From 0f75ff8cefa3c831db1b76acb2feed8c6e37a26c Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Mon, 25 May 2026 10:04:01 -0700
Subject: [PATCH 01/14] Add setting to govern `TextEditor::isModified` behavior

---
 src/config-schema.js | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/config-schema.js b/src/config-schema.js
index 4ee6161080..2c7740f3bf 100644
--- a/src/config-schema.js
+++ b/src/config-schema.js
@@ -663,6 +663,20 @@ const configSchema = {
         default: true,
         description:
           'Add multiple cursors when pressing the Ctrl key (Command key on macOS) and clicking the editor.'
+      },
+      // This setting relates to the behavior of `text-buffer` specifically
+      // (not treating a buffer as modified if its backing file is deleted and
+      // the file was not already considered to be modified at time of
+      // deletion).
+      //
+      // For other types of pane item, nothing else has changed;
+      // `shouldPromptToSave` is the source of truth. That's why this setting
+      // exists in the `editor` namespace rather than the `core` namespace.
+      promptWhenAbandoningDeletedFile: {
+        type: 'boolean',
+        title: 'Experimental: Prompt When Abandoning Deleted File',
+        default: true,
+        description: "Prompt before closing a buffer whose file on disk has been deleted. If disabled, you will still be prompted to save a deleted file on closing if the file had uncommitted changes in the buffer at time of deletion."
       }
     }
   }

From 2d3689edbd7a0a2dd72a9628ab6dc9fb195b4560 Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Mon, 25 May 2026 10:05:22 -0700
Subject: [PATCH 02/14] =?UTF-8?q?Change=20`TextEditor::isModified`=20to=20?=
 =?UTF-8?q?check=20config=E2=80=A6?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

…before deciding how to behave.
---
 src/text-editor.js | 48 +++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 41 insertions(+), 7 deletions(-)

diff --git a/src/text-editor.js b/src/text-editor.js
index 60102eaea1..21e7a51cb9 100644
--- a/src/text-editor.js
+++ b/src/text-editor.js
@@ -1031,8 +1031,8 @@ module.exports = class TextEditor {
     return this.getBuffer().onDidChangeModified(callback);
   }
 
-  // Extended: Calls your `callback` when the buffer's underlying file changes on
-  // disk at a moment when the result of {::isModified} is true.
+  // Extended: Calls your `callback` when the buffer's underlying file changes
+  // on disk at a moment when the result of {::isModified} is true.
   //
   // * `callback` {Function}
   //
@@ -1041,6 +1041,12 @@ module.exports = class TextEditor {
     return this.getBuffer().onDidConflict(callback);
   }
 
+  // Extended: Calls your `callback` when the buffer's underlying file is
+  // deleted on disk.
+  onDidDelete(callback) {
+    return this.getBuffer().onDidDelete(callback);
+  }
+
   // Extended: Calls your `callback` before text has been inserted.
   //
   // * `callback` {Function}
@@ -1433,23 +1439,28 @@ module.exports = class TextEditor {
     }
   }
 
-  // Essential: Returns the {String} path of this editor's text buffer.
+  // Essential: Returns the {String} path of this editor's text buffer, or
+  // `undefined` if the buffer is not associated with a file on disk.
   getPath() {
     return this.buffer.getPath();
   }
 
+  // Extended: Returns the file name of this editor's text buffer, or
+  // `undefined` if the buffer is not associated with a file on disk.
   getFileName() {
     const fullPath = this.getPath();
     if (fullPath) return path.basename(fullPath);
   }
 
+  // Extended: Returns the parent directory of this editor's text buffer, or
+  // `undefined` if the buffer is not associated with a file on disk.
   getDirectoryPath() {
     const fullPath = this.getPath();
     if (fullPath) return path.dirname(fullPath);
   }
 
-  // Extended: Returns the {String} character set encoding of this editor's text
-  // buffer.
+  // Extended: Returns the {String} character set encoding of this editor's
+  // text buffer.
   getEncoding() {
     return this.buffer.getEncoding();
   }
@@ -1457,13 +1468,22 @@ module.exports = class TextEditor {
   // Extended: Set the character set encoding to use in this editor's text
   // buffer.
   //
-  // * `encoding` The {String} character set encoding name such as 'utf8'
+  // * `encoding` The {String} character set encoding name, such as `utf8`.
   setEncoding(encoding) {
     this.buffer.setEncoding(encoding);
   }
 
   // Essential: Returns {Boolean} `true` if this editor has been modified.
   isModified() {
+    let promptWhenAbandoningDeletedFile = atom.config.get('editor.promptWhenAbandoningDeletedFile', {
+      scope: this.getRootScopeDescriptor()
+    });
+    // When `promptWhenAbandoningDeletedFile` is `true` (as is the default),
+    // replicate the legacy `isModified` behavior where buffers with no backing
+    // file _always_ return `true`.
+    if (promptWhenAbandoningDeletedFile && this.isDeleted()) {
+      return true;
+    }
     return this.buffer.isModified();
   }
 
@@ -1475,10 +1495,20 @@ module.exports = class TextEditor {
   // edit it in Pulsar, but before you're able to save those changes. It can
   // also happen if you switch branches in version control while a certain
   // buffer has uncommitted changes.
-  isInConflict () {
+  isInConflict() {
     return this.buffer.isInConflict();
   }
 
+  // Essential: Returns {Boolean} `true` if this editor's backing file was
+  // deleted.
+  //
+  // Will return `false` if the editor's buffer _never_ was associated with a
+  // file on disk, or if the buffer was re-saved to the same location or a
+  // different one.
+  isDeleted() {
+    return this.buffer.isDeleted();
+  }
+
   // Essential: Returns {Boolean} `true` if this editor has no content.
   isEmpty() {
     return this.buffer.isEmpty();
@@ -1514,6 +1544,10 @@ module.exports = class TextEditor {
     ) {
       return this.buffer.isInConflict();
     } else {
+      // Don't prompt when the user closes an editor if there are other editors
+      // in the window that belong to that buffer. In theory, this ensures
+      // we'll prompt only once for a given file when closing a window, but may
+      // need investigation in practice to be sure.
       return this.isModified() && !this.buffer.hasMultipleEditors();
     }
   }

From 1b77a3673e7c3ee2f4f8cfceb0bfde1317331694 Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Mon, 25 May 2026 10:06:31 -0700
Subject: [PATCH 03/14] Use a more accurate error message when a conflicted
 file is deleted

---
 src/pane.js | 118 ++++++++++++++++++++++++++++------------------------
 1 file changed, 64 insertions(+), 54 deletions(-)

diff --git a/src/pane.js b/src/pane.js
index 1881576aa0..819acf53aa 100644
--- a/src/pane.js
+++ b/src/pane.js
@@ -49,8 +49,10 @@ module.exports = class Pane {
     state.activeItem = items[activeItemIndex];
     if (!state.activeItem && activeItemURI) {
       state.activeItem = state.items.find(
-        item =>
-          typeof item.getURI === 'function' && item.getURI() === activeItemURI
+        item => {
+          let itemURI = item.getURI?.() ?? item.getUri?.();
+          return itemURI === activeItemURI;
+        }
       );
     }
 
@@ -485,7 +487,7 @@ module.exports = class Pane {
         itemStackIndices.length !== this.items.length ||
         itemStackIndices.includes(-1)
       ) {
-        itemStackIndices = this.items.map((item, i) => i);
+        itemStackIndices = this.items.map((_, i) => i);
       }
 
       for (let itemIndex of itemStackIndices) {
@@ -652,10 +654,9 @@ module.exports = class Pane {
       options = { index: options };
     }
 
-    const index =
-      options.index != null ? options.index : this.getActiveItemIndex() + 1;
-    const moved = options.moved != null ? options.moved : false;
-    const pending = options.pending != null ? options.pending : false;
+    const index = options.index ?? this.getActiveItemIndex() + 1;
+    const moved = options.moved ?? false;
+    const pending = options.pending ?? false;
 
     if (!item || typeof item !== 'object') {
       throw new Error(
@@ -663,7 +664,7 @@ module.exports = class Pane {
       );
     }
 
-    if (typeof item.isDestroyed === 'function' && item.isDestroyed()) {
+    if (item.isDestroyed?.()) {
       throw new Error(
         `Adding a pane item with URI '${typeof item.getURI === 'function' &&
           item.getURI()}' that has already been destroyed`
@@ -695,7 +696,7 @@ module.exports = class Pane {
 
     this.emitter.emit('did-add-item', { item, index, moved });
     if (!moved) {
-      if (this.container) this.container.didAddPaneItem(item, this, index);
+      this.container?.didAddPaneItem(item, this, index);
     }
 
     if (replacingPendingItem) this.destroyItem(lastPendingItem);
@@ -838,17 +839,18 @@ module.exports = class Pane {
     const index = this.items.indexOf(item);
     if (index === -1) return false;
 
