Fix maintenance of grammars for copied editors

spec/text-editor-spec.coffee

@@ -57,7 +57,7 @@ describe "TextEditor", ->
         expect(editor.tokensForScreenRow(1).length).toBe 2 # soft tab
 
   describe ".copy()", ->
-    it "returns a different edit session with the same initial state", ->
+    it "returns a different editor with the same initial state", ->
       editor.setSelectedBufferRange([[1, 2], [3, 4]])
       editor.addSelectionForBufferRange([[5, 6], [7, 8]], reversed: true)
       editor.firstVisibleScreenRow = 5

src/null-grammar.js

@@ -1,4 +1,13 @@
+/** @babel */
+
+import {Disposable} from 'event-kit'
+
 module.exports = Object.freeze({
   name: 'Null Grammar',
-  scopeName: 'text.plain'
+  scopeName: 'text.plain',
+  onDidUpdate (callback) {
+    return new Disposable(noop)
+  }
 })
+
+function noop () {}

src/text-editor-registry.js

@@ -2,6 +2,7 @@
 
 import {Emitter, Disposable, CompositeDisposable} from 'event-kit'
 import {Point, Range} from 'atom'
+import NullGrammar from './null-grammar'
 
 const EDITOR_SETTER_NAMES_BY_SETTING_KEY = [
   ['core.fileEncoding', 'setEncoding'],
@@ -129,6 +130,10 @@ export default class TextEditorRegistry {
     }
 
     this.editorsWithMaintainedGrammar.add(editor)
+    if (editor.getGrammar() !== NullGrammar) {
+      this.editorGrammarOverrides[editor.id] = editor.getGrammar().scopeName
+    }
+
     this.selectGrammarForEditor(editor)
     this.subscriptions.add(editor.onDidChangePath(() => {
       this.editorGrammarScores.delete(editor)

src/text-editor.coffee

@@ -156,7 +156,7 @@ class TextEditor extends Model
 
     @buffer ?= new TextBuffer
     @tokenizedBuffer ?= new TokenizedBuffer({
-      @tabLength, @buffer, @largeFileMode, @assert
+      grammar, @tabLength, @buffer, @largeFileMode, @assert
     })
     @displayLayer ?= @buffer.addDisplayLayer()
     @displayLayer.setTextDecorationLayer(@tokenizedBuffer)
@@ -187,9 +187,6 @@ class TextEditor extends Model
       priority: 0
       visible: lineNumberGutterVisible
 
-    if grammar?
-      @setGrammar(grammar)
-
   serialize: ->
     tokenizedBufferState = @tokenizedBuffer.serialize()
 
@@ -557,13 +554,12 @@ class TextEditor extends Model
     displayLayer = @displayLayer.copy()
     selectionsMarkerLayer = displayLayer.getMarkerLayer(@buffer.getMarkerLayer(@selectionsMarkerLayer.id).copy().id)
     softTabs = @getSoftTabs()
-    newEditor = new TextEditor({
+    new TextEditor({
       @buffer, selectionsMarkerLayer, @tabLength, softTabs,
       suppressCursorCreation: true,
       @firstVisibleScreenRow, @firstVisibleScreenColumn,
-      @clipboard, @assert, displayLayer
+      @clipboard, @assert, displayLayer, grammar: @getGrammar()
     })
-    newEditor
 
   # Controls visibility based on the given {Boolean}.
   setVisible: (visible) -> @tokenizedBuffer.setVisible(visible)

src/tokenized-buffer.coffee

@@ -12,7 +12,7 @@ NullGrammar = require './null-grammar'
 
 module.exports =
 class TokenizedBuffer extends Model
-  grammar: NullGrammar
+  grammar: null
   buffer: null
   tabLength: null
   tokenizedLines: null
@@ -31,7 +31,7 @@ class TokenizedBuffer extends Model
     new this(state)
 
   constructor: (params) ->
-    {@buffer, @tabLength, @largeFileMode, @assert} = params
+    {grammar, @buffer, @tabLength, @largeFileMode, @assert} = params
 
     @emitter = new Emitter
     @disposables = new CompositeDisposable
@@ -40,7 +40,7 @@ class TokenizedBuffer extends Model
     @disposables.add @buffer.preemptDidChange (e) => @handleBufferChange(e)
     @rootScopeDescriptor = new ScopeDescriptor(scopes: ['text.plain'])
 
-    @retokenizeLines()
+    @setGrammar(grammar ? NullGrammar)
 
   destroyed: ->
     @disposables.dispose()
@@ -79,7 +79,7 @@ class TokenizedBuffer extends Model
   onDidTokenize: (callback) ->
     @emitter.on 'did-tokenize', callback
 
-  setGrammar: (grammar, score) ->
+  setGrammar: (grammar) ->
     return unless grammar? and grammar isnt @grammar
 
     @grammar = grammar

src/workspace.coffee

@@ -165,8 +165,8 @@ class Workspace extends Model
   subscribeToAddedItems: ->
     @onDidAddPaneItem ({item, pane, index}) =>
       if item instanceof TextEditor
-        # @textEditorRegistry.maintainConfig(item)
-        # @textEditorRegistry.maintainGrammar(item)
+        @textEditorRegistry.maintainConfig(item)
+        @textEditorRegistry.maintainGrammar(item)
         @emitter.emit 'did-add-text-editor', {textEditor: item, pane, index}
 
   # Updates the application's title and proxy icon based on whichever file is