Subject: Re: [bug#50756] [PATCH] gnu: Add lttng-tools.

From: Olivier Dion <[email-masked]>
Date: Fri, 24 Sep 2021 11:13:44 -0400

On Fri, 24 Sep 2021, Xinglu Chen <[email-masked]> wrote:
> On Thu, Sep 23 2021, Olivier Dion via Guix-patches via wrote:

>> +(define-public lttng-tools
>> +  (package
>> +    (name "lttng-tools")
>> +    (version "2.12.5")
>
> Version 2.13 is available; any reason for not using it?

Would require to bump version of lttng-ust also I think.  I prefer to do all of this
in another patch.  

>> +    (arguments
>> +     `(#:tests? #f
>> +       #:parallel-tests? #f
>
> There is no need to set #:parallel-tests? if #:tests? is set to #f.

During my testing, I noticed that test in parallel are not working
because of how the lttng-daemon works.  So I disable the parallel option
in order to not forget it when testing will work in the future.  I
should probably add a comment to explain the rationale here.

>> +    (propagated-inputs
>> +     `(("libkmod" ,kmod)
>> +       ("modprobe" ,module-init-tools)))
>
> Any reason for the labels not being the same as the package?

I follow the naming convention in the description of the project's README
so it's easier to map the dependencies described by it to Guix's
packages.  I can change this, but I find it more clear that way.

>
>> +    (native-inputs
>> +     `(("pkg-config" ,pkg-config)
>> +       ("perl" ,perl)
>> +       ("libpfm4" ,libpfm4)
>> +       ("python" ,python-3)
>
> While running the configure script, I get
>
>   configure: You may configure with --enable-python-bindings if you want Python bindings.
>
> So you would have to pass the ‘--enable-python-bindings’ flag, and
> Python would be needed during runtime as well.

Does it tho?  Bindings can be generated at build time. While you would
require python-3 at runtime to use the bindings, you don't require
python-3 to use the other tools of the project.  I don't mind adding it
to the inputs, I'm just asking.

> Could you send an updated patch?

Will do soon!

-- 
Olivier Dion
Polymtl