Merge pull request #555 from gavin-ts/fix-elk-panic

elk: fix panic with empty label on image/icon

ci/release/changelogs/next.md

@@ -9,4 +9,5 @@
 #### Bugfixes ⛑️
 
 - Restricts where `near` key constant values can be used, with good error messages, instead of erroring (e.g. setting `near: top-center` on a container would cause bad layouts or error). [#538](https://github.com/terrastruct/d2/pull/538)
+- Fixes an error during ELK layout when images had empty labels. [#555](https://github.com/terrastruct/d2/pull/555)
 - Fixes rendering classes and tables with empty headers. [#498](https://github.com/terrastruct/d2/pull/498)

d2layouts/d2elklayout/layout.go

@@ -147,8 +147,10 @@ func Layout(ctx context.Context, g *d2graph.Graph) (err error) {
 
 	walk(g.Root, nil, func(obj, parent *d2graph.Object) {
 		height := obj.Height
-		if obj.Attributes.Shape.Value == d2target.ShapeImage || obj.Attributes.Icon != nil {
-			height += float64(*obj.LabelHeight) + label.PADDING
+		if obj.LabelWidth != nil && obj.LabelHeight != nil {
+			if obj.Attributes.Shape.Value == d2target.ShapeImage || obj.Attributes.Icon != nil {
+				height += float64(*obj.LabelHeight) + label.PADDING
+			}
 		}
 
 		n := &ELKNode{

e2etests/regression_test.go

@@ -248,6 +248,20 @@ code: |go
     b := a + 7
     fmt.Printf("%d", b)
 |
+`,
+		},
+		{
+			name: "elk_img_empty_label_panic",
+			script: `
+img: {
+	label: ""
+	shape: image
+	icon: https://icons.terrastruct.com/infra/019-network.svg
+}
+ico: {
+	label: ""
+	icon: https://icons.terrastruct.com/infra/019-network.svg
+}
 `,
 		},
 	}