Add edit stack element before and after accepting a completion

src/vs/editor/contrib/snippet/common/snippet.ts

@@ -775,18 +775,29 @@ class SnippetController implements ISnippetController {
 		return snippet.bind(model.getLineContent(typeRange.startLineNumber), typeRange.startLineNumber - 1, typeRange.startColumn - 1, editor);
 	}
 
-	private static _getCommandForSnippet(adaptedSnippet:ICodeSnippet, typeRange:EditorCommon.IEditorRange): EditorCommon.IIdentifiedSingleEditOperation {
-		var insertText = adaptedSnippet.lines.join('\n');
-		return EditOperation.replaceMove(typeRange, insertText);
+	private static _addCommandForSnippet(model:EditorCommon.ITextModel, adaptedSnippet:ICodeSnippet, typeRange:EditorCommon.IEditorRange, out:EditorCommon.IIdentifiedSingleEditOperation[]): void {
+		let insertText = adaptedSnippet.lines.join('\n');
+		let currentText = model.getValueInRange(typeRange, EditorCommon.EndOfLinePreference.LF);
+		if (insertText !== currentText) {
+			out.push(EditOperation.replaceMove(typeRange, insertText));
+		}
 	}
 
 	private _runForPrimarySelection(snippet: CodeSnippet, overwriteBefore: number, overwriteAfter: number): void {
-		var initialAlternativeVersionId = this._editor.getModel().getAlternativeVersionId();
+		let initialAlternativeVersionId = this._editor.getModel().getAlternativeVersionId();
+
+		let edits: EditorCommon.IIdentifiedSingleEditOperation[] = [];
 
-		var prepared = SnippetController._prepareSnippet(this._editor, this._editor.getSelection(), snippet, overwriteBefore, overwriteAfter);
-		this._editor.executeEdits('editor.contrib.insertSnippetHelper', [SnippetController._getCommandForSnippet(prepared.adaptedSnippet, prepared.typeRange)]);
+		let prepared = SnippetController._prepareSnippet(this._editor, this._editor.getSelection(), snippet, overwriteBefore, overwriteAfter);
+		SnippetController._addCommandForSnippet(this._editor.getModel(), prepared.adaptedSnippet, prepared.typeRange, edits);
 
-		var cursorOnly = SnippetController._getSnippetCursorOnly(prepared.adaptedSnippet);
+		if (edits.length > 0) {
+			this._editor.getModel().pushStackElement();
+			this._editor.executeEdits('editor.contrib.insertSnippetHelper', edits);
+			this._editor.getModel().pushStackElement();
+		}
+
+		let cursorOnly = SnippetController._getSnippetCursorOnly(prepared.adaptedSnippet);
 		if (cursorOnly) {
 			this._editor.setSelection(Selection.createSelection(cursorOnly.lineNumber, cursorOnly.column, cursorOnly.lineNumber, cursorOnly.column));
 		} else if (prepared.adaptedSnippet.placeHolders.length > 0) {
@@ -802,11 +813,15 @@ class SnippetController implements ISnippetController {
 			edits:EditorCommon.IIdentifiedSingleEditOperation[] = [];
 
 		for (let i = 0; i < selections.length; i++) {
-			var prepared = SnippetController._prepareSnippet(this._editor, selections[i], snippet, overwriteBefore, overwriteAfter);
-			edits.push(SnippetController._getCommandForSnippet(prepared.adaptedSnippet, prepared.typeRange));
+			let prepared = SnippetController._prepareSnippet(this._editor, selections[i], snippet, overwriteBefore, overwriteAfter);
+			SnippetController._addCommandForSnippet(this._editor.getModel(), prepared.adaptedSnippet, prepared.typeRange, edits);
 		}
 
-		this._editor.executeEdits('editor.contrib.insertSnippetHelper', edits);
+		if (edits.length > 0) {
+			this._editor.getModel().pushStackElement();
+			this._editor.executeEdits('editor.contrib.insertSnippetHelper', edits);
+			this._editor.getModel().pushStackElement();
+		}
 	}
 
 	private static _prepareSnippet(editor:EditorCommon.ICommonCodeEditor, selection:EditorCommon.IEditorSelection, snippet:CodeSnippet, overwriteBefore:number, overwriteAfter:number): { typeRange: EditorCommon.IEditorRange; adaptedSnippet: ICodeSnippet; } {