fix format on save problem that occurs when a provider returns no edits

src/vs/workbench/api/electron-browser/mainThreadSaveParticipant.ts

@@ -26,6 +26,7 @@ import { IEditorWorkerService } from 'vs/editor/common/services/editorWorkerServ
 import { ICodeEditor } from 'vs/editor/browser/editorBrowser';
 import { IProgressService2, ProgressLocation } from 'vs/platform/progress/common/progress';
 import { localize } from 'vs/nls';
+import { isFalsyOrEmpty } from 'vs/base/common/arrays';
 
 export interface ISaveParticipantParticipant extends ISaveParticipant {
 	// progressMessage: string;
@@ -208,7 +209,7 @@ class FormatOnSaveParticipant implements ISaveParticipantParticipant {
 				});
 
 		}).then(edits => {
-			if (edits && versionNow === model.getVersionId()) {
+			if (!isFalsyOrEmpty(edits) && versionNow === model.getVersionId()) {
 				const editor = findEditor(model, this._editorService);
 				if (editor) {
 					this._editsWithEditor(editor, edits);