+    // Don't allow deletion of permanent dock items unless `force` is `true`.
     if (
       !force &&
-      typeof item.isPermanentDockItem === 'function' &&
-      item.isPermanentDockItem() &&
+      item.isPermanentDockItem?.() &&
       (!this.container || this.container.getLocation() !== 'center')
     ) {
       return false;
     }
 
-    // In the case where there are no `onWillDestroyPaneItem` listeners, preserve the old behavior
-    // where `Pane.destroyItem` and callers such as `Pane.close` take effect synchronously.
+    // In the case where there are no `onWillDestroyPaneItem` listeners,
+    // preserve the old behavior where `Pane.destroyItem` and callers such as
+    // `Pane.close` take effect synchronously.
     if (this.emitter.listenerCountForEventName('will-destroy-item') > 0) {
       await this.emitter.emitAsync('will-destroy-item', { item, index });
     }
@@ -872,8 +874,7 @@ module.exports = class Pane {
 
     if (
       !force &&
-      typeof item.shouldPromptToSave === 'function' &&
-      item.shouldPromptToSave()
+      item.shouldPromptToSave?.()
     ) {
       if (!(await this.promptToSaveItem(item))) return false;
     }
@@ -900,8 +901,8 @@ module.exports = class Pane {
   // save. The user must decide whether to cancel the attempted save… or force
   // it and overwrite what's on disk.
   //
-  // Resolves with boolean `true` when a save can proceed… or rejects with an
-  // error when the save is aborted.
+  // Returns a {Promise} that resolves with {Boolean} `true` when a save can
+  // proceed… or rejects with an error when the save is aborted.
   promptOnConflict(item) {
     return new Promise((resolve, reject) => {
       // Don't prompt if the user hasn't opted into it.
@@ -914,18 +915,29 @@ module.exports = class Pane {
       }
       // Figure out how to describe the buffer in the dialog.
       const uri = item.getURI?.() ?? item.getUri?.() ?? null;
-      const title =
-        (typeof item.getTitle === 'function' && item.getTitle()) || uri;
+      const title = item.getTitle?.() || uri;
+
+      let message, detail;
+      let firstButton = item.isDeleted() ? 'Save' : 'Overwrite';
+      if (item.isDeleted()) {
+        // The message is a bit different when the file no longer exists on
+        // disk.
+        message = `'${title}' was deleted on disk. Do you still want to save this file?`;
+        detail = 'The contents of the buffer are stale because of pending changes.';
+      } else {
+        message = `'${title}' has changed on disk. Do you want to overwrite this file with your changes?`;
+        detail = 'The contents of the buffer may be stale.'
+      }
 
       this.applicationDelegate.confirm({
-        message: `'${title}' has changed on disk. Do you want to overwrite this file with your changes?`,
-        detail: 'The contents of the buffer may be stale.',
+        message,
+        detail,
 
         // TODO: Individual pane items may have additional strategies to
         // contribute (e.g., conflict resolution view). Implement a way for
         // them to contribute buttons to this dialog — and to handle them in
         // the callback below.
-        buttons: ['Overwrite', 'Cancel']
+        buttons: [firstButton, 'Cancel']
       }, (response) => {
         switch (response) {
           case 0:
@@ -937,26 +949,31 @@ module.exports = class Pane {
     });
   }
 
+  // Decide whether to show a dialog to the user inviting them to save the
+  // given pane item.
+  //
+  // In order to trigger prompt-to-save, a pane item must implement the
+  // `shouldPromptToSave` method and have it return `true` under the proper
+  // circumstances. It must also implement `getURI` and have it return a URI
+  // that represents the pane item.
+  //
+  // Returns a {Promise} that resolves with a {Boolean}. If `true`, the item
+  // should proceed with destruction; if `false`, the user has cancelled the
+  // closing of the pane item.
   promptToSaveItem(item, options = {}) {
-    return new Promise((resolve, reject) => {
-      if (
-        typeof item.shouldPromptToSave !== 'function' ||
-        !item.shouldPromptToSave(options)
-      ) {
+    return new Promise((resolve, _reject) => {
+      if (!item.shouldPromptToSave?.(options)) {
         return resolve(true);
       }
 
-      let uri;
-      if (typeof item.getURI === 'function') {
-        uri = item.getURI();
-      } else if (typeof item.getUri === 'function') {
-        uri = item.getUri();
-      } else {
+      // A pane item must have a URI so that we have a "title of last resort"
+      // to show in the dialog.
+      let uri = item.getURI?.() ?? item.getUri?.() ?? null;
+      if (!uri) {
         return resolve(true);
       }
 
-      const title =
-        (typeof item.getTitle === 'function' && item.getTitle()) || uri;
+      let title = item.getTitle?.() || uri;
 
       const saveDialog = (saveButtonText, saveFn, message) => {
         this.applicationDelegate.confirm(
@@ -973,6 +990,10 @@ module.exports = class Pane {
                   if (error instanceof SaveCancelledError) {
                     resolve(false);
                   } else if (error) {
+                    // For whatever reason, the save failed. In the event that
+                    // the failure is due to the location not existing (network
+                    // share?) or permissions being wrong… we offer the user
+                    // the ability to choose a new destination.
                     saveDialog(
                       'Save as',
                       this.saveItemAs,
@@ -996,7 +1017,7 @@ module.exports = class Pane {
       saveDialog(
         'Save',
         this.saveItem,
-        `'${title}' has changes, do you want to save them?`
+        `'${title}' has changes; do you want to save them?`
       );
     });
   }
@@ -1030,12 +1051,7 @@ module.exports = class Pane {
   saveItem(item, nextAction) {
     if (!item) return Promise.resolve();
 
-    let itemURI;
-    if (typeof item.getURI === 'function') {
-      itemURI = item.getURI();
-    } else if (typeof item.getUri === 'function') {
-      itemURI = item.getUri();
-    }
+    let itemURI = item.getURI?.() ?? item.getUri?.();
 
     if (itemURI != null) {
       if (typeof item.save === 'function') {
@@ -1095,10 +1111,7 @@ module.exports = class Pane {
     if (!item) return;
     if (typeof item.saveAs !== 'function') return;
 
-    const saveOptions =
-      typeof item.getSaveDialogOptions === 'function'
-        ? item.getSaveDialogOptions()
-        : {};
+    const saveOptions = item.getSaveDialogOptions?.() ?? {};
 
     const itemPath = item.getPath();
     if (itemPath && !saveOptions.defaultPath)
@@ -1141,7 +1154,7 @@ module.exports = class Pane {
   // Public: Save all items.
   saveItems() {
     for (let item of this.getItems()) {
-      if (typeof item.isModified === 'function' && item.isModified()) {
+      if (item.isModified?.()) {
         this.saveItem(item);
       }
     }
@@ -1153,11 +1166,9 @@ module.exports = class Pane {
   // * `uri` {String} containing a URI.
   itemForURI(uri) {
     return this.items.find(item => {
-      if (typeof item.getURI === 'function') {
-        return item.getURI() === uri;
-      } else if (typeof item.getUri === 'function') {
-        return item.getUri() === uri;
-      }
+      let itemUri = item.getURI?.() ?? item.getUri?.();
+      if (!itemUri) return false;
+      return uri === itemUri;
     });
   }
 
@@ -1440,8 +1451,7 @@ module.exports = class Pane {
   }
 
   handleSaveError(error, item) {
-    const itemPath =
-      error.path || (typeof item.getPath === 'function' && item.getPath());
+    const itemPath = error.path || item.getPath?.();
     const addWarningWithPath = (message, options) => {
       if (itemPath) message = `${message} '${itemPath}'`;
       this.notificationManager.addWarning(message, options);

From bb01cca5d8dab81979ff3f4f6e092d2c0fa7e6e3 Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Mon, 25 May 2026 10:21:10 -0700
Subject: [PATCH 04/14] =?UTF-8?q?[tabs]=20Refactor=20`tab-view.js`?=
 =?UTF-8?q?=E2=80=A6?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

…and add support for `deleted` and `conflicted` states.

