Properly serialize pane focus state

spec/pane-container-model-spec.coffee

@@ -0,0 +1,16 @@
+PaneContainerModel = require '../src/pane-container-model'
+PaneModel = require '../src/pane-model'
+
+describe "PaneContainerModel", ->
+  describe "serialization", ->
+    it "preserves the focused pane across serialization", ->
+      pane1A = new PaneModel
+      containerA = new PaneContainerModel(root: pane1A)
+      pane2A = pane1A.splitRight()
+      pane3A = pane2A.splitDown()
+      expect(pane3A.focused).toBe true
+
+      containerB = containerA.testSerialization()
+      [pane1A, pane2A, pane3A] = containerB.getPanes()
+      expect(pane3A.focusContext).toBe containerB.focusContext
+      expect(pane3A.focused).toBe true

src/pane-axis-model.coffee

@@ -16,7 +16,7 @@ class PaneAxisModel extends Model
 
   @property 'focusContext'
 
-  constructor: ({@orientation, children}) ->
+  constructor: ({@focusContext, @orientation, children}) ->
     @children = Sequence.fromArray(children ? [])
 
     @subscribe @$focusContext, (focusContext) =>
@@ -33,7 +33,8 @@ class PaneAxisModel extends Model
     @when @children.$length.becomesLessThan(1), 'destroy'
 
   deserializeParams: (params) ->
-    params.children = params.children.map (childState) -> atom.deserializers.deserialize(childState)
+    {focusContext} = params
+    params.children = params.children.map (childState) -> atom.deserializers.deserialize(childState, {focusContext})
     params
 
   serializeParams: ->

src/pane-container-model.coffee

@@ -20,7 +20,8 @@ class PaneContainerModel extends Model
         root.focusContext = @focusContext
 
   deserializeParams: (params) ->
-    params.root = atom.deserializers.deserialize(params.root)
+    params.focusContext ?= new FocusContext
+    params.root = atom.deserializers.deserialize(params.root, focusContext: params.focusContext)
     params
 
   serializeParams: (params) ->

src/pane-model.coffee

@@ -13,12 +13,13 @@ class PaneModel extends Model
   Focusable.includeInto(this)
 
   @properties
-    items: -> []
     activeItem: null
 
   constructor: (params) ->
     super
 
+    @focus() if params?.focused
+
     @items = Sequence.fromArray(params?.items ? [])
     @activeItem ?= @items[0]