refactor: rely on ValidationError for watch plugin key conflicts

CHANGELOG.md

@@ -6,7 +6,7 @@
 
 ### Features
 
-- `[jest-cli]` Watch plugin key registrations are now checked for conflicts. Some built-in keys, such as `p` and `t` for test limitation, are overridable, but most built-in keys are reserved (e.g. `q`, `a` or `o`), and any key registered by a third-party plugin cannot be overriden by another third-party plugin. Explicit error messages are logged to the console and Jest exits with code 64 (`EX_USAGE`).
+- `[jest-cli]` Watch plugin key registrations are now checked for conflicts. Some built-in keys, such as `p` and `t` for test limitation, are overridable, but most built-in keys are reserved (e.g. `q`, `a` or `o`), and any key registered by a third-party plugin cannot be overriden by another third-party plugin. Explicit validation errors are then triggered.
 
 ### Fixes
 

docs/WatchPlugins.md

@@ -222,10 +222,10 @@ Any key not used by built-in functionality can be claimed, as you would expect.
 
 ### When a conflict happens
 
-Should your plugin attempt to overwrite a reserved key, Jest will error out with exit code 64 (`EX_USAGE`) and a descriptive message, something like:
+Should your plugin attempt to overwrite a reserved key, Jest will error out with a descriptive message, something like:
 
-> Jest configuration error: watch plugin YourFaultyPlugin attempted to register key <q>, that is reserved internally for quitting watch mode. Please change the configuration key for this plugin.
+> Watch plugin YourFaultyPlugin attempted to register key <q>, that is reserved internally for quitting watch mode. Please change the configuration key for this plugin.
 
-Third-party plugins are also forbidden to overwrite a key reserved already by another third-party plugin present earlier in the configured plugins list (`watchPlugins` array setting). When this happens, you’ll also get a code-64 exit with an error message that tries to help you fix that:
+Third-party plugins are also forbidden to overwrite a key reserved already by another third-party plugin present earlier in the configured plugins list (`watchPlugins` array setting). When this happens, you’ll also get an error message that tries to help you fix that:
 
-> Jest configuration error: watch plugins YourFaultyPlugin and TheirFaultyPlugin both attempted to register key <x>. Please change the key configuration for one of the conflicting plugins to avoid overlap.
+> Watch plugins YourFaultyPlugin and TheirFaultyPlugin both attempted to register key <x>. Please change the key configuration for one of the conflicting plugins to avoid overlap.

packages/jest-cli/src/__tests__/watch.test.js

@@ -12,7 +12,6 @@ import chalk from 'chalk';
 import TestWatcher from '../TestWatcher';
 import {JestHook, KEYS} from 'jest-watcher';
 
-const exitMock = jest.fn();
 const runJestMock = jest.fn();
 const watchPluginPath = `${__dirname}/__fixtures__/watch_plugin`;
 const watchPlugin2Path = `${__dirname}/__fixtures__/watch_plugin2`;
@@ -44,7 +43,6 @@ jest.mock(
 );
 
 jest.doMock('chalk', () => new chalk.constructor({enabled: false}));
-jest.doMock('exit', () => exitMock);
 jest.doMock(
   '../runJest',
   () =>
@@ -98,7 +96,6 @@ const watch = require('../watch').default;
 const nextTick = () => new Promise(res => process.nextTick(res));
 
 afterEach(runJestMock.mockReset);
-afterEach(exitMock.mockReset);
 
 describe('Watch mode flows', () => {
   let pipe;
@@ -368,14 +365,6 @@ describe('Watch mode flows', () => {
   });
 
   describe('when dealing with potential watch plugin key conflicts', () => {
-    beforeEach(() => {
-      jest.spyOn(console, 'error');
-      console.error.mockImplementation(() => {});
-    });
-
-    afterEach(() => {
-      console.error.mockRestore();
-    });
 
     it.each`
       key    | plugin
@@ -404,27 +393,23 @@ describe('Watch mode flows', () => {
           {virtual: true},
         );
 
