preview tabs: Allow replacing preview tab when using code navigation (#10730)

This PR adds support for replacing the current preview tab when using
GoToDefinition. Previously a tab, that was navigated away from, was
converted into a permanent tab and the new tab was opened as preview.

Without `enable_preview_from_code_navigation`:


https://github.com/zed-industries/zed/assets/53836821/99840724-d6ff-4738-a9c4-ee71a0001634

With `enable_preview_from_code_navigation`:


https://github.com/zed-industries/zed/assets/53836821/8c60efcb-d597-40bf-b08b-13faf5a289b6

Note: In the future I would like to improve support for the navigation
history, because right now tabs that are not "normal" project items,
e.g. FindAllReferences cannot be reopened

Release Notes:

- Added support for replacing the current preview tab when using code
navigation (`enable_preview_from_code_navigation`)

crates/workspace/src/item.rs

@@ -45,6 +45,7 @@ pub struct ItemSettings {
 pub struct PreviewTabsSettings {
     pub enabled: bool,
     pub enable_preview_from_file_finder: bool,
+    pub enable_preview_from_code_navigation: bool,
 }
 
 #[derive(Clone, Default, Serialize, Deserialize, JsonSchema)]
@@ -78,15 +79,19 @@ pub struct ItemSettingsContent {
 
 #[derive(Clone, Default, Serialize, Deserialize, JsonSchema)]
 pub struct PreviewTabsSettingsContent {
-    /// Whether to show opened editors as preview editors.
-    /// Preview editors do not stay open, are reused until explicitly set to be kept open opened (via double-click or editing) and show file names in italic.
+    /// Whether to show opened editors as preview tabs.
+    /// Preview tabs do not stay open, are reused until explicitly set to be kept open opened (via double-click or editing) and show file names in italic.
     ///
     /// Default: true
     enabled: Option<bool>,
-    /// Whether to open a preview editor when opening a file using the file finder.
+    /// Whether to open tabs in preview mode when selected from the file finder.
     ///
     /// Default: false
     enable_preview_from_file_finder: Option<bool>,
+    /// Whether a preview tab gets replaced when code navigation is used to navigate away from the tab.
+    ///
+    /// Default: false
+    enable_preview_from_code_navigation: Option<bool>,
 }
 
 impl Settings for ItemSettings {

crates/workspace/src/pane.rs

@@ -623,21 +623,13 @@ impl Pane {
             self.activate_item(index, focus_item, focus_item, cx);
             existing_item
         } else {
-            let mut destination_index = None;
-            if allow_preview {
-                // If we are opening a new item as preview and we have an existing preview tab, remove it.
-                if let Some(item_idx) = self.preview_item_idx() {
-                    let prev_active_item_index = self.active_item_index;
-                    self.remove_item(item_idx, false, false, cx);
-                    self.active_item_index = prev_active_item_index;
-
-                    // If the item is being opened as preview and we have an existing preview tab,
-                    // open the new item in the position of the existing preview tab.
-                    if item_idx < self.items.len() {
-                        destination_index = Some(item_idx);
-                    }
-                }
-            }
+            // If the item is being opened as preview and we have an existing preview tab,
+            // open the new item in the position of the existing preview tab.
+            let destination_index = if allow_preview {
+                self.close_current_preview_item(cx)
+            } else {
+                None
+            };
 
             let new_item = build_item(cx);
 
@@ -651,6 +643,22 @@ impl Pane {
         }
     }
 
+    pub fn close_current_preview_item(&mut self, cx: &mut ViewContext<Self>) -> Option<usize> {
+        let Some(item_idx) = self.preview_item_idx() else {
+            return None;
+        };
+
+        let prev_active_item_index = self.active_item_index;
+        self.remove_item(item_idx, false, false, cx);
+        self.active_item_index = prev_active_item_index;
+
+        if item_idx < self.items.len() {
+            Some(item_idx)
+        } else {
+            None
+        }
+    }
+
     pub fn add_item(
         &mut self,
         item: Box<dyn ItemHandle>,

