Merge pull request #5423 from outcoldman/vscode and improve the proposed changes

- add `editor.useTabStops` for tab/backspace behaviour
- add `editor.trimAutoWhitespace` for auto inserted whitespace cleanup

src/vs/base/common/strings.ts

@@ -303,8 +303,8 @@ export function getLeadingWhitespace(str: string): string {
  * Returns last index of the string that is not whitespace.
  * If string is empty or contains only whitespaces, returns -1
  */
-export function lastNonWhitespaceIndex(str: string): number {
-	for (let i = str.length - 1; i >= 0; i--) {
+export function lastNonWhitespaceIndex(str: string, startIndex: number = str.length - 1): number {
+	for (let i = startIndex; i >= 0; i--) {
 		if (str.charAt(i) !== ' ' && str.charAt(i) !== '\t') {
 			return i;
 		}

src/vs/base/test/common/strings.test.ts

@@ -157,4 +157,15 @@ suite('Strings', () => {
 		assert.strictEqual(strings.repeat(' ', 0), '');
 		assert.strictEqual(strings.repeat('abc', 2), 'abcabc');
 	});
+
+	test('lastNonWhitespaceIndex', () => {
+		assert.strictEqual(strings.lastNonWhitespaceIndex('abc  \t \t '), 2);
+		assert.strictEqual(strings.lastNonWhitespaceIndex('abc'), 2);
+		assert.strictEqual(strings.lastNonWhitespaceIndex('abc\t'), 2);
+		assert.strictEqual(strings.lastNonWhitespaceIndex('abc '), 2);
+		assert.strictEqual(strings.lastNonWhitespaceIndex('abc  \t \t '), 2);
+		assert.strictEqual(strings.lastNonWhitespaceIndex('abc  \t \t abc \t \t '), 11);
+		assert.strictEqual(strings.lastNonWhitespaceIndex('abc  \t \t abc \t \t ', 8), 2);
+		assert.strictEqual(strings.lastNonWhitespaceIndex('  \t \t '), -1);
+	});
 });
\ No newline at end of file

src/vs/editor/common/config/commonEditorConfig.ts

@@ -107,6 +107,8 @@ export class InternalEditorOptions implements editorCommon.IInternalEditorOption
 	folding: boolean;
 	renderWhitespace: boolean;
 	indentGuides: boolean;
+	useTabStops: boolean;
+	trimAutoWhitespace: boolean;
 	layoutInfo: editorCommon.IEditorLayoutInfo;
 	fontInfo: editorCommon.FontInfo;
 	editorClassName: string;
@@ -173,6 +175,8 @@ export class InternalEditorOptions implements editorCommon.IInternalEditorOption
 		this.folding = Boolean(input.folding);
 		this.renderWhitespace = Boolean(input.renderWhitespace);
 		this.indentGuides = Boolean(input.indentGuides);
+		this.useTabStops = Boolean(input.useTabStops);
+		this.trimAutoWhitespace = Boolean(input.trimAutoWhitespace);
 		this.layoutInfo = {
 			width: Number(input.layoutInfo.width)|0,
 			height: Number(input.layoutInfo.height)|0,
@@ -359,6 +363,8 @@ class InternalEditorOptionsHelper {
 			folding: toBoolean(opts.folding),
 			renderWhitespace: toBoolean(opts.renderWhitespace),
 			indentGuides: toBoolean(opts.indentGuides),
+			useTabStops: toBoolean(opts.useTabStops),
+			trimAutoWhitespace: toBoolean(opts.trimAutoWhitespace),
 
 			layoutInfo: layoutInfo,
 			fontInfo: fontInfo,
@@ -443,9 +449,11 @@ class InternalEditorOptionsHelper {
 			folding:						(prevOpts.folding !== newOpts.folding),
 			renderWhitespace:				(prevOpts.renderWhitespace !== newOpts.renderWhitespace),
 			indentGuides:					(prevOpts.indentGuides !== newOpts.indentGuides),
+			useTabStops:					(prevOpts.useTabStops !== newOpts.useTabStops),
+			trimAutoWhitespace:				(prevOpts.trimAutoWhitespace !== newOpts.trimAutoWhitespace),
 
 			layoutInfo: 					(!EditorLayoutProvider.layoutEqual(prevOpts.layoutInfo, newOpts.layoutInfo)),
-			fontInfo: 					(!prevOpts.fontInfo.equals(newOpts.fontInfo)),
+			fontInfo: 						(!prevOpts.fontInfo.equals(newOpts.fontInfo)),
 			editorClassName: 				(prevOpts.editorClassName !== newOpts.editorClassName),
 			wrappingInfo:					(!this._wrappingInfoEqual(prevOpts.wrappingInfo, newOpts.wrappingInfo)),
 			observedOuterWidth:				(prevOpts.observedOuterWidth !== newOpts.observedOuterWidth),
@@ -926,6 +934,16 @@ let editorConfiguration:IConfigurationNode = {
 			'default': DefaultConfig.editor.folding,
 			'description': nls.localize('folding', "Controls whether the editor has code folding enabled")
 		},
+		'editor.useTabStops' : {
+			'type': 'boolean',
+			'default': DefaultConfig.editor.useTabStops,
+			'description': nls.localize('useTabStops', "Inserting and deleting whitespace follows tab stops")
+		},
+		'editor.trimAutoWhitespace' : {
+			'type': 'boolean',
+			'default': DefaultConfig.editor.trimAutoWhitespace,
+			'description': nls.localize('trimAutoWhitespace', "Remove trailing auto inserted whitespace")
+		},
 		'diffEditor.renderSideBySide' : {
 			'type': 'boolean',
 			'default': true,

src/vs/editor/common/config/defaultConfig.ts

@@ -90,6 +90,8 @@ class ConfigClass implements IConfiguration {
 			folding: true,
 			renderWhitespace: false,
 			indentGuides: false,
+			useTabStops: true,
+			trimAutoWhitespace: true,
 
 			fontFamily: (
 				platform.isMacintosh ? DEFAULT_MAC_FONT_FAMILY : (platform.isLinux ? DEFAULT_LINUX_FONT_FAMILY : DEFAULT_WINDOWS_FONT_FAMILY)

src/vs/editor/common/controller/cursor.ts

@@ -40,6 +40,7 @@ interface IMultipleCursorOperationContext {
 	hasExecutedCommands: boolean;
 	isCursorUndo: boolean;
 	executeCommands: editorCommon.ICommand[];
+	isAutoWhitespaceCommand: boolean[];
 	postOperationRunnables: IPostOperationRunnable[];
 	requestScrollDeltaLines: number;
 	setColumnSelectToLineNumber: number;
@@ -313,6 +314,7 @@ export class Cursor extends EventEmitter {
 			eventSource: eventSource,
 			eventData: eventData,
 			executeCommands: [],
+			isAutoWhitespaceCommand: [],
 			hasExecutedCommands: false,
 			isCursorUndo: false,
 			postOperationRunnables: [],
@@ -440,7 +442,7 @@ export class Cursor extends EventEmitter {
 		this._columnSelectToLineNumber = ctx.setColumnSelectToLineNumber;
 		this._columnSelectToVisualColumn = ctx.setColumnSelectToVisualColumn;
 
-		ctx.hasExecutedCommands = this._internalExecuteCommands(ctx.executeCommands, ctx.postOperationRunnables) || ctx.hasExecutedCommands;
+		ctx.hasExecutedCommands = this._internalExecuteCommands(ctx.executeCommands, ctx.isAutoWhitespaceCommand, ctx.postOperationRunnables) || ctx.hasExecutedCommands;
 		ctx.executeCommands = [];
 
 		if (ctx.shouldPushStackElementAfter) {
@@ -480,7 +482,7 @@ export class Cursor extends EventEmitter {
 		return true;
 	}
 
