Fix Recent list in dock does not show recent files/folders #74788 (#75108)

* Fix Recent list in dock does not show recent files/folders #74788

macOS only shows recent list with max number based on sytem config. It takes bottom n entries from the list added through Electron app.addRecentDocument. To match macOS dock recent list with VSCode internal recent list, this change add items into macOS recent document list in reverse order of internal recent list.

* remove dock recent entries limit

* add entry of folder (5) back to allow show some files

* fix showsing wrong folders in recentlist

* simplify adding platform RecentDocument in macOS

* update based on bpasero suggestion

* set max entries

* rename macro

src/vs/platform/history/electron-main/historyMainService.ts

@@ -28,8 +28,9 @@ import { ILifecycleService, LifecycleMainPhase } from 'vs/platform/lifecycle/ele
 export class HistoryMainService implements IHistoryMainService {
 
 	private static readonly MAX_TOTAL_RECENT_ENTRIES = 100;
-	private static readonly MAX_MACOS_DOCK_RECENT_FOLDERS = 10;
-	private static readonly MAX_MACOS_DOCK_RECENT_FILES = 5;
+
+	private static readonly MAX_MACOS_DOCK_RECENT_WORKSPACES = 7; // prefer more workspaces...
+	private static readonly MAX_MACOS_DOCK_RECENT_ENTRIES_TOTAL = 10; // ...compared to files
 
 	// Exclude some very common files from the dock/taskbar
 	private static readonly COMMON_FILES_FILTER = [
@@ -153,37 +154,58 @@ export class HistoryMainService implements IHistoryMainService {
 			return;
 		}
 
-		// macOS recent documents in the dock are behaving strangely. the entries seem to get
-		// out of sync quickly over time. the attempted fix is to always set the list fresh
-		// from our MRU history data. So we clear the documents first and then set the documents
-		// again.
+		// We clear all documents first to ensure an up-to-date view on the set. Since entries
+		// can get deleted on disk, this ensures that the list is always valid
 		app.clearRecentDocuments();
 
 		const mru = this.getRecentlyOpened();
 
-		// Fill in workspaces
-		for (let i = 0, entries = 0; i < mru.workspaces.length && entries < HistoryMainService.MAX_MACOS_DOCK_RECENT_FOLDERS; i++) {
+		// Collect max-N recent workspaces that are known to exist
+		const workspaceEntries: string[] = [];
+		let entries = 0;
+		for (let i = 0; i < mru.workspaces.length && entries < HistoryMainService.MAX_MACOS_DOCK_RECENT_WORKSPACES; i++) {
 			const loc = location(mru.workspaces[i]);
 			if (loc.scheme === Schemas.file) {
 				const workspacePath = originalFSPath(loc);
 				if (await exists(workspacePath)) {
-					app.addRecentDocument(workspacePath);
+					workspaceEntries.push(workspacePath);
 					entries++;
 				}
 			}
 		}
 
-		// Fill in files
-		for (let i = 0, entries = 0; i < mru.files.length && entries < HistoryMainService.MAX_MACOS_DOCK_RECENT_FILES; i++) {
+		// Collect max-N recent files that are known to exist
+		const fileEntries: string[] = [];
+		for (let i = 0; i < mru.files.length && entries < HistoryMainService.MAX_MACOS_DOCK_RECENT_ENTRIES_TOTAL; i++) {
 			const loc = location(mru.files[i]);
-			if (loc.scheme === Schemas.file && HistoryMainService.COMMON_FILES_FILTER.indexOf(basename(loc)) === -1) {
+			if (loc.scheme === Schemas.file) {
 				const filePath = originalFSPath(loc);
+				if (
+					HistoryMainService.COMMON_FILES_FILTER.indexOf(basename(loc)) !== -1 || // skip some well known file entries
+					workspaceEntries.indexOf(filePath) !== -1								// prefer a workspace entry over a file entry (e.g. for .code-workspace)
+				) {
+					continue;
+				}
+
 				if (await exists(filePath)) {
-					app.addRecentDocument(filePath);
+					fileEntries.push(filePath);
 					entries++;
 				}
 			}
 		}
+
+		// The apple guidelines (https://developer.apple.com/design/human-interface-guidelines/macos/menus/menu-anatomy/)
+		// explain that most recent entries should appear close to the interaction by the user (e.g. close to the
+		// mouse click). Most native macOS applications that add recent documents to the dock, show the most recent document
+		// to the bottom (because the dock menu is not appearing from top to bottom, but from the bottom to the top). As such
+		// we fill in the entries in reverse order so that the most recent shows up at the bottom of the menu.
+		//
+		// On top of that, the maximum number of documents can be configured by the user (defaults to 10). To ensure that
+		// we are not failing to show the most recent entries, we start by adding files first (in reverse order of recency)
+		// and then add folders (in reverse order of recency). Given that strategy, we can ensure that the most recent
+		// N folders are always appearing, even if the limit is low (https://github.com/microsoft/vscode/issues/74788)
+		fileEntries.reverse().forEach(fileEntry => app.addRecentDocument(fileEntry));
+		workspaceEntries.reverse().forEach(workspaceEntry => app.addRecentDocument(workspaceEntry));
 	}
 
 	clearRecentlyOpened(): void {