Wide gutter when PR branch is checked out (microsoft#167043)

Fixes microsoft#166910

Author: alexr00

src/vs/workbench/contrib/comments/browser/commentsEditorContribution.ts

@@ -896,46 +896,70 @@ export class CommentController implements IEditorContribution {
 		return;
 	}
 
+	private getExistingCommentEditorOptions(editor: ICodeEditor) {
+		const lineDecorationsWidth: number = editor.getOption(EditorOption.lineDecorationsWidth);
+		let extraEditorClassName: string[] = [];
+		const configuredExtraClassName = editor.getRawOptions().extraEditorClassName;
+		if (configuredExtraClassName) {
+			extraEditorClassName = configuredExtraClassName.split(' ');
+		}
+		return { lineDecorationsWidth, extraEditorClassName };
+	}
+
+	private getWithoutCommentsEditorOptions(editor: ICodeEditor, extraEditorClassName: string[], startingLineDecorationsWidth: number) {
+		let lineDecorationsWidth = startingLineDecorationsWidth;
+		const inlineCommentPos = extraEditorClassName.findIndex(name => name === 'inline-comment');
+		if (inlineCommentPos >= 0) {
+			extraEditorClassName.splice(inlineCommentPos, 1);
+		}
+
+		const options = editor.getOptions();
+		if (options.get(EditorOption.folding) && options.get(EditorOption.showFoldingControls) !== 'never') {
+			lineDecorationsWidth += 11; // 11 comes from https://github.com/microsoft/vscode/blob/94ee5f58619d59170983f453fe78f156c0cc73a3/src/vs/workbench/contrib/comments/browser/media/review.css#L485
+		}
+		lineDecorationsWidth -= 24;
+		return { extraEditorClassName, lineDecorationsWidth };
+	}
+
+	private getWithCommentsEditorOptions(editor: ICodeEditor, extraEditorClassName: string[], startingLineDecorationsWidth: number) {
+		let lineDecorationsWidth = startingLineDecorationsWidth;
+		const options = editor.getOptions();
+		if (options.get(EditorOption.folding) && options.get(EditorOption.showFoldingControls) !== 'never') {
+			lineDecorationsWidth -= 11;
+		}
+		lineDecorationsWidth += 24;
+		extraEditorClassName.push('inline-comment');
+		return { lineDecorationsWidth, extraEditorClassName };
+	}
+
+	private updateEditorLayoutOptions(editor: ICodeEditor, extraEditorClassName: string[], lineDecorationsWidth: number) {
+		editor.updateOptions({
+			extraEditorClassName: extraEditorClassName.join(' '),
+			lineDecorationsWidth: lineDecorationsWidth
+		});
+	}
+
 	private tryUpdateReservedSpace() {
 		if (!this.editor) {
 			return;
 		}
 
-		let lineDecorationsWidth: number = this.editor.getLayoutInfo().decorationsWidth;
 		const hasCommentsOrRanges = this._commentInfos.some(info => {
 			const hasRanges = Boolean(info.commentingRanges && (Array.isArray(info.commentingRanges) ? info.commentingRanges : info.commentingRanges.ranges).length);
 			return hasRanges || (info.threads.length > 0);
 		});
 
-		if (hasCommentsOrRanges) {
+		if (hasCommentsOrRanges && !this._commentingRangeSpaceReserved) {
 			this._workspaceHasCommenting.set(true);
-			if (!this._commentingRangeSpaceReserved) {
-				this._commentingRangeSpaceReserved = true;
-				let extraEditorClassName: string[] = [];
-				const configuredExtraClassName = this.editor.getRawOptions().extraEditorClassName;
-				if (configuredExtraClassName) {
-					extraEditorClassName = configuredExtraClassName.split(' ');
-				}
-
-				const options = this.editor.getOptions();
-				if (options.get(EditorOption.folding) && options.get(EditorOption.showFoldingControls) !== 'never') {
-					lineDecorationsWidth -= 27;
-				}
-				lineDecorationsWidth += 24;
-				extraEditorClassName.push('inline-comment');
-				this.editor.updateOptions({
-					extraEditorClassName: extraEditorClassName.join(' '),
-					lineDecorationsWidth: lineDecorationsWidth
-				});
-
-				// we only update the lineDecorationsWidth property but keep the width of the whole editor.
-				const originalLayoutInfo = this.editor.getLayoutInfo();
-
-				this.editor.layout({
-					width: originalLayoutInfo.width,
-					height: originalLayoutInfo.height
-				});
-			}
+			this._commentingRangeSpaceReserved = true;
+			const { lineDecorationsWidth, extraEditorClassName } = this.getExistingCommentEditorOptions(this.editor);
+			const newOptions = this.getWithCommentsEditorOptions(this.editor, extraEditorClassName, lineDecorationsWidth);
+			this.updateEditorLayoutOptions(this.editor, newOptions.extraEditorClassName, newOptions.lineDecorationsWidth);
+		} else if (!hasCommentsOrRanges && this._commentingRangeSpaceReserved) {
+			this._commentingRangeSpaceReserved = false;
+			const { lineDecorationsWidth, extraEditorClassName } = this.getExistingCommentEditorOptions(this.editor);
+			const newOptions = this.getWithoutCommentsEditorOptions(this.editor, extraEditorClassName, lineDecorationsWidth);
+			this.updateEditorLayoutOptions(this.editor, newOptions.extraEditorClassName, newOptions.lineDecorationsWidth);
 		}
 	}