crates/workspace/src/workspace.rs

@@ -2061,14 +2061,20 @@ impl Workspace {
         }
     }
 
-    pub fn add_item_to_active_pane(&mut self, item: Box<dyn ItemHandle>, cx: &mut WindowContext) {
-        self.add_item(self.active_pane.clone(), item, cx)
+    pub fn add_item_to_active_pane(
+        &mut self,
+        item: Box<dyn ItemHandle>,
+        destination_index: Option<usize>,
+        cx: &mut WindowContext,
+    ) {
+        self.add_item(self.active_pane.clone(), item, destination_index, cx)
     }
 
     pub fn add_item(
         &mut self,
         pane: View<Pane>,
         item: Box<dyn ItemHandle>,
+        destination_index: Option<usize>,
         cx: &mut WindowContext,
     ) {
         if let Some(text) = item.telemetry_event_text(cx) {
@@ -2077,7 +2083,9 @@ impl Workspace {
                 .report_app_event(format!("{}: open", text));
         }
 
-        pane.update(cx, |pane, cx| pane.add_item(item, true, true, None, cx));
+        pane.update(cx, |pane, cx| {
+            pane.add_item(item, true, true, destination_index, cx)
+        });
     }
 
     pub fn split_item(
@@ -2087,7 +2095,7 @@ impl Workspace {
         cx: &mut ViewContext<Self>,
     ) {
         let new_pane = self.split_pane(self.active_pane.clone(), split_direction, cx);
-        self.add_item(new_pane, item, cx);
+        self.add_item(new_pane, item, None, cx);
     }
 
     pub fn open_abs_path(
@@ -2259,10 +2267,21 @@ impl Workspace {
         }
 
         let item = cx.new_view(|cx| T::for_project_item(self.project().clone(), project_item, cx));
+
+        let item_id = item.item_id();
+        let mut destination_index = None;
         pane.update(cx, |pane, cx| {
+            if PreviewTabsSettings::get_global(cx).enable_preview_from_code_navigation {
+                if let Some(preview_item_id) = pane.preview_item_id() {
+                    if preview_item_id != item_id {
+                        destination_index = pane.close_current_preview_item(cx);
+                    }
+                }
+            }
             pane.set_preview_item_id(Some(item.item_id()), cx)
         });
-        self.add_item(pane, Box::new(item.clone()), cx);
+
+        self.add_item(pane, Box::new(item.clone()), destination_index, cx);
         item
     }
 
@@ -5157,7 +5176,7 @@ mod tests {
             item
         });
         workspace.update(cx, |workspace, cx| {
-            workspace.add_item_to_active_pane(Box::new(item1.clone()), cx);
+            workspace.add_item_to_active_pane(Box::new(item1.clone()), None, cx);
         });
         item1.update(cx, |item, _| assert_eq!(item.tab_detail.get(), Some(0)));
 
@@ -5169,7 +5188,7 @@ mod tests {
             item
         });
         workspace.update(cx, |workspace, cx| {
-            workspace.add_item_to_active_pane(Box::new(item2.clone()), cx);
+            workspace.add_item_to_active_pane(Box::new(item2.clone()), None, cx);
         });
         item1.update(cx, |item, _| assert_eq!(item.tab_detail.get(), Some(1)));
         item2.update(cx, |item, _| assert_eq!(item.tab_detail.get(), Some(1)));
@@ -5183,7 +5202,7 @@ mod tests {
             item
         });
         workspace.update(cx, |workspace, cx| {
-            workspace.add_item_to_active_pane(Box::new(item3.clone()), cx);
+            workspace.add_item_to_active_pane(Box::new(item3.clone()), None, cx);
         });
         item1.update(cx, |item, _| assert_eq!(item.tab_detail.get(), Some(1)));
         item2.update(cx, |item, _| assert_eq!(item.tab_detail.get(), Some(3)));
@@ -5227,7 +5246,7 @@ mod tests {
 
         // Add an item to an empty pane
         workspace.update(cx, |workspace, cx| {
-            workspace.add_item_to_active_pane(Box::new(item1), cx)
+            workspace.add_item_to_active_pane(Box::new(item1), None, cx)
         });
         project.update(cx, |project, cx| {
             assert_eq!(
@@ -5241,7 +5260,7 @@ mod tests {
 
