If you try to run download-logs on a build with no task id, you get an ugly error

$ koji download-logs --nvr     sway-rolling-3620220126153915.eef18be9
2022-01-27 15:56:55,581 [ERROR] koji: AssertionError: {'build_id': 1908800, 'cg_id': 2, 
# -snip lots of buildinfo data-
 'volume_name': 'DEFAULT', 'cg_name': 'module-build-service'}

The command includes the line assert binfo['task_id'], binfo. At one point it was fairly unusual for builds to not have a task, but now it is fairly common.

This command should at the very least give a sensible error, like "cannot determine task for this build".

otoh, going a step further, it would be even better if this command could download logs for such builds. The hub offers the getBuildLogs call, and it should be possible to construct those urls and download them. The buildinfo web page presents the build logs as reported by this call.