fix #87730.

src/vs/editor/contrib/comment/comment.ts

@@ -7,6 +7,7 @@ import * as nls from 'vs/nls';
 import { KeyChord, KeyCode, KeyMod } from 'vs/base/common/keyCodes';
 import { ICodeEditor } from 'vs/editor/browser/editorBrowser';
 import { EditorAction, IActionOptions, ServicesAccessor, registerEditorAction } from 'vs/editor/browser/editorExtensions';
+import { Range } from 'vs/editor/common/core/range';
 import { ICommand } from 'vs/editor/common/editorCommon';
 import { EditorContextKeys } from 'vs/editor/common/editorContextKeys';
 import { BlockCommentCommand } from 'vs/editor/contrib/comment/blockCommentCommand';
@@ -31,17 +32,38 @@ abstract class CommentLineAction extends EditorAction {
 
 		const model = editor.getModel();
 		const commands: ICommand[] = [];
-		const selections = editor.getSelections();
 		const modelOptions = model.getOptions();
 		const commentsOptions = editor.getOption(EditorOption.comments);
 
+		const selections = editor.getSelections().map((selection, index) => ({ selection, index, ignoreFirstLine: false }));
+		selections.sort((a, b) => Range.compareRangesUsingStarts(a.selection, b.selection));
+
+		// Remove selections that would result in copying the same line
+		let prev = selections[0];
+		for (let i = 1; i < selections.length; i++) {
+			const curr = selections[i];
+			if (prev.selection.endLineNumber === curr.selection.startLineNumber) {
+				// these two selections would copy the same line
+				if (prev.index < curr.index) {
+					// prev wins
+					curr.ignoreFirstLine = true;
+				} else {
+					// curr wins
+					prev.ignoreFirstLine = true;
+					prev = curr;
+				}
+			}
+		}
+
+
 		for (const selection of selections) {
 			commands.push(new LineCommentCommand(
-				selection,
+				selection.selection,
 				modelOptions.tabSize,
 				this._type,
 				commentsOptions.insertSpace,
-				commentsOptions.ignoreEmptyLines
+				commentsOptions.ignoreEmptyLines,
+				selection.ignoreFirstLine
 			));
 		}
 

src/vs/editor/contrib/comment/lineCommentCommand.ts

@@ -57,13 +57,15 @@ export class LineCommentCommand implements ICommand {
 	private _selectionId: string | null;
 	private _deltaColumn: number;
 	private _moveEndPositionDown: boolean;
+	private _ignoreFirstLine: boolean;
 
 	constructor(
 		selection: Selection,
 		tabSize: number,
 		type: Type,
 		insertSpace: boolean,
-		ignoreEmptyLines: boolean
+		ignoreEmptyLines: boolean,
+		ignoreFirstLine?: boolean
 	) {
 		this._selection = selection;
 		this._tabSize = tabSize;
@@ -73,6 +75,7 @@ export class LineCommentCommand implements ICommand {
 		this._deltaColumn = 0;
 		this._moveEndPositionDown = false;
 		this._ignoreEmptyLines = ignoreEmptyLines;
+		this._ignoreFirstLine = ignoreFirstLine || false;
 	}
 
 	/**
@@ -108,7 +111,7 @@ export class LineCommentCommand implements ICommand {
 	 * Analyze lines and decide which lines are relevant and what the toggle should do.
 	 * Also, build up several offsets and lengths useful in the generation of editor operations.
 	 */
-	public static _analyzeLines(type: Type, insertSpace: boolean, model: ISimpleModel, lines: ILinePreflightData[], startLineNumber: number, ignoreEmptyLines: boolean): IPreflightData {
+	public static _analyzeLines(type: Type, insertSpace: boolean, model: ISimpleModel, lines: ILinePreflightData[], startLineNumber: number, ignoreEmptyLines: boolean, ignoreFirstLine: boolean): IPreflightData {
 		let onlyWhitespaceLines = true;
 
 		let shouldRemoveComments: boolean;
@@ -124,6 +127,12 @@ export class LineCommentCommand implements ICommand {
 			const lineData = lines[i];
 			const lineNumber = startLineNumber + i;
 
