Fixes #82153: Allow `editor.fontLigatures` to contain font-feature-settings

src/vs/base/browser/fastDomNode.ts

@@ -18,6 +18,7 @@ export class FastDomNode<T extends HTMLElement> {
 	private _fontFamily: string;
 	private _fontWeight: string;
 	private _fontSize: number;
+	private _fontFeatureSettings: string;
 	private _lineHeight: number;
 	private _letterSpacing: number;
 	private _className: string;
@@ -38,6 +39,7 @@ export class FastDomNode<T extends HTMLElement> {
 		this._fontFamily = '';
 		this._fontWeight = '';
 		this._fontSize = -1;
+		this._fontFeatureSettings = '';
 		this._lineHeight = -1;
 		this._letterSpacing = -100;
 		this._className = '';
@@ -135,6 +137,14 @@ export class FastDomNode<T extends HTMLElement> {
 		this.domNode.style.fontSize = this._fontSize + 'px';
 	}
 
+	public setFontFeatureSettings(fontFeatureSettings: string): void {
+		if (this._fontFeatureSettings === fontFeatureSettings) {
+			return;
+		}
+		this._fontFeatureSettings = fontFeatureSettings;
+		this.domNode.style.fontFeatureSettings = this._fontFeatureSettings;
+	}
+
 	public setLineHeight(lineHeight: number): void {
 		if (this._lineHeight === lineHeight) {
 			return;

src/vs/editor/browser/config/charWidthReader.ts

@@ -71,6 +71,7 @@ class DomCharWidthReader {
 		regularDomNode.style.fontFamily = this._bareFontInfo.getMassagedFontFamily();
 		regularDomNode.style.fontWeight = this._bareFontInfo.fontWeight;
 		regularDomNode.style.fontSize = this._bareFontInfo.fontSize + 'px';
+		regularDomNode.style.fontFeatureSettings = this._bareFontInfo.fontFeatureSettings;
 		regularDomNode.style.lineHeight = this._bareFontInfo.lineHeight + 'px';
 		regularDomNode.style.letterSpacing = this._bareFontInfo.letterSpacing + 'px';
 		container.appendChild(regularDomNode);
@@ -79,6 +80,7 @@ class DomCharWidthReader {
 		boldDomNode.style.fontFamily = this._bareFontInfo.getMassagedFontFamily();
 		boldDomNode.style.fontWeight = 'bold';
 		boldDomNode.style.fontSize = this._bareFontInfo.fontSize + 'px';
+		boldDomNode.style.fontFeatureSettings = this._bareFontInfo.fontFeatureSettings;
 		boldDomNode.style.lineHeight = this._bareFontInfo.lineHeight + 'px';
 		boldDomNode.style.letterSpacing = this._bareFontInfo.letterSpacing + 'px';
 		container.appendChild(boldDomNode);
@@ -87,6 +89,7 @@ class DomCharWidthReader {
 		italicDomNode.style.fontFamily = this._bareFontInfo.getMassagedFontFamily();
 		italicDomNode.style.fontWeight = this._bareFontInfo.fontWeight;
 		italicDomNode.style.fontSize = this._bareFontInfo.fontSize + 'px';
+		italicDomNode.style.fontFeatureSettings = this._bareFontInfo.fontFeatureSettings;
 		italicDomNode.style.lineHeight = this._bareFontInfo.lineHeight + 'px';
 		italicDomNode.style.letterSpacing = this._bareFontInfo.letterSpacing + 'px';
 		italicDomNode.style.fontStyle = 'italic';

