Fix AnchorLayout children height bug (#8669)

kivy/tests/test_uix_anchorlayout.py

@@ -77,3 +77,40 @@ def test_anchor_layout_xy(self):
         layout = AnchorLayout(anchor_y='top', anchor_x='right')
         layout.add_widget(b(1, 0, 0))
         r(layout)
+
+
+class TestAnchorLayout:
+
+    def test_anchorlayout_no_height_control(self):
+        from kivy.uix.widget import Widget
+        from kivy.uix.anchorlayout import AnchorLayout
+
+        def update_height(widget, value):
+            widget.height = 2 * widget.width
+
+        widget = Widget(size_hint=(1, None))
+        widget.bind(width=update_height)
+        layout = AnchorLayout(size=(1000, 1000))
+        layout.add_widget(widget)
+
+        layout.do_layout()
+
+        assert widget.size == [1000, 2000]
+        assert widget.pos == [0, -500]
+
+    def test_anchorlayout_no_width_control(self):
+        from kivy.uix.widget import Widget
+        from kivy.uix.anchorlayout import AnchorLayout
+
+        def update_width(widget, value):
+            widget.width = 2 * widget.height
+
+        widget = Widget(size_hint=(None, 1))
+        widget.bind(height=update_width)
+        layout = AnchorLayout(size=(1000, 1000))
+        layout.add_widget(widget)
+
+        layout.do_layout()
+
+        assert widget.size == [2000, 1000]
+        assert widget.pos == [-500, 0]

kivy/uix/anchorlayout.py

@@ -86,7 +86,6 @@ def do_layout(self, *largs):
 
         for c in self.children:
             x, y = _x, _y
-            cw, ch = c.size
             shw, shh = c.size_hint
             shw_min, shh_min = c.size_hint_min
             shw_max, shh_max = c.size_hint_max
@@ -97,13 +96,17 @@ def do_layout(self, *largs):
                     cw = shw_min
                 elif shw_max is not None and cw > shw_max:
                     cw = shw_max
+                c.width = cw
 
             if shh is not None:
                 ch = shh * (height - pad_top - pad_bottom)
                 if shh_min is not None and ch < shh_min:
                     ch = shh_min
                 elif shh_max is not None and ch > shh_max:
                     ch = shh_max
+                c.height = ch
+
+            cw, ch = c.size
 
             if anchor_x == 'left':
                 x = x + pad_left
@@ -119,4 +122,3 @@ def do_layout(self, *largs):
                 y = y + (height - pad_top + pad_bottom - ch) / 2
 
             c.pos = x, y
-            c.size = cw, ch