From dc49660249b152dec9f6c6e498194da03fa56618 Mon Sep 17 00:00:00 2001
From: "Kent C. Dodds" <kent@doddsfamily.us>
Date: Fri, 20 Jan 2017 12:13:43 -0700
Subject: [PATCH] fix(modules): use prettier-eslint versions of modules if
 needed

This way you can install prettier-eslint and not have
prettier or eslint installed yourself and it should
still work.
---
 package.json                                        |  2 +-
 src/__mocks__/eslint.js                             |  9 +++++++--
 src/__mocks__/prettier.js                           |  1 +
 src/index.js                                        |  7 ++++++-
 src/index.test.js                                   | 12 ++++++++++++
 tests/fixtures/paths/node_modules/eslint/index.js   | 13 +++++++++++--
 tests/fixtures/paths/node_modules/prettier/index.js | 13 +++++++++++--
 7 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/package.json b/package.json
index 685557c4..487045f4 100644
--- a/package.json
+++ b/package.json
@@ -52,7 +52,7 @@
     }
   },
   "jest": {
-    "testEnvironment": "node",
+    "testEnvironment": "jest-environment-node",
     "coverageThreshold": {
       "global": {
         "branches": 100,
diff --git a/src/__mocks__/eslint.js b/src/__mocks__/eslint.js
index fb519228..a944b8d5 100644
--- a/src/__mocks__/eslint.js
+++ b/src/__mocks__/eslint.js
@@ -1,5 +1,5 @@
 // this mock file is so eslint doesn't attempt to actually
-// search around the filesystem for stuff
+// search around the file system for stuff
 
 const eslint = require.requireActual('eslint')
 const {CLIEngine} = eslint
@@ -17,9 +17,14 @@ module.exports = Object.assign(eslint, {
 })
 
 function MockCLIEngine(...args) {
+  global.__PRETTIER_ESLINT_TEST_STATE__.eslintPath = __filename
   CLIEngine.apply(this, args)
+  // not sure why, but in some cases, this.executeOnText is undefined...
+  // so we create a fakeCLIEngine to get a copy of that function
+  // and call it with apply :)
+  const fakeCLIEngine = new CLIEngine(...args)
   this.getConfigForFile = mockGetConfigForFileSpy
-  this._originalExecuteOnText = this.executeOnText
+  this._originalExecuteOnText = fakeCLIEngine.executeOnText
   this.executeOnText = mockExecuteOnTextSpy
 }
 
diff --git a/src/__mocks__/prettier.js b/src/__mocks__/prettier.js
index e7412083..ab323db1 100644
--- a/src/__mocks__/prettier.js
+++ b/src/__mocks__/prettier.js
@@ -10,6 +10,7 @@ Object.assign(prettier, {
 })
 
 function mockFormat(...args) {
+  global.__PRETTIER_ESLINT_TEST_STATE__.prettierPath = __filename
   if (mockFormatSpy.throwError) {
     throw mockFormatSpy.throwError
   }
diff --git a/src/index.js b/src/index.js
index 4577f8cd..eef649f5 100644
--- a/src/index.js
+++ b/src/index.js
@@ -120,7 +120,12 @@ function getConfig(filePath, eslintPath) {
 }
 
 function getModulePath(filePath = __filename, moduleName) {
-  return requireRelative.resolve(moduleName, filePath)
+  try {
+    return requireRelative.resolve(moduleName, filePath)
+  } catch (error) {
+    logError(`There was a problem finding the ${moduleName} module. Using prettier-eslint's version`, error.stack)
+    return require.resolve(moduleName)
+  }
 }
 
 function getESLintCLIEngine(eslintPath, eslintOptions) {
diff --git a/src/index.test.js b/src/index.test.js
index d03b2a84..cd86c6bd 100644
--- a/src/index.test.js
+++ b/src/index.test.js
@@ -203,6 +203,18 @@ test('resolves to the eslint module relative to the given filePath', () => {
   })
 })
 
+test('resolves to the local eslint module if none is found via the filePath', () => {
+  const filePath = '/blah-blah/default-config'
+  format({text: '', filePath})
+  expect(global.__PRETTIER_ESLINT_TEST_STATE__).toMatchObject({
+    // without Jest's mocking, these would actually resolve to the
+    // project modules :) The fact that jest's mocking is being
+    // applied is good enough for this test.
+    eslintPath: require.resolve('./__mocks__/eslint'),
+    prettierPath: require.resolve('./__mocks__/prettier'),
+  })
+})
+
 function getESLintConfigWithDefaultRules(overrides) {
   return {
     parserOptions: {
diff --git a/tests/fixtures/paths/node_modules/eslint/index.js b/tests/fixtures/paths/node_modules/eslint/index.js
index 811e3317..1544d74e 100644
--- a/tests/fixtures/paths/node_modules/eslint/index.js
+++ b/tests/fixtures/paths/node_modules/eslint/index.js
@@ -1,3 +1,12 @@
-module.exports = require('../../../../../src/__mocks__/eslint')
-global.__PRETTIER_ESLINT_TEST_STATE__.eslintPath = __filename
+const eslintMock = require('../../../../../src/__mocks__/eslint')
+module.exports = Object.assign({}, eslintMock, {
+  CLIEngine: MockMockCLIEngine
+})
 
+function MockMockCLIEngine(...args) {
+  try {
+    return eslintMock.CLIEngine.apply(this, args)
+  } finally {
+    global.__PRETTIER_ESLINT_TEST_STATE__.eslintPath = __filename
+  }
+}
diff --git a/tests/fixtures/paths/node_modules/prettier/index.js b/tests/fixtures/paths/node_modules/prettier/index.js
index a857f86f..69adb190 100644
--- a/tests/fixtures/paths/node_modules/prettier/index.js
+++ b/tests/fixtures/paths/node_modules/prettier/index.js
@@ -1,2 +1,11 @@
-module.exports = require('../../../../../src/__mocks__/prettier')
-global.__PRETTIER_ESLINT_TEST_STATE__.prettierPath = __filename
+const mockPrettier = require('../../../../../src/__mocks__/prettier')
+
+module.exports = {format: mockMockFormat}
+
+function mockMockFormat(...args) {
+  try {
+    return mockPrettier.format(...args)
+  } finally {
+    global.__PRETTIER_ESLINT_TEST_STATE__.prettierPath = __filename
+  }
+}