Log warning when ~/.atom/keymap.cson can't be parsed

Previously an uncaught error would be thrown and the file
would no longer be watched

spec/keymap-spec.coffee

@@ -400,6 +400,22 @@ describe "Keymap", ->
         keyBinding = keymap.keyBindingsForKeystroke('ctrl-l')[0]
         expect(keyBinding).toBeUndefined()
 
+    it "logs a warning when it can't be parsed", ->
+      keymapFilePath = path.join(configDirPath, "keymap.json")
+      fs.writeFileSync(keymapFilePath, '')
+      keymap.loadUserKeymap()
+
+      spyOn(keymap, 'loadUserKeymap').andCallThrough()
+      fs.writeFileSync(keymapFilePath, '}{')
+      spyOn(console, 'warn')
+
+      waitsFor ->
+        keymap.loadUserKeymap.callCount > 0
+
+      runs ->
+        expect(console.warn.callCount).toBe 1
+        expect(console.warn.argsForCall[0][0].length).toBeGreaterThan 0
+
   describe "when adding a binding with an invalid selector", ->
     it "logs a warning and does not add it", ->
       spyOn(console, 'warn')

src/keymap.coffee

@@ -135,9 +135,16 @@ class Keymap
     userKeymapPath = @getUserKeymapPath()
     if fs.isFileSync(userKeymapPath)
       @userKeymapPath = userKeymapPath
-      @load(userKeymapPath)
       @userKeymapFile = new File(userKeymapPath)
       @userKeymapFile.on 'contents-changed moved removed', => @loadUserKeymap()
+      @add(@userKeymapPath, @readUserKeymap())
+
+  readUserKeymap: ->
+    try
+      CSON.readFileSync(@userKeymapPath) ? {}
+    catch error
+      console.warn("Failed to load your keymap file: #{@userKeymapPath}", error.stack ? error)
+      {}
 
   loadDirectory: (directoryPath) ->
     platforms = ['darwin', 'freebsd', 'linux', 'sunos', 'win32']