Close outdated multidiff editors when PR is reopened

package.json

@@ -36,6 +36,7 @@
 		"quickDiffProvider",
 		"remoteCodingAgents",
 		"shareProvider",
+		"tabInputMultiDiff",
 		"tokenInformation",
 		"treeItemMarkdownLabel",
 		"treeViewMarkdownMessage"

src/@types/vscode.proposed.tabInputMultiDiff.d.ts

@@ -0,0 +1,22 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+// https://github.com/microsoft/vscode/issues/206411
+
+declare module 'vscode' {
+
+	export class TabInputTextMultiDiff {
+
+		readonly textDiffs: TabInputTextDiff[];
+
+		constructor(textDiffs: TabInputTextDiff[]);
+	}
+
+	export interface Tab {
+
+		readonly input: TabInputText | TabInputTextDiff | TabInputTextMultiDiff | TabInputCustom | TabInputWebview | TabInputNotebook | TabInputNotebookDiff | TabInputTerminal | unknown;
+
+	}
+}

src/view/reviewManager.ts

@@ -675,7 +675,46 @@ export class ReviewManager extends Disposable {
 		}
 	}
 
+	private isKnownTabInputType(tabInput: unknown): boolean {
+		// Note: This list includes all known TabInput types as of VS Code 1.107.0
+		// If new TabInput types are added to the VS Code API, this list will need to be updated
+		return (
+			tabInput instanceof vscode.TabInputText ||
+			tabInput instanceof vscode.TabInputTextDiff ||
+			tabInput instanceof vscode.TabInputCustom ||
+			tabInput instanceof vscode.TabInputWebview ||
+			tabInput instanceof vscode.TabInputNotebook ||
+			tabInput instanceof vscode.TabInputNotebookDiff ||
+			tabInput instanceof vscode.TabInputTerminal
+		);
+	}
+
+	private async _closeOutdatedMultiDiffEditors(pullRequest: PullRequestModel): Promise<void> {
+		// Close any multidiff editors for this PR that may be outdated
+		// Since TabInputMultiDiff is not yet available in the VS Code API (https://github.com/microsoft/vscode/issues/206411),
+		// we identify multidiff editors by their label pattern
+		// Note: This label matching is dependent on the exact localized string format from PullRequestModel.openChanges()
+		// If that format changes, this matching logic will need to be updated as well
+		const multiDiffLabel = vscode.l10n.t('Changes in Pull Request #{0}', pullRequest.number);
+
+		const closePromises: Promise<boolean>[] = [];
+		for (const tabGroup of vscode.window.tabGroups.all) {
+			for (const tab of tabGroup.tabs) {
+				// Multidiff editors have a specific label pattern and the input type is unknown
+				// since TabInputMultiDiff doesn't exist yet
+				if (tab.label === multiDiffLabel && !this.isKnownTabInputType(tab.input)) {
+					Logger.appendLine(`Closing outdated multidiff editor for PR #${pullRequest.number}`, this.id);
+					closePromises.push(Promise.resolve(vscode.window.tabGroups.close(tab)));
+				}
+			}
+		}
+		await Promise.all(closePromises);
+	}
+
 	public async _upgradePullRequestEditors(pullRequest: PullRequestModel) {
+		// Close any outdated multidiff editors first
+		await this._closeOutdatedMultiDiffEditors(pullRequest);
+
 		// Go through all open editors and find pr scheme editors that belong to the active pull request.
 		// Close the editors, and reopen them from the pull request.
 		const reopenFilenames: Set<[PRUriParams, PRUriParams]> = new Set();