Fix issue where height - totalvpad < 0 would cause render_lines crash

rich/console.py

@@ -1331,6 +1331,11 @@ def render_lines(
             _rendered = self.render(renderable, render_options)
             if style:
                 _rendered = Segment.apply_style(_rendered, style)
+
+            render_height = render_options.height
+            if render_height is not None:
+                render_height = max(0, render_height)
+
             lines = list(
                 islice(
                     Segment.split_and_crop_lines(
@@ -1340,7 +1345,7 @@ def render_lines(
                         pad=pad,
                     ),
                     None,
-                    render_options.height,
+                    render_height,
                 )
             )
             if render_options.height is not None:
@@ -2460,3 +2465,11 @@ def _svg_hash(svg_main_code: str) -> str:
             },
         }
     )
+    from rich.console import Console
+    from rich.padding import Padding
+
+    console = Console()
+    options = console.options.update_height(1)
+
+    padding = Padding("hello", pad=(1, 1, 1, 1))
+    console.render_lines(padding, options=options)

tests/test_console.py

@@ -20,6 +20,7 @@
 )
 from rich.control import Control
 from rich.measure import measure_renderables
+from rich.padding import Padding
 from rich.pager import SystemPager
 from rich.panel import Panel
 from rich.region import Region
@@ -988,3 +989,18 @@ def __rich_console__(self, console, options):
     expected = "╭──────────────────╮\n│ ╭──────────────╮ │\n│ │ foo          │ │\n│ ╰──────────────╯ │\n│ ╭──────────────╮ │\n│ │ bar          │ │\n│ ╰──────────────╯ │\n│                  │\n│                  │\n│                  │\n│                  │\n╰──────────────────╯\n"
 
     assert result == expected
+
+
+def test_render_lines_height_minus_vertical_pad_is_negative():
+    # https://github.com/Textualize/textual/issues/389
+    console = Console(
+        force_terminal=True,
+        color_system="truecolor",
+        width=20,
+        height=40,
+        legacy_windows=False,
+    )
+    options = console.options.update_height(1)
+
+    # Ensuring that no exception is raised...
+    console.render_lines(Padding("hello", pad=(1, 0)), options=options)