fix panic issue when extends.service is not present

Signed-off-by: Guillaume Lours <[email protected]>

Author: glours

loader/extends.go

@@ -68,7 +68,10 @@ func applyServiceExtends(ctx context.Context, name string, services map[string]a
 	)
 	switch v := extends.(type) {
 	case map[string]any:
-		ref = v["service"].(string)
+		ref, ok = v["service"].(string)
+		if !ok {
+			return nil, fmt.Errorf("extends.%s.service is required", name)
+		}
 		file = v["file"]
 		opts.ProcessEvent("extends", v)
 	case string:

loader/extends_test.go

@@ -184,6 +184,33 @@ services:
 	assert.NilError(t, err)
 }
 
+func TestExtendsWihtMissingService(t *testing.T) {
+	yaml := `
+name: test-extends-port
+services:
+  test:
+    image: test
+    extends:
+      file: testdata/extends/base.yaml
+`
+	abs, err := filepath.Abs(".")
+	assert.NilError(t, err)
+
+	_, err = LoadWithContext(context.Background(), types.ConfigDetails{
+		ConfigFiles: []types.ConfigFile{
+			{
+				Content:  []byte(yaml),
+				Filename: "(inline)",
+			},
+		},
+		WorkingDir: abs,
+	}, func(options *Options) {
+		options.ResolvePaths = false
+		options.SkipValidation = true
+	})
+	assert.Error(t, err, "extends.test.service is required")
+}
+
 func TestIncludeWithExtends(t *testing.T) {
 	yaml := `
 name: test-include-with-extends