Merge pull request #2045 from atom/cj-tabs-be-weird

Make Atom smarter about guessing if a file uses soft or hard tabs

spec/editor-spec.coffee

@@ -2594,6 +2594,10 @@ describe "Editor", ->
         atom.workspace.open('sample-with-tabs.coffee', softTabs: true).then (editor) ->
           expect(editor.getSoftTabs()).toBeFalsy()
 
+      waitsForPromise ->
+        atom.workspace.open('sample-with-tabs-and-initial-comment.js', softTabs: true).then (editor) ->
+          expect(editor.getSoftTabs()).toBeFalsy()
+
       waitsForPromise ->
         atom.workspace.open(null, softTabs: false).then (editor) ->
           expect(editor.getSoftTabs()).toBeFalsy()

spec/fixtures/sample-with-tabs-and-initial-comment.js

@@ -0,0 +1,8 @@
+/**
+ * Look, this is a comment. Don't go making assumtions that I want soft tabs
+ * because this block comment has leading spaces, Geez.
+ */
+
+if (beNice) {
+	console.log('Thank you for being nice.');
+}

src/editor.coffee

@@ -160,7 +160,7 @@ class Editor extends Model
 
     @displayBuffer ?= new DisplayBuffer({buffer, tabLength, softWrap})
     @buffer = @displayBuffer.buffer
-    @softTabs = @buffer.usesSoftTabs() ? @softTabs ? atom.config.get('editor.softTabs') ? true
+    @softTabs = @usesSoftTabs() ? @softTabs ? atom.config.get('editor.softTabs') ? true
 
     for marker in @findMarkers(@getSelectionMarkerAttributes())
       marker.setAttributes(preserveFolds: true)
@@ -317,6 +317,19 @@ class Editor extends Model
   # Public: Set the on-screen length of tab characters.
   setTabLength: (tabLength) -> @displayBuffer.setTabLength(tabLength)
 
+  # Public: Determine if the buffer uses hard or soft tabs.
+  #
+  # Returns `true` if the first non-comment line with leading whitespace starts
+  # with a space character. Returns `false` if it starts with a hard tab (`\t`).
+  #
+  # Returns a {Boolean},
+  usesSoftTabs: ->
+    for bufferRow in [0..@buffer.getLastRow()]
+      continue if @displayBuffer.tokenizedBuffer.lineForScreenRow(bufferRow).isComment()
+      if match = @buffer.lineForRow(bufferRow).match(/^\s/)
+        return match[0][0] != '\t'
+    undefined
+
   # Public: Clip the given {Point} to a valid position in the buffer.
   #
   # If the given {Point} describes a position that is actually reachable by the