fix: guard SelectInput callbacks against undefined and replace unsafe as-casts (#303)

* fix: guard Menu/Dashboard SelectInput callbacks against undefined

ink-select-input can invoke onSelect/onHighlight with undefined when
the items list is empty (e.g. immediately after returning from a
session), causing a crash on item.value access.

Replace the item as MenuItem cast — which hid the undefined at compile
time — with an items.find() lookup. Both callbacks now return early
when the raw argument is falsy or when no matching item is found,
making the undefined case and type safety explicit.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix: replace unsafe as-casts with type-safe alternatives

Audit all as-casts in src/ and replace each with a safe alternative:

- ConfigureCommand: narrow handler signatures from {value: string} to
  {value: StateDetectionStrategy}; cast drops away
- ConfigureMerge: introduce MenuItemValue union type; TypeScript narrows
  to EditField after 'separator'/'back' guards
- useGitStatus: remove redundant failure.value as GitError — Cause.failureOption
  already returns Option<GitError>
- autoApprovalVerifier: error as Error → instanceof guard with fallback
- projectManager (×3): as NodeJS.ErrnoException/Error → typeof object +
  'code' in error narrowing (handles both real Errors and plain objects)
- sessionManager (×2): (error as Error)?.message → instanceof guard

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: kbwo

bun.lock

@@ -284,12 +284,15 @@ const ConfigureCommand: React.FC<ConfigureCommandProps> = ({onComplete}) => {
 		}
 	};
 
-	const handleStrategySelect = (item: {label: string; value: string}) => {
+	const handleStrategySelect = (item: {
+		label: string;
+		value: StateDetectionStrategy;
+	}) => {
 		const preset = presets.find(p => p.id === selectedPresetId);
 		if (!preset) return;
 
 		const updatedPreset = {...preset};
-		updatedPreset.detectionStrategy = item.value as StateDetectionStrategy;
+		updatedPreset.detectionStrategy = item.value;
 
 		const updatedPresets = presets.map(p =>
 			p.id === preset.id ? updatedPreset : p,
@@ -300,8 +303,11 @@ const ConfigureCommand: React.FC<ConfigureCommandProps> = ({onComplete}) => {
 		setIsSelectingStrategy(false);
 	};
 
-	const handleAddStrategySelect = (item: {label: string; value: string}) => {
-		const strategy = item.value as StateDetectionStrategy;
+	const handleAddStrategySelect = (item: {
+		label: string;
+		value: StateDetectionStrategy;
+	}) => {
+		const strategy = item.value;
 		const defaultCommand = DEFAULT_COMMANDS[strategy];
 
 		setNewPreset({

src/components/ConfigureCommand.tsx

@@ -11,6 +11,7 @@ interface ConfigureMergeProps {
 }
 
 type EditField = 'mergeArgs' | 'rebaseArgs';
+type MenuItemValue = EditField | 'separator' | 'back';
 
 const DEFAULT_MERGE_ARGS = ['--no-ff'];
 const DEFAULT_REBASE_ARGS: string[] = [];
@@ -33,7 +34,7 @@ const ConfigureMerge: React.FC<ConfigureMergeProps> = ({onComplete}) => {
 	const formatArgs = (args: string[]) =>
 		args.length > 0 ? args.join(' ') : '(none)';
 
-	const menuItems = [
+	const menuItems: Array<{label: string; value: MenuItemValue}> = [
 		{
 			label: `Merge Arguments: ${formatArgs(getMergeArgs())}`,
 			value: 'mergeArgs',
@@ -46,16 +47,15 @@ const ConfigureMerge: React.FC<ConfigureMergeProps> = ({onComplete}) => {
 		{label: '<- Back', value: 'back'},
 	];
 
-	const handleSelect = (item: {label: string; value: string}) => {
+	const handleSelect = (item: {label: string; value: MenuItemValue}) => {
 		if (item.value === 'separator') return;
 		if (item.value === 'back') {
 			onComplete();
 			return;
 		}
 
