What Is Depcheck?
Depcheck was created to detect package builds with broken dependencies. As the test matures, it will eventually be a part of the rel-eng process to prevent broken builds from being pushed to the testing or stable package repositories.
How Does Depcheck Work?
Depcheck uses libsolv to compute package dependencies of proposed updates and evaluates whether these dependencies are satisfied. Always the whole set of builds submitted to a certain repository (fedora, updates or updates-testing) is considered together -- even though Bodhi update should be completely standalone, depcheck will be able to find and resolve dependencies between individual updates, as long as they are submitted together (request to be pushed to the same repository at the same time).
Known deficiencies
At the moment, depcheck only decides whether each of the submitted builds is installable. This is equivalent to trying to install that build into a completely empty environment (no RPM packages pre-installed). If some other package build (that is already present in the target repository) gets broken as a result of this, that's not currently detected by depcheck.
Understanding Failures
Unsatisfied dependencies
Looking at an example log, we see the following excerpt:
not ok - depcheck for Bodhi update openstack-zaqar-2014.2-0.3.b3.fc21 # FAIL
---
arch: i386
details:
output: |-
Build openstack-zaqar-2014.2-0.3.b3.fc21 failed depcheck
nothing provides python-oslo-utils needed by openstack-zaqar-2014.2-0.3.b3.fc21.noarch
nothing provides python-oslo-utils needed by openstack-zaqar-2014.2-0.3.b3.fc21.noarch
item: openstack-zaqar-2014.2-0.3.b3.fc21
outcome: FAILED
summary: openstack-zaqar-2014.2-0.3.b3.fc21 into F21 testing
type: bodhi_update
...
This is a similar message that you should see when trying to install this package using 
dnf
In this case, python-oslo-utils, but at the time the test ran, this was not provided by any available package.
Fixing Failures
Fortunately, the fixes for depcheck errors tend to be relatively straight-forward and tend to fall into one of two categories listed below.
- Problems caused by your package
Examine any changes toProvides,RequiresorBuildRequiresin thespecfile. Ensure correct spelling of all dependencies and confirm that any changed requirements do resolve for the appropriate release. If the dependencies of your package have not changed, it's possible that other packages no longer satisfy the dependencies as expected. Read below for further guidance.
The commandrepoqueryis helpful to track dependencies. - Problems caused by other package(s)
If your package failed because the dependencies of other packages changed (features they were providing changed or were removed), update the requirements of your package or consult with maintainers of the corresponding packages.
Other
Ignored builds
Sometimes, you'll encounter list of "ignored builds" in the report. First of all - do not be alarmed, it is not a wrong state (and we don't mark updates as FAILED if ignored builds occur). The ignored status usually means, that the update was probably changed, and more builds were added, and since we do some 'weird magic' with yum's database of installed packages, these are not recognized as updates, because these were tested in previous runs of Depcheck.
Getting Help
If you still don't understand why your update failed the test, if you think there's something wrong in our test or its documentation or if you have any other suggestions, please contact us.