By default, this does nothing cosmetic; UI themes must be updated to hook into these new class names.
---
 packages/tabs/lib/tab-view.js | 251 +++++++++++++++++++---------------
 1 file changed, 138 insertions(+), 113 deletions(-)

diff --git a/packages/tabs/lib/tab-view.js b/packages/tabs/lib/tab-view.js
index 177e42bbf7..4f528b23a5 100644
--- a/packages/tabs/lib/tab-view.js
+++ b/packages/tabs/lib/tab-view.js
@@ -5,6 +5,10 @@ const getIconServices = require('./get-icon-services');
 const layout = require('./layout');
 
 class TabView {
+  isModified = false;
+  isDeleted = false;
+  isConflicted = false;
+
   constructor({item, pane, didClickCloseIcon, tabs, location}) {
     this.item = item;
     this.pane = pane;
@@ -55,66 +59,78 @@ class TabView {
   }
 
   handleEvents() {
-    const titleChangedHandler = () => {
-      return this.updateTitle();
-    };
-
-    this.subscriptions.add(this.pane.onDidDestroy(() => this.destroy()));
-    this.subscriptions.add(this.pane.onItemDidTerminatePendingState(item => {
-      if (item === this.item) { return this.clearPending(); }
-    })
+    this.subscriptions.add(
+      // Destroy a tab when its pane item is destroyed.
+      this.pane.onDidDestroy(() => this.destroy()),
+      // Take a tab out of "pending" state when the same happens for the pane
+      // item.
+      this.pane.onItemDidTerminatePendingState(item => {
+        if (item === this.item) this.clearPending();
+      }),
+      // Update whether icons are shown when the user changes the associated
+      // setting.
+      atom.config.observe('tabs.showIcons', () => {
+        this.updateIconVisibility();
+      }),
+      // Update whether VCS status colors are used when the user changes the
+      // associated setting.
+      atom.config.observe('tabs.enableVcsColoring', isEnabled => {
+        if (isEnabled && (this.path != null)) {
+          this.setupVcsStatus();
+        } else {
+          this.unsetVcsStatus();
+        }
+      })
     );
 
+    const titleChangedHandler = () => this.updateTitle();
+
+    // Subscribe to title changes on this pane item.
     if (typeof this.item.onDidChangeTitle === 'function') {
       const onDidChangeTitleDisposable = this.item.onDidChangeTitle(titleChangedHandler);
-      if (Disposable.isDisposable(onDidChangeTitleDisposable)) {
-        this.subscriptions.add(onDidChangeTitleDisposable);
-      } else {
-        console.warn("::onDidChangeTitle does not return a valid Disposable!", this.item);
-      }
+      this.addItemDisposable(onDidChangeTitleDisposable, 'onDidChangeTitle');
     } else if (typeof this.item.on === 'function') {
-      //TODO Remove once old events are no longer supported
+      // TODO: Remove once old events are no longer supported.
       this.item.on('title-changed', titleChangedHandler);
-      this.subscriptions.add({dispose: () => {
-        return (typeof this.item.off === 'function' ? this.item.off('title-changed', titleChangedHandler) : undefined);
-      }
-      });
+      this.subscriptions.add(
+        new Disposable(() => {
+          this.item.off?.('title-changed', titleChangedHandler)
+        })
+      );
     }
 
-    const pathChangedHandler = path1 => {
-      this.path = path1;
+    const pathChangedHandler = newPath => {
+      this.path = newPath;
       this.updateDataAttributes();
       this.updateTitle();
       this.updateTooltip();
-      return this.updateIcon();
+      this.updateIcon();
     };
 
+    // Subscribe to path changes on this pane item.
     if (typeof this.item.onDidChangePath === 'function') {
       const onDidChangePathDisposable = this.item.onDidChangePath(pathChangedHandler);
-      if (Disposable.isDisposable(onDidChangePathDisposable)) {
-        this.subscriptions.add(onDidChangePathDisposable);
-      } else {
-        console.warn("::onDidChangePath does not return a valid Disposable!", this.item);
-      }
+      this.addItemDisposable(onDidChangePathDisposable, 'onDidChangePath');
     } else if (typeof this.item.on === 'function') {
-      //TODO Remove once old events are no longer supported
+      // TODO: Remove once old events are no longer supported.
       this.item.on('path-changed', pathChangedHandler);
-      this.subscriptions.add({dispose: () => {
-        return (typeof this.item.off === 'function' ? this.item.off('path-changed', pathChangedHandler) : undefined);
-      }
-      });
+      this.subscriptions.add(
+        new Disposable(() => {
+          this.item.off?.('path-changed', pathChangedHandler);
+        })
+      );
     }
 
-    const iconChangedHandler = () => {
-      return this.updateIcon();
-    };
-
-    this.subscriptions.add(getIconServices().onDidChange(() => this.updateIcon()));
+    const iconChangedHandler = () => this.updateIcon();
+    this.subscriptions.add(
+      getIconServices().onDidChange(iconChangedHandler)
+    );
 
+    // Subscribe to icon changes on this pane item.
     if (typeof this.item.onDidChangeIcon === 'function') {
-      const onDidChangeIconDisposable = typeof this.item.onDidChangeIcon === 'function' ? this.item.onDidChangeIcon(() => {
+      const onDidChangeIconDisposable = this.item.onDidChangeIcon(() => {
         return this.updateIcon();
-      }) : undefined;
+      });
       if (Disposable.isDisposable(onDidChangeIconDisposable)) {
         this.subscriptions.add(onDidChangeIconDisposable);
       } else {
@@ -123,68 +139,70 @@ class TabView {
     } else if (typeof this.item.on === 'function') {
       //TODO Remove once old events are no longer supported
       this.item.on('icon-changed', iconChangedHandler);
-      this.subscriptions.add({dispose: () => {
-        return (typeof this.item.off === 'function' ? this.item.off('icon-changed', iconChangedHandler) : undefined);
-      }
-      });
+      this.subscriptions.add(
+        new Disposable(() => {
+          this.item.off?.('icon-changed', iconChangedHandler);
+        })
+      );
     }
 
-    const modifiedHandler = () => {
-      return this.updateModifiedStatus();
-    };
+    const modifiedHandler = () => this.updateModifiedStatus();
 
+    // Subscribe to changes in "modified" status on this pane item.
     if (typeof this.item.onDidChangeModified === 'function') {
       const onDidChangeModifiedDisposable = this.item.onDidChangeModified(modifiedHandler);
-      if (Disposable.isDisposable(onDidChangeModifiedDisposable)) {
-        this.subscriptions.add(onDidChangeModifiedDisposable);
-      } else {
-        console.warn("::onDidChangeModified does not return a valid Disposable!", this.item);
-      }
+      this.addItemDisposable(onDidChangeModifiedDisposable, 'onDidChangeModified');
     } else if (typeof this.item.on === 'function') {
-      //TODO Remove once old events are no longer supported
+      // TODO: Remove once old events are no longer supported.
       this.item.on('modified-status-changed', modifiedHandler);
-      this.subscriptions.add({dispose: () => {
-        return (typeof this.item.off === 'function' ? this.item.off('modified-status-changed', modifiedHandler) : undefined);
-      }
-      });
+      this.subscriptions.add(
+        new Disposable(() => {
+          this.item.off?.('modified-status-changed', modifiedHandler)
+        })
+      );
     }
 
+    // Subscribe to changes in "conflicted" status on this pane item.
     if (typeof this.item.onDidConflict === 'function') {
       const onDidConflictDisposable = this.item.onDidConflict(() => {
         this.updateConflictedStatus();
       });
-      if (Disposable.isDisposable(onDidConflictDisposable)) {
-        this.subscriptions.add(onDidConflictDisposable);
-      } else {
-        console.warn("::onDidConflict does not return a valid Disposable!", this.item);
-      }
+      this.addItemDisposable(onDidConflictDisposable, 'onDidConflict');
     }
 
+    // Subscribe to changes in "deleted" status on this pane item.
+    if (typeof this.item.onDidDelete === 'function') {
+      let onDidDeleteDisposable = this.item.onDidDelete(() => {
+        this.terminatePendingState();
+        this.updateDeletedStatus();
+      });
+      this.addItemDisposable(onDidDeleteDisposable, 'onDidDelete');
+    }
+
+    // Subscribe to "save" events on this pane item, since those correlate with
+    // changes in several pane item states.
     if (typeof this.item.onDidSave === 'function') {
       const onDidSaveDisposable = this.item.onDidSave(event => {
         this.terminatePendingState();
         this.updateConflictedStatus();
+        this.updateDeletedStatus();
         if (event.path !== this.path) {
           this.path = event.path;
-          if (atom.config.get('tabs.enableVcsColoring')) { return this.setupVcsStatus(); }
+          if (atom.config.get('tabs.enableVcsColoring')) {
+            this.setupVcsStatus();
+          }
         }
       });
-
-      if (Disposable.isDisposable(onDidSaveDisposable)) {
-        this.subscriptions.add(onDidSaveDisposable);
-      } else {
-        console.warn("::onDidSave does not return a valid Disposable!", this.item);
-      }
+      this.addItemDisposable(onDidSaveDisposable, 'onDidSave');
     }
-    this.subscriptions.add(atom.config.observe('tabs.showIcons', () => {
-      return this.updateIconVisibility();
-    })
-    );
+  }
 
