From 8f9d3926002266ef354d7b9733b7892c27d16d99 Mon Sep 17 00:00:00 2001
From: Colin Grant <colin.grant@ericsson.com>
Date: Mon, 10 Jan 2022 17:22:43 -0700
Subject: [PATCH] No save dialog if another widget shares identical model

---
 packages/core/src/browser/saveable.ts           | 17 ++++++++++++-----
 .../core/src/browser/shell/application-shell.ts |  4 ++--
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/packages/core/src/browser/saveable.ts b/packages/core/src/browser/saveable.ts
index cea603bfaa8f2..5d7a8f88b7fc0 100644
--- a/packages/core/src/browser/saveable.ts
+++ b/packages/core/src/browser/saveable.ts
@@ -93,7 +93,7 @@ export namespace Saveable {
             await saveable.save(options);
         }
     }
-    export function apply(widget: Widget): SaveableWidget | undefined {
+    export function apply(widget: Widget, getOtherSaveables?: () => Array<Widget & (Saveable | SaveableSource)>): SaveableWidget | undefined {
         if (SaveableWidget.is(widget)) {
             return widget;
         }
@@ -104,8 +104,8 @@ export namespace Saveable {
         setDirty(widget, saveable.dirty);
         saveable.onDirtyChanged(() => setDirty(widget, saveable.dirty));
         const closeWidget = widget.close.bind(widget);
-        const closeWithoutSaving: SaveableWidget['closeWithoutSaving'] = async () => {
-            if (saveable.dirty && saveable.revert) {
+        const closeWithoutSaving: SaveableWidget['closeWithoutSaving'] = async (doRevert = true) => {
+            if (doRevert && saveable.dirty && saveable.revert) {
                 await saveable.revert();
             }
             closeWidget();
@@ -119,6 +119,10 @@ export namespace Saveable {
             closing = true;
             try {
                 const result = await shouldSave(saveable, () => {
+                    const notLastWithDocument = getOtherSaveables?.().some(otherWidget => otherWidget !== widget && Saveable.get(otherWidget) === saveable);
+                    if (notLastWithDocument) {
+                        return closeWithoutSaving(false).then(() => undefined);
+                    }
                     if (options && options.shouldSave) {
                         return options.shouldSave();
                     }
@@ -128,7 +132,7 @@ export namespace Saveable {
                     if (result) {
                         await Saveable.save(widget);
                     }
-                    await closeWithoutSaving();
+                    await closeWithoutSaving(result);
                 }
             } finally {
                 closing = false;
@@ -154,7 +158,10 @@ export namespace Saveable {
 }
 
 export interface SaveableWidget extends Widget {
-    closeWithoutSaving(): Promise<void>;
+    /**
+     * @param doRevert whether the saveable should be reverted before being saved. Defaults to `true`.
+     */
+    closeWithoutSaving(doRevert?: boolean): Promise<void>;
     closeWithSaving(options?: SaveableWidget.CloseOptions): Promise<void>;
 }
 export namespace SaveableWidget {
diff --git a/packages/core/src/browser/shell/application-shell.ts b/packages/core/src/browser/shell/application-shell.ts
index 4167fe7ea1303..b8a59aa417040 100644
--- a/packages/core/src/browser/shell/application-shell.ts
+++ b/packages/core/src/browser/shell/application-shell.ts
@@ -24,7 +24,7 @@ import { Message } from '@phosphor/messaging';
 import { IDragEvent } from '@phosphor/dragdrop';
 import { RecursivePartial, Event as CommonEvent, DisposableCollection, Disposable, environment } from '../../common';
 import { animationFrame } from '../browser';
-import { Saveable, SaveableWidget, SaveOptions } from '../saveable';
+import { Saveable, SaveableWidget, SaveOptions, SaveableSource } from '../saveable';
 import { StatusBarImpl, StatusBarEntry, StatusBarAlignment } from '../status-bar/status-bar';
 import { TheiaDockPanel, BOTTOM_AREA_ID, MAIN_AREA_ID } from './theia-dock-panel';
 import { SidePanelHandler, SidePanel, SidePanelHandlerFactory } from './side-panel-handler';
@@ -1025,7 +1025,7 @@ export class ApplicationShell extends Widget {
         }
         this.tracker.add(widget);
         this.checkActivation(widget);
-        Saveable.apply(widget);
+        Saveable.apply(widget, () => this.widgets.filter((maybeSaveable): maybeSaveable is Widget & SaveableSource => !!Saveable.get(maybeSaveable)));
         if (ApplicationShell.TrackableWidgetProvider.is(widget)) {
             for (const toTrack of widget.getTrackableWidgets()) {
                 this.track(toTrack);