fix: Prevent Promise.map from treating cy.retry failures as successes

cli/CHANGELOG.md

@@ -1,4 +1,12 @@
 <!-- See the ../guides/writing-the-cypress-changelog.md for details on writing the changelog. -->
+## 15.8.2
+
+_Released 12/30/2025 (PENDING)_
+
+**Bugfixes:**
+
+- Fixed a bug where `cy.wait()` with multiple aliases could crash with `TypeError: Cannot read properties of undefined` when a retry was canceled (e.g., via `Cypress.stop()`) or when retry logic executed between test runnables due to a Bluebird cancellation propagation bug, instead of properly failing the test. Fixed in [#33157](https://github.com/cypress-io/cypress/pull/33157).
+
 ## 15.8.1
 
 _Released 12/18/2025_

packages/driver/cypress/e2e/commands/waiting.cy.js

@@ -465,7 +465,15 @@ describe('src/cy/commands/waiting', () => {
         it('does not retry after 1 alias times out', {
           requestTimeout: 1000,
         }, (done) => {
-          Promise.onPossiblyUnhandledRejection(done)
+          let doneCalled = false
+          const callDoneOnce = () => {
+            if (!doneCalled) {
+              doneCalled = true
+              done()
+            }
+          }
+
+          Promise.onPossiblyUnhandledRejection(callDoneOnce)
 
           cy.on('command:retry', (options) => {
             // force bar to time out before foo
@@ -475,7 +483,7 @@ describe('src/cy/commands/waiting', () => {
           })
 
           cy.on('fail', (err) => {
-            done()
+            callDoneOnce()
           })
 
           cy

packages/driver/src/cy/retries.ts

@@ -82,19 +82,24 @@ export const create = (Cypress: ICypress, state: StateFunc, timeout: $Cy['timeou
         return `${msg2}${msg1}`
       })
 
-      if (error) {
-        const retryErr = mergeErrProps(error, retryErrProps)
+      // Always throw an error when timeout is exceeded, even if error is not set
+      // This handles edge cases where _runnableTimeout is manipulated (e.g., in tests)
+      // and ensures Promise.map correctly rejects instead of treating undefined as success
+      const retryErr = error
+        ? mergeErrProps(error, retryErrProps)
+        : errByPath('miscellaneous.retry_timed_out', {
+          ms: options._runnableTimeout,
+        })
 
-        throwErr(retryErr, {
-          onFail: (err) => {
-            if (onFail) {
-              err = onFail(err)
-            }
+      throwErr(retryErr, {
+        onFail: (err) => {
+          if (onFail) {
+            err = onFail(err)
+          }
 
-            finishAssertions(err)
-          },
-        })
-      }
+          finishAssertions(err)
+        },
+      })
     }
 
     const runnableHasChanged = () => {
@@ -122,13 +127,17 @@ export const create = (Cypress: ICypress, state: StateFunc, timeout: $Cy['timeou
     .delay(interval)
     .then(() => {
       if (ended()) {
-        return
+        // Reject the promise instead of returning undefined
+        // This prevents Promise.map from treating it as a successful resolution
+        // when one promise in the map should have failed
+        return Promise.reject(new Error('Retry ended: promise was canceled or runnable changed'))
       }
 
       Cypress.action('cy:command:retry', options)
 
       if (ended()) {
-        return
+        // Reject the promise instead of returning undefined
+        return Promise.reject(new Error('Retry ended: promise was canceled or runnable changed'))
       }
 
       // if we are unstable then remove