From 8018dc9d57f732b6d27aab104e2816e7b89eee0f Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Mon, 15 Aug 2016 17:05:18 -0700
Subject: [PATCH] Allow ATOM_HOME to be reassigned if the new value is valid

---
 spec/update-process-env-spec.js | 38 +++++++++++++++++++++++++++++++++
 src/update-process-env.js       |  5 +++++
 2 files changed, 43 insertions(+)

diff --git a/spec/update-process-env-spec.js b/spec/update-process-env-spec.js
index 39376b4c2..1de89beba 100644
--- a/spec/update-process-env-spec.js
+++ b/spec/update-process-env-spec.js
@@ -1,6 +1,8 @@
 /** @babel */
 /* eslint-env jasmine */
 
+import path from 'path'
+import temp from 'temp'
 import child_process from 'child_process'
 import {updateProcessEnv, shouldGetEnvFromShell} from '../src/update-process-env'
 import dedent from 'dedent'
@@ -44,6 +46,42 @@ describe('updateProcessEnv(launchEnv)', function () {
       // with another object.
       expect(process.env).toBe(initialProcessEnv)
     })
+
+    it('allows ATOM_HOME to be overwritten only if the new value is a valid path', function () {
+      newAtomHomePath = temp.mkdirSync('atom-home')
+
+      process.env = {
+        WILL_BE_DELETED: 'hi',
+        NODE_ENV: 'the-node-env',
+        NODE_PATH: '/the/node/path',
+        ATOM_HOME: '/the/atom/home'
+      }
+
+      updateProcessEnv({PWD: '/the/dir'})
+      expect(process.env).toEqual({
+        PWD: '/the/dir',
+        NODE_ENV: 'the-node-env',
+        NODE_PATH: '/the/node/path',
+        ATOM_HOME: '/the/atom/home'
+      })
+
+      updateProcessEnv({PWD: '/the/dir', ATOM_HOME: path.join(newAtomHomePath, 'non-existent')})
+      expect(process.env).toEqual({
+        PWD: '/the/dir',
+        NODE_ENV: 'the-node-env',
+        NODE_PATH: '/the/node/path',
+        ATOM_HOME: '/the/atom/home'
+      })
+
+
+      updateProcessEnv({PWD: '/the/dir', ATOM_HOME: newAtomHomePath})
+      expect(process.env).toEqual({
+        PWD: '/the/dir',
+        NODE_ENV: 'the-node-env',
+        NODE_PATH: '/the/node/path',
+        ATOM_HOME: newAtomHomePath
+      })
+    })
   })
 
   describe('when the launch environment does not come from a shell', function () {
diff --git a/src/update-process-env.js b/src/update-process-env.js
index 2bbbbfe7e..c65e8c4fd 100644
--- a/src/update-process-env.js
+++ b/src/update-process-env.js
@@ -1,5 +1,6 @@
 /** @babel */
 
+import fs from 'fs'
 import {spawnSync} from 'child_process'
 
 const ENVIRONMENT_VARIABLES_TO_PRESERVE = new Set([
@@ -37,6 +38,10 @@ function updateProcessEnv (launchEnv) {
         process.env[key] = envToAssign[key]
       }
     }
+
+    if (envToAssign.ATOM_HOME && fs.existsSync(envToAssign.ATOM_HOME)) {
+      process.env.ATOM_HOME = envToAssign.ATOM_HOME
+    }
   }
 }