make sure sequence terminates as soon as formatting results are in,

related to  https://github.com/Microsoft/vscode-languageserver-node/issues/305, fyi @dbauemer

src/vs/editor/contrib/format/format.ts

@@ -38,14 +38,14 @@ export function getDocumentRangeFormattingEdits(model: ITextModel, range: Range,
 
 	let result: TextEdit[];
 	return sequence(providers.map(provider => {
-		if (isFalsyOrEmpty(result)) {
-			return () => {
-				return asWinJsPromise(token => provider.provideDocumentRangeFormattingEdits(model, range, options, token)).then(value => {
-					result = value;
-				}, onUnexpectedExternalError);
-			};
-		}
-		return undefined;
+		return () => {
+			if (!isFalsyOrEmpty(result)) {
+				return undefined;
+			}
+			return asWinJsPromise(token => provider.provideDocumentRangeFormattingEdits(model, range, options, token)).then(value => {
+				result = value;
+			}, onUnexpectedExternalError);
+		};
 	})).then(() => result);
 }
 
@@ -59,14 +59,14 @@ export function getDocumentFormattingEdits(model: ITextModel, options: Formattin
 
 	let result: TextEdit[];
 	return sequence(providers.map(provider => {
-		if (isFalsyOrEmpty(result)) {
-			return () => {
-				return asWinJsPromise(token => provider.provideDocumentFormattingEdits(model, options, token)).then(value => {
-					result = value;
-				}, onUnexpectedExternalError);
-			};
-		}
-		return undefined;
+		return () => {
+			if (!isFalsyOrEmpty(result)) {
+				return undefined;
+			}
+			return asWinJsPromise(token => provider.provideDocumentFormattingEdits(model, options, token)).then(value => {
+				result = value;
+			}, onUnexpectedExternalError);
+		};
 	})).then(() => result);
 }
 

src/vs/workbench/test/electron-browser/api/extHostLanguageFeatures.test.ts

@@ -1034,6 +1034,13 @@ suite('ExtHostLanguageFeatures', function () {
 	});
 
 	test('Format Doc, order', function () {
+
+		disposables.push(extHost.registerDocumentFormattingEditProvider(defaultSelector, <vscode.DocumentFormattingEditProvider>{
+			provideDocumentFormattingEdits(): any {
+				return undefined;
+			}
+		}));
+
 		disposables.push(extHost.registerDocumentFormattingEditProvider(defaultSelector, <vscode.DocumentFormattingEditProvider>{
 			provideDocumentFormattingEdits(): any {
 				return [new types.TextEdit(new types.Range(0, 0, 0, 0), 'testing')];
@@ -1079,6 +1086,11 @@ suite('ExtHostLanguageFeatures', function () {
 				return [new types.TextEdit(new types.Range(0, 0, 0, 0), 'range')];
 			}
 		}));
+		disposables.push(extHost.registerDocumentRangeFormattingEditProvider(defaultSelector, <vscode.DocumentRangeFormattingEditProvider>{
+			provideDocumentRangeFormattingEdits(): any {
+				return [new types.TextEdit(new types.Range(2, 3, 4, 5), 'range2')];
+			}
+		}));
 		disposables.push(extHost.registerDocumentFormattingEditProvider(defaultSelector, <vscode.DocumentFormattingEditProvider>{
 			provideDocumentFormattingEdits(): any {
 				return [new types.TextEdit(new types.Range(0, 0, 1, 1), 'doc')];
@@ -1088,7 +1100,11 @@ suite('ExtHostLanguageFeatures', function () {
 			return getDocumentRangeFormattingEdits(model, new EditorRange(1, 1, 1, 1), { insertSpaces: true, tabSize: 4 }).then(value => {
 				assert.equal(value.length, 1);
 				let [first] = value;
-				assert.equal(first.text, 'range');
+				assert.equal(first.text, 'range2');
+				assert.equal(first.range.startLineNumber, 3);
+				assert.equal(first.range.startColumn, 4);
+				assert.equal(first.range.endLineNumber, 5);
+				assert.equal(first.range.endColumn, 6);
 			});
 		});
 	});