Created attachment 487415 [details]
temporary patch which fixes the problem

Description of problem:

If you want to rollback to a previous version of some package and that package is no longer in any of enabled/available repositories, yum instead of keeping the current package as it is removes the package.


Version-Release number of selected component (if applicable):

yum-rhn-plugin-0.5.4-17.el5


How reproducible:

Always


Steps to Reproduce:

1. Create a local repository and put there two versions of the same package and install it:

 $ mkdir /tmp/myrepo
 $ cp some_pkg-1.0.rpm some_pkg-1.1.rpm /tmp/myrepo
 $ createrepo /tmp/myrepo

 $ cat > /etc/yum.repos.d/my.repo <<ENDTAG
[myrepo]
name=myrepo
baseurl=file:///tmp/myrepo
enabled=1
gpgcheck=0
ENDTAG

 $ yum install some_pkg-1.0.rpm -y && yum install some_pkg-1.1.rpm -y

2. Remove older package and rebuild the repository:

 $ rm /tmp/myrepo/some_pkg-1.0.rpm
 $ createrepo /tmp/myrepo

3. Rollback to previous snapshot through WebUI which contains some_pkg-1.0.rpm

Systems -> Systems -> [some profile] -> Provisioning -> Snapshots -> [snapshot] -> 'Rollback to Snapshot'

4. Run rhn_check on client

 $ rhn_check


Actual results:

[root@localhost ~]# rpm -qa nxclient
nxclient-3.4.0-7
[root@localhost ~]# rhn_check
[root@localhost ~]# rpm -qa nxclient
[root@localhost ~]#


Expected results:

If yum cannot find older/snapshot package, it should leave the newer/current one as it is and return an error instead.

[root@localhost ~]# rpm -qa nxclient
nxclient-3.4.0-7
[root@localhost ~]# rhn_check
[root@localhost ~]# rpm -qa nxclient
nxclient-3.4.0-7
[root@localhost ~]#


Additional info:

The problem is caused by a missing condition which would check for presence of snapshot package in enabled repositories. The attached temporary patch fixes the problem - it returns an error back to Satellite about missing package required for rollback instead of only performing un-installation action.

The following is output from debugger which shows that package list is empty (because of the missing package in repo), which skips the package addition/installation and finally leads to system without any package:

> /usr/share/rhn/actions/packages.py(249)add_transaction_data()
-> for po in pkgs:
(Pdb) list
244                     # we are doing rollback, we want exact version
245                     # no dependecy check
246                     pkgs = self.pkgSack.searchNevra(name=pkgkeys['name'],
247                          epoch=pkgkeys['epoch'], arch=pkgkeys['arch'],
248                          ver=pkgkeys['version'], rel=pkgkeys['release'])
249  ->                 for po in pkgs:
250                          self.tsInfo.addInstall(po)
(Pdb) p pkgs
[]
(Pdb)

related code:

yum-rhn-plugin-svn-r197503/actions/packages.py:
210     def add_transaction_data(self, transaction_data):
211         """ Add packages to transaction. 
212             transaction_data is in format:
213             { 'packages' : [
214                 [['name', '1.0.0', '1', '', ''], 'e'], ...
215                 # name,    versio, rel., epoch, arch,   flag
216             ]}
217             where flag can be:
218                 i - install
219                 u - update
220                 e - remove
221                 r - rollback
222             Note: install and update will check for dependecies and
223             obsoletes and will install them if needed.
224             Rollback do not check anything and will assume that state
225             to which we are rolling back should be correct.
226         """
227         for pkgtup, action in transaction_data['packages']:
...
243             elif action == 'r':
244                 # we are doing rollback, we want exact version
245                 # no dependecy check
246                 pkgs = self.pkgSack.searchNevra(name=pkgkeys['name'],
247                      epoch=pkgkeys['epoch'], arch=pkgkeys['arch'],
248                      ver=pkgkeys['version'], rel=pkgkeys['release'])
249                 for po in pkgs:
250                      self.tsInfo.addInstall(po)