Remove leftover branch git config when deleting local branches

src/github/folderRepositoryManager.ts

@@ -2099,6 +2099,20 @@ export class FolderRepositoryManager extends Disposable {
 		const deleteConfig = async (branch: string) => {
 			await PullRequestGitHelper.associateBaseBranchWithBranch(this.repository, branch, undefined);
 			await PullRequestGitHelper.associateBranchWithPullRequest(this.repository, undefined, branch);
+			// Git normally removes the entire [branch "<name>"] section when a branch is deleted, but if the
+			// branch no longer exists the leftover section keeps the branch showing up in this list. Remove any
+			// remaining branch.<name>.* config entries so already-deleted branches don't reappear.
+			if (this.repository.unsetConfig) {
+				const prefix = `branch.${branch}.`;
+				const remaining = (await this.repository.getConfigs()).filter(config => config.key.startsWith(prefix));
+				for (const config of remaining) {
+					try {
+						await this.repository.unsetConfig(config.key);
+					} catch (e) {
+						Logger.error(`Failed to remove leftover git config ${config.key}: ${e}`, this.id);
+					}
+				}
+			}
 		};
 
 		// delete configs first since that can't be parallelized

src/test/github/folderRepositoryManager.test.ts

@@ -30,14 +30,15 @@ describe('PullRequestManager', function () {
 	let manager: FolderRepositoryManager;
 	let telemetry: MockTelemetry;
 	let mockThemeWatcher: MockThemeWatcher;
+	let repository: MockRepository;
 
 	beforeEach(function () {
 		sinon = createSandbox();
 		MockCommandRegistry.install(sinon);
 
 		telemetry = new MockTelemetry();
 		mockThemeWatcher = new MockThemeWatcher();
-		const repository = new MockRepository();
+		repository = new MockRepository();
 		const context = new MockExtensionContext();
 		const credentialStore = new CredentialStore(telemetry, context);
 		const repositoriesManager = new RepositoriesManager(credentialStore, telemetry);
@@ -68,6 +69,38 @@ describe('PullRequestManager', function () {
 			assert.deepStrictEqual(manager.activePullRequest, pr);
 		});
 	});
+
+	describe('deleteBranches', function () {
+		const noopProgress = { report: () => { } };
+
+		it('removes leftover branch config after deleting a branch', async function () {
+			await repository.createBranch('feature', false, 'commit-hash');
+			await repository.setConfig('branch.feature.remote', 'origin');
+			await repository.setConfig('branch.feature.merge', 'refs/heads/feature');
+			await repository.setConfig('branch.feature.github-pr-owner-number', 'owner#repo#1');
+
+			const nonExistant = new Set<string>();
+			await (manager as any).deleteBranches([{ label: 'feature' }], nonExistant, noopProgress, 1, 0, []);
+
+			const configs = await repository.getConfigs();
+			assert.strictEqual(configs.filter(c => c.key.startsWith('branch.feature.')).length, 0);
+			assert.strictEqual(nonExistant.has('feature'), false);
+		});
+
+		it('removes leftover branch config for a branch that no longer exists', async function () {
+			// The branch ref is already gone, but stale [branch "gone"] config remains.
+			await repository.setConfig('branch.gone.remote', 'origin');
+			await repository.setConfig('branch.gone.merge', 'refs/heads/gone');
+			await repository.setConfig('branch.gone.github-pr-owner-number', 'owner#repo#2');
+
+			const nonExistant = new Set<string>();
+			await (manager as any).deleteBranches([{ label: 'gone' }], nonExistant, noopProgress, 1, 0, []);
+
+			const configs = await repository.getConfigs();
+			assert.strictEqual(configs.filter(c => c.key.startsWith('branch.gone.')).length, 0);
+			assert.strictEqual(nonExistant.has('gone'), true);
+		});
+	});
 });
 
 describe('titleAndBodyFrom', function () {

src/test/mocks/mockRepository.ts

@@ -115,6 +115,12 @@ export class MockRepository implements Repository {
 		return oldValue;
 	}
 
+	async unsetConfig(key: string): Promise<string> {
+		const oldValue = this._config.get(key) || '';
+		this._config.delete(key);
+		return oldValue;
+	}
+
 	getObjectDetails(treeish: string, treePath: string): Promise<{ mode: string; object: string; size: number }> {
 		return Promise.reject(new Error(`Unexpected getObjectDetails(${treeish}, ${treePath})`));
 	}
@@ -181,7 +187,9 @@ export class MockRepository implements Repository {
 	async deleteBranch(name: string, force?: boolean | undefined): Promise<void> {
 		const index = this._branches.findIndex(b => b.name === name);
 		if (index === -1) {
-			throw new Error(`Attempt to delete nonexistent branch ${name}`);
+			const error: Error & { stderr?: string } = new Error(`Attempt to delete nonexistent branch ${name}`);
+			error.stderr = `error: branch '${name}' not found.`;
+			throw error;
 		}
 		this._branches.splice(index, 1);
 	}