src/vs/editor/browser/config/configuration.ts

@@ -11,7 +11,7 @@ import * as platform from 'vs/base/common/platform';
 import { CharWidthRequest, CharWidthRequestType, readCharWidths } from 'vs/editor/browser/config/charWidthReader';
 import { ElementSizeObserver } from 'vs/editor/browser/config/elementSizeObserver';
 import { CommonEditorConfiguration, IEnvConfiguration } from 'vs/editor/common/config/commonEditorConfig';
-import { EditorOption, IEditorConstructionOptions } from 'vs/editor/common/config/editorOptions';
+import { EditorOption, IEditorConstructionOptions, EditorFontLigatures } from 'vs/editor/common/config/editorOptions';
 import { BareFontInfo, FontInfo } from 'vs/editor/common/config/fontInfo';
 import { IDimension } from 'vs/editor/common/editorCommon';
 import { IAccessibilityService } from 'vs/platform/accessibility/common/accessibility';
@@ -79,6 +79,7 @@ export interface ISerializedFontInfo {
 	readonly fontFamily: string;
 	readonly fontWeight: string;
 	readonly fontSize: number;
+	fontFeatureSettings: string;
 	readonly lineHeight: number;
 	readonly letterSpacing: number;
 	readonly isMonospace: boolean;
@@ -151,11 +152,14 @@ class CSSBasedConfiguration extends Disposable {
 		return this._cache.getValues().filter(item => item.isTrusted);
 	}
 
-	public restoreFontInfo(savedFontInfo: ISerializedFontInfo[]): void {
+	public restoreFontInfo(savedFontInfos: ISerializedFontInfo[]): void {
 		// Take all the saved font info and insert them in the cache without the trusted flag.
 		// The reason for this is that a font might have been installed on the OS in the meantime.
-		for (let i = 0, len = savedFontInfo.length; i < len; i++) {
-			const fontInfo = new FontInfo(savedFontInfo[i], false);
+		for (let i = 0, len = savedFontInfos.length; i < len; i++) {
+			const savedFontInfo = savedFontInfos[i];
+			// compatibility with older versions of VS Code which did not store this...
+			savedFontInfo.fontFeatureSettings = savedFontInfo.fontFeatureSettings || EditorFontLigatures.OFF;
+			const fontInfo = new FontInfo(savedFontInfo, false);
 			this._writeToCache(fontInfo, fontInfo);
 		}
 	}
@@ -171,6 +175,7 @@ class CSSBasedConfiguration extends Disposable {
 					fontFamily: readConfig.fontFamily,
 					fontWeight: readConfig.fontWeight,
 					fontSize: readConfig.fontSize,
+					fontFeatureSettings: readConfig.fontFeatureSettings,
 					lineHeight: readConfig.lineHeight,
 					letterSpacing: readConfig.letterSpacing,
 					isMonospace: readConfig.isMonospace,
@@ -249,9 +254,9 @@ class CSSBasedConfiguration extends Disposable {
 
 		const maxDigitWidth = Math.max(digit0.width, digit1.width, digit2.width, digit3.width, digit4.width, digit5.width, digit6.width, digit7.width, digit8.width, digit9.width);
 
-		let isMonospace = true;
+		let isMonospace = (bareFontInfo.fontFeatureSettings === EditorFontLigatures.OFF);
 		const referenceWidth = monospace[0].width;
-		for (let i = 1, len = monospace.length; i < len; i++) {
+		for (let i = 1, len = monospace.length; isMonospace && i < len; i++) {
 			const diff = referenceWidth - monospace[i].width;
 			if (diff < -0.001 || diff > 0.001) {
 				isMonospace = false;
@@ -276,6 +281,7 @@ class CSSBasedConfiguration extends Disposable {
 			fontFamily: bareFontInfo.fontFamily,
 			fontWeight: bareFontInfo.fontWeight,
 			fontSize: bareFontInfo.fontSize,
+			fontFeatureSettings: bareFontInfo.fontFeatureSettings,
 			lineHeight: bareFontInfo.lineHeight,
 			letterSpacing: bareFontInfo.letterSpacing,
 			isMonospace: isMonospace,
@@ -294,6 +300,7 @@ export class Configuration extends CommonEditorConfiguration {
 		domNode.style.fontFamily = fontInfo.getMassagedFontFamily();
 		domNode.style.fontWeight = fontInfo.fontWeight;
 		domNode.style.fontSize = fontInfo.fontSize + 'px';
+		domNode.style.fontFeatureSettings = fontInfo.fontFeatureSettings;
 		domNode.style.lineHeight = fontInfo.lineHeight + 'px';
 		domNode.style.letterSpacing = fontInfo.letterSpacing + 'px';
 	}
@@ -302,6 +309,7 @@ export class Configuration extends CommonEditorConfiguration {
 		domNode.setFontFamily(fontInfo.getMassagedFontFamily());
 		domNode.setFontWeight(fontInfo.fontWeight);
 		domNode.setFontSize(fontInfo.fontSize);
+		domNode.setFontFeatureSettings(fontInfo.fontFeatureSettings);
 		domNode.setLineHeight(fontInfo.lineHeight);
 		domNode.setLetterSpacing(fontInfo.letterSpacing);
 	}

