Discussion: Hadrian's defaults

Phyx lonetiger at gmail.com
Tue Mar 19 06:47:36 UTC 2019

Agreed, I was also an opponent of -c as the default, and as you pointed out
it only works for the case where the default is used. But even if the
defaults are used it is still harmful to do it automatically as the user's
environment could have changed resulting in different configure output if
you automatically rerun it.

Not only isn't there a sane UX for this, there isn't even a safe way to do

Sent from my Mobile

On Fri, Mar 15, 2019, 16:51 Alp Mestanogullari <alp at well-typed.com> wrote:

> I have to admit I sympathize with Moritz's view. Since `-c` only
> "subsumes" the case where we call 'configure' with no extra env var or
> argument, and in the absence of a generic way to pass options to
> 'configure' when using -c, I'd quite like to keep -c as a "cherry on top",
> for users who just need to boot and configure with the default arguments
> and for whom hadrian provides a way to save a few keystrokes. Just like
> Moritz, I'm not even sure it would make all that much sense to provide a
> way to pass configure arguments through hadrian, I have a hard time seeing
> a better UX than just running configure with the extra arguments directly
> and _then_ calling hadrian to start the build.
> On 15/03/2019 14:35, Moritz Angermann wrote:
> Hi Arnaud,
> On Mar 15, 2019, at 8:32 PM, Spiwack, Arnaud <arnaud.spiwack at tweag.io> <arnaud.spiwack at tweag.io> wrote:
> On Thu, Mar 14, 2019 at 7:20 PM Herbert Valerio Riedel <hvriedel at gmail.com> <hvriedel at gmail.com> wrote:
> I don't have the ticket number at my fingertips but it should be fairly easy to find.
> I'm afraid it doesn't appear to be. Could you share your arguments in this thread?
> This was the last one that lead to the current `-c` state:
> - https://github.com/snowleopard/hadrian/issues/457
> There is also
> - https://github.com/snowleopard/hadrian/issues/655
> if you look through the issues on snowleopard/hadrian and sort by comment frequency
> you'll likely find quite a lot of further discussion about not making configure and
> boot the default.
> On Fri, Mar 15, 2019 at 3:10 AM Moritz Angermann <moritz.angermann at gmail.com> <moritz.angermann at gmail.com> wrote:
> It's magically conflating two different phases with `-c`. The configure phase and
> the build phase. Making this the default means it's always magic. I don't like magic!
> Unfortunately, I really don't understand what you are saying. What's magic about combining the phases?
> We have two phases:
> Phase 1: autoconf
>   This phase is essentially a code-generation phase, where specific templates are
>   instantiated to configure time value.  Which again can be split into two specific
>   subproblems:
>   - Generation of the configure script from the configure.ac and aclocal.m4 files
>     using autoconf.
>   - Generating code using the configure script by computing configure time calues
>     and filling those into the `.in` files producing the files that lack the `.in`
>     extension.
> Phase 2: building
>   This has been traditionally the job of make, and this is what hadrian should
>   replace.
> By subsuming the configure phase (by invoking ./configure) from hadrian we loose
> the phase distinction and if the `-c` flag is optional, users will *not even see*
> a flag that indicates that the system will run `./configure` for them. This is the
> magic I'm referring to and to which I strongly object.  If we can retire autoconf
> and do the whole configuration in hadrian, that story may change.  But as long as
> we are using an autoconf based configuration we should *not* run that magically.
> The `-c` flag is at least there to show that hadrian is explicilty instructed to
> run configure.
> ./configure supports its own set of flags, if hadrian subsumes those, we'd need
> some generic way of passing flags to ./configure, at which point I have to ask
> why do we do this in the first place and try to call ./configure from within hadrian?
> Unless you want to reconfigure ghc, or hack on it's autoconf part, you are likely
> going to run the following only:
> ./boot --hadrian
> ./configure <your flags of choice>
> ./hadrian/build.sh -j<N> ...
> ./hadrian/build.sh -j<N> ...
> ./hadrian/build.sh -j<N> ...
> ./hadrian/build.sh -j<N> ...
> ...
> the configure step is required, and should be explicit. That is where you configure
> your ghc build. Set host/build/target values, and other configure flags that
> influence how you want your ghc to be configure. Hadrian is there to build that
> configuration.  Mixing both may be convenient but hides the fact that there is a
> ./configure step.  I consider this hiding to be magic which is meant to benefit the
> user but hides what's really going on.  And again I don't like magic.
> Cheers,
>  Moritz
> PS: we also don't hide the `./configure` step in the usual `./configure <args> && make -j`
>     instructions when building other software, even though you could surely hack that into
>     your Makefile if you so wanted to.  Why start with ghc now?
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> --
> Alp Mestanogullari, Haskell Consultant
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