add tests for toInlineSuggestion prefix stripping logic and add advanced argument with default value (#4231)

Author: benibenj

src/extension/inlineEdits/test/vscode-node/isInlineSuggestion.spec.ts

@@ -275,6 +275,20 @@ function createDocumentSymbol(
 		assert.isUndefined(toInlineSuggestion(cursorPosition, document, replaceRange, replaceText));
 	});
 
+	test('next-line: non-empty replace range covering only whitespace on next line', () => {
+		const document = createMockDocument([
+			'    for item in items:',
+			'        ',
+			'other_code',
+		], 'python');
+		const cursorPosition = new Position(1, 4);
+		const replaceRange = new Range(0, 22, 1, 8);
+		const replaceText = '\n        process(item)\n    return result';
+
+		const result = toInlineSuggestion(cursorPosition, document, replaceRange, replaceText);
+		assert.isDefined(result);
+	});
+
 	test('next-line: range 2 lines ahead is rejected', () => {
 		const document = createMockDocument(['line 0', 'line 1', '', 'line 3']);
 		const cursorPosition = new Position(0, 6);
@@ -419,4 +433,118 @@ function createDocumentSymbol(
 		assert.isDefined(result);
 		assert.strictEqual(result!.newText, 'console.log');
 	});
+
+	// --- Prefix-stripping: multi-line range reduction ---
+
+	test('prefix-strip: multi-line range reduced to single-line edit on cursor line', () => {
+		// Range spans lines 0-1, replaced text = "abc\ndef", newText = "abc\ndefghi"
+		// Common prefix up to newline = "abc\n", strip it → range becomes (1,0)-(1,3), newText = "defghi"
+		const document = createMockDocument(['abc', 'def', 'other']);
+		const cursorPosition = new Position(1, 0);
+		const replaceRange = new Range(0, 0, 1, 3);
+		const replaceText = 'abc\ndefghi';
+
+		const result = toInlineSuggestion(cursorPosition, document, replaceRange, replaceText);
+		assert.isDefined(result);
+		assert.deepStrictEqual(result!.range, new Range(1, 0, 1, 3));
+		assert.strictEqual(result!.newText, 'defghi');
+	});
+
+	test('prefix-strip: no newline in common prefix, multi-line range still rejected', () => {
+		// Range spans lines 0-1, replaced = "ab\ncd", newText = "abXY"
+		// Common prefix = "ab" but no newline → no stripping → multi-line range rejected
+		const document = createMockDocument(['ab', 'cd', 'other']);
+		const cursorPosition = new Position(0, 0);
+		const replaceRange = new Range(0, 0, 1, 2);
+		const replaceText = 'abXY';
+
+		assert.isUndefined(toInlineSuggestion(cursorPosition, document, replaceRange, replaceText));
+	});
+
+	test('prefix-strip: strips multiple newlines to last boundary', () => {
+		// Range spans 3 lines: "line0\nline1\nxy", newText = "line0\nline1\nxyz"
+		// Common prefix includes two newlines, stripping to last → range becomes (2,0)-(2,2)
+		const document = createMockDocument(['line0', 'line1', 'xy', 'other']);
+		const cursorPosition = new Position(2, 0);
+		const replaceRange = new Range(0, 0, 2, 2);
+		const replaceText = 'line0\nline1\nxyz';
+
+		const result = toInlineSuggestion(cursorPosition, document, replaceRange, replaceText);
+		assert.isDefined(result);
+		assert.deepStrictEqual(result!.range, new Range(2, 0, 2, 2));
+		assert.strictEqual(result!.newText, 'xyz');
+	});
+
+	test('prefix-strip: after stripping still multi-line, rejected', () => {
+		// Range spans 3 lines: "a\nb\nc", newText = "a\nB\nC"
+		// Common prefix up to newline = "a\n", strip → range becomes (1,0)-(2,1) which is still multi-line
+		const document = createMockDocument(['a', 'b', 'c', 'other']);
+		const cursorPosition = new Position(1, 0);
+		const replaceRange = new Range(0, 0, 2, 1);
+		const replaceText = 'a\nB\nC';
+
+		assert.isUndefined(toInlineSuggestion(cursorPosition, document, replaceRange, replaceText));
+	});
+
+	test('prefix-strip: reduced to single line but cursor on different line, rejected', () => {
+		// Strip reduces range to line 1, but cursor is on line 0
+		const document = createMockDocument(['abc', 'def', 'other']);
+		const cursorPosition = new Position(0, 2);
+		const replaceRange = new Range(0, 0, 1, 3);
+		const replaceText = 'abc\ndefghi';
+
+		assert.isUndefined(toInlineSuggestion(cursorPosition, document, replaceRange, replaceText));
+	});
+
+	test('prefix-strip: reduced to single line, subword check fails', () => {
+		// After stripping "abc\n", range = (1,0)-(1,3) with replaced "def", newText = "xy"
+		// "def" is not a subword of "xy"
+		const document = createMockDocument(['abc', 'def', 'other']);
+		const cursorPosition = new Position(1, 0);
+		const replaceRange = new Range(0, 0, 1, 3);
+		const replaceText = 'abc\nxy';
+
+		assert.isUndefined(toInlineSuggestion(cursorPosition, document, replaceRange, replaceText));
+	});
+
+	test('prefix-strip: diverges before first newline, no stripping', () => {
+		// replaced = "ax\nyz", newText = "ab\nyz" → common prefix "a" has no newline → no strip
+		const document = createMockDocument(['ax', 'yz']);
+		const cursorPosition = new Position(0, 0);
+		const replaceRange = new Range(0, 0, 1, 2);
+		const replaceText = 'ab\nyz';
+
+		assert.isUndefined(toInlineSuggestion(cursorPosition, document, replaceRange, replaceText));
+	});
+
+	test('prefix-strip: range starts mid-line, strips prefix through newline', () => {
+		// Document: "hello world", "  ns", "other"
+		// Range (0,6)-(1,4) → replaced text = "world\n  ns", newText = "world\n  new_stuff"
+		// Common prefix = "world\n  " → last newline at index 5, strip "world\n"
+		// Reduced range: (1,0)-(1,4), newText = "  new_stuff"
+		// isSubword("  ns", "  new_stuff") → true
+		const document = createMockDocument(['hello world', '  ns', 'other']);
+		const cursorPosition = new Position(1, 0);
+		const replaceRange = new Range(0, 6, 1, 4);
+		const replaceText = 'world\n  new_stuff';
+
+		const result = toInlineSuggestion(cursorPosition, document, replaceRange, replaceText);
+		assert.isDefined(result);
+		assert.deepStrictEqual(result!.range, new Range(1, 0, 1, 4));
+		assert.strictEqual(result!.newText, '  new_stuff');
+	});
+
+	test('prefix-strip: empty newText after stripping prefix', () => {
+		// replaced = "abc\n", newText = "abc\n" → after stripping "abc\n", replaced="" and newText=""
+		// This is a no-op on the second line, succeeds as empty edit
+		const document = createMockDocument(['abc', '', 'other']);
+		const cursorPosition = new Position(1, 0);
+		const replaceRange = new Range(0, 0, 1, 0);
+		const replaceText = 'abc\n';
+
+		const result = toInlineSuggestion(cursorPosition, document, replaceRange, replaceText);
+		assert.isDefined(result);
+		assert.deepStrictEqual(result!.range, new Range(1, 0, 1, 0));
+		assert.strictEqual(result!.newText, '');
+	});
 });

