🐛[RUMF-1544] Fix badly polyfilled URL

.eslintrc.js

@@ -219,6 +219,7 @@ module.exports = {
       rules: {
         'local-rules/disallow-side-effects': 'error',
         'local-rules/disallow-zone-js-patched-values': 'error',
+        'local-rules/disallow-url-constructor-patched-values': 'error',
         'no-restricted-syntax': [
           'error',
           {

eslint-local-rules/disallowUrlConstructorPatchValues.js

@@ -0,0 +1,29 @@
+module.exports = {
+  meta: {
+    docs: {
+      description: 'Disallow problematic URL constructor patched values.',
+      recommended: false,
+    },
+    schema: [],
+  },
+
+  create(context) {
+    return {
+      'Program:exit'(node) {
+        const globalScope = context.getScope(node)
+        const variable = globalScope.set.get('URL')
+
+        if (variable && variable.defs.length === 0) {
+          variable.references.forEach((ref) => {
+            const idNode = ref.identifier
+            const parent = idNode.parent
+
+            if (parent && parent.type === 'NewExpression' && parent.callee === idNode) {
+              context.report(idNode, 'This value might be patched. Use `buildUrl` from @datadog/browser-core instead')
+            }
+          })
+        }
+      },
+    }
+  },
+}

eslint-local-rules/index.js

@@ -13,6 +13,7 @@ module.exports = {
   'disallow-protected-directory-import': require('./disallowProtectedDirectoryImport'),
   'disallow-test-import-export-from-src': require('./disallowTestImportExportFromSrc'),
   'disallow-zone-js-patched-values': require('./disallowZoneJsPatchedValues'),
+  'disallow-url-constructor-patched-values': require('./disallowUrlConstructorPatchValues.js'),
   'disallow-generic-utils': require('./disallowGenericUtils'),
   'secure-command-execution': require('./secureCommandExecution'),
 }

packages/core/src/tools/utils/urlPolyfill.spec.ts

@@ -30,6 +30,12 @@ describe('isValidUrl', () => {
     expect(isValidUrl('/plop')).toBe(false)
     expect(isValidUrl('')).toBe(false)
   })
+
+  it('should return the same result if the URL has been wrongfully overridden between calls', () => {
+    expect(isValidUrl('http://www.datadoghq.com')).toBe(true)
+    spyOn(window, 'URL').and.throwError('wrong URL override')
+    expect(isValidUrl('http://www.datadoghq.com')).toBe(true)
+  })
 })
 
 describe('getOrigin', () => {

packages/core/src/tools/utils/urlPolyfill.ts

@@ -34,11 +34,12 @@ export function getHash(url: string) {
 }
 
 export function buildUrl(url: string, base?: string) {
-  if (checkURLSupported()) {
+  const supportedURL = getSupportedUrl()
+  if (supportedURL) {
     try {
-      return base !== undefined ? new URL(url, base) : new URL(url)
+      return base !== undefined ? new supportedURL(url, base) : new supportedURL(url)
     } catch (error) {
-      throw new Error(`Failed to construct URL. ${jsonStringify({ url, base })!}`)
+      throw new Error(`Failed to construct URL: ${String(error)} ${jsonStringify({ url, base })!}`)
     }
   }
   if (base === undefined && !/:/.test(url)) {
@@ -57,19 +58,18 @@ export function buildUrl(url: string, base?: string) {
   return anchorElement
 }
 
+const originalURL = URL
 let isURLSupported: boolean | undefined
-function checkURLSupported() {
-  if (isURLSupported !== undefined) {
-    return isURLSupported
-  }
-  try {
-    const url = new URL('http://test/path')
-    isURLSupported = url.href === 'http://test/path'
-    return isURLSupported
-  } catch {
-    isURLSupported = false
+function getSupportedUrl(): typeof URL | undefined {
+  if (isURLSupported === undefined) {
+    try {
+      const url = new originalURL('http://test/path')
+      isURLSupported = url.href === 'http://test/path'
+    } catch {
+      isURLSupported = false
+    }
   }
-  return isURLSupported
+  return isURLSupported ? originalURL : undefined
 }
 
 export function getLocationOrigin() {

packages/rum/src/boot/recorderApi.ts

@@ -164,6 +164,9 @@ function isBrowserSupported() {
     // Array.from is a bit less supported by browsers than CSSSupportsRule, but has higher chances
     // to be polyfilled. Test for both to be more confident. We could add more things if we find out
     // this test is not sufficient.
-    typeof Array.from === 'function' && typeof CSSSupportsRule === 'function' && 'forEach' in NodeList.prototype
+    typeof Array.from === 'function' &&
+    typeof CSSSupportsRule === 'function' &&
+    typeof URL.createObjectURL === 'function' &&
+    'forEach' in NodeList.prototype
   )
 }