breaking: remove CDP from firefox with Cypress 15

.circleci/workflows.yml

@@ -656,11 +656,6 @@ commands:
         description: run subset of tests with injectDocumentDomain config enabled
         type: boolean
         default: false
-      is-firefox-cdp:
-        description: whether or not the group should be associated to the firefox CDP
-          run or not. This is determined by the browser version.
-        type: boolean
-        default: false
 
     steps:
       - restore_cached_workspace
@@ -701,9 +696,6 @@ commands:
             if << parameters.inject-document-domain >> ; then
               YARN_CMD="cypress:run:inject-document-domain"
               PARALLEL="--parallel --group 5x-driver-inject-document-domain-<<parameters.browser>>"
-            elif << parameters.is-firefox-cdp >> ; then
-              YARN_CMD="cypress:run"
-              PARALLEL="--parallel --group 5x-driver-cdp-<<parameters.browser>>"
             else
               YARN_CMD="cypress:run"
               PARALLEL="--parallel --group 5x-driver-<<parameters.browser>>"
@@ -2136,18 +2128,6 @@ jobs:
       - run-driver-integration-tests:
           browser: firefox
 
-  # Runs the driver tests using firefox 134, which does NOT use WebDriver BiDi
-  # This is to test and make sure there aren't regressions with the old CDP driver
-  driver-integration-tests-firefox-cdp:
-    <<: *defaults
-    resource_class: medium+
-    parallelism: 5
-    steps:
-      - run-driver-integration-tests:
-          browser: firefox
-          firefox-version: "134.0.2"
-          is-firefox-cdp: true
-
   driver-integration-tests-electron:
     <<: *defaults
     parallelism: 5
@@ -2888,7 +2868,6 @@ linux-x64-workflow: &linux-x64-workflow
           - run-webpack-dev-server-integration-tests
           - run-vite-dev-server-integration-tests
           - driver-integration-tests-firefox
-          - driver-integration-tests-firefox-cdp
           - driver-integration-tests-chrome
           - driver-integration-tests-chrome-inject-document-domain
           - driver-integration-tests-chrome-beta-inject-document-domain
@@ -2964,10 +2943,6 @@ linux-x64-workflow: &linux-x64-workflow
         context: test-runner:cypress-record-key
         requires:
           - build
-    - driver-integration-tests-firefox-cdp:
-        context: test-runner:cypress-record-key
-        requires:
-          - build
     - driver-integration-tests-electron:
         context: test-runner:cypress-record-key
         requires:
@@ -3110,7 +3085,6 @@ linux-x64-workflow: &linux-x64-workflow
           - linux-lint
           - percy-finalize
           - driver-integration-tests-firefox
-          - driver-integration-tests-firefox-cdp
           - driver-integration-tests-chrome
           - driver-integration-tests-chrome-beta
           - driver-integration-tests-chrome-inject-document-domain
@@ -3366,10 +3340,6 @@ linux-x64-contributor-workflow: &linux-x64-contributor-workflow
         context: test-runner:cypress-record-key
         requires:
           - contributor-pr
-    - driver-integration-tests-firefox-cdp:
-        context: test-runner:cypress-record-key
-        requires:
-          - contributor-pr
     - driver-integration-tests-electron:
         context: test-runner:cypress-record-key
         requires:
@@ -3511,7 +3481,6 @@ linux-x64-contributor-workflow: &linux-x64-contributor-workflow
           - linux-lint
           - percy-finalize
           - driver-integration-tests-firefox
-          - driver-integration-tests-firefox-cdp
           - driver-integration-tests-chrome
           - driver-integration-tests-chrome-beta
           - driver-integration-tests-electron

cli/CHANGELOG.md

@@ -1,11 +1,12 @@
 <!-- See the ../guides/writing-the-cypress-changelog.md for details on writing the changelog. -->
 ## 15.0.0
 
-_Released 7/1/2025 (PENDING)_
+_Released 07/01/2025 (PENDING)_
 
 **Breaking Changes:**
 
 - Removed support for Node.js 18 and Node.js 23. Addresses [#31302](https://github.com/cypress-io/cypress/issues/31302).
+- Removed support for [Chrome DevTools Protocol](https://chromedevtools.github.io/devtools-protocol) with the [firefox](https://www.mozilla.org/) browser. Addresses [#31189](https://github.com/cypress-io/cypress/issues/31189).
 