-    return this.subscriptions.add(atom.config.observe('tabs.enableVcsColoring', isEnabled => {
-      if (isEnabled && (this.path != null)) { return this.setupVcsStatus(); } else { return this.unsetVcsStatus(); }
-    })
-    );
+  addItemDisposable (disposable, methodName) {
+    if (!Disposable.isDisposable(disposable)) {
+      console.warn(`::${methodName} does not return a valid Disposable!`, this.item);
+      return;
+    }
+    this.subscriptions.add(disposable);
   }
 
   setupTooltip() {
@@ -198,11 +216,12 @@ class TabView {
       return this.element.dispatchEvent(new CustomEvent('mouseenter', {bubbles: true}));
     };
 
-    this.mouseEnterSubscription = { dispose: () => {
-      this.element.removeEventListener('mouseenter', onMouseEnter);
-      return this.mouseEnterSubscription = null;
-    }
-  };
+    this.mouseEnterSubscription = {
+      dispose: () => {
+        this.element.removeEventListener('mouseenter', onMouseEnter);
+        return this.mouseEnterSubscription = null;
+      }
+    };
 
     return this.element.addEventListener('mouseenter', onMouseEnter);
   }
@@ -328,72 +347,78 @@ class TabView {
   }
 
   updateConflictedStatus () {
-    if (this.item.isInConflict?.()) {
-      this.element.classList.add('conflicted');
-      this.isConflicted = true;
-    } else {
-      if (this.isConflicted) {
-        this.element.classList.remove('conflicted');
-      }
-      this.isConflicted = false;
-    }
+    this.isConflicted = this.item.isInConflict?.() ?? false;
+    this.toggleTabClass('conflicted', this.isConflicted);
     return this.isConflicted;
   }
 
   updateModifiedStatus() {
-    if (typeof this.item.isModified === 'function' ? this.item.isModified() : undefined) {
-      if (!this.isModified) { this.element.classList.add('modified'); }
-      return this.isModified = true;
-    } else {
-      if (this.isModified) { this.element.classList.remove('modified'); }
-      return this.isModified = false;
-    }
+    this.isModified = this.item.isModified?.() ?? false;
+    this.toggleTabClass('modified', this.isModified);
+    return this.isModified;
+  }
+
+  updateDeletedStatus () {
+    this.isDeleted = this.item.isDeleted?.() ?? false;
+    this.toggleTabClass('deleted', this.isDeleted);
+    return this.isDeleted;
   }
 
   setupVcsStatus() {
     if (this.path == null) { return; }
     return this.repoForPath(this.path).then(repo => {
       this.subscribeToRepo(repo);
-      return this.updateVcsStatus(repo);
+      this.updateVcsStatus(repo);
     });
   }
 
+  toggleTabClass (className, condition) {
+    if (condition) {
+      this.element.classList.add(className);
+    } else {
+      this.element.classList.remove(className);
+    }
+  }
+
   // Subscribe to the project's repo for changes to the VCS status of the file.
   subscribeToRepo(repo) {
-    if (repo == null) { return; }
+    if (repo == null) return;
 
     // Remove previous repo subscriptions.
-    if (this.repoSubscriptions != null) {
-      this.repoSubscriptions.dispose();
-    }
+    this.repoSubscriptions?.dispose();
     this.repoSubscriptions = new CompositeDisposable();
 
-    this.repoSubscriptions.add(repo.onDidChangeStatus(event => {
-      if (event.path === this.path) { return this.updateVcsStatus(repo, event.pathStatus); }
-    })
-    );
-    return this.repoSubscriptions.add(repo.onDidChangeStatuses(() => {
-      return this.updateVcsStatus(repo);
-    })
+    this.repoSubscriptions.add(
+      repo.onDidChangeStatus(event => {
+        if (event.path === this.path) {
+          return this.updateVcsStatus(repo, event.pathStatus);
+        }
+      }),
+
+      repo.onDidChangeStatuses(() => {
+        return this.updateVcsStatus(repo);
+      })
     );
   }
 
   repoForPath() {
     for (let dir of atom.project.getDirectories()) {
-      if (dir.contains(this.path)) { return atom.project.repositoryForDirectory(dir); }
+      if (dir.contains(this.path)) {
+        return atom.project.repositoryForDirectory(dir);
+      }
     }
     return Promise.resolve(null);
   }
 
   // Update the VCS status property of this tab using the repo.
   updateVcsStatus(repo, status) {
-    if (repo == null) { return; }
+    if (repo == null) return;
 
     let newStatus = null;
     if (repo.isPathIgnored(this.path)) {
       newStatus = 'ignored';
     } else {
-      if (status == null) { status = repo.getCachedPathStatus(this.path); }
+      status ??= repo.getCachedPathStatus(this.path);
       if (repo.isStatusModified(status)) {
         newStatus = 'modified';
       } else if (repo.isStatusNew(status)) {
@@ -410,7 +435,7 @@ class TabView {
   updateVcsColoring() {
     this.itemTitle.classList.remove('status-ignored', 'status-modified',  'status-added');
     if (this.status && atom.config.get('tabs.enableVcsColoring')) {
-      return this.itemTitle.classList.add(`status-${this.status}`);
+      this.itemTitle.classList.add(`status-${this.status}`);
     }
   }
 
@@ -419,7 +444,7 @@ class TabView {
       this.repoSubscriptions.dispose();
     }
     delete this.status;
-    return this.updateVcsColoring();
+    this.updateVcsColoring();
   }
 }
 

From 628a7bfb5fb225e66a21e9e388310ffc3d3431b0 Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Sat, 30 May 2026 16:31:03 -0700
Subject: [PATCH 05/14] Bump `@pulsar-edit/text-buffer` to `15.0.0`

---
 package.json |  2 +-
 yarn.lock    | 30 +++++++-----------------------
 2 files changed, 8 insertions(+), 24 deletions(-)

diff --git a/package.json b/package.json
index bef6184b8f..b240f4f966 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
     "@pulsar-edit/pathwatcher": "^9.0.2",
     "@pulsar-edit/scandal": "^4.0.0",
     "@pulsar-edit/superstring": "^3.0.5",
-    "@pulsar-edit/text-buffer": "^14.0.4",
+    "@pulsar-edit/text-buffer": "^15.0.0",
     "about": "file:packages/about",
     "archive-view": "file:packages/archive-view",
     "async": "3.2.6",
diff --git a/yarn.lock b/yarn.lock
index 199e62470d..f6c7f17269 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1726,7 +1726,7 @@
     unbzip2-stream "^1.4.3"
     yauzl "^3.2.0"
 
-"@pulsar-edit/pathwatcher@9.0.3", "@pulsar-edit/pathwatcher@^9.0.2":
+"@pulsar-edit/pathwatcher@9.0.3", "@pulsar-edit/pathwatcher@^9.0.2", "@pulsar-edit/pathwatcher@^9.0.3":
   version "9.0.3"
   resolved "https://registry.yarnpkg.com/@pulsar-edit/pathwatcher/-/pathwatcher-9.0.3.tgz#13dcbdbf4115904bfdf76509580612cf09e8043c"
   integrity sha512-S8QwhsUf/x617g6FEuPixdu1c3Mt4kzZsGaTrbogkaCJuY1mMAEkqkp6zEp4MM+UfWFruRszAOkdZYbI5gWW9Q==
@@ -1758,22 +1758,20 @@
   dependencies:
     node-addon-api "^8.5.0"
 
-"@pulsar-edit/text-buffer@^14.0.4":
-  version "14.0.4"
-  resolved "https://registry.yarnpkg.com/@pulsar-edit/text-buffer/-/text-buffer-14.0.4.tgz#9bf03445ab8da000c9c986255654acf04433e6bb"
-  integrity sha512-KiC/uA7zdnoI2pI3AyoYYXAdL5h6LyHURHl/URxkViQPjGeFXr3vRr6cb9OxsS1NRM4fVFtEdHFG8T7aafDdUQ==
+"@pulsar-edit/text-buffer@^15.0.0":
+  version "15.0.0"
+  resolved "https://registry.yarnpkg.com/@pulsar-edit/text-buffer/-/text-buffer-15.0.0.tgz#5c72fde1caa8d9aee71a4f98252550b32934401d"
+  integrity sha512-Ut7VbD+8NIUMlf79NFjUzhTBV5e/Ty2jLGWlxtOYM0RRuey4zFv3RedIFjbgWY+qQoRBbmigLmyvzewIMVrONA==
   dependencies:
-    "@pulsar-edit/pathwatcher" "^9.0.2"
+    "@pulsar-edit/pathwatcher" "^9.0.3"
     "@pulsar-edit/superstring" "^3.0.4"
     delegato "^1.0.0"
     diff "^2.2.1"
-    emissary "^1.0.0"
     event-kit "^2.4.0"
     fs-admin "^0.19.0"
     fs-plus "^3.0.0"
     grim "^2.0.2"
     mkdirp "^0.5.1"
-    serializable "^1.0.3"
     underscore-plus "^1.0.0"
     winattr "^3.0.0"
 
