MAJOR from the 2026-04-22 review (model_manager.rs:161-262): reqwest
does not return Err on 4xx/5xx by default. The resume branch
validated 206/200 and errored on anything else, but the non-resume
branch skipped the status check entirely — a 404 or 500 body was
streamed into .part and atomically renamed over the destination as
if it were the model file. For models without a sha256 declared,
this failure mode was silent and catastrophic (the engine would
crash loading an HTML error page as GGML on next launch).
Adds an is_success() check in the non-resume branch: any non-2xx
returns KonError::DownloadFailed with the HTTP status in the
message, and (importantly) we return before File::create so no
.part file is left behind.
Test: spawn_500_server that responds 500 to any request; a fresh
(no .part, no sha256) download must Err with "HTTP 500" and leave
neither .part nor dest on disk.
Jake
93a7165dac