-		const field = item.value as EditField;
-		setEditField(field);
-		switch (field) {
+		setEditField(item.value);
+		switch (item.value) {
 			case 'mergeArgs':
 				setInputValue(getMergeArgs().join(' '));
 				break;

src/components/ConfigureMerge.tsx

@@ -654,7 +654,11 @@ const Dashboard: React.FC<DashboardProps> = ({
 				>
 					<SelectInput
 						items={items}
-						onSelect={item => handleSelect(item as DashboardItem)}
+						onSelect={raw => {
+							const item = items.find(i => i.value === raw?.value);
+							if (!item) return;
+							handleSelect(item);
+						}}
 						isFocused={!displayError}
 						limit={limit}
 						initialIndex={selectedIndex}

src/components/Dashboard.tsx

@@ -580,17 +580,17 @@ const Menu: React.FC<MenuProps> = ({
 			>
 				<SelectInput
 					items={items}
-					onSelect={item => handleSelect(item as MenuItem)}
-					onHighlight={item => {
-						// ink-select-input may call onHighlight with undefined when items are empty
-						// (e.g., during menu re-mount after returning from a session), so guard it.
-						if (!item) {
-							return;
-						}
-						const menuItem = item as MenuItem;
-						if (menuItem.type === 'worktree') {
-							setHighlightedWorktreePath(menuItem.worktree.path);
-							setHighlightedSession(menuItem.session);
+					onSelect={raw => {
+						const item = items.find(i => i.value === raw?.value);
+						if (!item) return;
+						handleSelect(item);
+					}}
+					onHighlight={raw => {
+						const item = items.find(i => i.value === raw?.value);
+						if (!item) return;
+						if (item.type === 'worktree') {
+							setHighlightedWorktreePath(item.worktree.path);
+							setHighlightedSession(item.session);
 						}
 					}}
 					isFocused={!error}

src/components/Menu.tsx

@@ -128,7 +128,7 @@ function handleStatusExit(
 	} else if (Exit.isFailure(statusExit)) {
 		const failure = Cause.failureOption(statusExit.cause);
 		if (Option.isSome(failure)) {
-			const gitError = failure.value as GitError;
+			const gitError = failure.value;
 			update.gitStatus = undefined;
 			update.gitStatusError = formatGitError(gitError);
 			hasUpdate = true;

src/hooks/useGitStatus.ts

@@ -688,7 +688,8 @@ export class AutoApprovalVerifier {
 
 				return JSON.parse(responseText) as AutoApprovalResponse;
 			},
-			catch: (error: unknown) => error as Error,
+			catch: (error: unknown) =>
+				error instanceof Error ? error : new Error(String(error)),
 		});
 
 		return Effect.catchAll(attemptVerification, (error: Error) => {

src/services/autoApprovalVerifier.ts

@@ -254,7 +254,14 @@ export class ProjectManager implements IProjectManager {
 				);
 			} catch (error) {
 				// Silently skip directories we can't read
-				if ((error as NodeJS.ErrnoException).code !== 'EACCES') {
+				if (
+					!(
+						typeof error === 'object' &&
+						error !== null &&
+						'code' in error &&
+						error.code === 'EACCES'
+					)
+				) {
 					console.error(`Error scanning directory ${dir}:`, error);
 				}
 			}
@@ -351,7 +358,7 @@ export class ProjectManager implements IProjectManager {
 				return null;
 			}
 		} catch (error) {
-			result.error = `Failed to process: ${(error as Error).message}`;
+			result.error = `Failed to process: ${error instanceof Error ? error.message : String(error)}`;
 		}
 
 		return result;
@@ -470,11 +477,14 @@ export class ProjectManager implements IProjectManager {
 					return error;
 				}
 
-				const nodeError = error as NodeJS.ErrnoException;
-				const cause =
-					nodeError.code === 'ENOENT'
-						? `Projects directory does not exist: ${projectsDir}`
-						: String(error);
+				const isEnoent =
+					typeof error === 'object' &&
+					error !== null &&
+					'code' in error &&
+					error.code === 'ENOENT';
+				const cause = isEnoent
+					? `Projects directory does not exist: ${projectsDir}`
+					: String(error);
 
 				return new FileSystemError({
 					operation: 'read',

src/services/projectManager.ts

@@ -214,7 +214,7 @@ export class SessionManager extends EventEmitter implements ISessionManager {
 			.catch(async (error: unknown) => {
 				if (abortController.signal.aborted) {
 					logger.debug(
-						`[${session.id}] Auto-approval verification aborted (${(error as Error)?.message ?? 'aborted'})`,
+						`[${session.id}] Auto-approval verification aborted (${error instanceof Error ? error.message : 'aborted'})`,
 					);
 					return;
 				}
@@ -230,8 +230,9 @@ export class SessionManager extends EventEmitter implements ISessionManager {
 					await this.updateSessionState(session, 'waiting_input', {
 						autoApprovalFailed: true,
 						autoApprovalReason:
-							(error as Error | undefined)?.message ??
-							'Auto-approval verification failed',
+							error instanceof Error
+								? error.message
+								: 'Auto-approval verification failed',
 					});
 				}
 			})