From af2f3c30c703c3b385c5df1e7bd41cd514f434a1 Mon Sep 17 00:00:00 2001
From: Qingping Hou <dave2008713@gmail.com>
Date: Sat, 18 Jun 2016 17:24:38 -0700
Subject: [PATCH] uimanager(fix): handle last widget in broadcast event
 properly

---
 frontend/ui/uimanager.lua    |  8 +++++--
 spec/unit/uimanager_spec.lua | 42 ++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/frontend/ui/uimanager.lua b/frontend/ui/uimanager.lua
index 6eb3a0863..7d7e994d1 100644
--- a/frontend/ui/uimanager.lua
+++ b/frontend/ui/uimanager.lua
@@ -418,8 +418,12 @@ function UIManager:broadcastEvent(event)
     while (i <= #self._window_stack) do
         local prev_widget = self._window_stack[i].widget
         self._window_stack[i].widget:handleEvent(event)
-        if (self._window_stack[i].widget == prev_widget) then
-          i = i + 1
+        local top_widget = self._window_stack[i]
+        if top_widget == nil then
+            -- top widget closed itself
+            break
+        elseif (top_window.widget == prev_widget) then
+            i = i + 1
         end
     end
 end
diff --git a/spec/unit/uimanager_spec.lua b/spec/unit/uimanager_spec.lua
index c502b5ef6..a8dd67832 100644
--- a/spec/unit/uimanager_spec.lua
+++ b/spec/unit/uimanager_spec.lua
@@ -303,4 +303,46 @@ describe("UIManager spec", function()
         assert.is.same(call_signals[2], 1)
         assert.is.same(call_signals[3], 1)
     end)
+
+    it("should handle stack change when broadcasting events", function()
+        UIManager._window_stack = {
+            {
+                widget = {
+                    handleEvent = function()
+                        UIManager._window_stack[1] = nil
+                    end
+                }
+            },
+        }
+        UIManager:broadcastEvent("foo")
+        assert.is.same(#UIManager._window_stack, 0)
+
+        UIManager._window_stack = {
+            {
+                widget = {
+                    handleEvent = function()
+                        UIManager._window_stack[1] = nil
+                        UIManager._window_stack[2] = nil
+                        UIManager._window_stack[3] = nil
+                    end
+                }
+            },
+            {
+                widget = {
+                    handleEvent = function()
+                        assert.falsy(true);
+                    end
+                }
+            },
+            {
+                widget = {
+                    handleEvent = function()
+                        assert.falsy(true);
+                    end
+                }
+            },
+        }
+        UIManager:broadcastEvent("foo")
+        assert.is.same(#UIManager._window_stack, 0)
+    end)
 end)