src/vs/editor/browser/viewParts/lines/viewLine.ts

@@ -16,7 +16,7 @@ import { CharacterMapping, ForeignElementType, RenderLineInput, renderViewLine,
 import { ViewportData } from 'vs/editor/common/viewLayout/viewLinesViewportData';
 import { InlineDecorationType } from 'vs/editor/common/viewModel/viewModel';
 import { HIGH_CONTRAST, ThemeType } from 'vs/platform/theme/common/themeService';
-import { EditorOption } from 'vs/editor/common/config/editorOptions';
+import { EditorOption, EditorFontLigatures } from 'vs/editor/common/config/editorOptions';
 
 const canUseFastRenderedViewLine = (function () {
 	if (platform.isNative) {
@@ -77,7 +77,7 @@ export class ViewLineOptions {
 	public readonly canUseHalfwidthRightwardsArrow: boolean;
 	public readonly lineHeight: number;
 	public readonly stopRenderingLineAfter: number;
-	public readonly fontLigatures: boolean;
+	public readonly fontLigatures: string;
 
 	constructor(config: IConfiguration, themeType: ThemeType) {
 		this.themeType = themeType;
@@ -89,7 +89,6 @@ export class ViewLineOptions {
 		this.useMonospaceOptimizations = (
 			fontInfo.isMonospace
 			&& !options.get(EditorOption.disableMonospaceOptimizations)
-			&& !options.get(EditorOption.fontLigatures)
 		);
 		this.canUseHalfwidthRightwardsArrow = fontInfo.canUseHalfwidthRightwardsArrow;
 		this.lineHeight = options.get(EditorOption.lineHeight);
@@ -218,7 +217,7 @@ export class ViewLine implements IVisibleLine {
 			options.stopRenderingLineAfter,
 			options.renderWhitespace,
 			options.renderControlCharacters,
-			options.fontLigatures,
+			options.fontLigatures !== EditorFontLigatures.OFF,
 			selectionsOnLine
 		);
 

