Invalid platform format '{}'. Expected 'os-arch' or 'os-arch

Error message

Invalid platform format '{}'. Expected 'os-arch' or 'os-arch-qualifier'

What it means

Platform strings must follow os-arch[-qualifier]; Platform::parse splits on '-' and bails when fewer than two parts exist — in practice, when the string contains no hyphen at all (split never yields zero parts; an empty string yields one). The string reaches parse via `mise lock -p/--platform` or the `lockfile_platforms` setting, both of which parse and then validate each entry.

Source

Thrown at src/platform.rs:20

use eyre::{Result, bail};
use std::{collections::BTreeMap, fmt};

/// Represents a target platform for lockfile operations
#[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub(crate) struct Platform {
    pub os: String,
    pub arch: String,
    pub qualifier: Option<String>,
}

impl Platform {
    /// Parse a platform string in the format "os-arch" or "os-arch-qualifier"
    /// Qualifier may contain hyphens (e.g., "musl-baseline")
    pub(crate) fn parse(platform_str: &str) -> Result<Self> {
        let parts: Vec<&str> = platform_str.split('-').collect();

        match parts.len() {
            0 | 1 => bail!(
                "Invalid platform format '{}'. Expected 'os-arch' or 'os-arch-qualifier'",
                platform_str
            ),
            2 => Ok(Platform {
                os: parts[0].to_string(),
                arch: parts[1].to_string(),
                qualifier: None,
            }),
            _ => {
                // Join remaining parts as qualifier (handles compound qualifiers like "musl-baseline")
                let qualifier = parts[2..].join("-");
                Ok(Platform {
                    os: parts[0].to_string(),
                    arch: parts[1].to_string(),
                    qualifier: Some(qualifier),
                })
            }
        }

View on GitHub (pinned to 6f52dcdf99)

Solutions

Write the full os-arch pair: linux-x64, linux-arm64, macos-arm64, windows-x64.
Add a qualifier only when needed: linux-x64-musl or linux-x64-musl-baseline.
Check the effective list with `mise settings` to find the offending entry.

Example fix

# before — mise.toml
[settings]
lockfile_platforms = ["linux", "macos"]

# after
[settings]
lockfile_platforms = ["linux-x64", "macos-arm64"]

Defensive patterns

Strategy: validation

Validate before calling

# Reject platform strings without the os-arch shape before invoking mise
for p in "${PLATFORMS[@]}"; do
  [[ "$p" =~ ^[a-z0-9]+-[a-z0-9]+(-[a-z0-9-]+)?$ ]] || { echo "bad platform: $p"; exit 2; }
done
mise lock -p "${PLATFORMS[@]}"

Type guard

fn has_os_arch_shape(s: &str) -> bool {
    s.split('-').count() >= 2
}

Prevention

Always specify the full os-arch pair; never a bare OS or arch.
Keep the platform list in one shared config snippet that CI validates.
Copy platform strings from mise's own defaults rather than composing them by hand.

When it happens

Trigger: `mise lock -p linux`, `mise lock -p x64`, `lockfile_platforms = ["linux"]`, or an accidental "" entry in the settings list — any value lacking the os-arch hyphen structure.

Common situations: Assuming a bare OS or arch is sufficient; pasting Go/Rust target fragments like "x86_64" that are a single token; config edits leaving empty strings behind.

Related errors

AI-assisted analysis of jdx/mise@6f52dcdf99 (2026-08-22). Data as JSON: /api/errors/a21e6800b5b3cd41. Report an issue: GitHub.