fix(content): don't suppress non-extension unhandledrejection (#17)

Only call preventDefault() for unhandledrejection events attributable to LightSession; keep site errors visible in DevTools. Adds a small filter helper + unit tests.

Author: 11me

extension/src/content/content.ts

@@ -22,6 +22,7 @@ import {
 } from './status-bar';
 import { isEmptyChatView } from './chat-view';
 import { installUserCollapse, type UserCollapseController } from './user-collapse';
+import { isLightSessionRejection } from './rejection-filter';
 
 
 // ============================================================================
@@ -412,6 +413,23 @@ window.addEventListener('error', (event) => {
 });
 
 window.addEventListener('unhandledrejection', (event) => {
-  logError('Unhandled promise rejection:', event.reason);
-  event.preventDefault();
+  let extensionUrlPrefix: string | undefined;
+  try {
+    extensionUrlPrefix = browser?.runtime?.getURL?.('');
+  } catch {
+    extensionUrlPrefix = undefined;
+  }
+
+  // Do not suppress site (ChatGPT) errors. Only suppress if it clearly originates from LightSession.
+  const strictIsOurs = isLightSessionRejection(event.reason, extensionUrlPrefix);
+  const looseIsOurs = isLightSessionRejection(event.reason);
+
+  if (strictIsOurs || looseIsOurs) {
+    logError('Unhandled promise rejection:', event.reason);
+
+    // Only suppress default reporting if we are confident this originates from our extension.
+    if (strictIsOurs) {
+      event.preventDefault();
+    }
+  }
 });

extension/src/content/rejection-filter.ts

@@ -0,0 +1,49 @@
+/**
+ * Helpers for filtering global error events so we don't suppress site errors.
+ *
+ * The content script can observe `window` errors/rejections originating from the page.
+ * Calling `preventDefault()` on these events suppresses the browser's default reporting,
+ * so we must only suppress errors that are clearly caused by LightSession itself.
+ */
+
+export function isLightSessionRejection(
+  reason: unknown,
+  extensionUrlPrefix?: string,
+): boolean {
+  const parts: string[] = [];
+
+  if (typeof reason === 'string') {
+    parts.push(reason);
+  } else if (reason instanceof Error) {
+    if (typeof reason.message === 'string') parts.push(reason.message);
+    if (typeof reason.stack === 'string') parts.push(reason.stack);
+    if (typeof reason.name === 'string') parts.push(reason.name);
+  } else if (typeof reason === 'object' && reason !== null) {
+    const r = reason as Record<string, unknown>;
+    if (typeof r.message === 'string') parts.push(r.message);
+    if (typeof r.stack === 'string') parts.push(r.stack);
+    if (typeof r.name === 'string') parts.push(r.name);
+    // Some browsers use different keys on Error-like objects.
+    if (typeof r.filename === 'string') parts.push(r.filename);
+    if (typeof r.fileName === 'string') parts.push(r.fileName);
+  }
+
+  if (parts.length === 0) return false;
+
+  const haystack = parts.join('\n');
+
+  // The most reliable signal: our own extension base URL.
+  // If we have it, prefer it exclusively to avoid suppressing unrelated site errors.
+  if (extensionUrlPrefix) {
+    return haystack.includes(extensionUrlPrefix);
+  }
+
+  // Fallback heuristics (only used if runtime URL isn't available).
+  // Our logger prefix sometimes appears in thrown messages.
+  if (haystack.includes('LS:')) return true;
+
+  // Useful in dev builds / source maps.
+  if (haystack.includes('light-session')) return true;
+
+  return false;
+}

tests/unit/rejection-filter.test.ts

@@ -0,0 +1,35 @@
+import { describe, expect, it } from 'vitest';
+
+import { isLightSessionRejection } from '../../extension/src/content/rejection-filter';
+
+describe('isLightSessionRejection', () => {
+  it('returns false for empty/unknown reasons', () => {
+    expect(isLightSessionRejection(undefined)).toBe(false);
+    expect(isLightSessionRejection(null)).toBe(false);
+    expect(isLightSessionRejection(123)).toBe(false);
+    expect(isLightSessionRejection({})).toBe(false);
+  });
+
+  it('matches when reason string contains LS:', () => {
+    expect(isLightSessionRejection('LS: boom')).toBe(true);
+  });
+
+  it('does not match LS: in message when extension URL is provided but not present', () => {
+    const prefix = 'chrome-extension://abc123/';
+    expect(isLightSessionRejection('LS: boom', prefix)).toBe(false);
+  });
+
+  it('matches when Error.stack contains the extension base URL', () => {
+    const prefix = 'chrome-extension://abc123/';
+    const err = new Error('nope');
+    // Simulate a stack that points at our bundled content script URL.
+    err.stack = `Error: nope\n    at doThing (${prefix}dist/content.js:1:1)`;
+    expect(isLightSessionRejection(err, prefix)).toBe(true);
+  });
+
+  it('does not match non-LightSession errors by default', () => {
+    const err = new Error('Some site error');
+    err.stack = `Error: Some site error\n    at foo (https://chatgpt.com/app.js:1:1)`;
+    expect(isLightSessionRejection(err)).toBe(false);
+  });
+});