From 41a267d49b6087d521484b894a1a601369f17f95 Mon Sep 17 00:00:00 2001
From: "gcp-cherry-pick-bot[bot]"
 <98988430+gcp-cherry-pick-bot[bot]@users.noreply.github.com>
Date: Mon, 20 Jan 2025 10:48:23 +0100
Subject: [PATCH] editor: Hide horizontal scrollbar if not visible (cherry-pick
 #23337) (#23338)

Cherry-picked editor: Hide horizontal scrollbar if not visible (#23337)

This PR fixes two visual issues, that were caused by the fact that we
were always painting the horizontal scrollbar even if there is no
horizontal scrolling possible

Obscuring deleted lines when using the inline assistant:


https://github.com/user-attachments/assets/f8460c3f-403e-40a6-8622-65268ba2d875

Cutting off text even when horizontal scrolling is not possible:


https://github.com/user-attachments/assets/23c909f7-1c23-4693-8edc-40a2f089d4a8

This issue was only present in some themes (e.g. Nord, Catpuccin)


Closes #22716

Release Notes:

- Fixed an issue where horizontal scrollbars of editors would always be
painted (even if there is no horizontal scrolling to be done)

Co-authored-by: Bennet Bo Fenner <bennet@zed.dev>
---
 crates/assistant/src/inline_assistant.rs  | 1 +
 crates/assistant2/src/inline_assistant.rs | 1 +
 crates/editor/src/element.rs              | 8 ++++++--
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/crates/assistant/src/inline_assistant.rs b/crates/assistant/src/inline_assistant.rs
index 8acdaec50f..c9955cb9b4 100644
--- a/crates/assistant/src/inline_assistant.rs
+++ b/crates/assistant/src/inline_assistant.rs
@@ -1204,6 +1204,7 @@ impl InlineAssistant {
                     editor.set_show_wrap_guides(false, cx);
                     editor.set_show_gutter(false, cx);
                     editor.scroll_manager.set_forbid_vertical_scroll(true);
+                    editor.set_show_scrollbars(false, cx);
                     editor.set_read_only(true);
                     editor.set_show_inline_completions(Some(false), cx);
                     editor.highlight_rows::<DeletedLines>(
diff --git a/crates/assistant2/src/inline_assistant.rs b/crates/assistant2/src/inline_assistant.rs
index 6c142d376a..4c0b31741c 100644
--- a/crates/assistant2/src/inline_assistant.rs
+++ b/crates/assistant2/src/inline_assistant.rs
@@ -1276,6 +1276,7 @@ impl InlineAssistant {
                     editor.set_show_wrap_guides(false, cx);
                     editor.set_show_gutter(false, cx);
                     editor.scroll_manager.set_forbid_vertical_scroll(true);
+                    editor.set_show_scrollbars(false, cx);
                     editor.set_read_only(true);
                     editor.set_show_inline_completions(Some(false), cx);
                     editor.highlight_rows::<DeletedLines>(
diff --git a/crates/editor/src/element.rs b/crates/editor/src/element.rs
index 112b65f8fe..90abd3d629 100644
--- a/crates/editor/src/element.rs
+++ b/crates/editor/src/element.rs
@@ -1333,11 +1333,15 @@ impl EditorElement {
             total_text_units
                 .horizontal
                 .zip(track_bounds.horizontal)
-                .map(|(total_text_units_x, track_bounds_x)| {
+                .and_then(|(total_text_units_x, track_bounds_x)| {
+                    if text_units_per_page.horizontal >= total_text_units_x {
+                        return None;
+                    }
+
                     let thumb_percent =
                         (text_units_per_page.horizontal / total_text_units_x).min(1.);
 
-                    track_bounds_x.size.width * thumb_percent
+                    Some(track_bounds_x.size.width * thumb_percent)
                 }),
             total_text_units.vertical.zip(track_bounds.vertical).map(
                 |(total_text_units_y, track_bounds_y)| {