From 5e62217928a67f773e1346ac622cfbc96692ca92 Mon Sep 17 00:00:00 2001
From: Stephan Dilly <dilly.stephan@gmail.com>
Date: Thu, 10 Jun 2021 09:56:20 +0200
Subject: [PATCH] fix commit msg details lockin (#780)

---
 src/components/branchlist.rs            |  2 +-
 src/components/revision_files.rs        | 27 +++++++++++++------------
 src/components/utils/scroll_vertical.rs | 16 +++++++++++++--
 3 files changed, 29 insertions(+), 16 deletions(-)

diff --git a/src/components/branchlist.rs b/src/components/branchlist.rs
index 9b368407..2240743b 100644
--- a/src/components/branchlist.rs
+++ b/src/components/branchlist.rs
@@ -51,7 +51,7 @@ impl DrawableComponent for BranchListComponent {
         f: &mut Frame<B>,
         rect: Rect,
     ) -> Result<()> {
-        if self.visible {
+        if self.is_visible() {
             const PERCENT_SIZE: Size = Size::new(80, 50);
             const MIN_SIZE: Size = Size::new(60, 20);
 
diff --git a/src/components/revision_files.rs b/src/components/revision_files.rs
index 8266509b..85846984 100644
--- a/src/components/revision_files.rs
+++ b/src/components/revision_files.rs
@@ -218,21 +218,22 @@ impl DrawableComponent for RevisionFilesComponent {
         f: &mut Frame<B>,
         area: Rect,
     ) -> Result<()> {
-        let chunks = Layout::default()
-            .direction(Direction::Horizontal)
-            .constraints(
-                [
-                    Constraint::Percentage(40),
-                    Constraint::Percentage(60),
-                ]
-                .as_ref(),
-            )
-            .split(area);
+        if self.is_visible() {
+            let chunks = Layout::default()
+                .direction(Direction::Horizontal)
+                .constraints(
+                    [
+                        Constraint::Percentage(40),
+                        Constraint::Percentage(60),
+                    ]
+                    .as_ref(),
+                )
+                .split(area);
 
-        self.draw_tree(f, chunks[0]);
-
-        self.current_file.draw(f, chunks[1])?;
+            self.draw_tree(f, chunks[0]);
 
+            self.current_file.draw(f, chunks[1])?;
+        }
         Ok(())
     }
 }
diff --git a/src/components/utils/scroll_vertical.rs b/src/components/utils/scroll_vertical.rs
index ed25d79f..e47d77a4 100644
--- a/src/components/utils/scroll_vertical.rs
+++ b/src/components/utils/scroll_vertical.rs
@@ -65,8 +65,12 @@ impl VerticalScroll {
         );
         self.top.set(new_top);
 
-        let new_max = selection_max.saturating_sub(visual_height);
-        self.max_top.set(new_max);
+        if visual_height == 0 {
+            self.max_top.set(0);
+        } else {
+            let new_max = selection_max.saturating_sub(visual_height);
+            self.max_top.set(new_max);
+        }
 
         new_top
     }
@@ -101,6 +105,9 @@ const fn calc_scroll_top(
     selection: usize,
     selection_max: usize,
 ) -> usize {
+    if height_in_lines == 0 {
+        return 0;
+    }
     if selection_max <= height_in_lines {
         return 0;
     }
@@ -123,4 +130,9 @@ mod tests {
     fn test_scroll_no_scroll_to_top() {
         assert_eq!(calc_scroll_top(1, 10, 4, 4), 0);
     }
+
+    #[test]
+    fn test_scroll_zero_height() {
+        assert_eq!(calc_scroll_top(4, 0, 4, 3), 0);
+    }
 }