Ignore null bytes when measuring character widths in React editor

Fixes #2391

spec/editor-component-spec.coffee

@@ -227,6 +227,11 @@ describe "EditorComponent", ->
         else
           [node]
 
+    describe "when the buffer contains null bytes", ->
+      it "excludes the null byte from character measurement", ->
+        editor.setText("a\0b")
+        expect(editor.pixelPositionForScreenPosition([0, Infinity]).left).toEqual 2 * charWidth
+
   describe "gutter rendering", ->
     [lineNumberHasClass, gutter] = []
 

src/display-buffer.coffee

@@ -522,7 +522,7 @@ class DisplayBuffer extends Model
       charWidths = @getScopedCharWidths(token.scopes)
       for char in token.value
         return {top, left} if column is targetColumn
-        left += charWidths[char] ? defaultCharWidth
+        left += charWidths[char] ? defaultCharWidth unless char is '\0'
         column++
     {top, left}
 

src/lines-component.coffee

@@ -232,6 +232,8 @@ LinesComponent = React.createClass
       charWidths = editor.getScopedCharWidths(scopes)
 
       for char in value
+        continue if char is '\0'
+
         unless charWidths[char]?
           unless textNode?
             rangeForMeasurement ?= document.createRange()