 ## 14.2.2
 

packages/errors/src/errors.ts

@@ -1193,9 +1193,6 @@ export const AllCypressErrors = {
   CDP_RETRYING_CONNECTION: (attempt: string | number, browserName: string, connectRetryThreshold: number) => {
     return errTemplate`Still waiting to connect to ${fmt.off(_.capitalize(browserName))}, retrying in 1 second ${fmt.meta(`(attempt ${attempt}/${connectRetryThreshold})`)}`
   },
-  CDP_FIREFOX_DEPRECATED: () => {
-    return errTemplate`Since Firefox 129, Chrome DevTools Protocol (CDP) has been deprecated in Firefox. In Firefox 135 and above, Cypress defaults to automating the Firefox browser with WebDriver BiDi. Cypress will no longer support CDP within Firefox in the future and is planned for removal in Cypress 15.`
-  },
   BROWSER_PROCESS_CLOSED_UNEXPECTEDLY: (browserName: string) => {
     return errTemplate`\
       We detected that the ${fmt.highlight(browserName)} browser process closed unexpectedly.

packages/errors/test/unit/visualSnapshotErrors_spec.ts

@@ -1112,11 +1112,6 @@ describe('visual error templates', () => {
         default: [1, 'chrome', 62],
       }
     },
-    CDP_FIREFOX_DEPRECATED: () => {
-      return {
-        default: [],
-      }
-    },
     BROWSER_PROCESS_CLOSED_UNEXPECTEDLY: () => {
       return {
         default: ['chrome'],

packages/extension/app/v2/background.js

@@ -31,23 +31,6 @@ const checkIfFirefox = async () => {
   return name === 'Firefox'
 }
 
-// this check only applies to firefox versioning!
-const isBiDiEnabled = async (config) => {
-  if (!browser || !get(browser, 'runtime.getBrowserInfo') || config.IS_CDP_FORCED_FOR_FIREFOX) {
-    return false
-  }
-
-  const { version } = await browser.runtime.getBrowserInfo()
-
-  if (version) {
-    const [majorVersion] = version.split('.').map(Number)
-
-    return majorVersion >= 135
-  }
-
-  return false
-}
-
 const connect = function (host, path, extraOpts) {
   const listenToCookieChanges = once(() => {
     return browser.cookies.onChanged.addListener((info) => {
@@ -84,30 +67,6 @@ const connect = function (host, path, extraOpts) {
     })
   })
 
-  const listenToOnBeforeHeaders = once(() => {
-    // adds a header to the request to mark it as a request for the AUT frame
-    // itself, so the proxy can utilize that for injection purposes
-    browser.webRequest.onBeforeSendHeaders.addListener((details) => {
-      if (
-        // parentFrameId: 0 means the parent is the top-level, so if it isn't
-        // 0, it's nested inside the AUT and can't be the AUT itself
-        details.parentFrameId !== 0
-        // is the spec frame, not the AUT
-        || details.url.includes('__cypress')
-      ) return
-
-      return {
-        requestHeaders: [
-          ...details.requestHeaders,
-          {
-            name: 'X-Cypress-Is-AUT-Frame',
-            value: 'true',
-          },
-        ],
-      }
-    }, { urls: ['<all_urls>'], types: ['sub_frame'] }, ['blocking', 'requestHeaders'])
-  })
-
   const fail = (id, err) => {
     return ws.emit('automation:response', id, {
       __error: err.message,
@@ -167,13 +126,6 @@ const connect = function (host, path, extraOpts) {
     if (isFirefox) {
       // Non-Firefox browsers use CDP for this instead
       listenToDownloads()
-      // if BiDi is enabled, BiDi will handle the network interception.
-      // Otherwise, CDP does not support it for Firefox and we need to listen for it here.
-      const isBiDiTurnedOn = await isBiDiEnabled(config)
-
-      if (!isBiDiTurnedOn) {
-        listenToOnBeforeHeaders()
-      }
     }
   })
 

packages/extension/test/integration/v2/background_spec.js

@@ -293,120 +293,6 @@ describe('app/background', () => {
     })
   })
 
