"fold" command when invoked on a folded line should apply to the enclosing level. Fixes #87810

src/vs/editor/contrib/folding/folding.ts

@@ -14,7 +14,7 @@ import { ScrollType, IEditorContribution } from 'vs/editor/common/editorCommon';
 import { ITextModel } from 'vs/editor/common/model';
 import { registerEditorAction, registerEditorContribution, ServicesAccessor, EditorAction, registerInstantiatedEditorAction } from 'vs/editor/browser/editorExtensions';
 import { ICodeEditor, IEditorMouseEvent, MouseTargetType } from 'vs/editor/browser/editorBrowser';
-import { FoldingModel, setCollapseStateAtLevel, CollapseMemento, setCollapseStateLevelsDown, setCollapseStateLevelsUp, setCollapseStateForMatchingLines, setCollapseStateForType, toggleCollapseState } from 'vs/editor/contrib/folding/foldingModel';
+import { FoldingModel, setCollapseStateAtLevel, CollapseMemento, setCollapseStateLevelsDown, setCollapseStateLevelsUp, setCollapseStateForMatchingLines, setCollapseStateForType, toggleCollapseState, setCollapseStateUp } from 'vs/editor/contrib/folding/foldingModel';
 import { FoldingDecorationProvider } from './foldingDecorations';
 import { FoldingRegions, FoldingRegion } from './foldingRanges';
 import { EditorContextKeys } from 'vs/editor/common/editorContextKeys';
@@ -617,9 +617,10 @@ class FoldAction extends FoldingAction<FoldingArguments> {
 					{
 						name: 'Fold editor argument',
 						description: `Property-value pairs that can be passed through this argument:
-							* 'levels': Number of levels to fold. Defaults to 1.
+							* 'levels': Number of levels to fold.
 							* 'direction': If 'up', folds given number of levels up otherwise folds down.
 							* 'selectionLines': The start lines (0-based) of the editor selections to apply the fold action to. If not set, the active selection(s) will be used.
+							If no levels or direction is set, folds the region at the locations or if already collapsed, the first uncollapsed parent instead.
 						`,
 						constraint: foldingArgumentsConstraint,
 						schema: {
@@ -627,12 +628,10 @@ class FoldAction extends FoldingAction<FoldingArguments> {
 							'properties': {
 								'levels': {
 									'type': 'number',
-									'default': 1
 								},
 								'direction': {
 									'type': 'string',
 									'enum': ['up', 'down'],
-									'default': 'down'
 								},
 								'selectionLines': {
 									'type': 'array',
@@ -649,12 +648,20 @@ class FoldAction extends FoldingAction<FoldingArguments> {
 	}
 
 	invoke(_foldingController: FoldingController, foldingModel: FoldingModel, editor: ICodeEditor, args: FoldingArguments): void {
-		let levels = args && args.levels || 1;
 		let lineNumbers = this.getLineNumbers(args, editor);
-		if (args && args.direction === 'up') {
-			setCollapseStateLevelsUp(foldingModel, true, levels, lineNumbers);
+
+		const levels = args && args.levels;
+		const direction = args && args.direction;
+
+		if (typeof levels !== 'number' && typeof direction !== 'string') {
+			// fold the region at the location or if already collapsed, the first uncollapsed parent instead.
+			setCollapseStateUp(foldingModel, true, lineNumbers);
 		} else {
-			setCollapseStateLevelsDown(foldingModel, true, levels, lineNumbers);
+			if (direction === 'up') {
+				setCollapseStateLevelsUp(foldingModel, true, levels || 1, lineNumbers);
+			} else {
+				setCollapseStateLevelsDown(foldingModel, true, levels || 1, lineNumbers);
+			}
 		}
 	}
 }

