uimanager(fix): check active widgets in the correct order

frontend/ui/uimanager.lua

@@ -381,19 +381,33 @@ end
 -- transmit an event to an active widget
 function UIManager:sendEvent(event)
     if #self._window_stack == 0 then return end
+
+    local top_widget = self._window_stack[#self._window_stack]
     -- top level widget has first access to the event
-    if self._window_stack[#self._window_stack].widget:handleEvent(event) then
+    if top_widget.widget:handleEvent(event) then
         return
     end
-
-    -- if the event is not consumed, active widgets can access it
-    for _, widget in ipairs(self._window_stack) do
-        if widget.widget.is_always_active then
-            if widget.widget:handleEvent(event) then return end
+    if top_widget.widget.active_widgets then
+        for _, active_widget in ipairs(top_widget.widget.active_widgets) do
+            if active_widget:handleEvent(event) then return end
         end
-        if widget.widget.active_widgets then
-            for _, active_widget in ipairs(widget.widget.active_widgets) do
-                if active_widget:handleEvent(event) then return end
+    end
+
+    -- if the event is not consumed, active widgets (from top to bottom) can
+    -- access it. NOTE: _window_stack can shrink on close event
+    local checked_widgets = {top_widget}
+    for i = #self._window_stack-1, 1, -1 do
+        local widget = self._window_stack[i]
+        if checked_widgets[widget] == nil then
+            if widget.widget.is_always_active then
+                checked_widgets[widget] = true
+                if widget.widget:handleEvent(event) then return end
+            end
+            if widget.widget.active_widgets then
+                checked_widgets[widget] = true
+                for _, active_widget in ipairs(widget.widget.active_widgets) do
+                    if active_widget:handleEvent(event) then return end
+                end
             end
         end
     end

spec/unit/uimanager_spec.lua

@@ -191,4 +191,83 @@ describe("UIManager spec", function()
                        UIManager.auto_suspend_action)
         Device.isKobo = old_is_kobo
     end)
+
+    it("should check active widgets in order", function()
+        local call_signals = {false, false, false}
+        UIManager._window_stack = {
+            {
+                widget = {
+                    is_always_active = true,
+                    handleEvent = function()
+                        call_signals[1] = true
+                        return true
+                    end
+                }
+            },
+            {
+                widget = {
+                    is_always_active = true,
+                    handleEvent = function()
+                        call_signals[2] = true
+                        return true
+                    end
+                }
+            },
+            {
+                widget = {
+                    is_always_active = true,
+                    handleEvent = function()
+                        call_signals[3] = true
+                        return true
+                    end
+                }
+            },
+            {widget = {handleEvent = function()end}},
+        }
+
+        UIManager:sendEvent("foo")
+        assert.falsy(call_signals[1])
+        assert.falsy(call_signals[2])
+        assert.truthy(call_signals[3])
+    end)
+
+    it("should handle stack change when checking for active widgets", function()
+        -- this senario should only happen when other active widgets
+        -- are closed by the one widget's handleEvent
+
+        local call_signals = {0, 0, 0}
+        UIManager._window_stack = {
+            {
+                widget = {
+                    is_always_active = true,
+                    handleEvent = function()
+                        call_signals[1] = call_signals[1] + 1
+                    end
+                }
+            },
+            {
+                widget = {
+                    is_always_active = true,
+                    handleEvent = function()
+                        call_signals[2] = call_signals[2] + 1
+                    end
+                }
+            },
+            {
+                widget = {
+                    is_always_active = true,
+                    handleEvent = function()
+                        call_signals[3] = call_signals[3] + 1
+                        table.remove(UIManager._window_stack, 2)
+                    end
+                }
+            },
+            {widget = {handleEvent = function()end}},
+        }
+
+        UIManager:sendEvent("foo")
+        assert.is.same(call_signals[1], 1)
+        assert.is.same(call_signals[2], 0)
+        assert.is.same(call_signals[3], 1)
+    end)
 end)