Merge pull request #1311 from Textualize/fix-1309

Empty containers with auto dimensions will collapse

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Changed
 
 - Rebuilt `DirectoryTree` with new `Tree` control.
+- Empty containers with a dimension set to `"auto"` will now collapse instead of filling up the available space.
 - Container widgets now have default height of `1fr`.
 - The default `width` of a `Label` is now `auto`.
 

src/textual/_layout.py

@@ -67,7 +67,7 @@ class Layout(ABC):
                 )
                 width = child_width if width is None else max(width, child_width)
         if width is None:
-            width = container.width
+            width = 0
 
         return width
 
@@ -86,7 +86,7 @@ class Layout(ABC):
             int: Content height (in lines).
         """
         if not widget.displayed_children:
-            height = container.height
+            height = 0
         else:
             placements, *_ = widget._arrange(Size(width, container.height))
             height = max(

src/textual/box_model.py

@@ -124,7 +124,7 @@ def get_box_model(
         )
         content_height = min(content_height, max_height)
 
-    content_height = max(Fraction(1), content_height)
+    content_height = max(Fraction(0), content_height)
     model = BoxModel(
         content_width + gutter.width, content_height + gutter.height, margin
     )

src/textual/layouts/horizontal.py

@@ -73,7 +73,7 @@ class HorizontalLayout(Layout):
             int: Width of the content.
         """
         if not widget.displayed_children:
-            width = container.width
+            width = 0
         else:
             placements, *_ = widget._arrange(container)
             width = max(

src/textual/widgets/_input.py

@@ -61,12 +61,13 @@ class Input(Widget, can_focus=True):
         border: tall $background;
         width: 100%;
         height: 1;
+        min-height: 1;
     }
     Input.-disabled {
         opacity: 0.6;
     }
     Input:focus {
-       border: tall $accent;
+        border: tall $accent;
     }
     Input>.input--cursor {
         background: $surface;

tests/layouts/test_content_dimensions.py

@@ -0,0 +1,28 @@
+import pytest
+
+from textual.layouts.grid import GridLayout
+from textual.layouts.horizontal import HorizontalLayout
+from textual.layouts.vertical import VerticalLayout
+from textual.geometry import Size
+from textual.widget import Widget
+
+
+LAYOUTS = [GridLayout, HorizontalLayout, VerticalLayout]
+
+
+@pytest.mark.parametrize("layout", LAYOUTS)
+def test_empty_widget_height(layout):
+    """Test that an empty widget has height equal to 0."""
+    l = layout()
+    # Make sure this measurement does not depend on the width.
+    assert l.get_content_height(Widget(), Size(80, 24), Size(80, 24), 24) == 0
+    assert l.get_content_height(Widget(), Size(80, 24), Size(80, 24), 20) == 0
+    assert l.get_content_height(Widget(), Size(80, 24), Size(80, 24), 10) == 0
+    assert l.get_content_height(Widget(), Size(80, 24), Size(80, 24), 0) == 0
+
+
+@pytest.mark.parametrize("layout", LAYOUTS)
+def test_empty_widget_width(layout):
+    """Test that an empty widget has width equal to 0."""
+    l = layout()
+    assert l.get_content_width(Widget(), Size(80, 24), Size(80, 24)) == 0

tests/test_box_model.py

@@ -100,7 +100,7 @@ def test_width():
 
 
 def test_height():
-    """Test width settings."""
+    """Test height settings."""
     styles = Styles()
     one = Fraction(1)
 
@@ -123,7 +123,7 @@ def test_height():
     )
     assert box_model == BoxModel(Fraction(54), Fraction(16), Spacing(1, 2, 3, 4))
 
-    # Set width to 100 vw which should make it the width of the parent
+    # Set height to 100 vw which should make it the height of the parent
     styles.height = "100vh"
 
     box_model = get_box_model(
@@ -131,7 +131,7 @@ def test_height():
     )
     assert box_model == BoxModel(Fraction(54), Fraction(24), Spacing(1, 2, 3, 4))
 
-    # Set the width to 100% should make it fill the container size
+    # Set the height to 100% should make it fill the container size
     styles.height = "100%"
 
     box_model = get_box_model(
@@ -156,6 +156,14 @@ def test_height():
     )
     assert box_model == BoxModel(Fraction(54), Fraction(10), Spacing(1, 2, 3, 4))
 
+    # Set height to auto and set content height to 0 to check if box collapses.
+    styles.height = "auto"
+
+    box_model = get_box_model(
+        styles, Size(60, 20), Size(80, 24), one, one, get_auto_width, lambda *_: 0
+    )
+    assert box_model == BoxModel(Fraction(54), Fraction(0), Spacing(1, 2, 3, 4))
+
 
 def test_max():
     """Check that max_width and max_height are respected."""