src/vs/editor/contrib/folding/foldingModel.ts

@@ -273,7 +273,7 @@ export function toggleCollapseState(foldingModel: FoldingModel, levels: number,
  * @param levels The number of levels. Use 1 to only impact the regions at the location, use Number.MAX_VALUE for all levels.
  * @param lineNumbers the location of the regions to collapse or expand, or if not set, all regions in the model.
  */
-export function setCollapseStateLevelsDown(foldingModel: FoldingModel, doCollapse: boolean, levels = Number.MAX_VALUE, lineNumbers?: number[]) {
+export function setCollapseStateLevelsDown(foldingModel: FoldingModel, doCollapse: boolean, levels = Number.MAX_VALUE, lineNumbers?: number[]): void {
 	let toToggle: FoldingRegion[] = [];
 	if (lineNumbers && lineNumbers.length > 0) {
 		for (let lineNumber of lineNumbers) {
@@ -299,9 +299,9 @@ export function setCollapseStateLevelsDown(foldingModel: FoldingModel, doCollaps
  * Collapse or expand the regions at the given locations including all parents.
  * @param doCollapse Wheter to collase or expand
  * @param levels The number of levels. Use 1 to only impact the regions at the location, use Number.MAX_VALUE for all levels.
- * @param lineNumbers the location of the regions to collapse or expand, or if not set, all regions in the model.
+ * @param lineNumbers the location of the regions to collapse or expand.
  */
-export function setCollapseStateLevelsUp(foldingModel: FoldingModel, doCollapse: boolean, levels: number, lineNumbers: number[]) {
+export function setCollapseStateLevelsUp(foldingModel: FoldingModel, doCollapse: boolean, levels: number, lineNumbers: number[]): void {
 	let toToggle: FoldingRegion[] = [];
 	for (let lineNumber of lineNumbers) {
 		let regions = foldingModel.getAllRegionsAtLine(lineNumber, (region, level) => region.isCollapsed !== doCollapse && level <= levels);
@@ -310,6 +310,22 @@ export function setCollapseStateLevelsUp(foldingModel: FoldingModel, doCollapse:
 	foldingModel.toggleCollapseState(toToggle);
 }
 
+/**
+ * Collapse or expand a region at the given locations. If the inner most region is already collapsed/expanded, uses the first parent instead.
+ * @param doCollapse Wheter to collase or expand
+ * @param lineNumbers the location of the regions to collapse or expand.
+ */
+export function setCollapseStateUp(foldingModel: FoldingModel, doCollapse: boolean, lineNumbers: number[]): void {
+	let toToggle: FoldingRegion[] = [];
+	for (let lineNumber of lineNumbers) {
+		let regions = foldingModel.getAllRegionsAtLine(lineNumber, (region, ) => region.isCollapsed !== doCollapse);
+		if (regions.length > 0) {
+			toToggle.push(regions[0]);
+		}
+	}
+	foldingModel.toggleCollapseState(toToggle);
+}
+
 /**
  * Folds or unfolds all regions that have a given level, except if they contain one of the blocked lines.
  * @param foldLevel level. Level == 1 is the top level

src/vs/editor/contrib/folding/test/foldingModel.test.ts

@@ -3,7 +3,7 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 import * as assert from 'assert';
-import { FoldingModel, setCollapseStateAtLevel, setCollapseStateLevelsDown, setCollapseStateLevelsUp, setCollapseStateForMatchingLines } from 'vs/editor/contrib/folding/foldingModel';
+import { FoldingModel, setCollapseStateAtLevel, setCollapseStateLevelsDown, setCollapseStateLevelsUp, setCollapseStateForMatchingLines, setCollapseStateUp } from 'vs/editor/contrib/folding/foldingModel';
 import { TextModel, ModelDecorationOptions } from 'vs/editor/common/model/textModel';
 import { computeRanges } from 'vs/editor/contrib/folding/indentRangeProvider';
 import { TrackedRangeStickiness, IModelDeltaDecoration, ITextModel, IModelDecorationsChangeAccessor } from 'vs/editor/common/model';
@@ -587,6 +587,50 @@ suite('Folding Model', () => {
 
 	});
 
+	test('setCollapseStateUp', () => {
+		let lines = [
+		/* 1*/	'//#region',
+		/* 2*/	'//#endregion',
+		/* 3*/	'class A {',
+		/* 4*/	'  void foo() {',
+		/* 5*/	'    if (true) {',
+		/* 6*/	'        return;',
+		/* 7*/	'    }',
+		/* 8*/	'',
+		/* 9*/	'    if (true) {',
+		/* 10*/	'      return;',
+		/* 11*/	'    }',
+		/* 12*/	'  }',
+		/* 13*/	'}'];
+
+		let textModel = TextModel.createFromString(lines.join('\n'));
+		try {
+			let foldingModel = new FoldingModel(textModel, new TestDecorationProvider(textModel));
+
+			let ranges = computeRanges(textModel, false, { start: /^\/\/#region$/, end: /^\/\/#endregion$/ });
+			foldingModel.update(ranges);
+
+			let r1 = r(1, 2, false);
+			let r2 = r(3, 12, false);
+			let r3 = r(4, 11, false);
+			let r4 = r(5, 6, false);
+			let r5 = r(9, 10, false);
+			assertRanges(foldingModel, [r1, r2, r3, r4, r5]);
+
+			setCollapseStateUp(foldingModel, true, [5]);
+			assertFoldedRanges(foldingModel, [r4], '1');
+
+			setCollapseStateUp(foldingModel, true, [5]);
+			assertFoldedRanges(foldingModel, [r3, r4], '2');
+
+			setCollapseStateUp(foldingModel, true, [4]);
+			assertFoldedRanges(foldingModel, [r2, r3, r4], '2');
+		} finally {
+			textModel.dispose();
+		}
+
+	});
+
 
 	test('setCollapseStateForMatchingLines', () => {
 		let lines = [