detect self-reference and better report depends_on cycles

Signed-off-by: Nicolas De Loof <[email protected]>

Author: ndeloof

graph/cycle.go

@@ -50,8 +50,8 @@ func (g *graph[T]) checkCycle() error {
 func searchCycle[T any](path []string, v *vertex[T]) error {
 	names := utils.MapKeys(v.children)
 	for _, name := range names {
-		if i := slices.Index(path, name); i > 0 {
-			return fmt.Errorf("dependency cycle detected: %s", strings.Join(path[i:], " -> "))
+		if i := slices.Index(path, name); i >= 0 {
+			return fmt.Errorf("dependency cycle detected: %s -> %s", strings.Join(path[i:], " -> "), name)
 		}
 		ch := v.children[name]
 		err := searchCycle(append(path, name), ch)

graph/graph_test.go

@@ -325,7 +325,7 @@ func Test_detectCycle(t *testing.T) {
 	graph := exampleGraph()
 	graph.addEdge("B", "D")
 	err := graph.checkCycle()
-	assert.Error(t, err, "dependency cycle detected: D -> C -> B")
+	assert.Error(t, err, "dependency cycle detected: B -> D -> C -> B")
 }
 
 func TestWith_RootNodesAndUp(t *testing.T) {

loader/loader_test.go

@@ -2625,7 +2625,21 @@ func TestLoadDependsOnCycle(t *testing.T) {
 			},
 		},
 	})
-	assert.Error(t, err, "dependency cycle detected: service2 -> service3 -> service1", err)
+	assert.Error(t, err, "dependency cycle detected: service1 -> service2 -> service3 -> service1", err)
+}
+
+func TestLoadDependsOnSelf(t *testing.T) {
+	workingDir, err := os.Getwd()
+	assert.NilError(t, err)
+	_, err = LoadWithContext(context.Background(), types.ConfigDetails{
+		WorkingDir: filepath.Join(workingDir, "testdata"),
+		ConfigFiles: []types.ConfigFile{
+			{
+				Filename: filepath.Join(workingDir, "testdata", "compose-depends-on-self.yaml"),
+			},
+		},
+	})
+	assert.Error(t, err, "dependency cycle detected: service1 -> service1", err)
 }
 
 func TestLoadWithDependsOn(t *testing.T) {

loader/testdata/compose-depends-on-self.yaml

@@ -0,0 +1,6 @@
+name : depends-on-cycle
+services:
+  service1:
+    image: service1
+    depends_on:
+      - service1