fix(debugger): keep execution highlights synchronized (#681)

Inline debugger values looked up source identifiers in a plain object, so a name like toString on a nearby line resolved to an inherited Object.prototype member and crashed the editor's inline-values plugin. The execution-point subscription lived in that plugin, so after the crash the highlighted line stayed on the old position while the stack had moved on, and resume or stop did not clear it.

Locals are now kept in a prototype-free dictionary and looked up by own property, and the execution point is synced by its own plugin so an inline-value failure can't freeze it; hidden editors resync when remounted. Stepping, resume, run to cursor, reset frame and smart step clear the old execution point as soon as the request is sent, stale stack/locals responses from a previous stop are ignored, and another thread's continued event no longer clears the selected thread's execution point.

Fixes #668

src/features/debugger/__tests__/editor.test.ts

@@ -166,6 +166,60 @@ describe("breakpoint gutter clicks", () => {
 });
 
 describe("execution point", () => {
+  it("keeps the execution line synchronized if inline rendering throws", async () => {
+    useExecutionPoint.setState({ path: null, values: {} });
+    const errors: unknown[] = [];
+    const view = new EditorView({
+      state: EditorState.create({
+        doc: "x\nx\nx",
+        extensions: [executionPoint(ctx), EditorView.exceptionSink.of((e) => errors.push(e))],
+      }),
+      parent: document.body,
+    });
+    views.push(view);
+    const values: Record<string, string> = Object.defineProperty({}, "x", {
+      enumerable: true,
+      get() {
+        throw new Error("inline rendering failed");
+      },
+    });
+    useExecutionPoint.setState({ path: ctx.path, line: 0, top: true, values });
+    await flush();
+    expect(errors).toHaveLength(1);
+    useExecutionPoint.setState({ line: 2, values: {} });
+    await flush();
+    expect(view.dom.querySelectorAll(".cm-line")[2]!.className).toContain(styles.execLine);
+    useExecutionPoint.setState({ path: null });
+    await flush();
+    expect(view.dom.querySelector(`.${styles.execLine}`)).toBeNull();
+  });
+
+  it("keeps refreshing the execution line around Object.prototype names", async () => {
+    useExecutionPoint.setState({ path: null, values: {} });
+    const view = makeView("String text = Integer.toString(40);\nint count = 40;\ncount++;\ncount++;");
+    useExecutionPoint.setState({ path: ctx.path, line: 1, top: true, values: { text: "40" } });
+    await flush();
+    useExecutionPoint.setState({ line: 3, values: { text: "40", count: "42" } });
+    await flush();
+    expect(view.dom.querySelector(`.${styles.execLine}`)?.textContent).toContain("count++");
+    useExecutionPoint.setState({ path: null, values: {} });
+    await flush();
+    expect(view.dom.querySelector(`.${styles.execLine}`)).toBeNull();
+  });
+
+  it.each([2, null])("refreshes a cached editor state when remounted at %s", async (line) => {
+    useExecutionPoint.setState({ path: ctx.path, line: 0, top: true, values: {} });
+    const view = makeView("first\nsecond\nthird");
+    const state = view.state;
+    view.destroy();
+    views.splice(views.indexOf(view), 1);
+    useExecutionPoint.setState({ path: line == null ? null : ctx.path, line: line ?? 0, values: {} });
+    const restored = new EditorView({ state, parent: document.body });
+    views.push(restored);
+    await flush();
+    expect(restored.dom.querySelector(`.${styles.execLine}`)?.textContent ?? null).toBe(line == null ? null : "third");
+  });
+
   it("highlights the suspended line and shows inline values", async () => {
     const view = makeView("x = 1\ny = x + 1\nprint(y)");
     useExecutionPoint.setState({ path: ctx.path, line: 1, top: true, values: { x: "1", y: "2" } });