denoland/deno · error · AnyError

Unsupported platform for PR builds

Error message

Unsupported platform for PR builds: {}

What it means

When installing Deno from a PR or branch (`deno upgrade --pr` / branch flow), Deno maps the current Rust target triple to a CI artifact name. Only linux/macOS/windows on x86_64/aarch64 are recognized; anything else falls through to this bail. The artifact name is used to find the GitHub Actions build to download.

Solutions

1. Run the upgrade on one of the supported platforms: linux or macOS (x86_64/aarch64), or windows x86_64/aarch64.
2. If you are on an unsupported platform, download and build from source for that target instead of using PR artifacts.
3. Check what target your environment reports (e.g. `rustc -vV` / `deno -V` build info) and rule out a misdetected triple.
4. For linux non-x86_64, note PR release artifacts are typically only published for linux-x86_64; use the debug artifact or build locally.

case "$(uname -s)/$(uname -m)" in
  Linux/x86_64|Linux/aarch64|Darwin/x86_64|Darwin/arm64|MINGW*/x86_64) echo ok ;;
  *) echo "unsupported for PR artifacts; build from source"; exit 1 ;;
esac

When it happens

Trigger: Running `deno upgrade --pr <n>` (or the branch equivalent) on a host whose target triple matches none of the six supported combinations, e.g. linux riscv64, windows arm32, or an unusual/renamed triple string that does not contain the expected os/arch substrings checked in get_pr_artifact_name.

Common situations: Building/running Deno on niche architectures or musl variants that report unexpected triples; cross-compilation environments where the detected target differs from the real host; CI containers with custom toolchain targets.

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

• Could not find a " " artifact for PR # . Available…
• Downloaded artifact does not contain
• Could not find a " " artifact for branch ' '. Artifacts may…
• Downloaded artifact does not contain
• Failed to find PR #

AI-assisted analysis of denoland/deno@9ad36f7a2c (2026-08-20). Data as JSON: /api/errors/d1617388df7065d8. Report an issue: GitHub.

Appendix: source

Thrown at cli/tools/upgrade.rs:597

/// Get the artifact name for the current platform.
/// CI artifacts are named like `{profile}-{os}-{arch}-deno`.
fn get_pr_artifact_name() -> Result<String, AnyError> {
  let target = env!("TARGET");

  let (os, arch) = if target.contains("linux") && target.contains("x86_64") {
    ("linux", "x86_64")
  } else if target.contains("linux") && target.contains("aarch64") {
    ("linux", "aarch64")
  } else if target.contains("apple") && target.contains("x86_64") {
    ("macos", "x86_64")
  } else if target.contains("apple") && target.contains("aarch64") {
    ("macos", "aarch64")
  } else if target.contains("windows") && target.contains("x86_64") {
    ("windows", "x86_64")
  } else if target.contains("windows") && target.contains("aarch64") {
    ("windows", "aarch64")
  } else {
    bail!("Unsupported platform for PR builds: {}", target)
  };

  // Prefer release builds, fall back to debug
  Ok(format!("release-{os}-{arch}-deno"))
}

fn get_pr_debug_artifact_name() -> Result<String, AnyError> {
  let release_name = get_pr_artifact_name()?;
  Ok(release_name.replacen("release-", "debug-", 1))
}

fn upgrade_from_pr(
  pr_number: u64,
  upgrade_flags: &UpgradeFlags,
) -> Result<(), AnyError> {
  // Check that `gh` CLI is available
  let gh_version = Command::new("gh").arg("--version").output();
  if gh_version.is_err() {

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