@@ -4242,7 +4240,7 @@ electron@30.5.1:
     "@types/node" "^20.9.0"
     extract-zip "^2.0.1"
 
-emissary@^1.0.0, emissary@^1.2.0, emissary@^1.3.2, emissary@^1.3.3:
+emissary@^1.2.0, emissary@^1.3.2, emissary@^1.3.3:
   version "1.3.3"
   resolved "https://registry.yarnpkg.com/emissary/-/emissary-1.3.3.tgz#a618d92d682b232d31111dc3625a5df661799606"
   integrity sha512-pD6FWNBSlEOzSJDCTcSGVLgNnGw5fnCvvGMdQ/TN43efeXZ/QTq8+hZoK3OOEXPRNjMmSJmeOnEJh+bWT5O8rQ==
@@ -5231,11 +5229,6 @@ get-intrinsic@^1.2.4, get-intrinsic@^1.2.5, get-intrinsic@^1.2.6, get-intrinsic@
     hasown "^2.0.2"
     math-intrinsics "^1.1.0"
 
-get-parameter-names@~0.2.0:
-  version "0.2.0"
-  resolved "https://registry.yarnpkg.com/get-parameter-names/-/get-parameter-names-0.2.0.tgz#a2163ad092e350d94bee2958974fcece1bc53c99"
-  integrity sha512-QgxVvmXNqxCDYMwK8zwM5B0AMoLUGQ9MBw202kELskDTDEIveOwP6zR38F3XLA3v+rsuv6+DtCXjW0AEPE9+4Q==
-
 get-proto@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/get-proto/-/get-proto-1.0.1.tgz#150b3f2743869ef3e851ec0c49d15b1d14d00ee1"
@@ -8900,15 +8893,6 @@ semver@^7.0.0, semver@^7.3.2, semver@^7.3.4, semver@^7.3.5, semver@^7.3.7, semve
   resolved "https://registry.yarnpkg.com/semver/-/semver-7.7.3.tgz#4b5f4143d007633a8dc671cd0a6ef9147b8bb946"
   integrity sha512-SdsKMrI9TdgjdweUSR9MweHA4EJ8YxHn8DFaDisvhVlUOe4BF1tLD7GAj0lIqWVl+dPb/rExr0Btby5loQm20Q==
 
-serializable@^1.0.3:
-  version "1.0.3"
-  resolved "https://registry.yarnpkg.com/serializable/-/serializable-1.0.3.tgz#0a5a8b6b7777cb24544df11a6f889a6d2b3e1189"
-  integrity sha512-x4C87GbC+fSbj1NlmZrKW4tDN+sZodzTZNxELEH4iwXzg4xirHBQOIOpPatmksXkes07ZebIRpo6+UVS0rvwsw==
-  dependencies:
-    get-parameter-names "~0.2.0"
-    mixto "1.x"
-    underscore-plus "1.x"
-
 serialize-error@^7.0.1:
   version "7.0.1"
   resolved "https://registry.yarnpkg.com/serialize-error/-/serialize-error-7.0.1.tgz#f1360b0447f61ffb483ec4157c737fab7d778e18"

From 7b23eaf5a3166e27b95db7eae3c88d6bbd7b14f4 Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Sat, 30 May 2026 17:35:52 -0700
Subject: [PATCH 06/14] =?UTF-8?q?Style=20the=20tabs=20on=20built-in=20UI?=
 =?UTF-8?q?=20themes=E2=80=A6?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

…to reflect the “deleted” status of a file.
---
 packages/atom-dark-ui/styles/tabs.less        | 12 +++++++-
 packages/atom-light-ui/styles/tabs.less       |  8 +++++
 packages/one-dark-ui/styles/tabs.less         | 30 +++++++++++++++----
 .../styles/ui-variables-custom.less           |  4 ++-
 packages/one-light-ui/styles/tabs.less        | 28 +++++++++++++----
 .../styles/ui-variables-custom.less           |  4 ++-
 6 files changed, 73 insertions(+), 13 deletions(-)

diff --git a/packages/atom-dark-ui/styles/tabs.less b/packages/atom-dark-ui/styles/tabs.less
index a3e534882d..9aa8f145c1 100644
--- a/packages/atom-dark-ui/styles/tabs.less
+++ b/packages/atom-dark-ui/styles/tabs.less
@@ -25,9 +25,9 @@
     max-width: @tab-max-width;
     height: @tab-height;
     line-height: @tab-height;
+    color: @text-color;
     padding: 0;
     margin: 0 20px 0 5px;
-    color: @text-color;
 
     transition: color .1s ease-in;
     border: none;
@@ -91,6 +91,14 @@
       padding-top: @tab-top-padding;
       padding-right: 10px;
     }
+
+    &.deleted {
+      &, & .title {
+        color: @text-color-error;
+        text-decoration: line-through;
+        text-decoration-color: @text-color-error;
+      }
+    }
   }
 
   .tab.active {
@@ -132,9 +140,11 @@
   .placeholder {
     height: (@tab-height + @tab-top-padding + @tab-bottom-border-height);
     pointer-events: none;
+
     &:before {
       margin-left: -9px; // center between tabs
     }
+
     &:after {
       top: (@tab-height + @tab-top-padding + @tab-bottom-border-height - 2px);
       margin-left: -10px; // center between tabs
diff --git a/packages/atom-light-ui/styles/tabs.less b/packages/atom-light-ui/styles/tabs.less
index 687b1ba744..73153adebf 100644
--- a/packages/atom-light-ui/styles/tabs.less
+++ b/packages/atom-light-ui/styles/tabs.less
@@ -93,6 +93,14 @@
       padding-top: (@tab-top-padding + 1px);
       padding-right: 10px;
     }
+
+    &.deleted {
+      &, & .title {
+        color: @text-color-error;
+        text-decoration: line-through;
+        text-decoration-color: @text-color-error;
+      }
+    }
   }
 
   .tab.active {
diff --git a/packages/one-dark-ui/styles/tabs.less b/packages/one-dark-ui/styles/tabs.less
index b595f46024..b26ad41e7a 100644
--- a/packages/one-dark-ui/styles/tabs.less
+++ b/packages/one-dark-ui/styles/tabs.less
@@ -27,6 +27,7 @@
   // Tab ----------------------
 
   .tab {
+    --tab-color: @tab-text-color;
     position: relative;
     top: 0;
     padding: 0;
@@ -34,12 +35,12 @@
     height: inherit;
     font-size: inherit;
     line-height: @ui-tab-height;
-    color: @tab-text-color;
+    color: var(--tab-color);
     background-color: @tab-background-color;
     box-shadow: inherit;
     border-left: @tab-border;
     &.active {
-      color: @tab-text-color-active;
+      --tab-color: @tab-text-color-active;
       background-color: @tab-background-color-active;
       box-shadow: none;
     }
@@ -60,11 +61,16 @@
     .title {
       text-align: center;
       margin: 0 @title-padding;
+      color: var(--tab-color);
     }
 
     // VCS coloring ----------------------
-    &:not(.active) .status-added    { color: @tab-inactive-status-added; }
-    &:not(.active) .status-modified { color: @tab-inactive-status-modified; }
+    &:not(.active):has(.status-added) {
+      --tab-color: @tab-inactive-status-added;
+    }
+    &:not(.active):has(.status-modified) {
+      --tab-color: @tab-inactive-status-modified;
+    }
 
 
     // Icons ----------------------
@@ -116,6 +122,19 @@
     }
   }
 
+  // Deleted state ----------------------
+
+  .tab.deleted {
+    --tab-color: @text-color-error;
+    text-decoration: line-through;
+    text-decoration-color: var(--tab-color);
+
+    &:not(.active) {
+      --tab-color: @tab-inactive-status-deleted;
+    }
+  }
+
+
   // Modified icon ----------------------
 
   .tab.modified {
@@ -249,7 +268,8 @@ atom-dock .tab-bar .tab::before {
   &[data-type$="TimecopView"],
   &[data-type$="StyleguideView"],
   &[data-type="MarkdownPreviewView"] {
-    color: @tab-text-color-editor;
+    --tab-color: @tab-text-color-editor;
+    color: var(--tab-color);
     background-color: @tab-background-color-editor; // Match syntax background color
   }
 }
diff --git a/packages/one-dark-ui/styles/ui-variables-custom.less b/packages/one-dark-ui/styles/ui-variables-custom.less
index 62a5bdc51b..69b9c20dd6 100644
--- a/packages/one-dark-ui/styles/ui-variables-custom.less
+++ b/packages/one-dark-ui/styles/ui-variables-custom.less
@@ -105,10 +105,12 @@
 