src/vs/editor/browser/widget/diffEditorWidget.ts

@@ -20,7 +20,7 @@ import * as editorBrowser from 'vs/editor/browser/editorBrowser';
 import { ICodeEditorService } from 'vs/editor/browser/services/codeEditorService';
 import { CodeEditorWidget } from 'vs/editor/browser/widget/codeEditorWidget';
 import { DiffReview } from 'vs/editor/browser/widget/diffReview';
-import { IDiffEditorOptions, IEditorOptions, EditorLayoutInfo, IComputedEditorOptions, EditorOption, EditorOptions } from 'vs/editor/common/config/editorOptions';
+import { IDiffEditorOptions, IEditorOptions, EditorLayoutInfo, IComputedEditorOptions, EditorOption, EditorOptions, EditorFontLigatures } from 'vs/editor/common/config/editorOptions';
 import { IPosition, Position } from 'vs/editor/common/core/position';
 import { IRange, Range } from 'vs/editor/common/core/range';
 import { ISelection, Selection } from 'vs/editor/common/core/selection';
@@ -2060,7 +2060,7 @@ class InlineViewZonesComputer extends ViewZonesComputer {
 		const isBasicASCII = ViewLineRenderingData.isBasicASCII(lineContent, originalModel.mightContainNonBasicASCII());
 		const containsRTL = ViewLineRenderingData.containsRTL(lineContent, isBasicASCII, originalModel.mightContainRTL());
 		const output = renderViewLine(new RenderLineInput(
-			(fontInfo.isMonospace && !options.get(EditorOption.disableMonospaceOptimizations) && !options.get(EditorOption.fontLigatures)),
+			(fontInfo.isMonospace && !options.get(EditorOption.disableMonospaceOptimizations)),
 			fontInfo.canUseHalfwidthRightwardsArrow,
 			lineContent,
 			false,
@@ -2074,7 +2074,7 @@ class InlineViewZonesComputer extends ViewZonesComputer {
 			options.get(EditorOption.stopRenderingLineAfter),
 			options.get(EditorOption.renderWhitespace),
 			options.get(EditorOption.renderControlCharacters),
-			options.get(EditorOption.fontLigatures),
+			options.get(EditorOption.fontLigatures) !== EditorFontLigatures.OFF,
 			null // Send no selections, original line cannot be selected
 		), sb);
 

src/vs/editor/browser/widget/diffReview.ts

@@ -17,7 +17,7 @@ import { ICodeEditor } from 'vs/editor/browser/editorBrowser';
 import { EditorAction, ServicesAccessor, registerEditorAction } from 'vs/editor/browser/editorExtensions';
 import { ICodeEditorService } from 'vs/editor/browser/services/codeEditorService';
 import { DiffEditorWidget } from 'vs/editor/browser/widget/diffEditorWidget';
-import { IComputedEditorOptions, EditorOption } from 'vs/editor/common/config/editorOptions';
+import { IComputedEditorOptions, EditorOption, EditorFontLigatures } from 'vs/editor/common/config/editorOptions';
 import { LineTokens } from 'vs/editor/common/core/lineTokens';
 import { Position } from 'vs/editor/common/core/position';
 import { ILineChange, ScrollType } from 'vs/editor/common/editorCommon';
@@ -770,7 +770,7 @@ export class DiffReview extends Disposable {
 		const isBasicASCII = ViewLineRenderingData.isBasicASCII(lineContent, model.mightContainNonBasicASCII());
 		const containsRTL = ViewLineRenderingData.containsRTL(lineContent, isBasicASCII, model.mightContainRTL());
 		const r = renderViewLine(new RenderLineInput(
-			(fontInfo.isMonospace && !options.get(EditorOption.disableMonospaceOptimizations) && !options.get(EditorOption.fontLigatures)),
+			(fontInfo.isMonospace && !options.get(EditorOption.disableMonospaceOptimizations)),
 			fontInfo.canUseHalfwidthRightwardsArrow,
 			lineContent,
 			false,
@@ -784,7 +784,7 @@ export class DiffReview extends Disposable {
 			options.get(EditorOption.stopRenderingLineAfter),
 			options.get(EditorOption.renderWhitespace),
 			options.get(EditorOption.renderControlCharacters),
-			options.get(EditorOption.fontLigatures),
+			options.get(EditorOption.fontLigatures) !== EditorFontLigatures.OFF,
 			null
 		));
 

src/vs/editor/browser/widget/media/editor.css

@@ -21,12 +21,6 @@
 	position: relative;
 	overflow: visible;
 	-webkit-text-size-adjust: 100%;
-	-webkit-font-feature-settings: "liga" off, "calt" off;
-	font-feature-settings: "liga" off, "calt" off;
-}
-.monaco-editor.enable-ligatures {
-	-webkit-font-feature-settings: "liga" on, "calt" on;
-	font-feature-settings: "liga" on, "calt" on;
 }
 