-	private _getEditOperationsFromCommand(ctx: IExecContext, majorIdentifier: number, command: editorCommon.ICommand): ICommandData {
+	private _getEditOperationsFromCommand(ctx: IExecContext, majorIdentifier: number, command: editorCommon.ICommand, isAutoWhitespaceCommand:boolean): ICommandData {
 		// This method acts as a transaction, if the command fails
 		// everything it has done is ignored
 		var operations: editorCommon.IIdentifiedSingleEditOperation[] = [],
@@ -498,7 +500,8 @@ export class Cursor extends EventEmitter {
 				},
 				range: selection,
 				text: text,
-				forceMoveMarkers: false
+				forceMoveMarkers: false,
+				isAutoWhitespaceEdit: isAutoWhitespaceCommand
 			});
 		};
 
@@ -560,7 +563,7 @@ export class Cursor extends EventEmitter {
 		};
 	}
 
-	private _getEditOperations(ctx: IExecContext, commands: editorCommon.ICommand[]): ICommandsData {
+	private _getEditOperations(ctx: IExecContext, commands: editorCommon.ICommand[], isAutoWhitespaceCommand:boolean[]): ICommandsData {
 		var oneResult: ICommandData;
 		var operations: editorCommon.IIdentifiedSingleEditOperation[] = [];
 		var hadTrackedRanges: boolean[] = [];
@@ -568,7 +571,7 @@ export class Cursor extends EventEmitter {
 
 		for (var i = 0; i < commands.length; i++) {
 			if (commands[i]) {
-				oneResult = this._getEditOperationsFromCommand(ctx, i, commands[i]);
+				oneResult = this._getEditOperationsFromCommand(ctx, i, commands[i], isAutoWhitespaceCommand[i]);
 				operations = operations.concat(oneResult.operations);
 				hadTrackedRanges[i] = oneResult.hadTrackedRange;
 				anyoneHadTrackedRange = anyoneHadTrackedRange || hadTrackedRanges[i];
@@ -634,7 +637,7 @@ export class Cursor extends EventEmitter {
 		return loserCursorsMap;
 	}
 
-	private _collapseDeleteCommands(rawCmds: editorCommon.ICommand[], postOperationRunnables: IPostOperationRunnable[]): boolean {
+	private _collapseDeleteCommands(rawCmds: editorCommon.ICommand[], isAutoWhitespaceCommand:boolean[], postOperationRunnables: IPostOperationRunnable[]): boolean {
 		if (rawCmds.length === 1) {
 			return ;
 		}
@@ -690,15 +693,15 @@ export class Cursor extends EventEmitter {
 		}
 	}
 
-	private _internalExecuteCommands(commands: editorCommon.ICommand[], postOperationRunnables: IPostOperationRunnable[]): boolean {
+	private _internalExecuteCommands(commands: editorCommon.ICommand[], isAutoWhitespaceCommand: boolean[], postOperationRunnables: IPostOperationRunnable[]): boolean {
 		var ctx:IExecContext = {
 			selectionStartMarkers: [],
 			positionMarkers: []
 		};
 
-		this._collapseDeleteCommands(commands, postOperationRunnables);
+		this._collapseDeleteCommands(commands, isAutoWhitespaceCommand, postOperationRunnables);
 
-		var r = this._innerExecuteCommands(ctx, commands, postOperationRunnables);
+		var r = this._innerExecuteCommands(ctx, commands, isAutoWhitespaceCommand, postOperationRunnables);
 		for (var i = 0; i < ctx.selectionStartMarkers.length; i++) {
 			this.model._removeMarker(ctx.selectionStartMarkers[i]);
 			this.model._removeMarker(ctx.positionMarkers[i]);
@@ -719,7 +722,7 @@ export class Cursor extends EventEmitter {
 		return true;
 	}
 
-	private _innerExecuteCommands(ctx: IExecContext, commands: editorCommon.ICommand[], postOperationRunnables: IPostOperationRunnable[]): boolean {
+	private _innerExecuteCommands(ctx: IExecContext, commands: editorCommon.ICommand[], isAutoWhitespaceCommand: boolean[], postOperationRunnables: IPostOperationRunnable[]): boolean {
 
 		if (this.configuration.editor.readOnly) {
 			return false;
@@ -731,7 +734,7 @@ export class Cursor extends EventEmitter {
 
 		var selectionsBefore = this.cursors.getSelections();
 
-		var commandsData = this._getEditOperations(ctx, commands);
+		var commandsData = this._getEditOperations(ctx, commands, isAutoWhitespaceCommand);
 		if (commandsData.operations.length === 0 && !commandsData.anyoneHadTrackedRange) {
 			return false;
 		}
@@ -771,6 +774,10 @@ export class Cursor extends EventEmitter {
 			}
 			for (var i = 0; i < inverseEditOperations.length; i++) {
 				var op = inverseEditOperations[i];
+				if (!op.identifier) {
+					// perhaps auto whitespace trim edits
+					continue;
+				}
 				groupedInverseEditOperations[op.identifier.major].push(op);
 			}
 			var minorBasedSorter = (a:editorCommon.IIdentifiedSingleEditOperation, b:editorCommon.IIdentifiedSingleEditOperation) => {
@@ -1080,6 +1087,7 @@ export class Cursor extends EventEmitter {
 				shouldRevealVerticalInCenter: false,
 				shouldRevealHorizontal: true,
 				executeCommand: null,
+				isAutoWhitespaceCommand: false,
 				postOperationRunnable: null,
 				shouldPushStackElementBefore: false,
 				shouldPushStackElementAfter: false,
@@ -1100,6 +1108,7 @@ export class Cursor extends EventEmitter {
 			ctx.shouldPushStackElementAfter = ctx.shouldPushStackElementAfter || context.shouldPushStackElementAfter;
 
 			ctx.executeCommands[i] = context.executeCommand;
+			ctx.isAutoWhitespaceCommand[i] = context.isAutoWhitespaceCommand;
 			ctx.postOperationRunnables[i] = context.postOperationRunnable;
 		}
 

src/vs/editor/common/controller/oneCursor.ts

@@ -29,6 +29,7 @@ export interface IOneCursorOperationContext {
 	shouldPushStackElementBefore: boolean;
 	shouldPushStackElementAfter: boolean;
 	executeCommand: editorCommon.ICommand;
+	isAutoWhitespaceCommand: boolean;
 	postOperationRunnable: IPostOperationRunnable;
 	requestScrollDeltaLines: number;
 }
@@ -145,7 +146,13 @@ export class OneCursor {
 	private _selEndMarker: string;
 	private _selDirection: editorCommon.SelectionDirection;
 
-	constructor(editorId: number, model: editorCommon.IModel, configuration: editorCommon.IConfiguration, modeConfiguration: IModeConfiguration, viewModelHelper:IViewModelHelper) {
+	constructor(
+		editorId: number,
+		model: editorCommon.IModel,
+		configuration: editorCommon.IConfiguration,
+		modeConfiguration: IModeConfiguration,
+		viewModelHelper:IViewModelHelper
+	) {
 		this.editorId = editorId;
 		this.model = model;
 		this.configuration = configuration;
@@ -527,6 +534,9 @@ export class OneCursor {
 	public getVisibleColumnFromColumn(lineNumber:number, column:number): number {
 		return this.helper.visibleColumnFromColumn(this.model, lineNumber, column);
 	}
+	public getColumnFromVisibleColumn(lineNumber:number, column:number): number {
+		return this.helper.columnFromVisibleColumn(this.model, lineNumber, column);
+	}
 	public getViewVisibleColumnFromColumn(viewLineNumber:number, viewColumn:number): number {
 		return this.helper.visibleColumnFromColumn(this.viewModelHelper.viewModel, viewLineNumber, viewColumn);
 	}
@@ -1185,6 +1195,7 @@ export class OneCursorOp {
 		var enterAction = r.enterAction;
 		var indentation = r.indentation;
 
