Get indent guide specs passing again

spec/editor-component-spec.coffee

@@ -98,7 +98,7 @@ describe "EditorComponent", ->
         expect(line1LeafNodes[0].classList.contains('indent-guide')).toBe true
         expect(line1LeafNodes[1].classList.contains('indent-guide')).toBe false
 
-        line2LeafNodes = getLeafNodes(component.lineNodeForScreenRow(1))
+        line2LeafNodes = getLeafNodes(component.lineNodeForScreenRow(2))
         expect(line2LeafNodes[0].textContent).toBe '  '
         expect(line2LeafNodes[0].classList.contains('indent-guide')).toBe true
         expect(line2LeafNodes[1].textContent).toBe '  '
@@ -108,8 +108,7 @@ describe "EditorComponent", ->
       it "renders leading whitespace spans with the 'indent-guide' class for empty lines", ->
         editor.getBuffer().insert([1, Infinity], '\n')
 
-        lines = node.querySelectorAll('.line')
-        line2LeafNodes = getLeafNodes(lines[2])
+        line2LeafNodes = getLeafNodes(component.lineNodeForScreenRow(2))
 
         expect(line2LeafNodes.length).toBe 3
         expect(line2LeafNodes[0].textContent).toBe '  '
@@ -121,8 +120,7 @@ describe "EditorComponent", ->
 
       it "renders indent guides correctly on lines containing only whitespace", ->
         editor.getBuffer().insert([1, Infinity], '\n      ')
-        lines = node.querySelectorAll('.line')
-        line2LeafNodes = getLeafNodes(lines[2])
+        line2LeafNodes = getLeafNodes(component.lineNodeForScreenRow(2))
         expect(line2LeafNodes.length).toBe 3
         expect(line2LeafNodes[0].textContent).toBe '  '
         expect(line2LeafNodes[0].classList.contains('indent-guide')).toBe true
@@ -132,9 +130,8 @@ describe "EditorComponent", ->
         expect(line2LeafNodes[2].classList.contains('indent-guide')).toBe true
 
       it "does not render indent guides in trailing whitespace for lines containing non whitespace characters", ->
-        editor.getBuffer().setText ("  hi  ")
-        lines = node.querySelectorAll('.line')
-        line0LeafNodes = getLeafNodes(lines[0])
+        editor.getBuffer().setText "  hi  "
+        line0LeafNodes = getLeafNodes(component.lineNodeForScreenRow(0))
         expect(line0LeafNodes[0].textContent).toBe '  '
         expect(line0LeafNodes[0].classList.contains('indent-guide')).toBe true
         expect(line0LeafNodes[1].textContent).toBe '  '

src/lines-component.coffee

@@ -46,6 +46,7 @@ LinesComponent = React.createClass
   componentDidUpdate: (prevProps) ->
     @measureLineHeightAndCharWidth() unless isEqualForProperties(prevProps, @props, 'fontSize', 'fontFamily', 'lineHeight')
     @clearScreenRowCaches() unless prevProps.lineHeight is @props.lineHeight
+    @removeLineNodes() unless prevProps.showIndentGuide is @props.showIndentGuide
     @updateLines()
     @clearScopedCharWidths() unless isEqualForProperties(prevProps, @props, 'fontSize', 'fontFamily')
     @measureCharactersInNewLines() unless @props.scrollingVertically
@@ -62,10 +63,10 @@ LinesComponent = React.createClass
     endRow = Math.min(editor.getLineCount(), endRow + lineOverdrawMargin)
 
     visibleLines = editor.linesForScreenRows(startRow, endRow - 1)
-    @removeNonVisibleLineNodes(visibleLines)
+    @removeLineNodes(visibleLines)
     @appendOrUpdateVisibleLineNodes(visibleLines, startRow)
 
-  removeNonVisibleLineNodes: (visibleLines) ->
+  removeLineNodes: (visibleLines=[]) ->
     visibleLineIds = new Set
     visibleLineIds.add(line.id.toString()) for line in visibleLines
     node = @getDOMNode()
@@ -117,13 +118,23 @@ LinesComponent = React.createClass
     lineHTML = "<div class=\"line\" style=\"position: absolute; top: #{top}px;\">"
 
     if text is ""
-      lineHTML += "&nbsp;"
+      lineHTML += @buildEmptyLineInnerHTML(line)
     else
       lineHTML += @buildLineInnerHTML(line)
 
     lineHTML += "</div>"
     lineHTML
 
+  buildEmptyLineInnerHTML: (line) ->
+    {showIndentGuide} = @props
+    {indentLevel, tabLength} = line
+
+    if showIndentGuide and indentLevel > 0
+      indentSpan = "<span class='indent-guide'>#{multiplyString(' ', tabLength)}</span>"
+      multiplyString(indentSpan, indentLevel + 1)
+    else
+      "&nbsp;"
+
   buildLineInnerHTML: (line) ->
     {invisibles, mini, showIndentGuide} = @props
     {tokens, text} = line