Check for onEnterRules that decrease indentation when determining new line indent

Author: ssigwart

src/vs/editor/common/modes/languageConfigurationRegistry.ts

@@ -366,7 +366,7 @@ export class LanguageConfigurationRegistryImpl {
 	 *
 	 * This function only return the inherited indent based on above lines, it doesn't check whether current line should decrease or not.
 	 */
-	public getInheritIndentForLine(autoIndent: EditorAutoIndentStrategy, model: IVirtualModel, lineNumber: number, honorIntentialIndent: boolean = true): { indentation: string; action: IndentAction | null; line?: number; } | null {
+	public getInheritIndentForLine(autoIndent: EditorAutoIndentStrategy, model: IVirtualModel, lineNumber: number, honorIntentialIndent: boolean = true, indentConverter: IIndentConverter | undefined = undefined): { indentation: string; action: IndentAction | null; line?: number; } | null {
 		if (autoIndent < EditorAutoIndentStrategy.Full) {
 			return null;
 		}
@@ -442,8 +442,26 @@ export class LanguageConfigurationRegistryImpl {
 			}
 
 			if (honorIntentialIndent) {
+				let indentation = strings.getLeadingWhitespace(model.getLineContent(precedingUnIgnoredLine));
+				// Check for onEnter rules that should decrease the indent
+				if (indentConverter) {
+					const richEditSupport = this.getLanguageConfiguration(model.getLanguageId());
+					if (richEditSupport) {
+						const previousLineText = precedingUnIgnoredLine < 1 ? '' : model.getLineContent(precedingUnIgnoredLine - 1);
+						const afterEnterText = model.getLineContent(lineNumber);
+						const enterResult = richEditSupport.onEnter(autoIndent, previousLineText, precedingUnIgnoredLineContent, afterEnterText);
+						if (enterResult) {
+							if (enterResult.indentAction === IndentAction.Outdent) {
+								indentation = indentConverter.unshiftIndent(indentation);
+							} else if (enterResult.removeText && indentation.length >= enterResult.removeText) {
+								indentation = indentation.substring(0, indentation.length - enterResult.removeText - 1);
+							}
+						}
+					}
+				}
+
 				return {
-					indentation: strings.getLeadingWhitespace(model.getLineContent(precedingUnIgnoredLine)),
+					indentation: indentation,
 					action: null,
 					line: precedingUnIgnoredLine
 				};
@@ -505,7 +523,7 @@ export class LanguageConfigurationRegistryImpl {
 			return null;
 		}
 
-		const indent = this.getInheritIndentForLine(autoIndent, virtualModel, lineNumber);
+		const indent = this.getInheritIndentForLine(autoIndent, virtualModel, lineNumber, true, indentConverter);
 		const lineContent = virtualModel.getLineContent(lineNumber);
 
 		if (indent) {
@@ -613,7 +631,7 @@ export class LanguageConfigurationRegistryImpl {
 		};
 
 		const currentLineIndent = strings.getLeadingWhitespace(lineTokens.getLineContent());
-		const afterEnterAction = this.getInheritIndentForLine(autoIndent, virtualModel, range.startLineNumber + 1);
+		const afterEnterAction = this.getInheritIndentForLine(autoIndent, virtualModel, range.startLineNumber + 1, true, indentConverter);
 		if (!afterEnterAction) {
 			const beforeEnter = embeddedLanguage ? currentLineIndent : beforeEnterIndent;
 			return {

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

@@ -4529,6 +4529,57 @@ suite('Editor Controller - Indentation Rules', () => {
 		latexMode.dispose();
 		model.dispose();
 	});
+
+	test('Issue #136592: onEnterRules should be considered for new line indentation', () => {
+		const mode = new class extends MockMode {
+			constructor() {
+				super('onEnterMode');
+				this._register(LanguageConfigurationRegistry.register(this.languageId, {
+					indentationRules: {
+						increaseIndentPattern: /if/,
+						decreaseIndentPattern: /never/
+					},
+					onEnterRules: [{
+						beforeText: /outdent/,
+						action: {
+							indentAction: IndentAction.Outdent
+						}
+					}]
+				}));
+			}
+		}();
+		usingCursor({
+			text: [
+				'if (1)',
+				'    outdent',
+				'',
+				'if (1) {',
+				'    keep indent',
+				'',
+				'}'
+			],
+			languageId: mode.languageId,
+		}, (editor, model, viewModel) => {
+
+			// Use indent
+			moveTo(editor, viewModel, 6, 1);
+			viewModel.type('\n', 'keyboard');
+			assert.strictEqual(model.getLineContent(5), '    keep indent');
+			assert.strictEqual(model.getLineContent(6), '');
+			assert.strictEqual(model.getLineContent(7), '    ');
+			assertCursor(viewModel, new Position(7, 5));
+
+			// No indent
+			moveTo(editor, viewModel, 3, 1);
+			viewModel.type('\n', 'keyboard');
+			assert.strictEqual(model.getLineContent(1), 'if (1)');
+			assert.strictEqual(model.getLineContent(2), '    outdent');
+			assert.strictEqual(model.getLineContent(3), '');
+			assert.strictEqual(model.getLineContent(4), '');
+			assertCursor(viewModel, new Position(4, 1));
+		});
+		mode.dispose();
+	});
 });
 
 interface ICursorOpts {