+		ctx.isAutoWhitespaceCommand = true;
 		if (enterAction.indentAction === IndentAction.None) {
 			// Nothing special
 			this.actualType(cursor, '\n' + cursor.model.normalizeIndentation(indentation + enterAction.appendText), keepPosition, ctx, range);
@@ -1500,6 +1511,8 @@ export class OneCursorOp {
 
 		if (selection.isEmpty()) {
 
+			ctx.isAutoWhitespaceCommand = true;
+
 			let typeText = '';
 
 			if (cursor.model.getLineMaxColumn(selection.startLineNumber) === 1) {
@@ -1626,13 +1639,34 @@ export class OneCursorOp {
 
 		if (deleteSelection.isEmpty()) {
 			var position = cursor.getPosition();
-			var leftOfPosition = cursor.getLeftOfPosition(position.lineNumber, position.column);
-			deleteSelection = new Range(
-				leftOfPosition.lineNumber,
-				leftOfPosition.column,
-				position.lineNumber,
-				position.column
-			);
+
+			if (cursor.configuration.editor.useTabStops && position.column > 1) {
+				let lineContent = cursor.getLineContent(position.lineNumber);
+
+				let firstNonWhitespaceIndex = strings.firstNonWhitespaceIndex(lineContent);
+				let lastIndentationColumn = (
+					firstNonWhitespaceIndex === -1
+						? /* entire string is whitespace */lineContent.length + 1
+						: firstNonWhitespaceIndex + 1
+				);
+
+				if (position.column <= lastIndentationColumn) {
+					let fromVisibleColumn = cursor.getVisibleColumnFromColumn(position.lineNumber, position.column);
+					let toVisibleColumn = CursorMoveHelper.prevTabColumn(fromVisibleColumn, cursor.model.getOptions().tabSize);
+					let toColumn = cursor.getColumnFromVisibleColumn(position.lineNumber, toVisibleColumn);
+					deleteSelection = new Range(position.lineNumber, toColumn, position.lineNumber, position.column);
+				} else {
+					deleteSelection = new Range(position.lineNumber, position.column - 1, position.lineNumber, position.column);
+				}
+			} else {
+				var leftOfPosition = cursor.getLeftOfPosition(position.lineNumber, position.column);
+				deleteSelection = new Range(
+					leftOfPosition.lineNumber,
+					leftOfPosition.column,
+					position.lineNumber,
+					position.column
+				);
+			}
 		}
 
 		if (deleteSelection.isEmpty()) {
@@ -1648,21 +1682,11 @@ export class OneCursorOp {
 		return true;
 	}
 
-	private static _findLastNonWhitespaceChar(str:string, startIndex:number): number {
-		for (let chIndex = startIndex; chIndex >= 0; chIndex--) {
-			let ch = str.charAt(chIndex);
-			if (ch !== ' ' && ch !== '\t') {
-				return chIndex;
-			}
-		}
-		return -1;
-	}
-
 	private static deleteWordLeftWhitespace(cursor:OneCursor, ctx: IOneCursorOperationContext): boolean {
 		let position = cursor.getPosition();
 		let lineContent = cursor.getLineContent(position.lineNumber);
 		let startIndex = position.column - 2;
-		let lastNonWhitespace = this._findLastNonWhitespaceChar(lineContent, startIndex);
+		let lastNonWhitespace = strings.lastNonWhitespaceIndex(lineContent, startIndex);
 		if (lastNonWhitespace + 1 < startIndex) {
 			// bingo
 			ctx.executeCommand = new ReplaceCommand(new Range(position.lineNumber, lastNonWhitespace + 2, position.lineNumber, position.column), '');
@@ -1982,6 +2006,10 @@ class CursorHelper {
 		return this.moveHelper.visibleColumnFromColumn(model, lineNumber, column);
 	}
 
+	public columnFromVisibleColumn(model:ICursorMoveHelperModel, lineNumber:number, column:number): number {
+		return this.moveHelper.columnFromVisibleColumn(model, lineNumber, column);
+	}
+
 	private _createWord(lineContent: string, wordType:WordType, start: number, end: number): IFindWordResult {
 		// console.log('WORD ==> ' + start + ' => ' + end + ':::: <<<' + lineContent.substring(start, end) + '>>>');
 		return { start: start, end: end, wordType: wordType };

src/vs/editor/common/editorCommon.ts

@@ -513,6 +513,14 @@ export interface IEditorOptions {
 	 * Defaults to true.
 	 */
 	indentGuides?: boolean;
+	/**
+	 * Inserting and deleting whitespace follows tab stops.
+	 */
+	useTabStops?: boolean;
+	/**
+	 * Remove trailing auto inserted whitespace.
+	 */
+	trimAutoWhitespace?: boolean;
 	/**
 	 * The font family
 	 */
@@ -624,6 +632,8 @@ export interface IInternalEditorOptions {
 	folding: boolean;
 	renderWhitespace: boolean;
 	indentGuides: boolean;
+	useTabStops: boolean;
+	trimAutoWhitespace: boolean;
 
 	// ---- Options that are computed
 
@@ -702,6 +712,8 @@ export interface IConfigurationChangedEvent {
 	folding: boolean;
 	renderWhitespace: boolean;
 	indentGuides: boolean;
+	useTabStops: boolean;
+	trimAutoWhitespace: boolean;
 
 	// ---- Options that are computed
 	layoutInfo: boolean;
@@ -1121,6 +1133,11 @@ export interface IIdentifiedSingleEditOperation {
 	 * i.e. forceMoveMarkers = true => if `range` is collapsed, all markers at the position will be moved.
 	 */
 	forceMoveMarkers: boolean;
+	/**
+	 * This indicates that this operation is inserting automatic whitespace
+	 * that can be removed on next model edit operation if `config.trimAutoWhitespace` is true.
+	 */
+	isAutoWhitespaceEdit?: boolean;
 }
 
 /**
@@ -1168,23 +1185,27 @@ export interface ITextModelResolvedOptions {
 	tabSize: number;
 	insertSpaces: boolean;
 	defaultEOL: DefaultEndOfLine;
+	trimAutoWhitespace: boolean;
 }
 
 export interface ITextModelCreationOptions {
 	tabSize: number;
 	insertSpaces: boolean;
 	detectIndentation: boolean;
+	trimAutoWhitespace: boolean;
 	defaultEOL: DefaultEndOfLine;
 }
 
 export interface ITextModelUpdateOptions {
 	tabSize?: number;
 	insertSpaces?: boolean;
+	trimAutoWhitespace?: boolean;
 }
 
 export interface IModelOptionsChangedEvent {
 	tabSize: boolean;
 	insertSpaces: boolean;
+	trimAutoWhitespace: boolean;
 }
 
