Fix remaining case where workspace paths are lower cased

Fixes #16829

src/vs/platform/backup/electron-main/backupMainService.ts

@@ -117,16 +117,16 @@ export class BackupMainService implements IBackupMainService {
 		this.validateBackupWorkspaces(backups);
 	}
 
-	protected sanitizeFolderWorkspaces(backups: IBackupWorkspacesFormat): void {
-		// Merge duplicates for folder workspaces, don't worry about cleaning them up as they will
-		// be removed when there are no backups.
-		backups.folderWorkspaces = arrays.distinct(backups.folderWorkspaces.map(w => this.sanitizePath(w)));
+	protected dedupeFolderWorkspaces(backups: IBackupWorkspacesFormat): void {
+		// De-duplicate folder workspaces, don't worry about cleaning them up any duplicates as
+		// they will be removed when there are no backups.
+		backups.folderWorkspaces = arrays.distinct(backups.folderWorkspaces, ws => this.sanitizePath(ws));
 	}
 
 	private validateBackupWorkspaces(backups: IBackupWorkspacesFormat): void {
 		const staleBackupWorkspaces: { workspaceIdentifier: string; backupPath: string; isEmptyWorkspace: boolean }[] = [];
 
-		this.sanitizeFolderWorkspaces(backups);
+		this.dedupeFolderWorkspaces(backups);
 
 		backups.folderWorkspaces.forEach(workspacePath => {
 			const backupPath = path.join(this.backupHome, this.getWorkspaceHash(workspacePath));

src/vs/platform/backup/test/electron-main/backupMainService.test.ts

@@ -36,8 +36,8 @@ class TestBackupMainService extends BackupMainService {
 		super.loadSync();
 	}
 
-	public sanitizeFolderWorkspaces(backups: IBackupWorkspacesFormat): void {
-		super.sanitizeFolderWorkspaces(backups);
+	public dedupeFolderWorkspaces(backups: IBackupWorkspacesFormat): void {
+		super.dedupeFolderWorkspaces(backups);
 	}
 
 	public toBackupPath(workspacePath: string): string {
@@ -209,24 +209,25 @@ suite('BackupMainService', () => {
 		});
 	});
 
-	suite('sanitizeFolderWorkspaces', () => {
-		test('should merge same cased paths on Windows and Mac', () => {
+	suite('dedupeFolderWorkspaces', () => {
+		test('should ignore duplicates on Windows and Mac', () => {
 			// Skip test on Linux
 			if (platform.isLinux) {
 				return;
 			}
 
 			const backups: IBackupWorkspacesFormat = {
-				folderWorkspaces: platform.isWindows ? ['c:\\foo', 'C:\\FOO', 'c:\\FOO'] : ['/foo', '/FOO'],
+				folderWorkspaces: platform.isWindows ? ['c:\\FOO', 'C:\\FOO', 'c:\\foo'] : ['/FOO', '/foo'],
 				emptyWorkspaces: []
 			};
 
-			service.sanitizeFolderWorkspaces(backups);
+			service.dedupeFolderWorkspaces(backups);
 
+			assert.equal(backups.folderWorkspaces.length, 1);
 			if (platform.isWindows) {
-				assert.deepEqual(backups.folderWorkspaces, ['c:\\foo']);
+				assert.deepEqual(backups.folderWorkspaces, ['c:\\FOO'], 'should return the first duplicated entry');
 			} else {
-				assert.deepEqual(backups.folderWorkspaces, ['/foo']);
+				assert.deepEqual(backups.folderWorkspaces, ['/FOO'], 'should return the first duplicated entry');
 			}
 		});
 	});