tree 049246b202c90d5058dc8830255ab34d8a2042bf
parent 390754ab67d921db43e77e545a6c7f644ffe6733
author Zane Bitter <zbitter@redhat.com> 1499968767 -0400
committer Zane Bitter <zbitter@redhat.com> 1499972870 -0400

Don't load new copies of current resources

The Stack._find_filtered_resources() method returns Resource objects for
all resources associated with the Stack, regardless of whether they are
current (present in the template; latest version in the case of
convergence). To do this, it previously created a new Resource object
for every resource found in the database.

However, for those resources which *are* current this is unnecessary. We
can access the Resource object simply through self.resources. It turns
out this is necessary for obtaining the required_by list for legacy
stacks, because only the Resources obtained from self.resources also
appear in the Dependencies graph obtained from self.dependencies. The
required_by list is read when listing or showing resources, which would
either return an empty list or fail for legacy stacks.

This patch also makes the Resource.required_by() method more robust in
its error handling.

Change-Id: Id438336e5c88dc7c2d168ba01ee703faa17e8b8e
Closes-Bug: #1703703
Related-Bug: #1523748