 /* -------------------- Misc -------------------- */

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

@@ -178,7 +178,7 @@ export interface IEditorOptions {
 	 * Enable font ligatures.
 	 * Defaults to false.
 	 */
-	fontLigatures?: boolean;
+	fontLigatures?: boolean | string;
 	/**
 	 * Disable the use of `will-change` for the editor margin and lines layers.
 	 * The usage of `will-change` acts as a hint for browsers to create an extra layer.
@@ -641,6 +641,9 @@ export interface IEditorOption<K1 extends EditorOption, V> {
 type PossibleKeyName0<V> = { [K in keyof IEditorOptions]: IEditorOptions[K] extends V | undefined ? K : never }[keyof IEditorOptions];
 type PossibleKeyName<V> = NonNullable<PossibleKeyName0<V>>;
 
+/**
+ * @internal
+ */
 abstract class BaseEditorOption<K1 extends EditorOption, V> implements IEditorOption<K1, V> {
 
 	public readonly id: K1;
@@ -1044,7 +1047,7 @@ function _cursorStyleFromString(cursorStyle: 'line' | 'block' | 'underline' | 'l
 class EditorClassName extends ComputedEditorOption<EditorOption.editorClassName, string> {
 
 	constructor() {
-		super(EditorOption.editorClassName, [EditorOption.mouseStyle, EditorOption.fontLigatures, EditorOption.extraEditorClassName]);
+		super(EditorOption.editorClassName, [EditorOption.mouseStyle, EditorOption.extraEditorClassName]);
 	}
 
 	public compute(env: IEnvironmentalOptions, options: IComputedEditorOptions, _: string): string {
@@ -1055,9 +1058,6 @@ class EditorClassName extends ComputedEditorOption<EditorOption.editorClassName,
 		if (env.extraEditorClassName) {
 			className += ' ' + env.extraEditorClassName;
 		}
-		if (options.get(EditorOption.fontLigatures)) {
-			className += ' enable-ligatures';
-		}
 		if (options.get(EditorOption.mouseStyle) === 'default') {
 			className += ' mouse-default';
 		} else if (options.get(EditorOption.mouseStyle) === 'copy') {
@@ -1167,6 +1167,57 @@ class EditorFind extends BaseEditorOption<EditorOption.find, EditorFindOptions>
 
 //#endregion
 
+//#region fontLigatures
+
+/**
+ * @internal
+ */
+export class EditorFontLigatures extends BaseEditorOption<EditorOption.fontLigatures, string> {
+
+	public static OFF = '"liga" off, "calt" off';
+	public static ON = '"liga" on, "calt" on';
+
+	constructor() {
+		super(
+			EditorOption.fontLigatures, 'fontLigatures', EditorFontLigatures.OFF,
+			{
+				anyOf: [
+					{
+						type: 'boolean',
+						description: nls.localize('fontLigatures', "Enables/Disables font ligatures."),
+					},
+					{
+						type: 'string',
+						description: nls.localize('fontFeatureSettings', "Explicit font-feature-settings.")
+					}
+				],
+				default: false
+			}
+		);
+	}
+
+	public validate(input: any): string {
+		if (typeof input === 'undefined') {
+			return this.defaultValue;
+		}
+		if (typeof input === 'string') {
+			if (input === 'false') {
+				return EditorFontLigatures.OFF;
+			}
+			if (input === 'true') {
+				return EditorFontLigatures.ON;
+			}
+			return input;
+		}
+		if (Boolean(input)) {
+			return EditorFontLigatures.ON;
+		}
+		return EditorFontLigatures.OFF;
+	}
+}
+
+//#endregion
+
 //#region fontInfo
 
 class EditorFontInfo extends ComputedEditorOption<EditorOption.fontInfo, FontInfo> {
@@ -2910,10 +2961,7 @@ export const EditorOptions = {
 		{ description: nls.localize('fontFamily', "Controls the font family.") }
 	)),
 	fontInfo: register(new EditorFontInfo()),
-	fontLigatures: register(new EditorBooleanOption(
-		EditorOption.fontLigatures, 'fontLigatures', false,
-		{ description: nls.localize('fontLigatures', "Enables/Disables font ligatures.") }
-	)),
+	fontLigatures2: register(new EditorFontLigatures()),
 	fontSize: register(new EditorFontSize()),
 	fontWeight: register(new EditorStringOption(
 		EditorOption.fontWeight, 'fontWeight', EDITOR_FONT_DEFAULTS.fontWeight,