 /**

src/vs/editor/common/model/editableTextModel.ts

@@ -11,6 +11,7 @@ import {EditStack} from 'vs/editor/common/model/editStack';
 import {ILineEdit, ILineMarker, ModelLine} from 'vs/editor/common/model/modelLine';
 import {DeferredEventsBuilder, TextModelWithDecorations} from 'vs/editor/common/model/textModelWithDecorations';
 import {IMode} from 'vs/editor/common/modes';
+import * as strings from 'vs/base/common/strings';
 
 export interface IValidatedEditOperation {
 	sortIndex: number;
@@ -19,6 +20,7 @@ export interface IValidatedEditOperation {
 	rangeLength: number;
 	lines: string[];
 	forceMoveMarkers: boolean;
+	isAutoWhitespaceEdit: boolean;
 }
 
 interface IIdentifiedLineEdit extends ILineEdit{
@@ -37,6 +39,8 @@ export class EditableTextModel extends TextModelWithDecorations implements edito
 	private _hasEditableRange:boolean;
 	private _editableRangeId:string;
 
+	private _trimAutoWhitespaceLines: number[];
+
 	constructor(allowedEventTypes:string[], rawText:editorCommon.IRawText, modeOrPromise:IMode|TPromise<IMode>) {
 		allowedEventTypes.push(editorCommon.EventType.ModelContentChanged);
 		allowedEventTypes.push(editorCommon.EventType.ModelContentChanged2);
@@ -49,6 +53,7 @@ export class EditableTextModel extends TextModelWithDecorations implements edito
 
 		this._hasEditableRange = false;
 		this._editableRangeId = null;
+		this._trimAutoWhitespaceLines = null;
 	}
 
 	public dispose(): void {
@@ -63,6 +68,7 @@ export class EditableTextModel extends TextModelWithDecorations implements edito
 		this._commandManager = new EditStack(this);
 		this._hasEditableRange = false;
 		this._editableRangeId = null;
+		this._trimAutoWhitespaceLines = null;
 	}
 
 	public pushStackElement(): void {
@@ -71,6 +77,61 @@ export class EditableTextModel extends TextModelWithDecorations implements edito
 
 	public pushEditOperations(beforeCursorState:editorCommon.IEditorSelection[], editOperations:editorCommon.IIdentifiedSingleEditOperation[], cursorStateComputer:editorCommon.ICursorStateComputer): editorCommon.IEditorSelection[] {
 		return this.deferredEmit(() => {
+			if (this._options.trimAutoWhitespace && this._trimAutoWhitespaceLines) {
+				// Go through each saved line number and insert a trim whitespace edit
+				// if it is safe to do so (no conflicts with other edits).
+
+				let incomingEdits = editOperations.map((op) => {
+					return {
+						range: this.validateRange(op.range),
+						text: op.text
+					};
+				});
+
+				for (let i = 0, len = this._trimAutoWhitespaceLines.length; i < len; i++) {
+					let trimLineNumber = this._trimAutoWhitespaceLines[i];
+					let maxLineColumn = this.getLineMaxColumn(trimLineNumber);
+
+					let allowTrimLine = true;
+					for (let j = 0, lenJ = incomingEdits.length; j < lenJ; j++) {
+						let editRange = incomingEdits[i].range;
+						let editText = incomingEdits[i].text;
+
+						if (trimLineNumber < editRange.startLineNumber || trimLineNumber > editRange.endLineNumber) {
+							// `trimLine` is completely outside this edit
+							continue;
+						}
+
+						// At this point:
+						//   editRange.startLineNumber <= trimLine <= editRange.endLineNumber
+
+						if (
+							trimLineNumber === editRange.startLineNumber && editRange.startColumn === maxLineColumn
+							&& editRange.isEmpty() && editText && editText.length > 0 && editText.charAt(0) === '\n'
+						) {
+							// This edit inserts a new line (and maybe other text) after `trimLine`
+							continue;
+						}
+
+						// Looks like we can't trim this line as it would interfere with an incoming edit
+						allowTrimLine = false;
+						break;
+					}
+
+					if (allowTrimLine) {
+						editOperations.push({
+							identifier: null,
+							range: new Range(trimLineNumber, 1, trimLineNumber, maxLineColumn),
+							text: null,
+							forceMoveMarkers: false,
+							isAutoWhitespaceEdit: false
+						});
+					}
+
+				}
+
+				this._trimAutoWhitespaceLines = null;
+			}
 			return this._commandManager.pushEditOperation(beforeCursorState, editOperations, cursorStateComputer);
 		});
 	}
@@ -145,7 +206,8 @@ export class EditableTextModel extends TextModelWithDecorations implements edito
 			range: entireEditRange,
 			rangeLength: this.getValueLengthInRange(entireEditRange),
 			lines: result.join('').split('\n'),
-			forceMoveMarkers: forceMoveMarkers
+			forceMoveMarkers: forceMoveMarkers,
+			isAutoWhitespaceEdit: false
 		};
 	}
 
@@ -180,7 +242,8 @@ export class EditableTextModel extends TextModelWithDecorations implements edito
 				range: validatedRange,
 				rangeLength: this.getValueLengthInRange(validatedRange),
 				lines: op.text ? op.text.split(/\r\n|\r|\n/) : null,
-				forceMoveMarkers: op.forceMoveMarkers
+				forceMoveMarkers: op.forceMoveMarkers,
+				isAutoWhitespaceEdit: op.isAutoWhitespaceEdit || false
 			};
 		}
 
@@ -212,17 +275,61 @@ export class EditableTextModel extends TextModelWithDecorations implements edito
 		// Delta encode operations
 		let reverseRanges = EditableTextModel._getInverseEditRanges(operations);
 		let reverseOperations: editorCommon.IIdentifiedSingleEditOperation[] = [];
+
+		let newTrimAutoWhitespaceCandidates: { lineNumber:number,oldContent:string }[] = [];
+
 		for (let i = 0; i < operations.length; i++) {
+			let op = operations[i];
+			let reverseRange = reverseRanges[i];
+
 			reverseOperations[i] = {
-				identifier: operations[i].identifier,
-				range: reverseRanges[i],
-				text: this.getValueInRange(operations[i].range),
-				forceMoveMarkers: operations[i].forceMoveMarkers
+				identifier: op.identifier,
+				range: reverseRange,
+				text: this.getValueInRange(op.range),
+				forceMoveMarkers: op.forceMoveMarkers
 			};
+
+			if (this._options.trimAutoWhitespace && op.isAutoWhitespaceEdit && op.range.isEmpty()) {
+				// Record already the future line numbers that might be auto whitespace removal candidates on next edit
+				for (let lineNumber = reverseRange.startLineNumber; lineNumber <= reverseRange.endLineNumber; lineNumber++) {
+					let currentLineContent = '';
+					if (lineNumber === reverseRange.startLineNumber) {
+						currentLineContent = this.getLineContent(op.range.startLineNumber);
+						if (strings.firstNonWhitespaceIndex(currentLineContent) !== -1) {
+							continue;
+						}
+					}
+					newTrimAutoWhitespaceCandidates.push({ lineNumber:lineNumber, oldContent:currentLineContent });
+				}
+			}
 		}
 
 		this._applyEdits(operations);
 
+		this._trimAutoWhitespaceLines = null;
+		if (this._options.trimAutoWhitespace && newTrimAutoWhitespaceCandidates.length > 0) {
+			// sort line numbers auto whitespace removal candidates for next edit descending
+			newTrimAutoWhitespaceCandidates.sort((a,b) => b.lineNumber - a.lineNumber);
+
+			this._trimAutoWhitespaceLines = [];
+			for (let i = 0, len = newTrimAutoWhitespaceCandidates.length; i < len; i++) {
+				let lineNumber = newTrimAutoWhitespaceCandidates[i].lineNumber;
+				if (i > 0 && newTrimAutoWhitespaceCandidates[i - 1].lineNumber === lineNumber) {
+					// Do not have the same line number twice
+					continue;
+				}
+
+				let prevContent = newTrimAutoWhitespaceCandidates[i].oldContent;
+				let lineContent = this.getLineContent(lineNumber);
+
+				if (lineContent.length === 0 || lineContent === prevContent || strings.firstNonWhitespaceIndex(lineContent) !== -1) {
+					continue;
+				}
+
+				this._trimAutoWhitespaceLines.push(lineNumber);
+			}
+		}
+
 		return reverseOperations;
 	}
 
