feat: throw when writing to 'read only' properties of config

cli/types/cypress.d.ts

@@ -328,7 +328,7 @@ declare namespace Cypress {
     // 60000
     ```
      */
-    config<K extends keyof ConfigOptions>(key: K): ResolvedConfigOptions[K]
+    config<K extends keyof Config>(key: K): Config[K]
     /**
      * Sets one configuration value.
      * @see https://on.cypress.io/config
@@ -337,7 +337,7 @@ declare namespace Cypress {
     Cypress.config('viewportWidth', 800)
     ```
      */
-    config<K extends keyof ConfigOptions>(key: K, value: ResolvedConfigOptions[K]): void
+    config<K extends keyof TestConfigOverrides>(key: K, value: TestConfigOverrides[K]): void
     /**
      * Sets multiple configuration values at once.
      * @see https://on.cypress.io/config
@@ -2879,7 +2879,7 @@ declare namespace Cypress {
     xhrUrl: string
   }
 
-  interface TestConfigOverrides extends Partial<Pick<ConfigOptions, 'animationDistanceThreshold' | 'baseUrl' | 'defaultCommandTimeout' | 'env' | 'execTimeout' | 'includeShadowDom' | 'requestTimeout' | 'responseTimeout' | 'retries' | 'scrollBehavior' | 'taskTimeout' | 'viewportHeight' | 'viewportWidth' | 'waitForAnimations'>> {
+  interface TestConfigOverrides extends Partial<Pick<ConfigOptions, 'animationDistanceThreshold' | 'baseUrl' | 'blockHosts' | 'defaultCommandTimeout' | 'env' | 'execTimeout' | 'includeShadowDom' | 'numTestsKeptInMemory' | 'pageLoadTimeout' | 'redirectionLimit' | 'requestTimeout' | 'responseTimeout' | 'retries' | 'screenshotOnRunFailure' | 'slowTestThreshold' | 'scrollBehavior' | 'taskTimeout' | 'viewportHeight' | 'viewportWidth' | 'waitForAnimations'>> {
     browser?: IsBrowserMatcher | IsBrowserMatcher[]
     keystrokeDelay?: number
   }

packages/config/__snapshots__/index_spec.js

@@ -23,6 +23,7 @@ exports['src/index .getDefaultValues returns list of public config keys 1'] = {
   "e2e": {},
   "env": {},
   "execTimeout": 60000,
+  "exit": true,
   "experimentalFetchPolyfill": false,
   "experimentalInteractiveRunEvents": false,
   "experimentalSessionSupport": false,
@@ -33,6 +34,8 @@ exports['src/index .getDefaultValues returns list of public config keys 1'] = {
   "ignoreTestFiles": "*.hot-update.js",
   "includeShadowDom": false,
   "integrationFolder": "cypress/integration",
+  "isInteractive": true,
+  "keystrokeDelay": 0,
   "modifyObstructiveCode": true,
   "numTestsKeptInMemory": 50,
   "pageLoadTimeout": 60000,
@@ -97,6 +100,7 @@ exports['src/index .getPublicConfigKeys returns list of public config keys 1'] =
   "e2e",
   "env",
   "execTimeout",
+  "exit",
   "experimentalFetchPolyfill",
   "experimentalInteractiveRunEvents",
   "experimentalSessionSupport",
@@ -107,6 +111,7 @@ exports['src/index .getPublicConfigKeys returns list of public config keys 1'] =
   "ignoreTestFiles",
   "includeShadowDom",
   "integrationFolder",
+  "keystrokeDelay",
   "modifyObstructiveCode",
   "nodeVersion",
   "numTestsKeptInMemory",
@@ -142,5 +147,6 @@ exports['src/index .getPublicConfigKeys returns list of public config keys 1'] =
   "watchForFileChanges",
   "browsers",
   "hosts",
+  "isInteractive",
   "modifyObstructiveCode"
 ]

packages/config/__snapshots__/validation_spec.js

@@ -154,4 +154,4 @@ Expected \`mockConfigKey\` to be a fully qualified URL (starting with \`http://\
 
 exports['empty string'] = `
 Expected \`mockConfigKey\` to be a fully qualified URL (starting with \`http://\` or \`https://\`). Instead the value was: \`""\`
-`
+`

packages/config/lib/index.js

@@ -20,6 +20,7 @@ const breakingKeys = _.map(breakingOptions, 'name')
 const defaultValues = createIndex(options, 'name', 'defaultValue')
 const publicConfigKeys = _(options).reject({ isInternal: true }).map('name').value()
 const validationRules = createIndex(options, 'name', 'validation')
+const testConfigOverrideOptions = createIndex(options, 'name', 'canUpdateDuringTestTime')
 
 module.exports = {
   allowed: (obj = {}) => {
@@ -101,4 +102,16 @@ module.exports = {
       }
     })
   },
+
+  validateNoReadOnlyConfig: (config, onErr) => {
+    let errProperty
+
+    Object.keys(config).some((option) => {
+      return errProperty = testConfigOverrideOptions[option] === false ? option : undefined
+    })
+
+    if (errProperty) {
+      return onErr(errProperty)
+    }
+  },
 }