+			if (lineNumber === startLineNumber && ignoreFirstLine) {
+				// first line ignored
+				lineData.ignore = true;
+				continue;
+			}
+
 			const lineContent = model.getLineContent(lineNumber);
 			const lineContentStartOffset = strings.firstNonWhitespaceIndex(lineContent);
 
@@ -178,7 +187,7 @@ export class LineCommentCommand implements ICommand {
 	/**
 	 * Analyze all lines and decide exactly what to do => not supported | insert line comments | remove line comments
 	 */
-	public static _gatherPreflightData(type: Type, insertSpace: boolean, model: ITextModel, startLineNumber: number, endLineNumber: number, ignoreEmptyLines: boolean): IPreflightData {
+	public static _gatherPreflightData(type: Type, insertSpace: boolean, model: ITextModel, startLineNumber: number, endLineNumber: number, ignoreEmptyLines: boolean, ignoreFirstLine: boolean): IPreflightData {
 		const lines = LineCommentCommand._gatherPreflightCommentStrings(model, startLineNumber, endLineNumber);
 		if (lines === null) {
 			return {
@@ -186,7 +195,7 @@ export class LineCommentCommand implements ICommand {
 			};
 		}
 
-		return LineCommentCommand._analyzeLines(type, insertSpace, model, lines, startLineNumber, ignoreEmptyLines);
+		return LineCommentCommand._analyzeLines(type, insertSpace, model, lines, startLineNumber, ignoreEmptyLines, ignoreFirstLine);
 	}
 
 	/**
@@ -323,6 +332,12 @@ export class LineCommentCommand implements ICommand {
 		let s = this._selection;
 		this._moveEndPositionDown = false;
 
+		if (s.startLineNumber === s.endLineNumber && this._ignoreFirstLine) {
+			builder.addEditOperation(new Range(s.startLineNumber, model.getLineMaxColumn(s.startLineNumber), s.startLineNumber + 1, 1), s.startLineNumber === model.getLineCount() ? '' : '\n');
+			this._selectionId = builder.trackSelection(s);
+			return;
+		}
+
 		if (s.startLineNumber < s.endLineNumber && s.endColumn === 1) {
 			this._moveEndPositionDown = true;
 			s = s.setEndPosition(s.endLineNumber - 1, model.getLineMaxColumn(s.endLineNumber - 1));
@@ -334,7 +349,8 @@ export class LineCommentCommand implements ICommand {
 			model,
 			s.startLineNumber,
 			s.endLineNumber,
-			this._ignoreEmptyLines
+			this._ignoreEmptyLines,
+			this._ignoreFirstLine
 		);
 
 		if (data.supported) {

src/vs/editor/contrib/comment/test/lineCommentCommand.test.ts

@@ -91,7 +91,7 @@ suite('Editor Contrib - Line Comment Command', () => {
 			'    ',
 			'    c',
 			'\t\td'
-		]), createBasicLinePreflightData(['//', 'rem', '!@#', '!@#']), 1, true);
+		]), createBasicLinePreflightData(['//', 'rem', '!@#', '!@#']), 1, true, false);
 		if (!r.supported) {
 			throw new Error(`unexpected`);
 		}
@@ -122,7 +122,7 @@ suite('Editor Contrib - Line Comment Command', () => {
 			'    rem ',
 			'    !@# c',
 			'\t\t!@#d'
-		]), createBasicLinePreflightData(['//', 'rem', '!@#', '!@#']), 1, true);
+		]), createBasicLinePreflightData(['//', 'rem', '!@#', '!@#']), 1, true, false);
 		if (!r.supported) {
 			throw new Error(`unexpected`);
 		}