fix: proxy spec flake in firefox due to improper sweeping and correlation (#31651)

* fix: don't automatically remove requests when cdpRequestWillBeSentReceivedTimestamp is set to 0. Also, do not ass hashes to prerequest url as the urls do not have hashes when coming through the middleware

* Update packages/server/lib/browsers/bidi_automation.ts

Co-authored-by: Copilot <[email protected]>

---------

Co-authored-by: Copilot <[email protected]>

Author: AtofStryker

cli/CHANGELOG.md

@@ -10,6 +10,7 @@ _Released 6/17/2025_
 **Bugfixes:**
 
 - Fixed an issue when using `Cypress.stop()` where a run may be aborted prior to receiving the required runner events causing Test Replay to not be available. Addresses [#31781](https://github.com/cypress-io/cypress/issues/31781).
+- Fixed an issue where prerequests with Firefox BiDi were prematurely being removed or matched incorrectly. Addresses [#31482](https://github.com/cypress-io/cypress/issues/31482).
 
 ## 14.4.1
 

packages/proxy/lib/http/util/prerequests.ts

@@ -141,7 +141,7 @@ export class PreRequests {
       const now = Date.now()
 
       this.pendingPreRequests.removeMatching(({ cdpRequestWillBeSentReceivedTimestamp, browserPreRequest }) => {
-        if (cdpRequestWillBeSentReceivedTimestamp + this.sweepInterval < now) {
+        if (cdpRequestWillBeSentReceivedTimestamp !== 0 && (cdpRequestWillBeSentReceivedTimestamp + this.sweepInterval < now)) {
           debugVerbose('timed out unmatched pre-request: %o', browserPreRequest)
           metrics.unmatchedPreRequests++
 

packages/proxy/test/unit/http/util/prerequests.spec.ts

@@ -309,4 +309,20 @@ describe('http/util/prerequests', () => {
     expect(preRequests.pendingPreRequests.length).to.eq(1)
     expect(preRequests.pendingPreRequests.shift('GET-foo|bar')).not.to.be.undefined
   })
+
+  it('does not remove pre-requests when sweeping if cdpRequestWillBeSentReceivedTimestamp is 0', async () => {
+    // set the current time to 1000 ms
+    sinon.stub(Date, 'now').returns(1000)
+
+    // set a sweeper timer of 10 ms
+    preRequests = new PreRequests(10, 10)
+    preRequests.setProtocolManager(protocolManager)
+
+    preRequests.addPending({ requestId: '1234', url: 'foo', method: 'GET', cdpRequestWillBeSentReceivedTimestamp: 0 } as BrowserPreRequest)
+
+    // give the sweeper plenty of time to run. Iur request should still not be removed
+    await new Promise((resolve) => setTimeout(resolve, 1000))
+
+    expect(preRequests.pendingPreRequests.length).to.eq(1)
+  })
 })

packages/server/lib/browsers/bidi_automation.ts

@@ -172,10 +172,13 @@ export class BidiAutomation {
 
     const resourceType = normalizeResourceType(params.request.initiatorType)
 
+    const urlWithoutHash = url.includes('#') ? url.substring(0, url.indexOf('#')) : url
+
     const browserPreRequest: BrowserPreRequest = {
       requestId: params.request.request,
       method: params.request.method,
-      url,
+      // urls coming into the http middleware contain query params, but lack the hash. To get an accurate key to match on the prerequest, we need to remove the hash.
+      url: urlWithoutHash,
       headers: parsedHeaders,
       resourceType,
       originalResourceType: params.request.initiatorType || params.request.destination,

packages/server/lib/project-base.ts

@@ -641,7 +641,7 @@ export class ProjectBase extends EE {
 
     if (this.browser.family !== 'chromium') {
       // If we're not in chromium, our strategy for correlating service worker prerequests doesn't work in non-chromium browsers (https://github.com/cypress-io/cypress/issues/28079)
-      // in order to not hang for 2 seconds, we override the prerequest timeout to be 500 ms (which is what it has been historically)
+      // in order to not hang for 2 seconds, we override the prerequest timeout to be 500 ms (which is what it has been historically).
       this._server?.setPreRequestTimeout(500)
     }
   }

packages/server/test/unit/browsers/bidi_automation_spec.ts

@@ -382,6 +382,32 @@ describe('lib/browsers/bidi_automation', () => {
 
           expect(mockAutomationClient.onRemoveBrowserPreRequest).to.have.been.calledWith('request1')
         })
+
+        it('strips hashes out of the url when adding the prerequest', async () => {
+          BidiAutomation.create(mockWebdriverClient, mockAutomationClient)
+
+          mockRequest.request.url = 'https://www.foobar.com?foo=bar#hash'
+
+          mockWebdriverClient.emit('network.beforeRequestSent', mockRequest)
+
+          await flushPromises()
+
+          expect(mockAutomationClient.onBrowserPreRequest).to.have.been.calledWith({
+            requestId: 'request1',
+            method: 'GET',
+            url: 'https://www.foobar.com?foo=bar',
+            resourceType: 'xhr',
+            originalResourceType: 'xmlhttprequest',
+            initiator: {
+              type: 'preflight',
+            },
+            headers: {
+              foo: 'bar',
+            },
+            cdpRequestWillBeSentTimestamp: 0,
+            cdpRequestWillBeSentReceivedTimestamp: 0,
+          })
+        })
       })
 
       describe('responseStarted / responseCompleted', () => {