fix(webdriverio): handle 'no such alert' error when dialog closes early (webdriverio#14823) (webdriverio#14957)

Author: mccmrunal

packages/webdriverio/src/session/dialog.ts

@@ -57,10 +57,18 @@ export class DialogManager extends SessionManager {
      */
     async #handleUserPrompt(log: local.BrowsingContextUserPromptOpenedParameters) {
         if (this.#autoHandleDialog) {
-            return this.#browser.browsingContextHandleUserPrompt({
-                accept: false,
-                context: log.context
-            })
+            try {
+                return await this.#browser.browsingContextHandleUserPrompt({
+                    accept: false,
+                    context: log.context
+                })
+            } catch (err) {
+                // ignore error if dialog is already closed
+                if (err instanceof Error && err.message.includes('no such alert')) {
+                    return
+                }
+                throw err
+            }
         }
 
         const dialog = new Dialog(log, this.#browser)

packages/webdriverio/tests/session/dialog.test.ts

@@ -0,0 +1,65 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { DialogManager } from '../../src/session/dialog.js'
+
+describe('DialogManager', () => {
+    let browser: any
+    let dialogManager: DialogManager
+
+    beforeEach(() => {
+        browser = {
+            isBidi: true,
+            sessionId: 'session-id',
+            sessionSubscribe: vi.fn().mockResolvedValue({}),
+            on: vi.fn(),
+            off: vi.fn(),
+            removeAllListeners: vi.fn(),
+            emit: vi.fn(),
+            browsingContextHandleUserPrompt: vi.fn()
+        }
+        // Mock isEnabled to bypass environment check which disables it in unit tests
+        vi.spyOn(DialogManager.prototype, 'isEnabled').mockReturnValue(true)
+        dialogManager = new DialogManager(browser)
+    })
+
+    it('should ignore "no such alert" error when auto-handling dialogs', async () => {
+        const log = { context: 'some-context' } as any
+
+        // Mock handleUserPrompt to reject with "no such alert"
+        browser.browsingContextHandleUserPrompt.mockRejectedValue(new Error('no such alert'))
+
+        // We need to access the private #handleUserPrompt method or trigger it via the event listener
+        // Since it's bound in constructor: this.#browser.on('browsingContext.userPromptOpened', this.#handleUserPrompt.bind(this))
+        // We can simulate the event if we can get the listener.
+        // However, accessing private private method via trigger might be hard if not exposed.
+        // But since we are in test, we can try to call the listener registered to 'browsingContext.userPromptOpened'
+
+        // Better approach for unit testing private method logic if strictly private:
+        // Trigger the event handler registered in constructor
+        const calls = browser.on.mock.calls
+        const userPromptHandler = calls.find((call: unknown[]) => call[0] === 'browsingContext.userPromptOpened')?.[1]
+
+        expect(userPromptHandler).toBeDefined()
+
+        // Expectation: The promise should resolve without throwing (error caught internally)
+        await expect(userPromptHandler(log)).resolves.toBeUndefined()
+
+        // Verify handleUserPrompt was called
+        expect(browser.browsingContextHandleUserPrompt).toHaveBeenCalledWith({
+            accept: false,
+            context: 'some-context'
+        })
+    })
+
+    it('should re-throw other errors', async () => {
+        const log = { context: 'some-context' } as any
+        const msg = 'some other error'
+        browser.browsingContextHandleUserPrompt.mockRejectedValue(new Error(msg))
+
+        const calls = browser.on.mock.calls
+        const userPromptHandler = calls.find((call: unknown[]) => call[0] === 'browsingContext.userPromptOpened')?.[1]
+
+        expect(userPromptHandler).toBeDefined()
+
+        await expect(userPromptHandler(log)).rejects.toThrow(msg)
+    })
+})