d2cli: fix nested layer navigation in watch mode

ci/release/changelogs/next.md

@@ -19,3 +19,4 @@
 - CLI: Watch mode uses correct backlinks (`_` usages) [#2058](https://github.com/terrastruct/d2/pull/2058)
 - Vars: Spread variables are inserted in place instead of appending to end of scope [#2062](https://github.com/terrastruct/d2/pull/2062)
 - Imports: fix local icon imports from files that are imported [#2066](https://github.com/terrastruct/d2/pull/2066)
+- CLI: fixes edge case of watch mode links to nested board that had more nested boards not working [#2070](https://github.com/terrastruct/d2/pull/2070)

d2cli/watch.go

@@ -521,6 +521,7 @@ func (w *watcher) handleRoot(hw http.ResponseWriter, r *http.Request) {
 		boardPath = boardPath[:idx]
 	}
 	// if path is "/index", we just want "/"
+	boardPath = strings.TrimSuffix(boardPath, "/index")
 	if boardPath == "index" {
 		boardPath = ""
 	}

e2etests-cli/main_test.go

@@ -1045,8 +1045,72 @@ layers: {
 				aRE := regexp.MustCompile(`href=\\"([^\"]*)\\"`)
 				match := aRE.FindSubmatch(msg)
 				assert.Equal(t, 2, len(match))
-				assert.Equal(t, "index.svg", string(match[1]))
 
+				link := string(match[1])
+
+				err = getWatchPage(ctx, t, fmt.Sprintf("http://%s/%s", watchURL, link))
+				assert.Success(t, err)
+				_, _, err = c.Read(ctx)
+				assert.Success(t, err)
+				successRE := regexp.MustCompile(`broadcasting update to 1 client`)
+				_, err = waitLogs(ctx, stderr, successRE)
+				assert.Success(t, err)
+			},
+		},
+		{
+			name:   "watch-nested-layer-link",
+			serial: true,
+			run: func(t *testing.T, ctx context.Context, dir string, env *xos.Env) {
+				writeFile(t, dir, "index.d2", `
+a: {
+  link: layers.b
+}
+
+layers: {
+  b: {
+    hi
+
+    layers: {
+      hey: {
+        hey
+      }
+    }
+  }
+}`)
+				stderr := &stderrWrapper{}
+				tms := testMain(dir, env, "--watch", "--browser=0", "index.d2")
+				tms.Stderr = stderr
+
+				tms.Start(t, ctx)
+				defer func() {
+					// Manually close, since watcher is daemon
+					err := tms.Signal(ctx, os.Interrupt)
+					assert.Success(t, err)
+				}()
+
+				// Wait for watch server to spin up and listen
+				urlRE := regexp.MustCompile(`127.0.0.1:([0-9]+)`)
+				watchURL, err := waitLogs(ctx, stderr, urlRE)
+				assert.Success(t, err)
+
+				stderr.Reset()
+
+				// Start a client
+				c, _, err := websocket.Dial(ctx, fmt.Sprintf("ws://%s/watch", watchURL), nil)
+				assert.Success(t, err)
+				defer c.CloseNow()
+
+				// Get the link
+				_, msg, err := c.Read(ctx)
+				aRE := regexp.MustCompile(`href=\\"([^\"]*)\\"`)
+				match := aRE.FindSubmatch(msg)
+				assert.Equal(t, 2, len(match))
+				link := string(match[1])
+
+				err = getWatchPage(ctx, t, fmt.Sprintf("http://%s/%s", watchURL, link))
+				assert.Success(t, err)
+				_, _, err = c.Read(ctx)
+				assert.Success(t, err)
 				successRE := regexp.MustCompile(`broadcasting update to 1 client`)
 				_, err = waitLogs(ctx, stderr, successRE)
 				assert.Success(t, err)