jdx/mise · error

GitHub relay requires a POSIX target

Error message

GitHub relay requires a POSIX target: {}

What it means

The GitHub relay session implementation (`github_relay::unix::session`) only exists on Unix (POSIX) targets, using Unix domain sockets. On non-Unix builds mise refuses to create the relay and reports the socket path that would have been used.

Solutions

1. Run this command on Linux or macOS where Unix domain sockets are supported.
2. Use WSL on Windows to get a POSIX environment for the relay.
3. Fall back to plain `mise ssh` without --relay-session.

Example fix

// before (Windows cmd)
mise ssh --relay-session \\.\pipe\relay host
// after (WSL)
wsl
mise ssh --relay-session /tmp/relay.sock host

if (process.platform === 'win32' && args.includes('--relay-session')) { throw new Error('--relay-session requires POSIX; use WSL or plain ssh'); }

const isPosix = (p) => p === 'linux' || p === 'darwin' || p !== 'win32' && p !== 'win32';
const posixOk = (p) => ['linux','darwin','freebsd','openbsd'].includes(p);

try { await run('mise ssh --relay-session ...') } catch (e) { if (String(e).includes('requires a POSIX target')) { /* fall back to plain ssh */ } }

When it happens

Trigger: Compiling/running a non-`unix` target (e.g. Windows) of mise and invoking `mise ssh --relay-session <socket>`.

Common situations: Running the relay feature from Windows or another non-POSIX platform; running a Windows-built mise binary where Unix socket support is unavailable.

Understand the failure class

Background: "unsupported platform" / "not supported on this platform" errors: what they mean and how to fix them — this error's family across 47 libraries.

Related errors

• cannot nest relay sessions
• GitHub relay requires Linux or macOS
• a repository preview directory requires a dry run
• brew import is not supported on windows
• cannot set up from a setup repository

AI-assisted analysis of jdx/mise@533346cc37 (2026-09-17). Data as JSON: /api/errors/3a2c7022b2f1e0c9. Report an issue: GitHub.

Appendix: source

Thrown at src/cli/ssh.rs:171

        )?;
        if let Some(socket) = self.relay_session {
            if scope.is_some() {
                bail!("cannot nest relay sessions");
            }
            #[cfg(unix)]
            {
                crate::ui::ctrlc::exit_on_ctrl_c(false);
                let mut command = self.command;
                if let Some(first) = self.destination {
                    command.insert(0, first);
                }
                return crate::system::remote::interruptible(crate::github_relay::unix::session(
                    &socket, command,
                ))
                .await;
            }
            #[cfg(not(unix))]
            bail!("GitHub relay requires a POSIX target: {}", socket.display());
        }
        let destination = self
            .destination
            .ok_or_else(|| eyre::eyre!("an SSH destination is required"))?;
        if let Some(scope) = scope {
            #[cfg(unix)]
            {
                let mut host = crate::system::remote::ad_hoc_host(
                    &destination,
                    std::env::current_dir()?,
                    &[],
                )?;
                host.port = self.port;
                host.identity_file = self.identity_file;
                host.ssh_options = self.ssh_option;
                return crate::system::remote::ssh(&host, scope, &self.command).await;
            }
            #[cfg(not(unix))]

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