Pulp does not resync yum metadata files on change

[pulpbot]

Author: bherring (bherring)

Redmine Issue: 4824, https://pulp.plan.io/issues/4824

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Pulp uses revision numbers in repomd.xml to determine if contents need to be updated on sync. However "modifyrepo" does not generate new revision numbers for non rpm data.

Steps:
1) Setup the following repo

$ mkdir /tmp/my-data
$ cd /tmp/my-data
$ wget https://partha.fedorapeople.org/test-repos/rpm-with-productid/elephant-0.3-0.8.noarch.rpm
$ createrepo .
$ echo "100000" >> productid
$ modifyrepo  --mdtype=productid productid repodata
$ grep revision repodata/repomd.xml
  <revision>1554217257</revision>

2) Sync this repo
3) Now update the repo

$ cd /tmp/my-data
$ echo "100001" >> productid
$ modifyrepo  --mdtype=productid productid repodata
$ grep revision repodata/repomd.xml
  <revision>1554217257</revision>

Notice that the revision number did not change even though a metadata file got updated. Try resyncing this change and notice that the productid change will get ignored.