@@ -311,7 +418,8 @@ export class EditableTextModel extends TextModelWithDecorations implements edito
 				lineEditsQueue.reverse();
 
 				// `lineEditsQueue` now contains edits from smaller (line number,column) to larger (line number,column)
-				let currentLineNumber = lineEditsQueue[0].lineNumber, currentLineNumberStart = 0;
+				let currentLineNumber = lineEditsQueue[0].lineNumber;
+				let currentLineNumberStart = 0;
 
 				for (let i = 1, len = lineEditsQueue.length; i < len; i++) {
 					let lineNumber = lineEditsQueue[i].lineNumber;

src/vs/editor/common/model/mirrorModel.ts

@@ -222,7 +222,8 @@ export class MirrorModelEmbedded extends AbstractMirrorModel implements editorCo
 			tabSize: actualModelOptions.tabSize,
 			insertSpaces: actualModelOptions.insertSpaces,
 			detectIndentation: false,
-			defaultEOL: actualModelOptions.defaultEOL
+			defaultEOL: actualModelOptions.defaultEOL,
+			trimAutoWhitespace: actualModelOptions.trimAutoWhitespace
 		});
 	}
 

src/vs/editor/common/model/textModel.ts

@@ -11,7 +11,7 @@ import {Range} from 'vs/editor/common/core/range';
 import * as editorCommon from 'vs/editor/common/editorCommon';
 import {ModelLine} from 'vs/editor/common/model/modelLine';
 import {guessIndentation} from 'vs/editor/common/model/indentationGuesser';
-import {DEFAULT_INDENTATION} from 'vs/editor/common/config/defaultConfig';
+import {DEFAULT_INDENTATION, DefaultConfig} from 'vs/editor/common/config/defaultConfig';
 
 var LIMIT_FIND_COUNT = 999;
 
@@ -21,6 +21,7 @@ export class TextModel extends OrderGuaranteeEventEmitter implements editorCommo
 		tabSize: DEFAULT_INDENTATION.tabSize,
 		insertSpaces: DEFAULT_INDENTATION.insertSpaces,
 		detectIndentation: false,
+		trimAutoWhitespace: DefaultConfig.editor.trimAutoWhitespace,
 		defaultEOL: editorCommon.DefaultEndOfLine.LF
 	};
 
@@ -56,7 +57,8 @@ export class TextModel extends OrderGuaranteeEventEmitter implements editorCommo
 		let somethingChanged = false;
 		let changed:editorCommon.IModelOptionsChangedEvent = {
 			tabSize: false,
-			insertSpaces: false
+			insertSpaces: false,
+			trimAutoWhitespace: false
 		};
 
 		if (typeof newOpts.insertSpaces !== 'undefined') {
@@ -73,6 +75,13 @@ export class TextModel extends OrderGuaranteeEventEmitter implements editorCommo
 				this._options.tabSize = newOpts.tabSize;
 			}
 		}
+		if (typeof newOpts.trimAutoWhitespace !== 'undefined') {
+			if (this._options.trimAutoWhitespace !== newOpts.trimAutoWhitespace) {
+				somethingChanged = true;
+				changed.trimAutoWhitespace = true;
+				this._options.trimAutoWhitespace = newOpts.trimAutoWhitespace;
+			}
+		}
 
 		if (somethingChanged) {
 			this.emit(editorCommon.EventType.ModelOptionsChanged, changed);
@@ -244,6 +253,7 @@ export class TextModel extends OrderGuaranteeEventEmitter implements editorCommo
 			rawText = TextModel.toRawText(value, {
 				tabSize: this._options.tabSize,
 				insertSpaces: this._options.insertSpaces,
+				trimAutoWhitespace: this._options.trimAutoWhitespace,
 				detectIndentation: false,
 				defaultEOL: this._options.defaultEOL
 			});
@@ -624,12 +634,14 @@ export class TextModel extends OrderGuaranteeEventEmitter implements editorCommo
 			resolvedOpts = {
 				tabSize: guessedIndentation.tabSize,
 				insertSpaces: guessedIndentation.insertSpaces,
+				trimAutoWhitespace: opts.trimAutoWhitespace,
 				defaultEOL: opts.defaultEOL
 			};
 		} else {
 			resolvedOpts = {
 				tabSize: opts.tabSize,
 				insertSpaces: opts.insertSpaces,
+				trimAutoWhitespace: opts.trimAutoWhitespace,
 				defaultEOL: opts.defaultEOL
 			};
 		}
@@ -832,6 +844,7 @@ export class RawText {
 		return TextModel.toRawText(rawText, {
 			tabSize: opts.tabSize,
 			insertSpaces: opts.insertSpaces,
+			trimAutoWhitespace: opts.trimAutoWhitespace,
 			detectIndentation: false,
 			defaultEOL: opts.defaultEOL
 		});

src/vs/editor/common/model/textModelWithTokens.ts

@@ -443,7 +443,8 @@ export class TextModelWithTokens extends TextModel implements editorCommon.IToke
 				tabSize: this._options.tabSize,
 				insertSpaces: this._options.insertSpaces,
 				detectIndentation: false,
-				defaultEOL: this._options.defaultEOL
+				defaultEOL: this._options.defaultEOL,
+				trimAutoWhitespace: this._options.trimAutoWhitespace
 			});
 		}
 		this.setValueFromRawText(rawText, newModeOrPromise);

src/vs/editor/common/services/modelServiceImpl.ts

@@ -26,7 +26,7 @@ import {IModelService} from 'vs/editor/common/services/modelService';
 import {IResourceService} from 'vs/editor/common/services/resourceService';
 import * as platform from 'vs/base/common/platform';
 import {IConfigurationService} from 'vs/platform/configuration/common/configuration';
-import {DEFAULT_INDENTATION} from 'vs/editor/common/config/defaultConfig';
+import {DEFAULT_INDENTATION, DefaultConfig} from 'vs/editor/common/config/defaultConfig';
 import {IMessageService} from 'vs/platform/message/common/message';
 
 export interface IRawModelData {
@@ -180,6 +180,7 @@ interface IRawConfig {
 		tabSize?: any;
 		insertSpaces?: any;
 		detectIndentation?: any;
+		trimAutoWhitespace?: any;
 	};
 }
 
@@ -219,7 +220,8 @@ export class ModelServiceImpl implements IModelService {
 			tabSize: DEFAULT_INDENTATION.tabSize,
 			insertSpaces: DEFAULT_INDENTATION.insertSpaces,
 			detectIndentation: DEFAULT_INDENTATION.detectIndentation,
-			defaultEOL: (platform.isLinux || platform.isMacintosh) ? editorCommon.DefaultEndOfLine.LF : editorCommon.DefaultEndOfLine.CRLF
+			defaultEOL: (platform.isLinux || platform.isMacintosh) ? editorCommon.DefaultEndOfLine.LF : editorCommon.DefaultEndOfLine.CRLF,
+			trimAutoWhitespace: DefaultConfig.editor.trimAutoWhitespace
 		};
 		this._threadService = threadService;
 		this._markerService = markerService;
@@ -240,7 +242,6 @@ export class ModelServiceImpl implements IModelService {
 		}
 
 		let readConfig = (config: IRawConfig) => {
-			const eol = config.files && config.files.eol;
 
 			let shouldShowMigrationMessage = false;
 
