Throw an error when the input version is not found

[clarafu]

If we can't find a version for an input, we should throw an error while
we construct the plan.

Signed-off-by: Clara Fu cfu@pivotal.io

Contributor Checklist

Are the following items included as part of this PR? Please delete checkbox items that don't apply.

• Unit tests
• Integration tests (if applicable)
• Updated documentation (located at https://github.com/concourse/docs)
• Updated release notes (located at https://github.com/concourse/concourse/tree/master/release-notes)

Reviewer Checklist

This section is intended for the core maintainers only, to track review progress. Please do not
fill out this section.

• Code reviewed
• Tests reviewed
• Documentation reviewed
• Release notes reviewed
• PR acceptance performed
• New config flags added? Ensure that they are added to the BOSH
  and Helm packaging; otherwise, ignored for the integration tests (for example, if they are Garden configs that are not displayed in the --help text).

[vito]

I think this works but I have no way of verifying it as we don't log or emit the error anywhere.

concourse/atc/scheduler/buildstarter.go

Lines 177 to 184 in 232f86e

	plan, err := s.factory.Create(job.Config(), resourceConfigs, resourceTypes, buildInputs)
	if err != nil {
	// Don't use ErrorBuild because it logs a build event, and this build hasn't started
	if err = nextPendingBuild.Finish(db.BuildStatusErrored); err != nil {
	logger.Error("failed-to-mark-build-as-errored", err)
	}
	return false, nil
	}

Can we emit a log and show the error in the UI?

[clarafu]

@vito Could we just log the error without showing it in the UI?

[vito]

@clarafu no

[clarafu]

@vito

[deniseyu]

Going to re-trigger testflight on this, it looks like a Docker flake

[vito]

It would be nice to show it in the UI but this is good enough for now. Seems like showing it in the UI will take more work than expected.