-        watch(
-          Object.assign({}, globalConfig, {
-            rootDir: __dirname,
-            watchPlugins: [{config: {}, path: pluginPath}],
-          }),
-          contexts,
-          pipe,
-          hasteMapInstances,
-          stdin,
-        );
-
-        expect(console.error).toHaveBeenLastCalledWith(
-          expect.stringMatching(
-            new RegExp(
-              `Jest configuration error: watch plugin OffendingWatchPlugin attempted to register key <${key}>, that is reserved internally for .+\\.\\s+Please change the configuration key for this plugin\\.`,
-              'm',
-            ),
+        expect(() => {
+          watch(
+            Object.assign({}, globalConfig, {
+              rootDir: __dirname,
+              watchPlugins: [{config: {}, path: pluginPath}],
+            }),
+            contexts,
+            pipe,
+            hasteMapInstances,
+            stdin,
+          );
+        }).toThrowError(
+          new RegExp(
+            `Watch plugin OffendingWatchPlugin attempted to register key <${key}>,\\s+that is reserved internally for .+\\.\\s+Please change the configuration key for this plugin\\.`,
+            'm',
           ),
         );
-
-        expect(exitMock).toHaveBeenCalled();
       },
     );
 
@@ -466,8 +451,6 @@ describe('Watch mode flows', () => {
           hasteMapInstances,
           stdin,
         );
-
-        expect(exitMock).not.toHaveBeenCalled();
       },
     );
 
@@ -497,24 +480,20 @@ describe('Watch mode flows', () => {
         return pluginPath;
       });
 
-      watch(
-        Object.assign({}, globalConfig, {
-          rootDir: __dirname,
-          watchPlugins: pluginPaths.map(path => ({config: {}, path})),
-        }),
-        contexts,
-        pipe,
-        hasteMapInstances,
-        stdin,
-      );
-
-      expect(console.error).toHaveBeenLastCalledWith(
-        expect.stringMatching(
-          /Jest configuration error: watch plugins OffendingFooThirdPartyWatchPlugin and OffendingBarThirdPartyWatchPlugin both attempted to register key <!>\.\s+Please change the key configuration for one of the conflicting plugins to avoid overlap\./m,
-        ),
+      expect(() => {
+        watch(
+          Object.assign({}, globalConfig, {
+            rootDir: __dirname,
+            watchPlugins: pluginPaths.map(path => ({config: {}, path})),
+          }),
+          contexts,
+          pipe,
+          hasteMapInstances,
+          stdin,
+        );
+      }).toThrowError(
+        /Watch plugins OffendingFooThirdPartyWatchPlugin and OffendingBarThirdPartyWatchPlugin both attempted to register key <!>\.\s+Please change the key configuration for one of the conflicting plugins to avoid overlap\./m,
       );
-
-      expect(exitMock).toHaveBeenCalled();
     });
   });
 

packages/jest-cli/src/watch.js

@@ -37,6 +37,7 @@ import {
   getSortedUsageRows,
   filterInteractivePlugins,
 } from './lib/watch_plugins_helpers';
+import {ValidationError} from 'jest-validate';
 import activeFilters from './lib/active_filters_message';
 
 let hasExitListener = false;
@@ -411,7 +412,6 @@ const checkForConflicts = (watchPluginKeys, plugin, globalConfig) => {
   }
 
   const conflictor = watchPluginKeys.get(key);
-
   if (!conflictor || conflictor.overwritable) {
     watchPluginKeys.set(key, {
       overwritable: false,
@@ -422,19 +422,26 @@ const checkForConflicts = (watchPluginKeys, plugin, globalConfig) => {
 
   let error;
   if (conflictor.forbiddenOverwriteMessage) {
-    error = `Jest configuration error: watch plugin ${getPluginIdentifier(
-      plugin,
-    )} attempted to register key <${key}>, that is reserved internally for ${
-      conflictor.forbiddenOverwriteMessage
-    }.   Please change the configuration key for this plugin.`;
+    error = `
+  Watch plugin ${chalk.bold.red(
+    getPluginIdentifier(plugin),
+  )} attempted to register key ${chalk.bold.red(`<${key}>`)},
+  that is reserved internally for ${chalk.bold.red(
+    conflictor.forbiddenOverwriteMessage,
+  )}.
+  Please change the configuration key for this plugin.`.trim();
   } else {
     const plugins = [conflictor.plugin, plugin]
-      .map(getPluginIdentifier)
+      .map(p => chalk.bold.red(getPluginIdentifier(p)))
       .join(' and ');
-    error = `Jest configuration error: watch plugins ${plugins} both attempted to register key <${key}>. Please change the key configuration for one of the conflicting plugins to avoid overlap.`;
+    error = `
+  Watch plugins ${plugins} both attempted to register key ${chalk.bold.red(
+      `<${key}>`,
+    )}.
+  Please change the key configuration for one of the conflicting plugins to avoid overlap.`.trim();
   }
-  console.error('\n\n' + chalk.red(error));
-  exit(64); // EX_USAGE
+
+  throw new ValidationError('Watch plugin configuration error', error);
 };
 
 const getPluginIdentifier = plugin =>