Fix markdown server not updating documents properly on folder rename (microsoft#164752)

Fixes microsoft#164562

Author: mjbvz

extensions/markdown-language-features/server/src/workspace.ts

@@ -64,6 +64,10 @@ class VsCodeDocument implements md.ITextDocument {
 		throw new Error('Document has been closed');
 	}
 
+	hasInMemoryDoc(): boolean {
+		return !this.inMemoryDoc;
+	}
+
 	isDetached(): boolean {
 		return !this.onDiskDoc && !this.inMemoryDoc;
 	}
@@ -166,12 +170,23 @@ export class VsCodeClientWorkspace implements md.IWorkspaceWithWatching {
 			if (doc.isDetached()) {
 				// The document has been fully closed
 				this.doDeleteDocument(uri);
-			} else {
-				// The document still exists on disk
-				// To be safe, tell the service that the document has changed because the
-				// in-memory doc contents may be different than the disk doc contents.
-				this._onDidChangeMarkdownDocument.fire(doc);
+				return;
 			}
+
+			// Check that if file has been deleted on disk.
+			// This can happen when directories are renamed / moved. VS Code's file system watcher does not
+			// notify us when this happens.
+			if (await this.stat(uri) === undefined) {
+				if (this._documentCache.get(uri) === doc && !doc.hasInMemoryDoc()) {
+					this.doDeleteDocument(uri);
+					return;
+				}
+			}
+
+			// The document still exists on disk
+			// To be safe, tell the service that the document has changed because the
+			// in-memory doc contents may be different than the disk doc contents.
+			this._onDidChangeMarkdownDocument.fire(doc);
 		});
 
 		connection.onDidChangeWatchedFiles(async ({ changes }) => {