Preserve PR diff scroll position

src/commands.ts

@@ -46,10 +46,12 @@ import { CategoryTreeNode } from './view/treeNodes/categoryNode';
 import { CommitNode } from './view/treeNodes/commitNode';
 import {
 	FileChangeNode,
+	getPullRequestDiffViewState,
 	GitFileChangeNode,
 	InMemFileChangeNode,
 	openFileCommand,
 	RemoteFileChangeNode,
+	storePullRequestDiffViewState,
 } from './view/treeNodes/fileChangeNode';
 import { PRNode } from './view/treeNodes/pullRequestNode';
 import { RepositoryChangesNode } from './view/treeNodes/repositoryChangesNode';
@@ -99,6 +101,32 @@ export async function openDescription(
 	}
 }
 
+function cacheActivePullRequestDiffViewState(): void {
+	const input = vscode.window.tabGroups.activeTabGroup.activeTab?.input;
+	const editor = vscode.window.activeTextEditor;
+	if (!(input instanceof vscode.TabInputTextDiff) || !editor || editor.document.uri.toString() !== input.modified.toString()) {
+		return;
+	}
+
+	const visibleRange = editor.visibleRanges[0];
+	if (visibleRange) {
+		storePullRequestDiffViewState(input.original, input.modified, visibleRange);
+	}
+}
+
+function restoreActivePullRequestDiffViewState(): void {
+	const input = vscode.window.tabGroups.activeTabGroup.activeTab?.input;
+	const editor = vscode.window.activeTextEditor;
+	if (!(input instanceof vscode.TabInputTextDiff) || !editor || editor.document.uri.toString() !== input.modified.toString()) {
+		return;
+	}
+
+	const visibleRange = getPullRequestDiffViewState(input.original, input.modified);
+	if (visibleRange) {
+		editor.revealRange(visibleRange, vscode.TextEditorRevealType.AtTop);
+	}
+}
+
 export async function openPullRequestOnGitHub(e: PRNode | RepositoryChangesNode | IssueModel | NotificationTreeItem, telemetry: ITelemetry) {
 	if (e instanceof PRNode || e instanceof RepositoryChangesNode) {
 		vscode.commands.executeCommand('vscode.open', vscode.Uri.parse(e.pullRequestModel.html_url));
@@ -308,7 +336,10 @@ export function registerCommands(
 			if (!folderManager) {
 				return;
 			}
-			return fileChangeNode.openDiff(folderManager);
+			cacheActivePullRequestDiffViewState();
+			await fileChangeNode.openDiff(folderManager);
+			restoreActivePullRequestDiffViewState();
+			return;
 		} else if (fileChangeNode || vscode.window.activeTextEditor) {
 			const editor = fileChangeNode instanceof vscode.Uri ? vscode.window.visibleTextEditors.find(editor => editor.document.uri.toString() === fileChangeNode.toString())! : vscode.window.activeTextEditor!;
 			const visibleRanges = editor.visibleRanges;

src/test/view/fileChangeNode.test.ts

@@ -0,0 +1,41 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { strict as assert } from 'assert';
+import * as vscode from 'vscode';
+import { clearPullRequestDiffViewStates, getPullRequestDiffViewState, storePullRequestDiffViewState } from '../../view/treeNodes/fileChangeNode';
+
+describe('fileChangeNode diff view state', function () {
+	beforeEach(function () {
+		clearPullRequestDiffViewStates();
+	});
+
+	afterEach(function () {
+		clearPullRequestDiffViewStates();
+	});
+
+	it('stores diff view state per original and modified uri pair', function () {
+		const original = vscode.Uri.parse('review:/repo/file.ts?base=true');
+		const modified = vscode.Uri.parse('review:/repo/file.ts?base=false');
+		const range = new vscode.Range(10, 0, 25, 0);
+
+		storePullRequestDiffViewState(original, modified, range);
+
+		assert.deepStrictEqual(getPullRequestDiffViewState(original, modified), range);
+		assert.strictEqual(getPullRequestDiffViewState(original, vscode.Uri.parse('review:/repo/file.ts?base=false&other=true')), undefined);
+	});
+
+	it('overwrites the saved state for the same diff pair', function () {
+		const original = vscode.Uri.parse('review:/repo/file.ts?base=true');
+		const modified = vscode.Uri.parse('review:/repo/file.ts?base=false');
+		const firstRange = new vscode.Range(1, 0, 5, 0);
+		const secondRange = new vscode.Range(20, 0, 30, 0);
+
+		storePullRequestDiffViewState(original, modified, firstRange);
+		storePullRequestDiffViewState(original, modified, secondRange);
+
+		assert.deepStrictEqual(getPullRequestDiffViewState(original, modified), secondRange);
+	});
+});

src/view/treeNodes/fileChangeNode.ts

@@ -15,6 +15,24 @@ import { IResolvedPullRequestModel, PullRequestModel } from '../../github/pullRe
 import { FileChangeModel, GitFileChangeModel, InMemFileChangeModel, RemoteFileChangeModel } from '../fileChangeModel';
 import { TreeNode, TreeNodeParent } from './treeNode';
 
+const pullRequestDiffViewStates = new Map<string, vscode.Range>();
+
+export function getPullRequestDiffViewStateKey(original: vscode.Uri, modified: vscode.Uri): string {
+	return `${original.toString()}::${modified.toString()}`;
+}
+
+export function storePullRequestDiffViewState(original: vscode.Uri, modified: vscode.Uri, visibleRange: vscode.Range): void {
+	pullRequestDiffViewStates.set(getPullRequestDiffViewStateKey(original, modified), visibleRange);
+}
+
+export function getPullRequestDiffViewState(original: vscode.Uri, modified: vscode.Uri): vscode.Range | undefined {
+	return pullRequestDiffViewStates.get(getPullRequestDiffViewStateKey(original, modified));
+}
+
+export function clearPullRequestDiffViewStates(): void {
+	pullRequestDiffViewStates.clear();
+}
+
 export function openFileCommand(uri: vscode.Uri, inputOpts: vscode.TextDocumentShowOptions = {}): vscode.Command {
 	const activeTextEditor = vscode.window.activeTextEditor;
 	const opts = {
@@ -294,13 +312,11 @@ export class InMemFileChangeNode extends FileChangeNode implements vscode.TreeIt
 		if (this.status === GitChangeType.ADD) {
 			this.command = openFileCommand(this.changeModel.filePath);
 		} else {
-			this.command = await openDiffCommand(
-				this.folderRepositoryManager,
-				this.changeModel.parentFilePath,
-				this.changeModel.filePath,
-				undefined,
-				this.changeModel.status,
-			);
+			this.command = {
+				command: 'pr.openDiffView',
+				arguments: [this],
+				title: 'Open Changed File in pull request',
+			};
 		}
 	}
 }
@@ -408,13 +424,11 @@ export class GitFileChangeNode extends FileChangeNode implements vscode.TreeItem
 		} else {
 			const openDiff = vscode.workspace.getConfiguration(GIT, this.pullRequestManager.repository.rootUri).get(OPEN_DIFF_ON_CLICK, true);
 			if (openDiff && this.status !== GitChangeType.ADD) {
-				this.command = await openDiffCommand(
-					this.pullRequestManager,
-					this.changeModel.parentFilePath,
-					this.changeModel.filePath,
-					this.opts,
-					this.status,
-				);
+				this.command = {
+					command: 'pr.openDiffView',
+					arguments: [this],
+					title: 'Open Changed File in pull request',
+				};
 			} else {
 				this.command = this.openFileCommand();
 			}