fix(tags): return empty array after final pagination marker

Signed-off-by: Joonas Bergius <joonas@defenseunicorns.com>

registry/handlers/api_test.go

@@ -546,6 +546,12 @@ func TestTagsAPI(t *testing.T) {
 				"sb71y",
 			}},
 		},
+		{
+			name:               "page after last tag",
+			queryParams:        url.Values{"last": []string{"sb71y"}, "n": []string{"1"}},
+			expectedStatusCode: http.StatusOK,
+			expectedBody:       tagsAPIResponse{Name: imageName.Name(), Tags: []string{}},
+		},
 		{
 			name:               "page size bigger than full list",
 			queryParams:        url.Values{"n": []string{"100"}},
@@ -601,7 +607,7 @@ func TestTagsAPI(t *testing.T) {
 					t.Fatalf("unexpected error decoding response body: %v", err)
 				}
 				if !reflect.DeepEqual(body, test.expectedBody) {
-					t.Fatalf("expected response body to be:\n%+v\ngot:\n%+v", test.expectedBody, body)
+					t.Fatalf("expected response body to be:\n%#v\ngot:\n%#v", test.expectedBody, body)
 				}
 			}
 

registry/handlers/tags.go

@@ -79,7 +79,9 @@ func (th *tagsHandler) GetTags(w http.ResponseWriter, r *http.Request) {
 			// err is either io.EOF
 			moreEntries = false
 		}
-		filled = returnedTags
+		if returnedTags != nil {
+			filled = returnedTags
+		}
 	}
 
 	w.Header().Set("Content-Type", "application/json")