[[!comment format=mdwn
 username="joey"
 subject="""comment 10"""
 date="2015-12-03T15:05:21Z"
 content="""

	trivial (trivial p `changesFile` f) `changesFile` f'

The parenthesized property here is all marked trivial, so a change to f
won't result in MadeChange, though a change to f' will.

The only way propellor might intercept the output of a program is if you're
using the new Concurrent module. In that case it should buffer program output
and display it all at once. There could potentially be a bug there that
hid program output. I certianly can't reproduce changesFile hiding the output
of a program:

	*Propellor.Property.Apt> runPropellor (Host "localhost" [] mempty) $ ensureProperty $ trivial (buildDep ["git-annex"]) `changesFile` "/var/lib/dpkg/status"
	Reading package lists... Done
	Building dependency tree       
	Reading state information... Done
	0 upgraded, 0 newly installed, 0 to remove and 707 not upgraded.
	NoChange

	*Propellor.Property.Apt Propellor.Property.Concurrent> withConcurrentOutput $ runPropellor (Host "localhost" [] mempty) $ ensureProperty $ (trivial (buildDep ["git-annex"]) `changesFile` "/var/lib/dpkg/status") `concurrently` cmdProperty "echo" ["hi"]
	hi
	Reading package lists...
	Building dependency tree...
	Reading state information...
	0 upgraded, 0 newly installed, 0 to remove and 707 not upgraded.
	MadeChange
"""]]
