Problem

PR #8 added two decorations on top of the URL fix:

1. `curl -sSLf` (fail on HTTP errors)
2. `file /usr/local/bin/anvil | grep -q ‘ELF’ || exit 1` (post-download sanity check)

Neither does what I claimed:

1. `-f` is useless against the actual failure mode. The broken `/cli/download` URL responds `302 Location: /` with a `phoenix_flash=Not found.` cookie. `-L` follows the redirect to a 200 (login page). `-f` only trips on direct 4xx/5xx. The HTML still lands on disk.

2. `file` is not in the CI base image. `hexpm/elixir:1.18.4-erlang-28.0.2-debian-bookworm-20250811` doesn’t include it, and the release step’s apt install line only adds `git jq curl`. With `file` missing, the pipe produces empty stdout, `grep -q ELF` exits 1, and the `||` branch fires with an incorrect message — the download was probably fine, I just can’t tell.

Observed on pipeline `27af6331f1` against main commit `42afe6a` (PR #8’s squash merge):

/bin/sh: 25: file: not found
anvil download is not an ELF binary

My earlier local dry-run added `file` to the apt install list in the test harness, which is why it passed locally. That was a test-harness cheat that let a broken fix through.

Fix

Drop both decorations. The only thing that fixes anything is the URL change (which landed in PR #8 and is preserved here). The minimal working script is:

```yaml curl -sL "https://anvil.fangorn.io/runner/download?os=\$(uname -s)&arch=$(uname -m)" -o /usr/local/bin/anvil chmod +x /usr/local/bin/anvil ```

Proof on the actual runner (carl)

Verified directly on carl — the same aarch64 Raspberry Pi that executes ex_git_objectstore CI jobs:

curl -sL \"https://anvil.fangorn.io/runner/download?os=Linux&arch=aarch64\" -o anvil
chmod +x anvil

Result:

• 8,705,904 bytes downloaded
• First 4 bytes: `177 E L F` (the ELF magic)
• `./anvil –version` → `anvil 2026.04.3`
• `./anvil release create –help` → shows `–tag`, `–title`, `–body`, `–repo` — matches exactly what the release script passes

No `file(1)` required. No `-f` flag. Just the URL.

Diff

-      # Install anvil CLI. The /runner/download endpoint serves the real
-      # binary (anvil and anvil-runner are a single binary per the April
-      # 2026 unification). /cli/download returns an HTML error page on
-      # this server, which previously got written to /usr/local/bin/anvil
-      # and crashed with \`Syntax error: newline unexpected\` at runtime.
-      # Fail loud if curl ever stops returning an ELF binary.
-      curl -sSLf \"https://anvil.fangorn.io/runner/download?...\" -o /usr/local/bin/anvil
+      # Install anvil CLI. /runner/download serves the unified
+      # anvil/anvil-runner binary (fangorn/anvil#49 merged the two).
+      curl -sL \"https://anvil.fangorn.io/runner/download?...\" -o /usr/local/bin/anvil
       chmod +x /usr/local/bin/anvil
-      file /usr/local/bin/anvil | grep -q 'ELF' || { echo \"anvil download is not an ELF binary\"; head -5 /usr/local/bin/anvil; exit 1; }

Net: 3 insertions, 8 deletions. The only functional change from current main is removing the `file` check.

🤖 Generated with Claude Code