 @tab-text-color:                    @text-color-subtle;
 @tab-text-color-active:             @text-color-highlight;
-@tab-text-color-editor:             contrast(@ui-syntax-color, darken(@ui-syntax-color, 50%), @text-color-highlight );
+@tab-text-color-editor:             contrast(@ui-syntax-color, darken(@ui-syntax-color, 50%), @text-color-highlight);
+@tab-text-color-editor-deleted:     @syntax-color-removed;
 @tab-background-color-editor:       @ui-syntax-color;
 @tab-inactive-status-added:         fade(@text-color-success, 55%);
 @tab-inactive-status-modified:      fade(@text-color-warning, 55%);
+@tab-inactive-status-deleted:       fade(@text-color-error, 55%);
 
 
 @tooltip-background-color:          @accent-bg-color;
diff --git a/packages/one-light-ui/styles/tabs.less b/packages/one-light-ui/styles/tabs.less
index b595f46024..fbc02885b0 100644
--- a/packages/one-light-ui/styles/tabs.less
+++ b/packages/one-light-ui/styles/tabs.less
@@ -27,6 +27,7 @@
   // Tab ----------------------
 
   .tab {
+    --tab-color: @tab-text-color;
     position: relative;
     top: 0;
     padding: 0;
@@ -34,12 +35,12 @@
     height: inherit;
     font-size: inherit;
     line-height: @ui-tab-height;
-    color: @tab-text-color;
+    color: var(--tab-color);
     background-color: @tab-background-color;
     box-shadow: inherit;
     border-left: @tab-border;
     &.active {
-      color: @tab-text-color-active;
+      --tab-color: @tab-text-color-active;
       background-color: @tab-background-color-active;
       box-shadow: none;
     }
@@ -60,11 +61,16 @@
     .title {
       text-align: center;
       margin: 0 @title-padding;
+      color: var(--tab-color);
     }
 
     // VCS coloring ----------------------
-    &:not(.active) .status-added    { color: @tab-inactive-status-added; }
-    &:not(.active) .status-modified { color: @tab-inactive-status-modified; }
+    &:not(.active):has(.status-added) {
+      --tab-color: @tab-inactive-status-added;
+    }
+    &:not(.active):has(.status-modified) {
+      --tab-color: @tab-inactive-status-modified;
+    }
 
 
     // Icons ----------------------
@@ -116,6 +122,18 @@
     }
   }
 
+  // Deleted state ----------------------
+
+  .tab.deleted {
+    --tab-color: @text-color-error;
+    text-decoration: line-through;
+    text-decoration-color: var(--tab-color);
+
+    &:not(.active) {
+      --tab-color: @tab-inactive-status-deleted;
+    }
+  }
+
   // Modified icon ----------------------
 
   .tab.modified {
@@ -249,7 +267,7 @@ atom-dock .tab-bar .tab::before {
   &[data-type$="TimecopView"],
   &[data-type$="StyleguideView"],
   &[data-type="MarkdownPreviewView"] {
-    color: @tab-text-color-editor;
+    --tab-color: @tab-text-color-editor;
     background-color: @tab-background-color-editor; // Match syntax background color
   }
 }
diff --git a/packages/one-light-ui/styles/ui-variables-custom.less b/packages/one-light-ui/styles/ui-variables-custom.less
index c685bfc105..117a81c668 100644
--- a/packages/one-light-ui/styles/ui-variables-custom.less
+++ b/packages/one-light-ui/styles/ui-variables-custom.less
@@ -88,10 +88,12 @@
 
 @tab-text-color:                    @text-color-subtle;
 @tab-text-color-active:             @text-color-highlight;
-@tab-text-color-editor:             contrast(@ui-syntax-color, lighten(@ui-syntax-color, 70%), @text-color-highlight );
+@tab-text-color-editor:             contrast(@ui-syntax-color, lighten(@ui-syntax-color, 70%), @text-color-highlight);
+@tab-text-color-editor-deleted:     @syntax-color-removed;
 @tab-background-color-editor:       @ui-syntax-color;
 @tab-inactive-status-added:         fade(@text-color-success, 77%);
 @tab-inactive-status-modified:      fade(@text-color-warning, 77%);
+@tab-inactive-status-deleted:       fade(@text-color-error, 55%);
 
 @tooltip-background-color:          @accent-bg-color;
 @tooltip-text-color:                @accent-bg-text-color;

From c1aba5a6607aed3bb555f11d16873887f0a0743b Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Sat, 30 May 2026 17:36:20 -0700
Subject: [PATCH 07/14] Fix interpretation of `isDestroyed` on pane items

---
 src/pane.js | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/pane.js b/src/pane.js
index 819acf53aa..bced730f48 100644
--- a/src/pane.js
+++ b/src/pane.js
@@ -664,7 +664,7 @@ module.exports = class Pane {
       );
     }
 
-    if (item.isDestroyed?.()) {
+    if (this.paneItemIsDestroyed(item)) {
       throw new Error(
         `Adding a pane item with URI '${typeof item.getURI === 'function' &&
           item.getURI()}' that has already been destroyed`
@@ -704,6 +704,15 @@ module.exports = class Pane {
     return item;
   }
 
+  paneItemIsDestroyed (item) {
+    if (typeof item.isDestroyed === 'boolean') {
+      return item.isDestroyed;
+    } else if (typeof item.isDestroyed === 'function') {
+      return item.isDestroyed();
+    }
+    return false;
+  }
+
   setPendingItem(item) {
     if (this.pendingItem !== item) {
       const mostRecentPendingItem = this.pendingItem;

From 14969b3519ae38eab608bed19cc415bbf9ff68eb Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Sat, 30 May 2026 18:37:01 -0700
Subject: [PATCH 08/14] [tabs] Add specs for `TabView`

---
 packages/tabs/spec/tabs-spec.js | 157 ++++++++++++++++++++++++++++++++
 1 file changed, 157 insertions(+)

diff --git a/packages/tabs/spec/tabs-spec.js b/packages/tabs/spec/tabs-spec.js
index 3f95ad533f..6c8b399e9e 100644
--- a/packages/tabs/spec/tabs-spec.js
+++ b/packages/tabs/spec/tabs-spec.js
@@ -1,4 +1,5 @@
 const _ = require('underscore-plus');
+const { Emitter } = require('atom');
 const path = require('path');
 const temp = require('temp');
 const TabBarView = require('../lib/tab-bar-view');
@@ -6,6 +7,90 @@ const layout = require('../lib/layout');
 const main = require('../lib/main');
 let {triggerMouseEvent, triggerClickEvent, buildDragEvents, buildDragEnterLeaveEvents, buildWheelEvent, buildWheelPlusShiftEvent} = require("./event-helpers.js");
 
+class SamplePaneItem {
+  _isModified = false;
+  _isConflicted = false;
+  _isDeleted = false;
+  constructor(slug) {
+    this._slug = slug;
+    this.element = document.createElement('div');
+    this.emitter = new Emitter();
+  }
+  getTitle() { return "Anything"; }
+  getPath() { return `foo://${this._slug ?? 'bar'}`; }
+  onDidChangeTitle(cb) {
+    return this.emitter.on('did-change-title', cb);
+  }
+  onDidChangeIcon(cb) {
+    return this.emitter.on('did-change-icon', cb);
+  }
+  onDidChangeModified(cb) {
+    return this.emitter.on('did-change-modified', cb);
+  }
+  onDidSave(cb) {
+    return this.emitter.on('did-save', cb);
+  }
+  onDidChangePath(cb) {
+    return this.emitter.on('did-change-path', cb);
+  }
+  onDidDelete (cb) {
+    return this.emitter.on('did-change-deleted', cb);
+  }
+  onDidConflict (cb) {
+    return this.emitter.on('did-conflict', cb);
+  }
+
+  save() {
+    // Mimic what saving would do for a typical pane item -- clear any
+    // "deleted" state and then trigger a save event.
+    this._isDeleted = false;
+    this._isConflicted = false;
+    this._trigger('did-save', { path: this.getPath() });
+  }
+
+  isModified () {
+    return this._isModified;
+  }
+
+  isInConflict () {
+    return this._isConflicted;
+  }
+
+  isDeleted() {
+    return this._isDeleted;
+  }
+
+  _setIsModified (isModified) {
+    let wasModified = this._isModified;
+    this._isModified = isModified;
+    if (isModified !== wasModified) {
+      this._trigger('did-change-modified', isModified);
+    }
+  }
+
+  _setIsConflicted (isConflicted) {
+    let wasConflicted = this._isConflicted;
+    this._isConflicted = isConflicted;
+    if (isConflicted && !wasConflicted) {
+      this._trigger('did-conflict', isConflicted);
+    }
+  }
+
+  _setIsDeleted (isDeleted) {
+    let wasDeleted = this._isDeleted;
+    this._isDeleted = isDeleted;
+    if (isDeleted && !wasDeleted) {
+      console.log('Triggering deletion change!');
+      this._trigger('did-change-deleted', isDeleted);
+    }
+  }
+
+  _trigger (eventName, ...args) {
+    this.emitter.emit(eventName, ...args);
+  }
+}
+
+
 describe("Tabs package main", () => {
   let centerElement = null;
 