src/extension/inlineEdits/vscode-node/inlineCompletionProvider.ts

@@ -146,6 +146,7 @@ export class InlineCompletionProviderImpl extends Disposable implements InlineCo
 
 	private readonly _displayNextEditorNES: boolean;
 	private readonly _renameSymbolSuggestions: IObservable<boolean>;
+	private readonly _inlineCompletionsAdvanced: IObservable<boolean>;
 
 	constructor(
 		private readonly model: InlineEditModel,
@@ -170,6 +171,7 @@ export class InlineCompletionProviderImpl extends Disposable implements InlineCo
 		this._logger = this._logService.createSubLogger(['NES', 'Provider']);
 		this._displayNextEditorNES = this._configurationService.getExperimentBasedConfig(ConfigKey.Advanced.UseAlternativeNESNotebookFormat, this._expService);
 		this._renameSymbolSuggestions = this._configurationService.getExperimentBasedConfigObservable(ConfigKey.Advanced.InlineEditsRenameSymbolSuggestions, this._expService);
+		this._inlineCompletionsAdvanced = this._configurationService.getExperimentBasedConfigObservable(ConfigKey.TeamInternal.InlineEditsInlineCompletionsAdvanced, this._expService);
 
 		this.setCurrentModelId = (modelId: string) => this._modelService.setCurrentModelId(modelId);
 
