldersAPIEndpoint(t *testing.T) {
 			Error              error
 			ExpectedStatusCode int
 		}{
-			{Error: models.ErrFolderWithSameUIDExists, ExpectedStatusCode: 400},
+			{Error: models.ErrFolderWithSameUIDExists, ExpectedStatusCode: 409},
 			{Error: models.ErrFolderTitleEmpty, ExpectedStatusCode: 400},
-			{Error: models.ErrFolderSameNameExists, ExpectedStatusCode: 400},
+			{Error: models.ErrFolderSameNameExists, ExpectedStatusCode: 409},
 			{Error: models.ErrDashboardInvalidUid, ExpectedStatusCode: 400},
 			{Error: models.ErrDashboardUidTooLong, ExpectedStatusCode: 400},
 			{Error: models.ErrFolderAccessDenied, ExpectedStatusCode: 403},