editor: Fix soft-wrap in auto-height editors (#54051)

We had an internal report of soft wrap not working in git panel's commit
editor. Given the following settings:
```json
{
  "languages": {
    "Git Commit": {
      "preferred_line_length": 80,
      "soft_wrap": "preferred_line_length",
    },
  },
}
```
We would not soft-wrap in narrow viewports. As it turned out, the
problem was that we were always prefering a `preferred_line_length` as
our soft wrap boundary over the actual width of the editor.

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [ ] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [ ] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Closes #ISSUE

Release Notes:

- Fixed git commits editor not respecting soft wrap boundaries.
- settings: Removed `"soft_wrap": "preferred_line_length"` in favour of
`"soft_wrap": "bounded"`. Soft wrap now always respects editor width
when it's enabled.

assets/settings/default.json

@@ -1393,9 +1393,7 @@
   //      "soft_wrap": "prefer_line", // (deprecated, same as "none")
   // 2. Soft wrap lines that overflow the editor.
   //      "soft_wrap": "editor_width",
-  // 3. Soft wrap lines at the preferred line length.
-  //      "soft_wrap": "preferred_line_length",
-  // 4. Soft wrap lines at the preferred line length or the editor width (whichever is smaller).
+  // 3. Soft wrap lines at the preferred line length or the editor width (whichever is smaller).
   //      "soft_wrap": "bounded",
   "soft_wrap": "none",
   // The column at which to soft-wrap lines, for buffers where soft-wrap

crates/editor/src/editor.rs

@@ -550,8 +550,6 @@ pub enum SoftWrap {
     None,
     /// Soft wrap lines that exceed the editor width.
     EditorWidth,
-    /// Soft wrap lines at the preferred line length.
-    Column(u32),
     /// Soft wrap line at the preferred line length or the editor width (whichever is smaller).
     Bounded(u32),
 }
@@ -21924,9 +21922,6 @@ impl Editor {
         let settings = self.buffer.read(cx).language_settings(cx);
         if settings.show_wrap_guides {
             match self.soft_wrap_mode(cx) {
-                SoftWrap::Column(soft_wrap) => {
-                    wrap_guides.push((soft_wrap as usize, true));
-                }
                 SoftWrap::Bounded(soft_wrap) => {
                     wrap_guides.push((soft_wrap as usize, true));
                 }
@@ -21946,9 +21941,6 @@ impl Editor {
                 SoftWrap::None
             }
             language_settings::SoftWrap::EditorWidth => SoftWrap::EditorWidth,
-            language_settings::SoftWrap::PreferredLineLength => {
-                SoftWrap::Column(settings.preferred_line_length)
-            }
             language_settings::SoftWrap::Bounded => {
                 SoftWrap::Bounded(settings.preferred_line_length)
             }
@@ -22025,9 +22017,7 @@ impl Editor {
             let soft_wrap = match self.soft_wrap_mode(cx) {
                 SoftWrap::GitDiff => return,
                 SoftWrap::None => language_settings::SoftWrap::EditorWidth,
-                SoftWrap::EditorWidth | SoftWrap::Column(_) | SoftWrap::Bounded(_) => {
-                    language_settings::SoftWrap::None
-                }
+                SoftWrap::EditorWidth | SoftWrap::Bounded(_) => language_settings::SoftWrap::None,
             };
             self.soft_wrap_mode_override = Some(soft_wrap);
         }

crates/editor/src/element.rs

@@ -12403,7 +12403,6 @@ fn calculate_wrap_width(
         SoftWrap::GitDiff => None,
         SoftWrap::None => Some(wrap_width_for(MAX_LINE_LEN as u32 / 2)),
         SoftWrap::EditorWidth => Some(editor_width),
-        SoftWrap::Column(column) => Some(wrap_width_for(column)),
         SoftWrap::Bounded(column) => Some(editor_width.min(wrap_width_for(column))),
     }
 }
@@ -12442,7 +12441,8 @@ fn compute_auto_height_layout(
     let overscroll = size(em_width, px(0.));
 
     let editor_width = text_width - gutter_dimensions.margin - overscroll.width - em_width;
-    let wrap_width = calculate_wrap_width(editor.soft_wrap_mode(cx), editor_width, em_width);
+    let wrap_width = calculate_wrap_width(editor.soft_wrap_mode(cx), editor_width, em_width)
+        .map(|width| width.min(editor_width));
     if wrap_width.is_some() && editor.set_wrap_width(wrap_width, cx) {
         snapshot = editor.snapshot(window, cx);
     }
@@ -12807,7 +12807,7 @@ mod tests {
 