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

@@ -28,27 +28,29 @@ export class BareFontInfo {
 		const fontFamily = options.get(EditorOption.fontFamily);
 		const fontWeight = options.get(EditorOption.fontWeight);
 		const fontSize = options.get(EditorOption.fontSize);
+		const fontFeatureSettings = options.get(EditorOption.fontLigatures);
 		const lineHeight = options.get(EditorOption.lineHeight);
 		const letterSpacing = options.get(EditorOption.letterSpacing);
-		return BareFontInfo._create(fontFamily, fontWeight, fontSize, lineHeight, letterSpacing, zoomLevel, ignoreEditorZoom);
+		return BareFontInfo._create(fontFamily, fontWeight, fontSize, fontFeatureSettings, lineHeight, letterSpacing, zoomLevel, ignoreEditorZoom);
 	}
 
 	/**
 	 * @internal
 	 */
-	public static createFromRawSettings(opts: { fontFamily?: string; fontWeight?: string; fontSize?: number; lineHeight?: number; letterSpacing?: number; }, zoomLevel: number, ignoreEditorZoom: boolean = false): BareFontInfo {
+	public static createFromRawSettings(opts: { fontFamily?: string; fontWeight?: string; fontSize?: number; fontLigatures?: boolean | string; lineHeight?: number; letterSpacing?: number; }, zoomLevel: number, ignoreEditorZoom: boolean = false): BareFontInfo {
 		const fontFamily = EditorOptions.fontFamily.validate(opts.fontFamily);
 		const fontWeight = EditorOptions.fontWeight.validate(opts.fontWeight);
 		const fontSize = EditorOptions.fontSize.validate(opts.fontSize);
+		const fontFeatureSettings = EditorOptions.fontLigatures2.validate(opts.fontLigatures);
 		const lineHeight = EditorOptions.lineHeight.validate(opts.lineHeight);
 		const letterSpacing = EditorOptions.letterSpacing.validate(opts.letterSpacing);
-		return BareFontInfo._create(fontFamily, fontWeight, fontSize, lineHeight, letterSpacing, zoomLevel, ignoreEditorZoom);
+		return BareFontInfo._create(fontFamily, fontWeight, fontSize, fontFeatureSettings, lineHeight, letterSpacing, zoomLevel, ignoreEditorZoom);
 	}
 
 	/**
 	 * @internal
 	 */
-	private static _create(fontFamily: string, fontWeight: string, fontSize: number, lineHeight: number, letterSpacing: number, zoomLevel: number, ignoreEditorZoom: boolean): BareFontInfo {
+	private static _create(fontFamily: string, fontWeight: string, fontSize: number, fontFeatureSettings: string, lineHeight: number, letterSpacing: number, zoomLevel: number, ignoreEditorZoom: boolean): BareFontInfo {
 		if (lineHeight === 0) {
 			lineHeight = Math.round(GOLDEN_LINE_HEIGHT_RATIO * fontSize);
 		} else if (lineHeight < MINIMUM_LINE_HEIGHT) {
@@ -64,6 +66,7 @@ export class BareFontInfo {
 			fontFamily: fontFamily,
 			fontWeight: fontWeight,
 			fontSize: fontSize,
+			fontFeatureSettings: fontFeatureSettings,
 			lineHeight: lineHeight,
 			letterSpacing: letterSpacing
 		});
@@ -73,6 +76,7 @@ export class BareFontInfo {
 	readonly fontFamily: string;
 	readonly fontWeight: string;
 	readonly fontSize: number;
+	readonly fontFeatureSettings: string;
 	readonly lineHeight: number;
 	readonly letterSpacing: number;
 
