From e95c40c1e461f83f5ff1c68d61253ab23c85f86b Mon Sep 17 00:00:00 2001
From: Alex Ross <alros@microsoft.com>
Date: Fri, 6 Nov 2020 14:46:46 +0100
Subject: [PATCH] API proposal for revealing tree view when no elements Fixes
 #90005

---
 src/vs/vscode.proposed.d.ts                       |  4 ++++
 .../workbench/api/browser/mainThreadTreeViews.ts  |  8 ++++----
 src/vs/workbench/api/common/extHost.protocol.ts   |  2 +-
 src/vs/workbench/api/common/extHostTreeViews.ts   | 15 ++++++++++-----
 4 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index 720a42a0f11ca..e289a214eaa03 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -1038,6 +1038,10 @@ declare module 'vscode' {
 		 */
 		constructor(label: TreeItemLabel, collapsibleState?: TreeItemCollapsibleState);
 	}
+
+	export interface TreeView<T> extends Disposable {
+		reveal(element: T | undefined, options?: { select?: boolean, focus?: boolean, expand?: boolean | number }): Thenable<void>;
+	}
 	//#endregion
 
 	//#region Task presentation group: https://github.com/microsoft/vscode/issues/47265
diff --git a/src/vs/workbench/api/browser/mainThreadTreeViews.ts b/src/vs/workbench/api/browser/mainThreadTreeViews.ts
index 7d0d71cc4f3e1..51f47b691ff61 100644
--- a/src/vs/workbench/api/browser/mainThreadTreeViews.ts
+++ b/src/vs/workbench/api/browser/mainThreadTreeViews.ts
@@ -52,14 +52,14 @@ export class MainThreadTreeViews extends Disposable implements MainThreadTreeVie
 		});
 	}
 
-	$reveal(treeViewId: string, item: ITreeItem, parentChain: ITreeItem[], options: IRevealOptions): Promise<void> {
-		this.logService.trace('MainThreadTreeViews#$reveal', treeViewId, item, parentChain, options);
+	$reveal(treeViewId: string, itemInfo: { item: ITreeItem, parentChain: ITreeItem[] } | undefined, options: IRevealOptions): Promise<void> {
+		this.logService.trace('MainThreadTreeViews#$reveal', treeViewId, itemInfo?.item, itemInfo?.parentChain, options);
 
 		return this.viewsService.openView(treeViewId, options.focus)
 			.then(() => {
 				const viewer = this.getTreeView(treeViewId);
-				if (viewer) {
-					return this.reveal(viewer, this._dataProviders.get(treeViewId)!, item, parentChain, options);
+				if (viewer && itemInfo) {
+					return this.reveal(viewer, this._dataProviders.get(treeViewId)!, itemInfo.item, itemInfo.parentChain, options);
 				}
 				return undefined;
 			});
diff --git a/src/vs/workbench/api/common/extHost.protocol.ts b/src/vs/workbench/api/common/extHost.protocol.ts
index 0b400e29bcbca..001715a81a81a 100644
--- a/src/vs/workbench/api/common/extHost.protocol.ts
+++ b/src/vs/workbench/api/common/extHost.protocol.ts
@@ -292,7 +292,7 @@ export interface MainThreadTextEditorsShape extends IDisposable {
 export interface MainThreadTreeViewsShape extends IDisposable {
 	$registerTreeViewDataProvider(treeViewId: string, options: { showCollapseAll: boolean, canSelectMany: boolean; }): void;
 	$refresh(treeViewId: string, itemsToRefresh?: { [treeItemHandle: string]: ITreeItem; }): Promise<void>;
-	$reveal(treeViewId: string, treeItem: ITreeItem, parentChain: ITreeItem[], options: IRevealOptions): Promise<void>;
+	$reveal(treeViewId: string, itemInfo: { item: ITreeItem, parentChain: ITreeItem[] } | undefined, options: IRevealOptions): Promise<void>;
 	$setMessage(treeViewId: string, message: string): void;
 	$setTitle(treeViewId: string, title: string, description: string | undefined): void;
 }
diff --git a/src/vs/workbench/api/common/extHostTreeViews.ts b/src/vs/workbench/api/common/extHostTreeViews.ts
index d7194fc231745..4fc0dc1fdb6c8 100644
--- a/src/vs/workbench/api/common/extHostTreeViews.ts
+++ b/src/vs/workbench/api/common/extHostTreeViews.ts
@@ -293,7 +293,7 @@ class ExtHostTreeView<T> extends Disposable {
 		return this.elements.get(treeItemHandle);
 	}
 
-	reveal(element: T, options?: IRevealOptions): Promise<void> {
+	reveal(element: T | undefined, options?: IRevealOptions): Promise<void> {
 		options = options ? options : { select: true, focus: false };
 		const select = isUndefinedOrNull(options.select) ? true : options.select;
 		const focus = isUndefinedOrNull(options.focus) ? false : options.focus;
@@ -302,10 +302,15 @@ class ExtHostTreeView<T> extends Disposable {
 		if (typeof this.dataProvider.getParent !== 'function') {
 			return Promise.reject(new Error(`Required registered TreeDataProvider to implement 'getParent' method to access 'reveal' method`));
 		}
-		return this.refreshPromise
-			.then(() => this.resolveUnknownParentChain(element))
-			.then(parentChain => this.resolveTreeNode(element, parentChain[parentChain.length - 1])
-				.then(treeNode => this.proxy.$reveal(this.viewId, treeNode.item, parentChain.map(p => p.item), { select, focus, expand })), error => this.logService.error(error));
+
+		if (element) {
+			return this.refreshPromise
+				.then(() => this.resolveUnknownParentChain(element))
+				.then(parentChain => this.resolveTreeNode(element, parentChain[parentChain.length - 1])
+					.then(treeNode => this.proxy.$reveal(this.viewId, { item: treeNode.item, parentChain: parentChain.map(p => p.item) }, { select, focus, expand })), error => this.logService.error(error));
+		} else {
+			return this.proxy.$reveal(this.viewId, undefined, { select, focus, expand });
+		}
 	}
 
 	private _message: string = '';