fix(erlang): respect compile false for precompiled installs

[risu729]

Summary

• make core:erlang treat erlang.compile=false as strict precompiled mode instead of falling back to kerl
• keep the existing fallback to kerl when erlang.compile is unset, and keep compile=true source-only
• add an e2e regression for an unsupported distro (ImageOS=nobara-43) that asserts no build-install fallback happens

Investigation

Discussion #9433 shows Unsupported OS version: nobara-43, followed by kerl build-install. Python and Node already bail when compile=false cannot find a precompiled artifact. Ruby is different and currently documents fallback behavior for ruby.compile=false.

Validation

• cargo fmt --check
• git diff --check
• shellcheck e2e/core/test_erlang_precompiled_strict
• mise run build
• mise run test:e2e e2e/core/test_erlang_precompiled_strict

Discussion: #9433

This PR description was generated by an AI coding assistant.

[gemini-code-assist]

Code Review

This pull request implements stricter enforcement for Erlang precompiled binary usage. It introduces a precompiled_unavailable helper in src/plugins/core/erlang.rs that triggers a failure if erlang.compile is disabled and binaries cannot be found, rather than silently falling back. An E2E test was also added to validate this behavior on unsupported platforms. I have no feedback to provide.

[greptile-apps]

Greptile Summary

This PR introduces a precompiled_unavailable helper in erlang.rs that centralises the "no precompiled binary found" logic: when erlang.compile=false it bails with a clear error instead of silently falling through to kerl build-install, while the default (None) preserves the existing kerl fallback. A new e2e test exercises this path on Linux using ImageOS=nobara-43 to assert that neither installation succeeds nor a kerl fallback occurs.

• src/plugins/core/erlang.rs: All six former debug!+Ok(None) early-returns are replaced by self.precompiled_unavailable(…), which either bails (compile=false) or logs-debug+returns-None (compile=None). The #[cfg(not(any(linux, macos, windows)))] stub is updated to preserve the compile=true→kerl path while bailing for compile=false.
• e2e/core/test_erlang_precompiled_strict: New test file with a Linux guard, an expected-failure if block, and two assertions on the captured output — one confirming the "unsupported OS version" message and one ruling out any build-install invocation.

Confidence Score: 5/5

The change is safe to merge; it only tightens an explicit opt-in (compile=false) while leaving the default kerl fallback untouched.

The core logic change is small and well-scoped: the new precompiled_unavailable helper is called only when a precompiled path would have silently returned None, so existing default behaviour is unchanged. All three platform branches (linux, macos, windows, and the catch-all) are updated consistently. The e2e test directly validates the new bail path with a real unsupported OS value and guards against regression to the kerl fallback.

No files require special attention.

Important Files Changed

Filename	Overview
src/plugins/core/erlang.rs	Adds precompiled_unavailable helper that bails when compile=false, replacing all silent debug!+Ok(None) fallbacks with the new centralised check. Logic is consistent across linux, macos, windows, and other-platform branches.
e2e/core/test_erlang_precompiled_strict	Adds a regression test that exercises the strict-precompiled path on Linux using ImageOS=nobara-43; includes a Linux guard. Two existing open threads from prior review rounds cover set -e interaction and the platform guard (guard is now present).

_{Reviews (3): Last reviewed commit: "test(erlang): match shell test formattin..." | Re-trigger Greptile}