         // Add a second item to a non-empty pane
         workspace.update(cx, |workspace, cx| {
-            workspace.add_item_to_active_pane(Box::new(item2), cx)
+            workspace.add_item_to_active_pane(Box::new(item2), None, cx)
         });
         assert_eq!(cx.window_title().as_deref(), Some("two.txt — root1"));
         project.update(cx, |project, cx| {
@@ -5296,7 +5315,7 @@ mod tests {
         // When there are no dirty items, there's nothing to do.
         let item1 = cx.new_view(|cx| TestItem::new(cx));
         workspace.update(cx, |w, cx| {
-            w.add_item_to_active_pane(Box::new(item1.clone()), cx)
+            w.add_item_to_active_pane(Box::new(item1.clone()), None, cx)
         });
         let task = workspace.update(cx, |w, cx| w.prepare_to_close(false, cx));
         assert!(task.await.unwrap());
@@ -5310,8 +5329,8 @@ mod tests {
                 .with_project_items(&[TestProjectItem::new(1, "1.txt", cx)])
         });
         workspace.update(cx, |w, cx| {
-            w.add_item_to_active_pane(Box::new(item2.clone()), cx);
-            w.add_item_to_active_pane(Box::new(item3.clone()), cx);
+            w.add_item_to_active_pane(Box::new(item2.clone()), None, cx);
+            w.add_item_to_active_pane(Box::new(item3.clone()), None, cx);
         });
         let task = workspace.update(cx, |w, cx| w.prepare_to_close(false, cx));
         cx.executor().run_until_parked();
@@ -5355,10 +5374,10 @@ mod tests {
                 .with_project_items(&[TestProjectItem::new_untitled(cx)])
         });
         let pane = workspace.update(cx, |workspace, cx| {
-            workspace.add_item_to_active_pane(Box::new(item1.clone()), cx);
-            workspace.add_item_to_active_pane(Box::new(item2.clone()), cx);
-            workspace.add_item_to_active_pane(Box::new(item3.clone()), cx);
-            workspace.add_item_to_active_pane(Box::new(item4.clone()), cx);
+            workspace.add_item_to_active_pane(Box::new(item1.clone()), None, cx);
+            workspace.add_item_to_active_pane(Box::new(item2.clone()), None, cx);
+            workspace.add_item_to_active_pane(Box::new(item3.clone()), None, cx);
+            workspace.add_item_to_active_pane(Box::new(item4.clone()), None, cx);
             workspace.active_pane().clone()
         });
 
@@ -5480,9 +5499,9 @@ mod tests {
         //     multi-entry items:   (3, 4)
         let left_pane = workspace.update(cx, |workspace, cx| {
             let left_pane = workspace.active_pane().clone();
-            workspace.add_item_to_active_pane(Box::new(item_2_3.clone()), cx);
+            workspace.add_item_to_active_pane(Box::new(item_2_3.clone()), None, cx);
             for item in single_entry_items {
-                workspace.add_item_to_active_pane(Box::new(item), cx);
+                workspace.add_item_to_active_pane(Box::new(item), None, cx);
             }
             left_pane.update(cx, |pane, cx| {
                 pane.activate_item(2, true, true, cx);
@@ -5553,7 +5572,7 @@ mod tests {
         });
         let item_id = item.entity_id();
         workspace.update(cx, |workspace, cx| {
-            workspace.add_item_to_active_pane(Box::new(item.clone()), cx);
+            workspace.add_item_to_active_pane(Box::new(item.clone()), None, cx);
         });
 
         // Autosave on window change.
@@ -5638,7 +5657,7 @@ mod tests {
 
         // Add the item again, ensuring autosave is prevented if the underlying file has been deleted.
         workspace.update(cx, |workspace, cx| {
-            workspace.add_item_to_active_pane(Box::new(item.clone()), cx);
+            workspace.add_item_to_active_pane(Box::new(item.clone()), None, cx);
         });
         item.update(cx, |item, cx| {
             item.project_items[0].update(cx, |item, _| {
@@ -5676,7 +5695,7 @@ mod tests {
         let toolbar_notify_count = Rc::new(RefCell::new(0));
 
         workspace.update(cx, |workspace, cx| {
-            workspace.add_item_to_active_pane(Box::new(item.clone()), cx);
+            workspace.add_item_to_active_pane(Box::new(item.clone()), None, cx);
             let toolbar_notification_count = toolbar_notify_count.clone();
             cx.observe(&toolbar, move |_, _, _| {
                 *toolbar_notification_count.borrow_mut() += 1