From e6cac10a238c8b6ed095332133bb5a6d12bcb4ad Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Wed, 5 Oct 2016 12:03:53 -0700
Subject: [PATCH] Always return Disposable from maintain{Config,Grammar}

---
 spec/text-editor-registry-spec.js | 40 +++++++++++++++++++++++++++++++
 src/text-editor-registry.js       |  6 +++--
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/spec/text-editor-registry-spec.js b/spec/text-editor-registry-spec.js
index 812676305..05c9548b7 100644
--- a/spec/text-editor-registry-spec.js
+++ b/spec/text-editor-registry-spec.js
@@ -125,6 +125,25 @@ describe('TextEditorRegistry', function () {
       expect(editor.getGrammar().name).toBe('Null Grammar')
       expect(retainedEditorCount(registry)).toBe(0)
     })
+
+    describe('when called twice with a given editor', function () {
+      it('does nothing the second time', async function () {
+        await atom.packages.activatePackage('language-javascript')
+        const disposable1 = registry.maintainGrammar(editor)
+        const disposable2 = registry.maintainGrammar(editor)
+
+        editor.getBuffer().setPath('test.js')
+        expect(editor.getGrammar().name).toBe('JavaScript')
+
+        disposable2.dispose()
+        editor.getBuffer().setPath('test.txt')
+        expect(editor.getGrammar().name).toBe('Null Grammar')
+
+        disposable1.dispose()
+        editor.getBuffer().setPath('test.js')
+        expect(editor.getGrammar().name).toBe('Null Grammar')
+      })
+    })
   })
 
   describe('.setGrammarOverride', function () {
@@ -625,6 +644,27 @@ describe('TextEditorRegistry', function () {
       expect(delegate.getNonWordCharacters(['e.f', 'g.h'])).toBe('(){}[]')
       expect(delegate.getNonWordCharacters(['i.j'])).toBe('()')
     })
+
+    describe('when called twice with a given editor', function () {
+      it('does nothing the second time', async function () {
+        editor.update({scrollSensitivity: 50})
+
+        const disposable1 = registry.maintainConfig(editor)
+        const disposable2 = registry.maintainConfig(editor)
+        await initialPackageActivation
+
+        atom.config.set('editor.scrollSensitivity', 60)
+        expect(editor.getScrollSensitivity()).toBe(60)
+
+        disposable2.dispose()
+        atom.config.set('editor.scrollSensitivity', 70)
+        expect(editor.getScrollSensitivity()).toBe(70)
+
+        disposable1.dispose()
+        atom.config.set('editor.scrollSensitivity', 80)
+        expect(editor.getScrollSensitivity()).toBe(70)
+      })
+    })
   })
 
   describe('serialization', function () {
diff --git a/src/text-editor-registry.js b/src/text-editor-registry.js
index bda3712e7..9868df2d5 100644
--- a/src/text-editor-registry.js
+++ b/src/text-editor-registry.js
@@ -157,7 +157,7 @@ export default class TextEditorRegistry {
   // configuration.
   maintainConfig (editor) {
     if (this.editorsWithMaintainedConfig.has(editor)) {
-      return
+      return new Disposable(noop)
     }
     this.editorsWithMaintainedConfig.add(editor)
 
@@ -202,7 +202,7 @@ export default class TextEditorRegistry {
   // grammar.
   maintainGrammar (editor) {
     if (this.editorsWithMaintainedGrammar.has(editor)) {
-      return
+      return new Disposable(noop)
     }
 
     this.editorsWithMaintainedGrammar.add(editor)
@@ -391,6 +391,8 @@ function shouldEditorUseSoftTabs (editor, tabType, softTabs) {
   }
 }
 
+function noop () {}
+
 class ScopedSettingsDelegate {
   constructor (config) {
     this.config = config