@@ -96,6 +181,7 @@ describe("TabBarView", () => {
   }
 
   beforeEach(() => {
+    atom.config.set('tabs.enableItemStatusColoring', true);
     deserializerDisposable = atom.deserializers.add(TestView);
     item1 = new TestView('Item 1', undefined, "squirrel", "sample.js");
     item2 = new TestView('Item 2');
@@ -219,6 +305,7 @@ describe("TabBarView", () => {
   describe("when a new item is added to the pane", () => {
     it("adds the 'modified' class to the new tab if the item is initially modified", () => {
       let editor2 = null;
+      let paneItem = null;
 
       waitsForPromise(() => {
         if (atom.workspace.createItemForURI != null) {
@@ -232,9 +319,79 @@ describe("TabBarView", () => {
         editor2.insertText('x');
         pane.activateItem(editor2);
         expect(tabBar.tabForItem(editor2).element).toHaveClass('modified');
+        if (paneItem) {
+          pane.removeItem(paneItem);
+        }
       });
     });
 
+    it("adds a 'deleted' class if the item signals that it is entering the 'deleted' state", () => {
+      paneItem = new SamplePaneItem('test-1');
+      console.log('Adding to pane:', pane);
+      pane.addItem(paneItem);
+
+      let tabBar = new TabBarView(pane, 'center');
+
+      let tab = tabBar.tabs.find(t => t.item === paneItem);
+      expect(!!tab).toBe(true);
+
+      expect(tab.element).not.toHaveClass('deleted');
+
+      paneItem._setIsDeleted(true);
+
+      expect(tab.element).toHaveClass('deleted');
+
+      // Toggling this setting should immediately remove/restore the
+      // associated class name.
+      atom.config.set('tabs.enableItemStatusColoring', false);
+      expect(tab.element).not.toHaveClass('deleted');
+
+      atom.config.set('tabs.enableItemStatusColoring', true);
+      expect(tab.element).toHaveClass('deleted');
+
+      paneItem.save();
+      expect(tab.element).not.toHaveClass('deleted');
+
+      // When this setting is `false`, no status-related class names should be
+      // added to the tab.
+      atom.config.set('tabs.enableItemStatusColoring', false);
+      paneItem._setIsDeleted(true);
+      expect(tab.element).not.toHaveClass('deleted');
+    });
+
+    it("adds a 'conflicted' class if the item signals that it is entering the 'conflicted' state", () => {
+      paneItem = new SamplePaneItem('test-1');
+      pane.addItem(paneItem);
+
+      let tabBar = new TabBarView(pane, 'center');
+
+      let tab = tabBar.tabs.find(t => t.item === paneItem);
+      expect(!!tab).toBe(true);
+
+      expect(tab.element).not.toHaveClass('conflicted');
+
+      paneItem._setIsConflicted(true);
+
+      expect(tab.element).toHaveClass('conflicted');
+
+      // Toggling this setting should immediately remove/restore the
+      // associated class name.
+      atom.config.set('tabs.enableItemStatusColoring', false);
+      expect(tab.element).not.toHaveClass('conflicted');
+
+      atom.config.set('tabs.enableItemStatusColoring', true);
+      expect(tab.element).toHaveClass('conflicted');
+
+      paneItem.save();
+      expect(tab.element).not.toHaveClass('conflicted');
+
+      // When this setting is `false`, no status-related class names should be
+      // added to the tab.
+      atom.config.set('tabs.enableItemStatusColoring', false);
+      paneItem._setIsConflicted(true);
+      expect(tab.element).not.toHaveClass('conflicted');
+    });
+
     describe("when addNewTabsAtEnd is set to true in package settings", () => {
       it("adds a tab for the new item at the end of the tab bar", () => {
         atom.config.set("tabs.addNewTabsAtEnd", true);

From d7da43cac87a0bc75e49b6be0fcc8f2d57ef5a70 Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Sat, 30 May 2026 18:39:14 -0700
Subject: [PATCH 09/14] =?UTF-8?q?[tabs]=20Make=20the=20new=20status=20colo?=
 =?UTF-8?q?ring=20governed=20by=20a=20setting=E2=80=A6?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

…named `tabs.enableItemStatusColoring`.
---
 packages/tabs/lib/tab-view.js | 31 +++++++++++++++++++++++--------
 packages/tabs/package.json    |  6 ++++++
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/packages/tabs/lib/tab-view.js b/packages/tabs/lib/tab-view.js
index 4f528b23a5..79e28cb864 100644
--- a/packages/tabs/lib/tab-view.js
+++ b/packages/tabs/lib/tab-view.js
@@ -80,7 +80,9 @@ class TabView {
         } else {
           this.unsetVcsStatus();
         }
-      })
+      }),
+
+      atom.config.observe('tabs.enableItemStatusColoring', this.setBufferStatusColoring.bind(this))
     );
 
     const titleChangedHandler = () => this.updateTitle();
@@ -197,6 +199,18 @@ class TabView {
     }
   }
 
+  setBufferStatusColoring (isEnabled) {
+    console.log('Setting buffer status coloring to', isEnabled);
+    this.useBufferStatusColoring = isEnabled;
+    if (!isEnabled) {
+      this.toggleTabClass('conflicted', false);
+      this.toggleTabClass('deleted', false);
+    } else {
+      this.toggleTabClass('conflicted', this.isConflicted);
+      this.toggleTabClass('deleted', this.isDeleted);
+    }
+  }
+
   addItemDisposable (disposable, methodName) {
     if (!Disposable.isDisposable(disposable)) {
       console.warn(`::${methodName} does not return a valid Disposable!`, this.item);
@@ -348,22 +362,23 @@ class TabView {
 
   updateConflictedStatus () {
     this.isConflicted = this.item.isInConflict?.() ?? false;
-    this.toggleTabClass('conflicted', this.isConflicted);
+    this.toggleTabClass('conflicted', this.useBufferStatusColoring && this.isConflicted);
     return this.isConflicted;
   }
 
+  updateDeletedStatus () {
+    this.isDeleted = this.item.isDeleted?.() ?? false;
+    console.log('using buffer status coloring?', this.useBufferStatusColoring);
+    this.toggleTabClass('deleted', this.useBufferStatusColoring && this.isDeleted);
+    return this.isDeleted;
+  }
+
   updateModifiedStatus() {
     this.isModified = this.item.isModified?.() ?? false;
     this.toggleTabClass('modified', this.isModified);
     return this.isModified;
   }
 
-  updateDeletedStatus () {
-    this.isDeleted = this.item.isDeleted?.() ?? false;
-    this.toggleTabClass('deleted', this.isDeleted);
-    return this.isDeleted;
-  }
-
   setupVcsStatus() {
     if (this.path == null) { return; }
     return this.repoForPath(this.path).then(repo => {
diff --git a/packages/tabs/package.json b/packages/tabs/package.json
index e4b22ec4f1..9c52b18817 100644
--- a/packages/tabs/package.json
+++ b/packages/tabs/package.json
@@ -60,6 +60,12 @@
       "default": false,
       "description": "Color file names in tabs based on VCS status, similar to how file names are colored in the tree view."
     },
+    "enableItemStatusColoring": {
+      "type": "boolean",
+      "title": "Enable Item Status Coloring",
+      "default": true,
+      "description": "Color tab names based on internal item status. “Deleted” status means the item once had a file on disk but it was deleted. “Conflicted” status means the file on disk changed while the item had unsaved changes. (Not all themes add styles for these states.)"
+    },
     "addNewTabsAtEnd": {
       "type": "boolean",
       "default": false,

From 12ad10ddf36149940c28c83aa7205a0de35b2743 Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Sat, 30 May 2026 19:41:18 -0700
Subject: [PATCH 10/14] [tabs] Remove logging

---
 packages/tabs/lib/tab-view.js | 2 --
 1 file changed, 2 deletions(-)

diff --git a/packages/tabs/lib/tab-view.js b/packages/tabs/lib/tab-view.js
index 79e28cb864..39e1f09654 100644
--- a/packages/tabs/lib/tab-view.js
+++ b/packages/tabs/lib/tab-view.js
@@ -200,7 +200,6 @@ class TabView {
   }
 
   setBufferStatusColoring (isEnabled) {
-    console.log('Setting buffer status coloring to', isEnabled);
     this.useBufferStatusColoring = isEnabled;
     if (!isEnabled) {
       this.toggleTabClass('conflicted', false);
@@ -368,7 +367,6 @@ class TabView {
 
   updateDeletedStatus () {
     this.isDeleted = this.item.isDeleted?.() ?? false;
-    console.log('using buffer status coloring?', this.useBufferStatusColoring);
     this.toggleTabClass('deleted', this.useBufferStatusColoring && this.isDeleted);
     return this.isDeleted;
   }

