fix(postbuildstepper): only create PR#channel for configured source branches

[steveej]

previously it would create a channel for every PR

cc @alastairong1

[steveej]

6fe021d introduces the test to expose the bug

this repo isn't configured to run the cargo tests yet. here's the result from the local run:

running 1 test
test business::tests::test_process_holo_nixpkgs_release ... FAILED

failures:

---- business::tests::test_process_holo_nixpkgs_release stdout ----
thread 'business::tests::test_process_holo_nixpkgs_release' panicked at applications/postbuildstepper/src/lib.rs:708:17:
assertion `left == right` failed
  left: Some(["1"])
 right: None
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    business::tests::test_process_holo_nixpkgs_release

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s

error: test failed, to rerun pass `--lib`

the integration test did fail on CI

Test "ensure there's channel artifact after the PR" failed with error: "command grep '2410 2410' /tmp/hydra-compat/channels/2410/holo-nixpkgs/nixexprs.tar.xz unexpectedly succeeded"

---

f5f9c46 introduces the bugfix

[JettTech]

Looks great! Good catch ..and nice test addition. :) I just left one question/optional suggestion. This is good to merge either way.

[JettTech]

Should we add some kind of log or notification hook for whenever this occurs?

[steveej]

there's a debug! one that prints this further up.
and the call to create_channel_artifacts has info! level messages for artifacts that are actually created.

do you think that's sufficient?

[JettTech]

I saw the debug a bit earlier, which could be fine for now... but depending on how long we need to support the legacy channels, it might be nice to have some other mechanism that notifies us more directly or loudly than developer logs, such as push messages, or emails via a monitoring tool like Grafana or Sentry or even a mm plugin, etc.

[steveej]

it might be nice to have some other mechanism that notifies us more directly or loudly than developer logs, such as push messages, or emails via a monitoring tool like Grafana or Sentry or even a mm plugin, etc.

agreed, however out of scope for this bugfix PR.