fix: add cy.then timeouts to cy.session

cli/CHANGELOG.md

@@ -3,6 +3,10 @@
 
 _Released 6/3/2025 (PENDING)_
 
+**Bugfixes:**
+
+- Fixed an issue where `cy.session` may fail internally if navigating to `about:blank` takes longer than the `defaultCommandTimeout`. Addresses [#29496](https://github.com/cypress-io/cypress/issues/29496).
+
 **Dependency Updates:**
 
 - Updated `@sinonjs/fake-timers` from `10.3.0` to `11.3.1`. Addressed in [#31746](https://github.com/cypress-io/cypress/pull/31746).

packages/app/src/runner/aut-iframe.ts

@@ -126,6 +126,8 @@ export class AutIframe {
   visitBlankPage = (testIsolation?: boolean) => {
     return new Promise<void>((resolve) => {
       if (!this.$iframe) {
+        resolve()
+
         return
       }
 

packages/driver/src/cy/commands/sessions/index.ts

@@ -21,6 +21,8 @@ import {
  *  - session data SHOULD be cleared between specs in run mode
  */
 export default function (Commands, Cypress, cy) {
+  const COMMAND_TIMEOUT = 20000
+
   const sessionsManager = new SessionsManager(Cypress, cy)
   const sessions = sessionsManager.sessions
 
@@ -149,7 +151,7 @@ export default function (Commands, Cypress, cy) {
           message: '',
           type: 'system',
         }, (setupLogGroup) => {
-          return cy.then(async () => {
+          return cy.then({ timeout: COMMAND_TIMEOUT }, async () => {
             // Catch when a cypress command fails in the setup function to correctly update log status
             // before failing command and ending command queue.
             cy.state('onQueueFailed', (err, _queue) => {
@@ -180,7 +182,7 @@ export default function (Commands, Cypress, cy) {
               cy.breakSubjectLinksToCurrentChainer()
             }
           })
-          .then(async () => {
+          .then({ timeout: COMMAND_TIMEOUT }, async () => {
             cy.state('onQueueFailed', null)
             const data = await sessions.getCurrentSessionData()
 
@@ -241,7 +243,7 @@ export default function (Commands, Cypress, cy) {
             }
           },
         }, (validateLog) => {
-          return cy.then(async () => {
+          return cy.then({ timeout: COMMAND_TIMEOUT }, async () => {
             const isValidSession = true
             let caughtCommandErr = false
             let _commandToRunAfterValidation
@@ -350,7 +352,7 @@ export default function (Commands, Cypress, cy) {
               throw err
             }
 
-            _commandToRunAfterValidation = cy.then(async () => {
+            _commandToRunAfterValidation = cy.then({ timeout: COMMAND_TIMEOUT }, async () => {
               Cypress.state('onQueueFailed', null)
 
               if (caughtCommandErr) {
@@ -434,16 +436,16 @@ export default function (Commands, Cypress, cy) {
        *   2. validate session
        */
       const createSessionWorkflow = (existingSession, step: 'create' | 'recreate') => {
-        return cy.then(async () => {
+        return cy.then({ timeout: COMMAND_TIMEOUT }, async () => {
           setSessionLogStatus(statusMap.inProgress(step))
 
           await navigateAboutBlank()
           await sessions.clearCurrentSessionData()
 
           return cy.whenStable(() => createSession(existingSession, step))
         })
-        .then(() => validateSession(existingSession, step))
-        .then(async (isValidSession: boolean) => {
+        .then({ timeout: COMMAND_TIMEOUT }, () => validateSession(existingSession, step))
+        .then({ timeout: COMMAND_TIMEOUT }, async (isValidSession: boolean) => {
           if (!isValidSession) {
             return 'failed'
           }
@@ -462,15 +464,15 @@ export default function (Commands, Cypress, cy) {
        *   3. if validation fails, catch error and recreate session
        */
       const restoreSessionWorkflow = (existingSession: Cypress.SessionData) => {
-        return cy.then(async () => {
+        return cy.then({ timeout: COMMAND_TIMEOUT }, async () => {
           setSessionLogStatus(statusMap.inProgress(SESSION_STEPS.restore))
           await navigateAboutBlank()
           await sessions.clearCurrentSessionData()
 
           return restoreSession(existingSession)
         })
-        .then(() => validateSession(existingSession, SESSION_STEPS.restore))
-        .then((isValidSession: boolean) => {
+        .then({ timeout: COMMAND_TIMEOUT }, () => validateSession(existingSession, SESSION_STEPS.restore))
+        .then({ timeout: COMMAND_TIMEOUT }, (isValidSession: boolean) => {
           if (!isValidSession) {
             return createSessionWorkflow(existingSession, SESSION_STEPS.recreate)
           }
@@ -495,7 +497,7 @@ export default function (Commands, Cypress, cy) {
       }
 
       return logGroup(Cypress, groupDetails, (log) => {
-        return cy.then(async () => {
+        return cy.then({ timeout: COMMAND_TIMEOUT }, async () => {
           _log = log
 
           if (!session.hydrated) {
@@ -511,7 +513,7 @@ export default function (Commands, Cypress, cy) {
           }
 
           return restoreSessionWorkflow(session)
-        }).then((status: 'created' | 'restored' | 'recreated' | 'failed') => {
+        }).then({ timeout: COMMAND_TIMEOUT }, (status: 'created' | 'restored' | 'recreated' | 'failed') => {
           return navigateAboutBlank()
           .then(() => {
             setSessionLogStatus(status)