Fix indentation issues when pasting with trailing newline

Fixes microsoft#85781
Fixes microsoft#147223
Fixes microsoft#33760
Fixes microsoft#65614
Fixes microsoft#86301

(Some of the issues above were closed as being limitations of the
regex based indentation rules, but this change is able to fix them.)

Note that ReindentSelectedLinesAction already does the same thing as
this fix (which is what inspired it -- I noticed that running Reindent
Selected Lines on the equivalent code didn't have the same issues): see
https://github.com/microsoft/vscode/blob/6cbd9e8f3c5a59c5b1170aac8f2b5e9b0b4edfee/src/vs/editor/contrib/indentation/browser/indentation.ts#L390-L392

Author: russelldavis

src/vs/editor/contrib/indentation/browser/indentation.ts

@@ -521,17 +521,26 @@ export class AutoIndentOnPaste implements IEditorContribution {
 			}
 		};
 
+		let endLineNumber = range.endLineNumber;
+
+		// Don't indent the final line if the range ends at the start of it, because it will mess up
+		// the indentation of the preexisting code (outside the paste range) on that line.
+		// See https://github.com/microsoft/vscode/issues/85781 and https://github.com/microsoft/vscode/issues/147223
+		if (range.endColumn === 1) {
+			endLineNumber--;
+		}
+
 		let startLineNumber = range.startLineNumber;
 
-		while (startLineNumber <= range.endLineNumber) {
+		while (startLineNumber <= endLineNumber) {
 			if (this.shouldIgnoreLine(model, startLineNumber)) {
 				startLineNumber++;
 				continue;
 			}
 			break;
 		}
 
-		if (startLineNumber > range.endLineNumber) {
+		if (startLineNumber > endLineNumber) {
 			return;
 		}
 
@@ -568,15 +577,15 @@ export class AutoIndentOnPaste implements IEditorContribution {
 		const firstLineNumber = startLineNumber;
 
 		// ignore empty or ignored lines
-		while (startLineNumber < range.endLineNumber) {
+		while (startLineNumber < endLineNumber) {
 			if (!/\S/.test(model.getLineContent(startLineNumber + 1))) {
 				startLineNumber++;
 				continue;
 			}
 			break;
 		}
 
-		if (startLineNumber !== range.endLineNumber) {
+		if (startLineNumber !== endLineNumber) {
 			const virtualModel = {
 				tokenization: {
 					getLineTokens: (lineNumber: number) => {
@@ -604,7 +613,7 @@ export class AutoIndentOnPaste implements IEditorContribution {
 
 				if (newSpaceCntOfSecondLine !== oldSpaceCntOfSecondLine) {
 					const spaceCntOffset = newSpaceCntOfSecondLine - oldSpaceCntOfSecondLine;
-					for (let i = startLineNumber + 1; i <= range.endLineNumber; i++) {
+					for (let i = startLineNumber + 1; i <= endLineNumber; i++) {
 						const lineContent = model.getLineContent(i);
 						const originalIndent = strings.getLeadingWhitespace(lineContent);
 						const originalSpacesCnt = indentUtils.getSpaceCnt(originalIndent, tabSize);

src/vs/editor/contrib/indentation/test/browser/indentation.test.ts

@@ -271,6 +271,47 @@ suite('Editor Contrib - Auto Indent On Paste', () => {
 			assert.strictEqual(model.getValue(), pasteText);
 		});
 	});
+
+	test('issue #85781: Do not indent the final line if the selection ends at the start of it', () => {
+		const languageId = 'indentFinalLine';
+		const lines = [
+			'if (true) {',
+			'    console.log("end");',
+			'}',
+		];
+		const model = createTextModel(lines.join('\n'), languageId, {});
+		disposables.add(model);
+		withTestCodeEditor(model, { autoIndent: 'full' }, (editor, viewModel, instantiationService) => {
+			const languageService = instantiationService.get(ILanguageService);
+			const languageConfigurationService = instantiationService.get(ILanguageConfigurationService);
+			disposables.add(languageService.registerLanguage({ id: languageId }));
+			disposables.add(languageConfigurationService.register(languageId, {
+				brackets: [
+					['{', '}'],
+					['[', ']'],
+					['(', ')']
+				],
+				indentationRules: javascriptIndentationRules,
+				onEnterRules: javascriptOnEnterRules
+			}));
+
+			const autoIndentOnPasteController = editor.registerAndInstantiateContribution(AutoIndentOnPaste.ID, AutoIndentOnPaste);
+			const pasteLines = [
+				'console.log(1);',
+				'console.log(2);',
+			];
+
+			viewModel.setSelections('test', [new Selection(2, 1, 2, 1)]);
+			viewModel.paste(pasteLines.join('\n') + '\n', false, undefined, 'keyboard');
+			autoIndentOnPasteController.trigger(new Range(2, 1, 4, 1));
+			const expectText = [
+				lines[0],
+				...pasteLines.map(line => '    ' + line),
+				...lines.slice(1),
+			].join('\n');
+			assert.strictEqual(model.getValue(), expectText);
+		});
+	});
 });
 
 suite('Editor Contrib - Keep Indent On Paste', () => {