@@ -84,6 +88,7 @@ export class BareFontInfo {
 		fontFamily: string;
 		fontWeight: string;
 		fontSize: number;
+		fontFeatureSettings: string;
 		lineHeight: number;
 		letterSpacing: number;
 	}) {
@@ -91,6 +96,7 @@ export class BareFontInfo {
 		this.fontFamily = String(opts.fontFamily);
 		this.fontWeight = String(opts.fontWeight);
 		this.fontSize = opts.fontSize;
+		this.fontFeatureSettings = opts.fontFeatureSettings;
 		this.lineHeight = opts.lineHeight | 0;
 		this.letterSpacing = opts.letterSpacing;
 	}
@@ -99,7 +105,7 @@ export class BareFontInfo {
 	 * @internal
 	 */
 	public getId(): string {
-		return this.zoomLevel + '-' + this.fontFamily + '-' + this.fontWeight + '-' + this.fontSize + '-' + this.lineHeight + '-' + this.letterSpacing;
+		return this.zoomLevel + '-' + this.fontFamily + '-' + this.fontWeight + '-' + this.fontSize + '-' + this.fontFeatureSettings + '-' + this.lineHeight + '-' + this.letterSpacing;
 	}
 
 	/**
@@ -138,6 +144,7 @@ export class FontInfo extends BareFontInfo {
 		fontFamily: string;
 		fontWeight: string;
 		fontSize: number;
+		fontFeatureSettings: string;
 		lineHeight: number;
 		letterSpacing: number;
 		isMonospace: boolean;
@@ -165,6 +172,7 @@ export class FontInfo extends BareFontInfo {
 			this.fontFamily === other.fontFamily
 			&& this.fontWeight === other.fontWeight
 			&& this.fontSize === other.fontSize
+			&& this.fontFeatureSettings === other.fontFeatureSettings
 			&& this.lineHeight === other.lineHeight
 			&& this.letterSpacing === other.letterSpacing
 			&& this.typicalHalfwidthCharacterWidth === other.typicalHalfwidthCharacterWidth

src/vs/editor/test/common/mocks/testConfiguration.ts

@@ -4,7 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { CommonEditorConfiguration, IEnvConfiguration } from 'vs/editor/common/config/commonEditorConfig';
-import { IEditorOptions } from 'vs/editor/common/config/editorOptions';
+import { IEditorOptions, EditorFontLigatures } from 'vs/editor/common/config/editorOptions';
 import { BareFontInfo, FontInfo } from 'vs/editor/common/config/fontInfo';
 import { AccessibilitySupport } from 'vs/platform/accessibility/common/accessibility';
 
@@ -33,6 +33,7 @@ export class TestConfiguration extends CommonEditorConfiguration {
 			fontFamily: 'mockFont',
 			fontWeight: 'normal',
 			fontSize: 14,
+			fontFeatureSettings: EditorFontLigatures.OFF,
 			lineHeight: 19,
 			letterSpacing: 1.5,
 			isMonospace: true,

src/vs/monaco.d.ts

@@ -2581,7 +2581,7 @@ declare namespace monaco.editor {
 		 * Enable font ligatures.
 		 * Defaults to false.
 		 */
-		fontLigatures?: boolean;
+		fontLigatures?: boolean | string;
 		/**
 		 * Disable the use of `will-change` for the editor margin and lines layers.
 		 * The usage of `will-change` acts as a hint for browsers to create an extra layer.
@@ -4124,6 +4124,7 @@ declare namespace monaco.editor {
 		readonly fontFamily: string;
 		readonly fontWeight: string;
 		readonly fontSize: number;
+		readonly fontFeatureSettings: string;
 		readonly lineHeight: number;
 		readonly letterSpacing: number;
 	}