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/state.ts

@@ -644,6 +644,7 @@ export function selectSession(id: DebugSessionId) {
 
 export async function selectThread(id: DebugSessionId, threadId: number) {
   patch(id, { selectedThread: threadId, frames: [], selectedFrame: null });
+  updateExecutionPoint();
   await loadFrames(id, threadId, true);
 }
 
@@ -652,7 +653,7 @@ export function selectFrame(id: DebugSessionId, frameId: number, reveal = true)
   updateExecutionPoint();
   const s = useDebug.getState().sessions[id];
   const frame = s?.frames.find((f) => f.id === frameId);
-  if (reveal && frame?.path) {
+  if (reveal && useDebug.getState().active === id && frame?.path) {
     void maybeEditorService()?.openFile(frame.path, {
       selection: { line: frame.line, col: frame.column },
       focus: false,
@@ -662,6 +663,7 @@ export function selectFrame(id: DebugSessionId, frameId: number, reveal = true)
 }
 
 async function loadFrames(id: DebugSessionId, threadId: number, reveal: boolean) {
+  const before = useDebug.getState().sessions[id];
   let frames: StackFrame[] = [];
   try {
     frames = await call(commands.debugStackTrace(id, threadId));
@@ -669,7 +671,7 @@ async function loadFrames(id: DebugSessionId, threadId: number, reveal: boolean)
     console.warn("stackTrace failed", e);
   }
   const s = useDebug.getState().sessions[id];
-  if (!s || s.status !== "paused" || s.selectedThread !== threadId) return;
+  if (!s || s.status !== "paused" || s.selectedThread !== threadId || s.frames !== before?.frames) return;
   patch(id, { frames });
   const top = frames.find((f) => f.path && f.presentationHint !== "label") ?? frames[0];
   if (top?.path && (s.stopReason === "breakpoint" || s.stopReason === "function breakpoint")) {
@@ -707,19 +709,21 @@ async function loadThreads(id: DebugSessionId) {
 
 /** Locals of `frameId` (first non-expensive scope) for inline values. */
 async function loadLocals(id: DebugSessionId, frameId: number) {
-  const values: Record<string, string> = {};
+  const frames = useDebug.getState().sessions[id]?.frames;
+  const values: Record<string, string> = Object.create(null);
   try {
     const scopes = await call(commands.debugScopes(id, frameId));
     const scope = scopes.find((sc) => !sc.expensive);
     if (scope) {
       const vars = await call(commands.debugVariables(id, scope.variablesReference));
-      for (const v of vars) if (v.name && !(v.name in values)) values[v.name] = v.value;
+      for (const v of vars) if (v.name && !Object.hasOwn(values, v.name)) values[v.name] = v.value;
     }
   } catch {
     // No inline values.
   }
   const s = useDebug.getState().sessions[id];
-  if (useDebug.getState().active !== id || s?.selectedFrame !== frameId) return;
+  if (useDebug.getState().active !== id || s?.status !== "paused" || s.selectedFrame !== frameId || s.frames !== frames)
+    return;
   useExecutionPoint.setState({ values });
 }
 
@@ -729,6 +733,7 @@ export async function showExecutionPoint(id: DebugSessionId) {
   if (!s || s.status !== "paused" || s.stoppedThread == null) return;
   if (s.selectedThread !== s.stoppedThread) {
     patch(id, { selectedThread: s.stoppedThread, frames: [], selectedFrame: null });
+    updateExecutionPoint();
     await loadFrames(id, s.stoppedThread, false);
   }
   const cur = useDebug.getState().sessions[id];
@@ -757,6 +762,32 @@ export function updateExecutionPoint() {
   useExecutionPoint.setState({ path: frame.path, line: frame.line, top, values: {} });
 }
 
+/** Invalidate suspended data before sending a command that resumes execution. */
+export async function resumeExecution(id: DebugSessionId, request: () => Promise<unknown>) {
+  const before = useDebug.getState().sessions[id];
+  if (!before || before.status !== "paused") return;
+  const frames: StackFrame[] = [];
+  patch(id, { status: "running", frames, selectedFrame: null, stoppedThread: null });
+  updateExecutionPoint();
+  try {
+    await request();
+  } catch (e) {
+    const current = useDebug.getState().sessions[id];
+    // A stop/continue/termination received during the request owns the newer state.
+    if (current?.status === "running" && current.frames === frames) {
+      patch(id, {
+        status: before.status,
+        frames: before.frames,
+        selectedFrame: before.selectedFrame,
+        stoppedThread: before.stoppedThread,
+      });
+      updateExecutionPoint();
+      if (before.selectedFrame != null) void loadLocals(id, before.selectedFrame);
+    }
+    throw e;
+  }
+}
+
 // --- watches -------------------------------------------------------------------
 
 export function addWatch(expression: string) {
@@ -862,6 +893,7 @@ export function handleDebugEvent(id: DebugSessionId, event: DebugEvent) {
       });
       useDebug.setState((st) => ({ active: id, stopSeq: st.stopSeq + 1 }));
       publishContext();
+      updateExecutionPoint();
       void loadThreads(id);
       void loadFrames(id, event.threadId, true);
       const dbg = workflowSettings().debugger;
@@ -876,6 +908,7 @@ export function handleDebugEvent(id: DebugSessionId, event: DebugEvent) {
     case "continued": {
       const cur = useDebug.getState().sessions[id]!;
       if (cur.status === "terminated") break;
+      if (!event.allThreadsContinued && event.threadId !== (cur.selectedThread ?? cur.stoppedThread)) break;
       patch(id, {
         status: "running",
         frames: [],