         update_test_language_settings(cx, &|s| {
             s.defaults.preferred_line_length = Some(5_u32);
-            s.defaults.soft_wrap = Some(language_settings::SoftWrap::PreferredLineLength);
+            s.defaults.soft_wrap = Some(language_settings::SoftWrap::Bounded);
         });
 
         let editor = window.root(cx).unwrap();
@@ -13163,7 +13163,7 @@ mod tests {
                     s.defaults.tab_size = NonZeroU32::new(tab_size);
                     s.defaults.show_whitespaces = Some(ShowWhitespaceSetting::All);
                     s.defaults.preferred_line_length = Some(editor_width as u32);
-                    s.defaults.soft_wrap = Some(language_settings::SoftWrap::PreferredLineLength);
+                    s.defaults.soft_wrap = Some(language_settings::SoftWrap::Bounded);
                 });
 
                 let actual_invisibles = collect_invisibles_from_new_editor(
@@ -13615,11 +13615,6 @@ mod tests {
             Some(px(800.0)),
         );
 
-        assert_eq!(
-            calculate_wrap_width(SoftWrap::Column(72), editor_width, em_width),
-            Some(px((72.0 * 8.0_f32).ceil())),
-        );
-
         assert_eq!(
             calculate_wrap_width(SoftWrap::Bounded(72), editor_width, em_width),
             Some(px((72.0 * 8.0_f32).ceil())),

crates/editor/src/scroll.rs

@@ -882,10 +882,8 @@ impl Editor {
         // configure the editor to only display a certain number of columns. If
         // that ever happens, this could probably be removed.
         let settings = AllLanguageSettings::get_global(cx);
-        if matches!(
-            settings.defaults.soft_wrap,
-            SoftWrap::PreferredLineLength | SoftWrap::Bounded
-        ) && (settings.defaults.preferred_line_length as f64) < visible_column_count
+        if matches!(settings.defaults.soft_wrap, SoftWrap::Bounded)
+            && (settings.defaults.preferred_line_length as f64) < visible_column_count
         {
             visible_column_count = settings.defaults.preferred_line_length as f64;
         }

crates/language/src/language.rs

@@ -108,7 +108,6 @@ pub(crate) fn to_settings_soft_wrap(value: language_core::SoftWrap) -> settings:
         language_core::SoftWrap::None => settings::SoftWrap::None,
         language_core::SoftWrap::PreferLine => settings::SoftWrap::PreferLine,
         language_core::SoftWrap::EditorWidth => settings::SoftWrap::EditorWidth,
-        language_core::SoftWrap::PreferredLineLength => settings::SoftWrap::PreferredLineLength,
         language_core::SoftWrap::Bounded => settings::SoftWrap::Bounded,
     }
 }

crates/language_core/src/language_config.rs

@@ -19,9 +19,8 @@ pub enum SoftWrap {
     PreferLine,
     /// Soft wrap lines that exceed the editor width.
     EditorWidth,
-    /// Soft wrap lines at the preferred line length.
-    PreferredLineLength,
     /// Soft wrap line at the preferred line length or the editor width (whichever is smaller).
+    #[serde(alias = "preferred_line_length")]
     Bounded,
 }
 

crates/settings_content/src/language.rs

@@ -394,9 +394,8 @@ pub enum SoftWrap {
     PreferLine,
     /// Soft wrap lines that exceed the editor width.
     EditorWidth,
-    /// Soft wrap lines at the preferred line length.
-    PreferredLineLength,
     /// Soft wrap line at the preferred line length or the editor width (whichever is smaller).
+    #[serde(alias = "preferred_line_length")]
     Bounded,
 }
 

crates/vim/src/test/neovim_backed_test_context.rs

@@ -287,8 +287,7 @@ impl NeovimBackedTestContext {
         self.update(|_, cx| {
             SettingsStore::update_global(cx, |settings, cx| {
                 settings.update_user_settings(cx, |settings| {
-                    settings.project.all_languages.defaults.soft_wrap =
-                        Some(SoftWrap::PreferredLineLength);
+                    settings.project.all_languages.defaults.soft_wrap = Some(SoftWrap::Bounded);
                     settings
                         .project
                         .all_languages

docs/src/reference/all-settings.md

@@ -2759,7 +2759,7 @@ To override settings for a language, add an entry for that languages name to the
     "C": {
       "format_on_save": "off",
       "preferred_line_length": 64,
-      "soft_wrap": "preferred_line_length"
+      "soft_wrap": "bounded"
     },
     "JSON": {
       "tab_size": 4
@@ -5494,7 +5494,7 @@ To preview and enable a settings profile, open the command palette via {#kb comm
       "format_on_save": "on",
       "formatter": "language_server",
       "preferred_line_length": 64,
-      "soft_wrap": "preferred_line_length"
+      "soft_wrap": "bounded"
     }
   }
 }