-  context('add header to aut iframe requests', () => {
-    beforeEach(() => {
-      browser.runtime.getBrowserInfo = sinon.stub().resolves({ name: 'Firefox', version: '135.0.1' })
-    })
-
-    it('allows for CDP to be used as an escape hatch if BiDi would otherwise be enabled', async function () {
-      sinon.stub(browser.webRequest.onBeforeSendHeaders, 'addListener')
-
-      await this.connect({
-        IS_CDP_FORCED_FOR_FIREFOX: true,
-      })
-
-      expect(browser.webRequest.onBeforeSendHeaders.addListener).to.be.called
-    })
-
-    context('BiDi enabled', () => {
-      it('does not attach onBeforeSendHeaders listener if BiDi is enabled', async function () {
-        sinon.stub(browser.webRequest.onBeforeSendHeaders, 'addListener')
-
-        await this.connect()
-
-        expect(browser.webRequest.onBeforeSendHeaders.addListener).not.to.be.called
-      })
-    })
-
-    context('CDP enabled', () => {
-      beforeEach(() => {
-        browser.runtime.getBrowserInfo = sinon.stub().resolves({ name: 'Firefox', version: '134' })
-      })
-
-      it('does not add header if it is the top frame', async function () {
-        const details = {
-          parentFrameId: -1,
-        }
-
-        sinon.stub(browser.webRequest.onBeforeSendHeaders, 'addListener')
-
-        await this.connect()
-
-        const result = browser.webRequest.onBeforeSendHeaders.addListener.lastCall.args[0](details)
-
-        expect(result).to.be.undefined
-      })
-
-      it('does not add header if it is a nested frame', async function () {
-        const details = {
-          parentFrameId: 12345,
-        }
-
-        sinon.stub(browser.webRequest.onBeforeSendHeaders, 'addListener')
-
-        await this.connect()
-
-        const result = browser.webRequest.onBeforeSendHeaders.addListener.lastCall.args[0](details)
-
-        expect(result).to.be.undefined
-      })
-
-      it('does not add header if it is a spec frame request', async function () {
-        const details = {
-          parentFrameId: 0,
-          type: 'sub_frame',
-          url: '/__cypress/integration/spec.js',
-        }
-
-        sinon.stub(browser.webRequest.onBeforeSendHeaders, 'addListener')
-
-        await this.connect()
-        const result = browser.webRequest.onBeforeSendHeaders.addListener.lastCall.args[0](details)
-
-        expect(result).to.be.undefined
-      })
-
-      it('appends X-Cypress-Is-AUT-Frame header to AUT iframe request', async function () {
-        const details = {
-          parentFrameId: 0,
-          type: 'sub_frame',
-          url: 'http://localhost:3000/index.html',
-          requestHeaders: [
-            { name: 'X-Foo', value: 'Bar' },
-          ],
-        }
-
-        sinon.stub(browser.webRequest.onBeforeSendHeaders, 'addListener')
-
-        await this.connect()
-        const result = browser.webRequest.onBeforeSendHeaders.addListener.lastCall.args[0](details)
-
-        expect(result).to.deep.equal({
-          requestHeaders: [
-            {
-              name: 'X-Foo',
-              value: 'Bar',
-            },
-            {
-              name: 'X-Cypress-Is-AUT-Frame',
-              value: 'true',
-            },
-          ],
-        })
-      })
-
-      it('does not add before-headers listener if in non-Firefox browser', async function () {
-        browser.runtime.getBrowserInfo = undefined
-
-        const onBeforeSendHeaders = sinon.stub(browser.webRequest.onBeforeSendHeaders, 'addListener')
-
-        await this.connect()
-
-        expect(onBeforeSendHeaders).not.to.be.called
-      })
-    })
-  })
-
   context('.getAll', () => {
     it('resolves with specific cookie properties', () => {
       sinon.stub(browser.cookies, 'getAll').resolves([

