Flash red and show an error message when there's an error on moving a file

spec/extensions/tree-view-spec.coffee

@@ -554,6 +554,20 @@ describe "TreeView", ->
                 expect(fs.exists(newPath)).toBeTruthy()
                 expect(fs.exists(filePath)).toBeFalsy()
 
+          describe "when a file or directory already exists at the target path", ->
+            it "shows an error message and does not close the dialog", ->
+              runs ->
+                fs.write(fs.join(rootDirPath, 'target.txt'), '')
+                newPath = fs.join(rootDirPath, 'target.txt')
+                moveDialog.miniEditor.setText(newPath)
+
+                moveDialog.trigger 'tree-view:confirm'
+
+                expect(moveDialog.prompt.text()).toContain 'Error'
+                expect(moveDialog.prompt.text()).toContain 'already exists'
+                expect(moveDialog.prompt).toHaveClass('error')
+                expect(moveDialog.hasParent()).toBeTruthy()
+
         describe "when 'tree-view:cancel' is triggered on the move dialog", ->
           it "removes the dialog and focuses the tree view", ->
             treeView.attachToDom()

src/extensions/command-panel.coffee

@@ -47,9 +47,7 @@ class CommandPanel extends View
       @commandInterpreter.eval(@rootView.activeEditor(), command)
     catch error
       if error instanceof SyntaxError
-        @addClass 'error'
-        removeErrorClass = => @removeClass 'error'
-        window.setTimeout(removeErrorClass, 200)
+        @flashError()
         return
       else
         throw error

src/extensions/tree-view/dialog.coffee

@@ -25,10 +25,14 @@ class Dialog extends View
       @miniEditor.setSelectionBufferRange(range)
 
   confirm: ->
-    @onConfirm(@miniEditor.getText())
+    return if @onConfirm(@miniEditor.getText()) is false
     @remove()
     $('#root-view').focus()
 
   cancel: ->
     @remove()
     $('.tree-view').focus()
+
+  showError: (message) ->
+    @prompt.text(message)
+    @prompt.flashError()

src/extensions/tree-view/tree-view.coffee

@@ -151,8 +151,12 @@ class TreeView extends View
       onConfirm: (newPath) =>
         newPath = @rootView.project.resolve(newPath)
         directoryPath = fs.directory(newPath)
-        fs.makeDirectory(directoryPath) unless fs.exists(directoryPath)
-        fs.move(oldPath, newPath)
+        try
+          fs.makeDirectory(directoryPath) unless fs.exists(directoryPath)
+          fs.move(oldPath, newPath)
+        catch e
+          dialog.showError("Error: " + e.message + " Try a different path:")
+          return false
 
     @rootView.append(dialog)
 

src/stdlib/jquery-extensions.coffee

@@ -25,3 +25,8 @@ $.fn.preempt = (eventName, handler) ->
 
 $.fn.hasParent = ->
   @parent()[0]?
+
+$.fn.flashError = ->
+  @addClass 'error'
+  removeErrorClass = => @removeClass 'error'
+  window.setTimeout(removeErrorClass, 200)

static/atom.css

@@ -58,3 +58,8 @@ body {
   border-top: 5px solid #515151;
 }
 
+.error {
+  background: #991212;
+  -webkit-transition: background 200ms ease-out;
+}
+

static/command-panel.css

@@ -4,11 +4,6 @@
   background: #515151;
   display: -webkit-box;
   padding: 3px;
-  -webkit-transition: background 200ms ease-out;
-}
-
-.command-panel.error {
-  background: #991212;
 }
 
 .command-panel .prompt {