@@ -386,7 +388,7 @@ export class InlineCompletionProviderImpl extends Disposable implements InlineCo
 			} else if (targetDocument === document) {
 				// nes is for this same document.
 				const allowInlineCompletions = this.model.inlineEditsInlineCompletionsEnabled.get();
-				const inlineSuggestion = allowInlineCompletions ? toInlineSuggestion(position, document, range, result.edit.newText) : undefined;
+				const inlineSuggestion = allowInlineCompletions ? toInlineSuggestion(position, document, range, result.edit.newText, this._inlineCompletionsAdvanced.get()) : undefined;
 				isInlineCompletion = !!inlineSuggestion;
 				completionItem = serveAsCompletionsProvider && !isInlineCompletion ?
 					undefined :

src/extension/inlineEdits/vscode-node/isInlineSuggestion.ts

@@ -16,7 +16,7 @@ export interface InlineSuggestionEdit {
  * If so, returns the (possibly adjusted) range and text that touches the cursor position,
  * which is required for VS Code to render ghost text.
  */
-export function toInlineSuggestion(cursorPos: Position, doc: TextDocument, range: Range, newText: string): InlineSuggestionEdit | undefined {
+export function toInlineSuggestion(cursorPos: Position, doc: TextDocument, range: Range, newText: string, advanced: boolean = true): InlineSuggestionEdit | undefined {
 	// If multi line insertion starts on the next line
 	// All new lines have to be newly created lines
 	if (range.isEmpty && cursorPos.line + 1 === range.start.line && range.start.character === 0
@@ -29,6 +29,26 @@ export function toInlineSuggestion(cursorPos: Position, doc: TextDocument, range
 		return { range: adjustedRange, newText: textBetweenCursorAndRange + newText };
 	}
 
+	if (advanced) {
+		// If the range spans multiple lines, try to reduce it by stripping a common
+		// prefix (up to a newline boundary) from the replaced text and newText.
+		if (range.start.line !== range.end.line) {
+			const fullReplacedText = doc.getText(range);
+			let commonLen = 0;
+			const maxLen = Math.min(fullReplacedText.length, newText.length);
+			while (commonLen < maxLen && fullReplacedText[commonLen] === newText[commonLen]) {
+				commonLen++;
+			}
+			const lastNewline = fullReplacedText.substring(0, commonLen).lastIndexOf('\n');
+			if (lastNewline >= 0) {
+				const strippedLen = lastNewline + 1;
+				newText = newText.substring(strippedLen);
+				const newStart = doc.positionAt(doc.offsetAt(range.start) + strippedLen);
+				range = new Range(newStart, range.end);
+			}
+		}
+	}
+
 	if (range.start.line !== range.end.line || range.start.line !== cursorPos.line) {
 		return undefined;
 	}

src/platform/configuration/common/configurationService.ts

@@ -785,6 +785,7 @@ export namespace ConfigKey {
 		export const InlineEditsXtabProviderModelConfiguration = defineTeamInternalSetting<xtabPromptOptions.ModelConfiguration | undefined>('chat.advanced.inlineEdits.xtabProvider.modelConfiguration', ConfigType.Simple, undefined, xtabPromptOptions.MODEL_CONFIGURATION_VALIDATOR);
 		export const InlineEditsNextCursorPredictionLintOptions = defineTeamInternalSetting<xtabPromptOptions.LintOptions | undefined>('chat.advanced.inlineEdits.nextCursorPrediction.lintOptions', ConfigType.Simple, undefined, xtabPromptOptions.LINT_OPTIONS_VALIDATOR);
 		export const InlineEditsInlineCompletionsEnabled = defineTeamInternalSetting<boolean>('chat.advanced.inlineEdits.inlineCompletions.enabled', ConfigType.Simple, true, vBoolean());
+		export const InlineEditsInlineCompletionsAdvanced = defineTeamInternalSetting<boolean>('chat.advanced.inlineEdits.inlineCompletions.advancedDetection', ConfigType.ExperimentBased, true, vBoolean());
 		export const InlineEditsXtabProviderUsePrediction = defineTeamInternalSetting<boolean>('chat.advanced.inlineEdits.xtabProvider.usePrediction', ConfigType.ExperimentBased, true, vBoolean());
 		export const InlineEditsXtabLanguageContextEnabledLanguages = defineTeamInternalSetting<LanguageContextLanguages>('chat.advanced.inlineEdits.xtabProvider.languageContext.enabledLanguages', ConfigType.Simple, LANGUAGE_CONTEXT_ENABLED_LANGUAGES);
 		export const InlineEditsXtabLanguageContextTraitsPosition = defineTeamInternalSetting<'before' | 'after'>('chat.advanced.inlineEdits.xtabProvider.languageContext.traitsPosition', ConfigType.ExperimentBased, 'before');