packages/graphql/schemas/schema.graphql

@@ -1129,7 +1129,6 @@ enum ErrorTypeEnum {
   CANNOT_TRASH_ASSETS
   CDP_COULD_NOT_CONNECT
   CDP_COULD_NOT_RECONNECT
-  CDP_FIREFOX_DEPRECATED
   CDP_RETRYING_CONNECTION
   CDP_VERSION_TOO_OLD
   CHROME_WEB_SECURITY_NOT_SUPPORTED

packages/launcher/lib/known-browsers.ts

@@ -1,5 +1,24 @@
 import type { Browser, BrowserValidatorResult, FoundBrowser } from '@packages/types'
 
+const firefoxValidatorFn = (browser: FoundBrowser, platform: NodeJS.Platform): BrowserValidatorResult => {
+  try {
+    if (browser.majorVersion) {
+      const majorVersion = Number(browser.majorVersion)
+
+      if (majorVersion < 135) {
+        return {
+          isSupported: false,
+          warningMessage: `Cypress does not support running ${browser.displayName} version ${browser.majorVersion} due to lack of WebDriver BiDi support. To use ${browser.displayName} with Cypress, install version 135 or newer.`,
+        }
+      }
+    }
+  } catch (e) { /* empty */ }
+
+  return {
+    isSupported: true,
+  }
+}
+
 /** list of the browsers we can detect and use by default */
 export const knownBrowsers: Browser[] = [
   {
@@ -62,9 +81,10 @@ export const knownBrowsers: Browser[] = [
     family: 'firefox',
     channel: 'stable',
     displayName: 'Firefox',
-    // Mozilla Firefox 70.0.1
+    // Mozilla Firefox 135.0.1
     versionRegex: /^Mozilla Firefox ([^\sab]+)$/m,
     binary: 'firefox',
+    validator: firefoxValidatorFn,
   },
   {
     name: 'firefox',
@@ -75,6 +95,7 @@ export const knownBrowsers: Browser[] = [
     versionRegex: /^Mozilla Firefox (\S+b\S*)$/m,
     // ubuntu PPAs install it as firefox
     binary: ['firefox-developer-edition', 'firefox'],
+    validator: firefoxValidatorFn,
   },
   {
     name: 'firefox',
@@ -85,6 +106,7 @@ export const knownBrowsers: Browser[] = [
     versionRegex: /^Mozilla Firefox (\S+a\S*)$/m,
     // ubuntu PPAs install it as firefox-trunk
     binary: ['firefox-nightly', 'firefox-trunk'],
+    validator: firefoxValidatorFn,
   },
   {
     name: 'edge',

packages/launcher/test/unit/browsers_spec.ts

@@ -71,6 +71,25 @@ describe('browsers', () => {
         expect(result.isSupported).to.be.true
         expect(result.warningMessage).to.be.undefined
       })
+
+      describe('firefox validation', () => {
+        const FIREFOX_KNOWN_BROWSER_CHANNELS = knownBrowsers.filter((browser) => {
+          return browser.family === 'firefox'
+        })
+
+        FIREFOX_KNOWN_BROWSER_CHANNELS.forEach((browser) => {
+          it(`${browser.channel}: fails validation when Firefox major version is below 135`, () => {
+            // @ts-expect-error
+            const result = browser.validator({
+              majorVersion: '134',
+              displayName: 'Firefox',
+            })
+
+            expect(result.isSupported).to.be.false
+            expect(result.warningMessage).to.equal('Cypress does not support running Firefox version 134 due to lack of WebDriver BiDi support. To use Firefox with Cypress, install version 135 or newer.')
+          })
+        })
+      })
     })
   })
 })