Merge pull request #2207 from alixander/import-icon-bug

d2ir: fix icon substitutions

ci/release/changelogs/next.md

@@ -5,3 +5,5 @@
 - Composition: links pointing to own board are purged [#2203](https://github.com/terrastruct/d2/pull/2203)
 
 #### Bugfixes ⛑️
+
+- Imports: fixes using substitutions in `icon` values [#2207](https://github.com/terrastruct/d2/pull/2207)

d2ir/compile.go

@@ -984,6 +984,10 @@ func (c *compiler) extendLinks(m *Map, importF *Field, importDir string) {
 		}
 		if f.Name == "icon" && f.Primary() != nil {
 			val := f.Primary().Value.ScalarString()
+			// It's likely a substitution
+			if val == "" {
+				continue
+			}
 			u, err := url.Parse(html.UnescapeString(val))
 			isRemoteImg := err == nil && strings.HasPrefix(u.Scheme, "http")
 			if isRemoteImg {

e2etests-cli/main_test.go

@@ -821,6 +821,33 @@ a.b.c.d
 				assert.Testdata(t, ".svg", svg)
 			},
 		},
+		{
+			name: "chain_icon_import",
+			run: func(t *testing.T, ctx context.Context, dir string, env *xos.Env) {
+				writeFile(t, dir, "hello-world.d2", `...@y
+hello.class: Ecs`)
+				writeFile(t, dir, "y.d2", `
+...@x
+classes: {
+    Ecs: {
+        shape: "circle"
+        icon: ${icons.ecs}
+    }
+}
+`)
+				writeFile(t, dir, "x.d2", `
+vars: {
+    icons: {
+        ecs: "https://icons.terrastruct.com/aws%2FCompute%2FAmazon-Elastic-Container-Service.svg"
+    }
+}
+`)
+				err := runTestMain(t, ctx, dir, env, filepath.Join(dir, "hello-world.d2"))
+				assert.Success(t, err)
+				svg := readFile(t, dir, "hello-world.svg")
+				assert.Testdata(t, ".svg", svg)
+			},
+		},
 		{
 			name: "board_import",
 			run: func(t *testing.T, ctx context.Context, dir string, env *xos.Env) {