@@ -260,12 +261,18 @@ export class ModelServiceImpl implements IModelService {
 			}
 
 			let newDefaultEOL = this._modelCreationOptions.defaultEOL;
+			const eol = config.files && config.files.eol;
 			if (eol === '\r\n') {
 				newDefaultEOL = editorCommon.DefaultEndOfLine.CRLF;
 			} else if (eol === '\n') {
 				newDefaultEOL = editorCommon.DefaultEndOfLine.LF;
 			}
 
+			let trimAutoWhitespace = this._modelCreationOptions.trimAutoWhitespace;
+			if (config.editor && typeof config.editor.trimAutoWhitespace !== 'undefined') {
+				trimAutoWhitespace = (config.editor.trimAutoWhitespace === 'false' ? false : Boolean(config.editor.trimAutoWhitespace));
+			}
+
 			let detectIndentation = DEFAULT_INDENTATION.detectIndentation;
 			if (config.editor && typeof config.editor.detectIndentation !== 'undefined') {
 				detectIndentation = (config.editor.detectIndentation === 'false' ? false : Boolean(config.editor.detectIndentation));
@@ -275,7 +282,8 @@ export class ModelServiceImpl implements IModelService {
 				tabSize: tabSize,
 				insertSpaces: insertSpaces,
 				detectIndentation: detectIndentation,
-				defaultEOL: newDefaultEOL
+				defaultEOL: newDefaultEOL,
+				trimAutoWhitespace: trimAutoWhitespace
 			});
 
 
@@ -300,6 +308,7 @@ export class ModelServiceImpl implements IModelService {
 			(this._modelCreationOptions.detectIndentation === newOpts.detectIndentation)
 			&& (this._modelCreationOptions.insertSpaces === newOpts.insertSpaces)
 			&& (this._modelCreationOptions.tabSize === newOpts.tabSize)
+			&& (this._modelCreationOptions.trimAutoWhitespace === newOpts.trimAutoWhitespace)
 		) {
 			// Same indent opts, no need to touch created models
 			this._modelCreationOptions = newOpts;
@@ -315,10 +324,14 @@ export class ModelServiceImpl implements IModelService {
 
 			if (this._modelCreationOptions.detectIndentation) {
 				modelData.model.detectIndentation(this._modelCreationOptions.insertSpaces, this._modelCreationOptions.tabSize);
+				modelData.model.updateOptions({
+					trimAutoWhitespace: this._modelCreationOptions.trimAutoWhitespace
+				});
 			} else {
 				modelData.model.updateOptions({
 					insertSpaces: this._modelCreationOptions.insertSpaces,
-					tabSize: this._modelCreationOptions.tabSize
+					tabSize: this._modelCreationOptions.tabSize,
+					trimAutoWhitespace: this._modelCreationOptions.trimAutoWhitespace
 				});
 			}
 		}