From db327b82312abd3353f61585247ef096cc1f4344 Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Sat, 30 May 2026 20:22:09 -0700
Subject: [PATCH 11/14] Be paranoid about calling certain methods on pane items

---
 src/pane.js | 46 +++++++++++++++++++++++++++++-----------------
 1 file changed, 29 insertions(+), 17 deletions(-)

diff --git a/src/pane.js b/src/pane.js
index bced730f48..20bc67d0ba 100644
--- a/src/pane.js
+++ b/src/pane.js
@@ -16,7 +16,27 @@ class SaveConflictedError extends Error {
   name = 'SaveConflictedError';
 }
 
-
+// Handles values that could be booleans, functions, or undefined.
+//
+// Pane items implement several `isX` methods — `isDestroyed`, `isDeleted`,
+// `isModified`, et cetera. But all of these are optional. We could just do
+// `item.isDestroyed?.()` — except that, in at least one high-profile case, a
+// package has implemented defined `isDestroyed` _incorrectly_ as a boolean
+// instead of a function! And calling `item.isDestroyed?.()` on a boolean
+// throws an error.
+//
+// So this is our way of handling such scenarios without re-introducing lots of
+// boilerplate. We use this for some `isX` methods, but not all. (Newer methods
+// don't get this treatment because of almost zero chance of misimplementation
+// in the wild.)
+function interpret(booleanOrFunction) {
+  if (typeof booleanOrFunction === 'boolean') {
+    return booleanOrFunction;
+  } else if (typeof booleanOrFunction === 'function') {
+    return booleanOrFunction();
+  }
+  return false;
+}
 
 // Extended: A container for presenting content in the center of the workspace.
 // Panes can contain multiple items, one of which is *active* at a given time.
@@ -664,7 +684,7 @@ module.exports = class Pane {
       );
     }
 
-    if (this.paneItemIsDestroyed(item)) {
+    if (interpret(item.isDestroyed)) {
       throw new Error(
         `Adding a pane item with URI '${typeof item.getURI === 'function' &&
           item.getURI()}' that has already been destroyed`
@@ -704,15 +724,6 @@ module.exports = class Pane {
     return item;
   }
 
-  paneItemIsDestroyed (item) {
-    if (typeof item.isDestroyed === 'boolean') {
-      return item.isDestroyed;
-    } else if (typeof item.isDestroyed === 'function') {
-      return item.isDestroyed();
-    }
-    return false;
-  }
-
   setPendingItem(item) {
     if (this.pendingItem !== item) {
       const mostRecentPendingItem = this.pendingItem;
@@ -851,15 +862,15 @@ module.exports = class Pane {
     // Don't allow deletion of permanent dock items unless `force` is `true`.
     if (
       !force &&
-      item.isPermanentDockItem?.() &&
+      interpret(item.isPermanentDockItem) &&
       (!this.container || this.container.getLocation() !== 'center')
     ) {
       return false;
     }
 
     // In the case where there are no `onWillDestroyPaneItem` listeners,
-    // preserve the old behavior where `Pane.destroyItem` and callers such as
-    // `Pane.close` take effect synchronously.
+    // preserve the old behavior where `Pane::destroyItem` and callers such as
+    // `Pane::close` take effect synchronously.
     if (this.emitter.listenerCountForEventName('will-destroy-item') > 0) {
       await this.emitter.emitAsync('will-destroy-item', { item, index });
     }
@@ -927,8 +938,9 @@ module.exports = class Pane {
       const title = item.getTitle?.() || uri;
 
       let message, detail;
-      let firstButton = item.isDeleted() ? 'Save' : 'Overwrite';
-      if (item.isDeleted()) {
+      let isDeleted = interpret(item.isDeleted);
+      let firstButton = isDeleted ? 'Save' : 'Overwrite';
+      if (isDeleted) {
         // The message is a bit different when the file no longer exists on
         // disk.
         message = `'${title}' was deleted on disk. Do you still want to save this file?`;
@@ -1163,7 +1175,7 @@ module.exports = class Pane {
   // Public: Save all items.
   saveItems() {
     for (let item of this.getItems()) {
-      if (item.isModified?.()) {
+      if (interpret(item.isModified)) {
         this.saveItem(item);
       }
     }

From 73d7fa778f3be20fe2dedaf7a6b3a8b32b77661a Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Sat, 30 May 2026 22:58:12 -0700
Subject: [PATCH 12/14] =?UTF-8?q?Whoops=20=E2=80=94=20fix=20binding=20issu?=
 =?UTF-8?q?es?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/pane.js | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/pane.js b/src/pane.js
index 20bc67d0ba..27fdf834a0 100644
--- a/src/pane.js
+++ b/src/pane.js
@@ -29,11 +29,12 @@ class SaveConflictedError extends Error {
 // boilerplate. We use this for some `isX` methods, but not all. (Newer methods
 // don't get this treatment because of almost zero chance of misimplementation
 // in the wild.)
-function interpret(booleanOrFunction) {
+function interpret(obj, booleanOrFunctionName) {
+  let booleanOrFunction = obj[booleanOrFunctionName];
   if (typeof booleanOrFunction === 'boolean') {
     return booleanOrFunction;
   } else if (typeof booleanOrFunction === 'function') {
-    return booleanOrFunction();
+    return obj[booleanOrFunctionName]();
   }
   return false;
 }
@@ -684,7 +685,7 @@ module.exports = class Pane {
       );
     }
 
-    if (interpret(item.isDestroyed)) {
+    if (interpret(item, 'isDestroyed')) {
       throw new Error(
         `Adding a pane item with URI '${typeof item.getURI === 'function' &&
           item.getURI()}' that has already been destroyed`
@@ -862,7 +863,7 @@ module.exports = class Pane {
     // Don't allow deletion of permanent dock items unless `force` is `true`.
     if (
       !force &&
-      interpret(item.isPermanentDockItem) &&
+      interpret(item, 'isPermanentDockItem') &&
       (!this.container || this.container.getLocation() !== 'center')
     ) {
       return false;
@@ -938,7 +939,7 @@ module.exports = class Pane {
       const title = item.getTitle?.() || uri;
 
       let message, detail;
-      let isDeleted = interpret(item.isDeleted);
+      let isDeleted = interpret(item, 'isDeleted');
       let firstButton = isDeleted ? 'Save' : 'Overwrite';
       if (isDeleted) {
         // The message is a bit different when the file no longer exists on
@@ -1175,7 +1176,7 @@ module.exports = class Pane {
   // Public: Save all items.
   saveItems() {
     for (let item of this.getItems()) {
-      if (interpret(item.isModified)) {
+      if (interpret(item, 'isModified')) {
         this.saveItem(item);
       }
     }

From 18706dc76c58cd33a18db62eeeac25a03565f9a4 Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Sat, 30 May 2026 23:25:02 -0700
Subject: [PATCH 13/14] Stop trying to be fancy

---
 src/pane.js | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/pane.js b/src/pane.js
index 27fdf834a0..11406d0caa 100644
--- a/src/pane.js
+++ b/src/pane.js
@@ -31,9 +31,7 @@ class SaveConflictedError extends Error {
 // in the wild.)
 function interpret(obj, booleanOrFunctionName) {
   let booleanOrFunction = obj[booleanOrFunctionName];
-  if (typeof booleanOrFunction === 'boolean') {
-    return booleanOrFunction;
-  } else if (typeof booleanOrFunction === 'function') {
+  if (typeof booleanOrFunction === 'function') {
     return obj[booleanOrFunctionName]();
   }
   return false;

From dd43d3ffdb7ff9e2b870d8a731ff18303c23ebb6 Mon Sep 17 00:00:00 2001
From: Andrew Dupont <github@andrewdupont.net>
Date: Sat, 30 May 2026 23:44:16 -0700
Subject: [PATCH 14/14] Fix pane specs (again)

---
 src/pane.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/pane.js b/src/pane.js
index 11406d0caa..a4dda357bd 100644
--- a/src/pane.js
+++ b/src/pane.js
@@ -986,13 +986,13 @@ module.exports = class Pane {
         return resolve(true);
       }
 
-      // A pane item must have a URI so that we have a "title of last resort"
-      // to show in the dialog.
-      let uri = item.getURI?.() ?? item.getUri?.() ?? null;
-      if (!uri) {
+      // If the item has no way of providing us a URI, then it probably wasn't
+      // designed to represent a resource that can be saved.
+      if (typeof item.getURI !== 'function' && typeof item.getUri !== 'function') {
         return resolve(true);
       }
 
+      let uri = item.getURI?.() ?? item.getUri?.();
       let title = item.getTitle?.() || uri;
 
       const saveDialog = (saveButtonText, saveFn, message) => {