From 1569f9d9d7e97d7bfdccff0174c2e861401b07f7 Mon Sep 17 00:00:00 2001
From: Matt Bierner <matb@microsoft.com>
Date: Tue, 16 May 2023 12:28:14 -0700
Subject: [PATCH] Don't cancel file reopen if language has changed (#182657)

Fixes #182526

The chat panel changes the language of a document. This revealed a bug in JS/TS about language changes.

Normally changing a language should close and reopen a text document. However we added an optimization to not do this full flow if the open then close happens quickly

However this causes issues if the file changes languages as TS gets into a state where its doc language id does not match VS Code's language id. To fix this, I've limited the optimization to only apply when the expected script kinds match
---
 .../src/tsServer/bufferSyncSupport.ts         | 38 +++++++++++--------
 1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/extensions/typescript-language-features/src/tsServer/bufferSyncSupport.ts b/extensions/typescript-language-features/src/tsServer/bufferSyncSupport.ts
index 7ccfd67ba0f..a38b67f0a02 100644
--- a/extensions/typescript-language-features/src/tsServer/bufferSyncSupport.ts
+++ b/extensions/typescript-language-features/src/tsServer/bufferSyncSupport.ts
@@ -16,7 +16,7 @@ import { ResourceMap } from '../utils/resourceMap';
 import { API } from './api';
 import type * as Proto from './protocol/protocol';
 
-const enum BufferKind {
+const enum BufferLanguage {
 	TypeScript = 1,
 	JavaScript = 2,
 }
@@ -27,7 +27,9 @@ const enum BufferState {
 	Closed = 2,
 }
 
-function mode2ScriptKind(mode: string): 'TS' | 'TSX' | 'JS' | 'JSX' | undefined {
+type ScriptKind = 'TS' | 'TSX' | 'JS' | 'JSX';
+
+function mode2ScriptKind(mode: string): ScriptKind | undefined {
 	switch (mode) {
 		case languageModeIds.typescript: return 'TS';
 		case languageModeIds.typescriptreact: return 'TSX';
@@ -42,14 +44,16 @@ const enum BufferOperationType { Close, Open, Change }
 class CloseOperation {
 	readonly type = BufferOperationType.Close;
 	constructor(
-		public readonly args: string
+		public readonly args: string,
+		public readonly scriptKind: ScriptKind | undefined,
 	) { }
 }
 
 class OpenOperation {
 	readonly type = BufferOperationType.Open;
 	constructor(
-		public readonly args: Proto.OpenRequestArgs
+		public readonly args: Proto.OpenRequestArgs,
+		public readonly scriptKind: ScriptKind | undefined,
 	) { }
 }
 
@@ -83,7 +87,7 @@ class BufferSynchronizer {
 
 	public open(resource: vscode.Uri, args: Proto.OpenRequestArgs) {
 		if (this.supportsBatching) {
-			this.updatePending(resource, new OpenOperation(args));
+			this.updatePending(resource, new OpenOperation(args, args.scriptKindName));
 		} else {
 			this.client.executeWithoutWaitingForResponse('open', args);
 		}
@@ -92,9 +96,9 @@ class BufferSynchronizer {
 	/**
 	 * @return Was the buffer open?
 	 */
-	public close(resource: vscode.Uri, filepath: string): boolean {
+	public close(resource: vscode.Uri, filepath: string, scriptKind: ScriptKind | undefined): boolean {
 		if (this.supportsBatching) {
-			return this.updatePending(resource, new CloseOperation(filepath));
+			return this.updatePending(resource, new CloseOperation(filepath, scriptKind));
 		} else {
 			const args: Proto.FileRequestArgs = { file: filepath };
 			this.client.executeWithoutWaitingForResponse('close', args);
@@ -172,8 +176,10 @@ class BufferSynchronizer {
 				const existing = this._pending.get(resource);
 				switch (existing?.type) {
 					case BufferOperationType.Open:
-						this._pending.delete(resource);
-						return false; // Open then close. No need to do anything
+						if (existing.scriptKind === op.scriptKind) {
+							this._pending.delete(resource);
+							return false; // Open then close. No need to do anything
+						}
 				}
 				break;
 			}
@@ -230,16 +236,16 @@ class SyncedBuffer {
 		return this.document.lineCount;
 	}
 
-	public get kind(): BufferKind {
+	public get language(): BufferLanguage {
 		switch (this.document.languageId) {
 			case languageModeIds.javascript:
 			case languageModeIds.javascriptreact:
-				return BufferKind.JavaScript;
+				return BufferLanguage.JavaScript;
 
 			case languageModeIds.typescript:
 			case languageModeIds.typescriptreact:
 			default:
-				return BufferKind.TypeScript;
+				return BufferLanguage.TypeScript;
 		}
 	}
 
@@ -252,7 +258,7 @@ class SyncedBuffer {
 			return false;
 		}
 		this.state = BufferState.Closed;
-		return this.synchronizer.close(this.resource, this.filepath);
+		return this.synchronizer.close(this.resource, this.filepath, mode2ScriptKind(this.document.languageId));
 	}
 
 	public onContentChanged(events: readonly vscode.TextDocumentContentChangeEvent[]): void {
@@ -749,11 +755,11 @@ export default class BufferSyncSupport extends Disposable {
 			return false;
 		}
 
-		switch (buffer.kind) {
-			case BufferKind.JavaScript:
+		switch (buffer.language) {
+			case BufferLanguage.JavaScript:
 				return this._validateJavaScript;
 
-			case BufferKind.TypeScript:
+			case BufferLanguage.TypeScript:
 			default:
 				return this._validateTypeScript;
 		}