src/vs/editor/test/common/controller/cursor.test.ts

@@ -1111,7 +1111,8 @@ suite('Editor Controller - Regression tests', () => {
 				defaultEOL: DefaultEndOfLine.LF,
 				detectIndentation: false,
 				insertSpaces: false,
-				tabSize: 4
+				tabSize: 4,
+				trimAutoWhitespace: false
 			}
 		}, (model, cursor) => {
 			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
@@ -1198,7 +1199,8 @@ suite('Editor Controller - Regression tests', () => {
 				defaultEOL: DefaultEndOfLine.LF,
 				detectIndentation: false,
 				insertSpaces: false,
-				tabSize: 4
+				tabSize: 4,
+				trimAutoWhitespace: true
 			},
 			mode: new OnEnterMode(IndentAction.Indent),
 		}, (model, cursor) => {
@@ -1219,7 +1221,8 @@ suite('Editor Controller - Regression tests', () => {
 				defaultEOL: DefaultEndOfLine.LF,
 				detectIndentation: false,
 				insertSpaces: false,
-				tabSize: 4
+				tabSize: 4,
+				trimAutoWhitespace: true
 			},
 		}, (model, cursor) => {
 			moveTo(cursor, 1, 2, false);
@@ -1240,7 +1243,7 @@ suite('Editor Controller - Regression tests', () => {
 				'     function baz() {'
 			],
 			mode: new OnEnterMode(IndentAction.IndentOutdent),
-			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF }
+			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF, trimAutoWhitespace: true }
 		}, (model, cursor) => {
 			moveTo(cursor, 1, 6, false);
 			cursorEqual(cursor, 1, 6, 1, 6);
@@ -1256,7 +1259,7 @@ suite('Editor Controller - Regression tests', () => {
 			text: [
 				'      '
 			],
-			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF }
+			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF, trimAutoWhitespace: true }
 		}, (model, cursor) => {
 			moveTo(cursor, 1, 7, false);
 			cursorEqual(cursor, 1, 7, 1, 7);
@@ -1282,7 +1285,8 @@ suite('Editor Controller - Regression tests', () => {
 				defaultEOL: DefaultEndOfLine.LF,
 				detectIndentation: false,
 				insertSpaces: false,
-				tabSize: 4
+				tabSize: 4,
+				trimAutoWhitespace: true
 			},
 		}, (model, cursor) => {
 			moveTo(cursor, 7, 1, false);
@@ -1342,7 +1346,7 @@ suite('Editor Controller - Regression tests', () => {
 				'hello'
 			],
 			mode: new SurroundingMode(),
-			modelOpts: { tabSize: 4, insertSpaces: true, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF }
+			modelOpts: { tabSize: 4, insertSpaces: true, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF, trimAutoWhitespace: true }
 		}, (model, cursor) => {
 			moveTo(cursor, 1, 3, false);
 			moveTo(cursor, 1, 5, true);
@@ -1364,7 +1368,7 @@ suite('Editor Controller - Regression tests', () => {
 				'};'
 			],
 			mode: new SurroundingMode(),
-			modelOpts: { tabSize: 4, insertSpaces: true, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF }
+			modelOpts: { tabSize: 4, insertSpaces: true, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF, trimAutoWhitespace: true }
 		}, (model, cursor) => {
 			moveTo(cursor, 3, 2, false);
 			moveTo(cursor, 1, 14, true);
@@ -1413,7 +1417,7 @@ suite('Editor Controller - Regression tests', () => {
 				'just some text',
 			],
 			mode: null,
-			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF }
+			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF, trimAutoWhitespace: true }
 		}, (model, cursor) => {
 			moveTo(cursor, 1, 1, false);
 			moveTo(cursor, 3, 4, true);
@@ -1456,7 +1460,7 @@ suite('Editor Controller - Regression tests', () => {
 				'\t};',
 				'}',
 			],
-			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF	}
+			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF, trimAutoWhitespace: true }
 		}, (model, cursor) => {
 			moveTo(cursor, 3, 2, false);
 			cursorCommand(cursor, H.Tab);
@@ -1871,7 +1875,7 @@ suite('Editor Controller - Cursor Configuration', () => {
 				'',
 				'1'
 			],
-			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF }
+			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF, trimAutoWhitespace: true }
 		}, (model, cursor) => {
 			cursorCommand(cursor, H.MoveTo, { position: new Position(1, 21) }, null, 'keyboard');
 			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
@@ -1889,7 +1893,7 @@ suite('Editor Controller - Cursor Configuration', () => {
 				'',
 				'1'
 			],
-			modelOpts: { insertSpaces: true, tabSize: 13, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF }
+			modelOpts: { insertSpaces: true, tabSize: 13, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF, trimAutoWhitespace: true }
 		}, (model, cursor) => {
 			// Tab on column 1
 			cursorCommand(cursor, H.MoveTo, { position: new Position(2, 1) }, null, 'keyboard');
@@ -1953,7 +1957,7 @@ suite('Editor Controller - Cursor Configuration', () => {
 				'\thello'
 			],
 			mode: new OnEnterMode(IndentAction.Indent),
-			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF }
+			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF, trimAutoWhitespace: true }
 		}, (model, cursor) => {
 			moveTo(cursor, 1, 7, false);
 			cursorEqual(cursor, 1, 7, 1, 7);
@@ -1969,7 +1973,7 @@ suite('Editor Controller - Cursor Configuration', () => {
 				'\thello'
 			],
 			mode: new OnEnterMode(IndentAction.None),
-			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF }
+			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF, trimAutoWhitespace: true }
 		}, (model, cursor) => {
 			moveTo(cursor, 1, 7, false);
 			cursorEqual(cursor, 1, 7, 1, 7);
@@ -1985,7 +1989,7 @@ suite('Editor Controller - Cursor Configuration', () => {
 				'\thell()'
 			],
 			mode: new OnEnterMode(IndentAction.IndentOutdent),
-			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF }
+			modelOpts: { insertSpaces: true, tabSize: 4, detectIndentation: false, defaultEOL: DefaultEndOfLine.LF, trimAutoWhitespace: true }
 		}, (model, cursor) => {
 			moveTo(cursor, 1, 7, false);
 			cursorEqual(cursor, 1, 7, 1, 7);
@@ -2078,6 +2082,324 @@ suite('Editor Controller - Cursor Configuration', () => {
 			assert.equal(model.getLineContent(4), '');
 		});
 	});
+
+	test('removeAutoWhitespace off', () => {
+		usingCursor({
+			text: [
+				'    some  line abc  '
+			],
+			modelOpts: {
+				insertSpaces: true,
+				tabSize: 4,
+				detectIndentation: false,
+				defaultEOL: DefaultEndOfLine.LF,
+				trimAutoWhitespace: false
+			}
+		}, (model, cursor) => {
+
+			// Move cursor to the end, verify that we do not trim whitespaces if line has values
+			moveTo(cursor, 1, model.getLineContent(1).length + 1);
+			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    some  line abc  ');
+			assert.equal(model.getLineContent(2), '    ');
+
+			// Try to enter again, we should trimmed previous line
+			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    some  line abc  ');
+			assert.equal(model.getLineContent(2), '    ');
+			assert.equal(model.getLineContent(3), '    ');
+		});
+	});
+
+	test('removeAutoWhitespace on: removes only whitespace the cursor added 1', () => {
+		usingCursor({
+			text: [
+				'    '
+			],
+			modelOpts: {
+				insertSpaces: true,
+				tabSize: 4,
+				detectIndentation: false,
+				defaultEOL: DefaultEndOfLine.LF,
+				trimAutoWhitespace: true
+			}
+		}, (model, cursor) => {
+			moveTo(cursor, 1, model.getLineContent(1).length + 1);
+			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    ');
+			assert.equal(model.getLineContent(2), '    ');
+
+			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    ');
+			assert.equal(model.getLineContent(2), '');
+			assert.equal(model.getLineContent(3), '    ');
+		});
+	});
+
+	test('removeAutoWhitespace on: removes only whitespace the cursor added 2', () => {
+		usingCursor({
+			text: [
+				'    if (a) {',
+				'        ',
+				'',
+				'',
+				'    }'
+			],
+			modelOpts: {
+				insertSpaces: true,
+				tabSize: 4,
+				detectIndentation: false,
+				defaultEOL: DefaultEndOfLine.LF,
+				trimAutoWhitespace: true
+			}
+		}, (model, cursor) => {
+
+			moveTo(cursor, 3, 1);
+			cursorCommand(cursor, H.Tab, null, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    if (a) {');
+			assert.equal(model.getLineContent(2), '        ');
+			assert.equal(model.getLineContent(3), '    ');
+			assert.equal(model.getLineContent(4), '');
+			assert.equal(model.getLineContent(5), '    }');
+
+			moveTo(cursor, 4, 1);
+			cursorCommand(cursor, H.Tab, null, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    if (a) {');
+			assert.equal(model.getLineContent(2), '        ');
+			assert.equal(model.getLineContent(3), '');
+			assert.equal(model.getLineContent(4), '    ');
+			assert.equal(model.getLineContent(5), '    }');
+
+			moveTo(cursor, 5, model.getLineMaxColumn(5));
+			cursorCommand(cursor, H.Type, { text: 'something' }, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    if (a) {');
+			assert.equal(model.getLineContent(2), '        ');
+			assert.equal(model.getLineContent(3), '');
+			assert.equal(model.getLineContent(4), '');
+			assert.equal(model.getLineContent(5), '    }something');
+		});
+	});
+
+	test('removeAutoWhitespace on: test 1', () => {
+		usingCursor({
+			text: [
+				'    some  line abc  '
+			],
+			modelOpts: {
+				insertSpaces: true,
+				tabSize: 4,
+				detectIndentation: false,
+				defaultEOL: DefaultEndOfLine.LF,
+				trimAutoWhitespace: true
+			}
+		}, (model, cursor) => {
+
+			// Move cursor to the end, verify that we do not trim whitespaces if line has values
+			moveTo(cursor, 1, model.getLineContent(1).length + 1);
+			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    some  line abc  ');
+			assert.equal(model.getLineContent(2), '    ');
+
+			// Try to enter again, we should trimmed previous line
+			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    some  line abc  ');
+			assert.equal(model.getLineContent(2), '');
+			assert.equal(model.getLineContent(3), '    ');
+
+			// More whitespaces
+			cursorCommand(cursor, H.Tab, null, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    some  line abc  ');
+			assert.equal(model.getLineContent(2), '');
+			assert.equal(model.getLineContent(3), '        ');
+
+			// Enter and verify that trimmed again
+			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    some  line abc  ');
+			assert.equal(model.getLineContent(2), '');
+			assert.equal(model.getLineContent(3), '');
+			assert.equal(model.getLineContent(4), '        ');
+
+			// Trimmed if we will keep only text
+			moveTo(cursor, 1, 5);
+			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    ');
+			assert.equal(model.getLineContent(2), '    some  line abc  ');
+			assert.equal(model.getLineContent(3), '');
+			assert.equal(model.getLineContent(4), '');
+			assert.equal(model.getLineContent(5), '');
+
+			// Trimmed if we will keep only text by selection
+			moveTo(cursor, 2, 5);
+			moveTo(cursor, 3, 1, true);
+			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
+			assert.equal(model.getLineContent(1), '    ');
+			assert.equal(model.getLineContent(2), '    ');
+			assert.equal(model.getLineContent(3), '');
+			assert.equal(model.getLineContent(4), '');
+			assert.equal(model.getLineContent(5), '');
+		});
+	});
+
+	test('UseTabStops is off', () => {
+		usingCursor({
+			text: [
+				'    x',
+				'        a    ',
+				'    '
+			],
+			modelOpts: {
+				insertSpaces: true,
+				tabSize: 4,
+				detectIndentation: false,
+				defaultEOL: DefaultEndOfLine.LF,
+				trimAutoWhitespace: true
+			}
+		}, (model, cursor) => {
+			cursor.configuration.editor.useTabStops = false;
+
+			// DeleteLeft removes just one whitespace
+			moveTo(cursor, 2, 9);
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getLineContent(2), '       a    ');
+		});
+	});
+
+	test('Backspace removes whitespaces with tab size', () => {
+		usingCursor({
+			text: [
+				' \t \t     x',
+				'        a    ',
+				'    '
+			],
+			modelOpts: {
+				insertSpaces: true,
+				tabSize: 4,
+				detectIndentation: false,
+				defaultEOL: DefaultEndOfLine.LF,
+				trimAutoWhitespace: true
+			}
+		}, (model, cursor) => {
+			cursor.configuration.editor.useTabStops = true;
+
+			// DeleteLeft does not remove tab size, because some text exists before
+			moveTo(cursor, 2, model.getLineContent(2).length + 1);
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getLineContent(2), '        a   ');
+
+			// DeleteLeft removes tab size = 4
+			moveTo(cursor, 2, 9);
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getLineContent(2), '    a   ');
+
+			// DeleteLeft removes tab size = 4
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getLineContent(2), 'a   ');
+
+			// Undo DeleteLeft - get us back to original indentation
+			cursorCommand(cursor, H.Undo, {});
+			assert.equal(model.getLineContent(2), '        a   ');
+
+			// Nothing is broken when cursor is in (1,1)
+			moveTo(cursor, 1, 1);
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getLineContent(1), ' \t \t     x');
+
+			// DeleteLeft stops at tab stops even in mixed whitespace case
+			moveTo(cursor, 1, 10);
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getLineContent(1), ' \t \t    x');
+
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getLineContent(1), ' \t \tx');
+
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getLineContent(1), ' \tx');
+
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getLineContent(1), 'x');
+
+			// DeleteLeft on last line
+			moveTo(cursor, 3, model.getLineContent(3).length + 1);
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getLineContent(3), '');
+
+			// DeleteLeft with removing new line symbol
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), 'x\n        a   ');
+
+			// In case of selection DeleteLeft only deletes selected text
+			moveTo(cursor, 2, 3);
+			moveTo(cursor, 2, 4, true);
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getLineContent(2), '       a   ');
+		});
+	});
+
+	test('PR #5423: Auto indent + undo + redo is funky', () => {
+		usingCursor({
+			text: [
+				''
+			],
+			modelOpts: {
+				defaultEOL: DefaultEndOfLine.LF,
+				detectIndentation: false,
+				insertSpaces: false,
+				tabSize: 4,
+				trimAutoWhitespace: true
+			}
+		}, (model, cursor) => {
+			cursorCommand(cursor, H.Type, { text: '\n' }, null, 'keyboard');
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n', 'assert1');
+
+			cursorCommand(cursor, H.Tab, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n\t', 'assert2');
+
+			cursorCommand(cursor, H.Type, { text: 'y'}, null, 'keyboard');
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n\ty', 'assert2');
+
+			cursorCommand(cursor, H.Type, { text: '\n'}, null, 'keyboard');
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n\ty\n\t', 'assert3');
+
+			cursorCommand(cursor, H.Type, { text: 'x' });
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n\ty\n\tx', 'assert4');
+
+			cursorCommand(cursor, H.CursorLeft, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n\ty\n\tx', 'assert5');
+
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n\ty\nx', 'assert6');
+
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n\tyx', 'assert7');
+
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n\tx', 'assert8');
+
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\nx', 'assert9');
+
+			cursorCommand(cursor, H.DeleteLeft, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), 'x', 'assert10');
+
+			cursorCommand(cursor, H.Undo, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\nx', 'assert11');
+
+			cursorCommand(cursor, H.Undo, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n\ty\nx', 'assert12');
+
+			cursorCommand(cursor, H.Undo, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n\ty\n\tx', 'assert13');
+
+			cursorCommand(cursor, H.Redo, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\n\ty\nx', 'assert14');
+
+			cursorCommand(cursor, H.Redo, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), '\nx', 'assert15');
+
+			cursorCommand(cursor, H.Redo, {});
+			assert.equal(model.getValue(EndOfLinePreference.LF), 'x', 'assert16');
+		});
+	});
 });
 
