patch: --enable-tests and --only-dependencies

[Thomas Tuegel]

On Fri, Feb 17, 2012 at 1:42 AM, Andres Löh <andres at well-typed.com> wrote:
>> These lines control whether a package is actually built with its tests
>> and benchmarks. Although the resolver pulls in benchmark dependencies
>> now, I didn't enable actually building the benchmarks because we
>> wouldn't do anything with the results anyway.
>>
>> Actually, since we won't be running test suites automatically (until
>> the next release of Cabal), they should probably be disabled, too.
>
> I'm still not sure if I understand this. If you enable tests and
> benchmarks, shouldn't they then at least be installed? Whereas if you
> pull in the dependencies, but then don't build them, what did you pull
> in the dependencies for?

The dependencies are pulled in for the case where you do 'cabal
install --enable-benchmarks --only-dependencies' to quickly pull in
all the deps for a project you are developing.

>> I'm working on the patch for Cabal that we need in order to run tests
>> automatically. Hopefully, I'll send it to the list this afternoon.
>> Then, after the cabal-install release, we can turn automatic tests
>> back on.
>
> Got it. Is it actually wise to run tests automatically and fail the
> installation if tests fail? Don't you think there might be users who'd
> like to have the test suites installed, be able to run them in their
> own time, and look closely at the results, even if some of them might
> fail?

Now I understand what you mean. However: tests and benchmarks never
get installed. They never live outside the build directory, so if they
don't get run before install takes place, they'll be deleted with the
build directory. This is why I don't know what we'd do with benchmarks
if we built them: we could run them, but what would we do with the
results?

On the other hand, we can do something with the results of tests:
refuse to install. The only opportunity a user gets to run the test
suites is before install, so if they configured with '--enable-tests',
this is probably what they want.

-- 
Thomas Tuegel