can1357/oh-my-pi · error · Error

No isolation backend is available.

Error message

No isolation backend is available.

What it means

ensureIsolation tries each available isolation backend (e.g. git worktree, fallbacks) in order; each failure's message is recorded as fallbackReason. If every backend fails — or none is compiled/available — it throws with the last failure reason, or the generic message when no reason was captured.

Source

Thrown at packages/coding-agent/src/task/worktree.ts:545

			// frozen repo that still borrows the source object DB via alternates.
			await vcs.detachGitDir(mergedDir, sourceCommonDir);
			return {
				mergedDir,
				backend: candidate,
				fellBack: candidate !== resolution.kind || resolution.fellBack,
				fallbackReason,
			};
		} catch (err) {
			await fs.rm(baseDir, { recursive: true, force: true });
			const message = errorMessage(err);
			if (!natives.isoIsUnavailableError(message)) {
				throw err;
			}
			fallbackReason ??= message;
		}
	}

	throw new Error(fallbackReason ?? "No isolation backend is available.");
}

/** Tear down a handle returned by {@link ensureIsolation}. */
export async function cleanupIsolation(handle: IsolationHandle): Promise<void> {
	try {
		try {
			await natives.isoStop(handle.backend, handle.mergedDir);
		} catch (err) {
			logger.warn("isolation backend stop failed during cleanup", {
				backend: handle.backend,
				mergedDir: handle.mergedDir,
				error: err instanceof Error ? err.message : String(err),
			});
		}
	} finally {
		// baseDir is the parent of the merged directory
		const baseDir = path.dirname(handle.mergedDir);
		await fs.rm(baseDir, { recursive: true, force: true });

View on GitHub (pinned to 9690622007)

Solutions

1. Ensure the workspace is a valid Git repository so the worktree backend is available
2. Read any preceding log/fallback messages for the underlying per-backend failure
3. Disable isolation via `task.isolation.mode: none` if isolation is not required

Example fix

// before: subagent task in non-git dir
$ omp  // -> No isolation backend is available.
// after
$ git init && omp

// check a worktree-capable git repo exists before requesting isolation
const root = await getRepoRoot(cwd); // throws early with a specific reason if not

let handle: IsolationHandle | null = null;
try {
	handle = await ensureIsolation(opts);
} catch (err) {
	logger.warn("Isolation unavailable, running in-place", { reason: (err as Error).message });
	return runInPlace(opts);
}

When it happens

Trigger: Calling ensureIsolation (directly or via runIsolatedSubprocess/handle) when no backend attempt succeeded and fallbackReason was never set — i.e. zero backends were available to try in the current environment.

Common situations: Running in a workspace with no Git repo and no other isolation backend; stripped-down builds or environments where backend detection finds nothing; all backends failed with errors that were rethrown rather than recorded.

Related errors

• Isolated subagent execution could not be prepared: ${message
• not a repository: {path}
• reference not found: {name}
• object not found: {spec}
• cherry-pick of {sha} is empty

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/a4ba82ede1514534. Report an issue: GitHub.