 interface ICursorOpts {

src/vs/editor/test/common/model/editableTextModel.test.ts

@@ -21,7 +21,8 @@ suite('EditorModel - EditableTextModel._getInverseEdits', () => {
 			range: new Range(startLineNumber, startColumn, endLineNumber, endColumn),
 			rangeLength: rangeLength,
 			lines: text,
-			forceMoveMarkers: false
+			forceMoveMarkers: false,
+			isAutoWhitespaceEdit: false
 		};
 	}
 
@@ -270,7 +271,8 @@ suite('EditorModel - EditableTextModel._toSingleEditOperation', () => {
 			range: new Range(startLineNumber, startColumn, endLineNumber, endColumn),
 			rangeLength: rangeLength,
 			lines: text,
-			forceMoveMarkers: false
+			forceMoveMarkers: false,
+			isAutoWhitespaceEdit: false
 		};
 	}
 

src/vs/editor/test/common/model/mirrorModel.test.ts

@@ -106,6 +106,7 @@ suite('Editor Model - MirrorModel', () => {
 			options: {
 				tabSize: 4,
 				insertSpaces: true,
+				trimAutoWhitespace: true,
 				defaultEOL: editorCommon.DefaultEndOfLine.LF
 			}
 		})]));
@@ -336,6 +337,7 @@ suite('Editor Model - MirrorModel Eventing', () => {
 			options: {
 				tabSize: 4,
 				insertSpaces: true,
+				trimAutoWhitespace: true,
 				defaultEOL: editorCommon.DefaultEndOfLine.LF
 			}
 		})]));

src/vs/editor/test/common/model/textModel.test.ts

@@ -15,7 +15,8 @@ function testGuessIndentation(defaultInsertSpaces:boolean, defaultTabSize:number
 		tabSize: defaultTabSize,
 		insertSpaces: defaultInsertSpaces,
 		detectIndentation: true,
-		defaultEOL: DefaultEndOfLine.LF
+		defaultEOL: DefaultEndOfLine.LF,
+		trimAutoWhitespace: true
 	}));
 	var r = m.getOptions();
 	m.dispose();
@@ -473,6 +474,7 @@ suite('Editor Model - TextModel', () => {
 			options: {
 				tabSize: 4,
 				insertSpaces: false,
+				trimAutoWhitespace: true,
 				defaultEOL: DefaultEndOfLine.LF
 			}
 		});
@@ -511,6 +513,7 @@ suite('Editor Model - TextModel', () => {
 			options: {
 				tabSize: 4,
 				insertSpaces: true,
+				trimAutoWhitespace: true,
 				defaultEOL: DefaultEndOfLine.LF
 			}
 		});

src/vs/workbench/test/node/api/extHostApiCommands.test.ts

@@ -89,6 +89,7 @@ suite('ExtHostLanguageFeatureCommands', function() {
 				options: {
 					tabSize: 4,
 					insertSpaces: true,
+					trimAutoWhitespace: true,
 					defaultEOL: EditorCommon.DefaultEndOfLine.LF
 				}
 			},

src/vs/workbench/test/node/api/extHostLanguageFeatures.test.ts

@@ -77,6 +77,7 @@ suite('ExtHostLanguageFeatures', function() {
 				options: {
 					tabSize: 4,
 					insertSpaces: true,
+					trimAutoWhitespace: true,
 					defaultEOL: EditorCommon.DefaultEndOfLine.LF
 				}
 			},