misc: rerun tests on unloadEvent instead of on beforeunload

cli/CHANGELOG.md

@@ -1,4 +1,11 @@
 <!-- See the ../guides/writing-the-cypress-changelog.md for details on writing the changelog. -->
+## 15.13.0
+
+_Released 03/11/2026 (PENDING)_
+
+**Misc:**
+
+- Rerun tests on `pagehide` or `unload` instead of on `beforeunload`. Addressed in [#33456](https://github.com/cypress-io/cypress/pull/33456).
 
 ## 15.12.0
 
@@ -9,6 +16,7 @@ _Released 03/10/2026_
 - Adds an option to enable word wrap for Studio panel code. Addressed in [#33411](https://github.com/cypress-io/cypress/pull/33411).
 
 **Bugfixes:**
+
 - Fixed an issue where sending SIGINT (e.g. Ctrl+C) to exit Cypress left the terminal displaying raw characters. Fixes [#33367](https://github.com/cypress-io/cypress/issues/33367). Addressed in [#33431](https://github.com/cypress-io/cypress/pull/33431).
 - Fixed an issue in develop mode (when running Cypress via gulp with file watching) where closing the Electron window did not exit the gulp process, leaving it running. Addressed in [#33431](https://github.com/cypress-io/cypress/pull/33431).
 - Fixed an issue where internal tags on stderr streams were surfacing to the end user CLI during component testing. Addresses [#32769](https://github.com/cypress-io/cypress/issues/32769). Addressed in [#33400](https://github.com/cypress-io/cypress/pull/33400).

packages/app/src/runner/event-manager.ts

@@ -65,6 +65,7 @@ export class EventManager {
   studioStore: ReturnType<typeof useStudioStore>
   promptStore: ReturnType<typeof usePromptStore>
   specDirtyDataStore: ReturnType<typeof useSpecDirtyDataStore>
+  _deferCleanupToUnload = false
 
   constructor (
     // import '@packages/driver'
@@ -361,8 +362,13 @@ export class EventManager {
     // event as a proxy for AUT unloads.
     const unloadEvent = this.isBrowserFamily('chromium') ? 'pagehide' : 'unload'
 
-    $window.on(unloadEvent, (e) => {
-      this._clearAllCookies()
+    $window.on(unloadEvent, () => {
+      if (this._deferCleanupToUnload) {
+        this._runFullUnloadCleanup()
+        this._deferCleanupToUnload = false
+      } else {
+        this._clearAllCookies()
+      }
     })
 
     // when our window triggers beforeunload
@@ -372,11 +378,18 @@ export class EventManager {
     // that Cypress knows not to set any more
     // cookies
     $window.on('beforeunload', () => {
-      telemetry.getSpan('cypress:app')?.end()
-      this.reporterBus.emit('reporter:restart:test:run')
+      if (this.specDirtyDataStore.isDirty()) {
+        // Used to handle Studio unsaved changes. It defers the cleanup to the unload event
+        // so that the test is not rerun if the user cancels the beforeunload dialog.
+        this._deferCleanupToUnload = true
 
-      this._clearAllCookies()
-      this._setUnload()
+        return
+      }
+
+      // Clear any stale flag from a previously cancelled beforeunload so the unload
+      // handler does not run full cleanup again
+      this._deferCleanupToUnload = false
+      this._runFullUnloadCleanup()
     })
 
     this.addPromptListeners()
@@ -998,6 +1011,13 @@ export class EventManager {
     this.ws.emit('reload:browser', window.location.toString(), browser && browser.name)
   }
 
+  _runFullUnloadCleanup () {
+    telemetry.getSpan('cypress:app')?.end()
+    this.reporterBus.emit('reporter:restart:test:run')
+    this._clearAllCookies()
+    this._setUnload()
+  }
+
   // clear all the cypress specific cookies
   // whenever our app starts
   // and additional when we stop running our tests