bug#41451: Haskell packages retain references to bootstrap variants

bug#41451: Haskell packages retain references to bootstrap variants

[Ricardo Wurmus]

Some Haskell packages have a “-bootstrap” variant to cut dependency
cycles.  Unfortunately, these bootstrap variants remain in the reference
graph alongside their non-bootstrap counterparts.

An example:

--8<---------------cut here---------------start------------->8---
$ guix gc -R /gnu/store/1k0dqlyqyvhd3ax60a2y6l2sip0z7b26-ghc-scientific-0.3.6.2 | grep -- -bootstrap
/gnu/store/lvas21ha80yp02lc3z8fgpcaf59n1jp7-ghc-unordered-containers-bootstrap-0.2.10.0-doc
/gnu/store/22309kdxaapz6z3jm6wfy6bk1yybvxg9-ghc-hashable-bootstrap-1.2.7.0-doc
/gnu/store/mhpfjyx302d89w9484ivylczp8pzzfl2-ghc-hashable-bootstrap-1.2.7.0
/gnu/store/bfc5iyrlqr23fhp8awmd481za4aank9h-ghc-nats-bootstrap-1.1.2
/gnu/store/1nym2bjr3adhy1pa79iiasnfdz285b08-ghc-unordered-containers-bootstrap-0.2.10.0
/gnu/store/xjgjshwhpc36nfagfz0bg3nrg6fkn615-ghc-integer-logarithms-bootstrap-1.0.3
/gnu/store/jljsapda2vbxn7p37i6sk026r9gbrib7-ghc-scientific-bootstrap-0.3.6.2
/gnu/store/gjsmr0nrgsdyxcq9wizcx31cxpg7f9x7-ghc-semigroups-bootstrap-0.18.5
/gnu/store/ywlnsg1lcf0yzisivi7gm2pmls5jnxbb-ghc-attoparsec-bootstrap-0.13.2.3
/gnu/store/w0q1s85mwvxk44gcs9lmh994rm8p7ik6-ghc-wcwidth-bootstrap-0.0.2
/gnu/store/ibk4x2bkqm7krc6cc2d61hvi213zvvfq-ghc-splitmix-bootstrap-0.0.3
/gnu/store/57zjc7i8hb9sb18yflr46yi1vvr21y31-ghc-clock-bootstrap-0.8
--8<---------------cut here---------------end--------------->8---

-- 
Ricardo

bug#41451: Haskell packages retain references to bootstrap variants

[Ricardo Wurmus]

Ricardo Wurmus <rekado@elephly.net> writes:

> Some Haskell packages have a “-bootstrap” variant to cut dependency
> cycles.  Unfortunately, these bootstrap variants remain in the reference
> graph alongside their non-bootstrap counterparts.

On a related note, Haskell packages retain needless references to *all*
other Haskell packages at build time.  That’s because we *copy* their
.conf files at build time to create a package cache, and these .conf
files thus propagate even to unrelated packages.

We are effectively using propagation via the lib/ghc-8.6.5/<name>.conf.d
directory.

I don’t know if all the files in there are really necessary, but it
seems to me that perhaps this leads to spurious references.

-- 
Ricardo

bug#41451: Haskell packages retain references to bootstrap variants

[Ludovic Courtès]

Ricardo Wurmus <rekado@elephly.net> skribis:

> Ricardo Wurmus <rekado@elephly.net> writes:
>
>> Some Haskell packages have a “-bootstrap” variant to cut dependency
>> cycles.  Unfortunately, these bootstrap variants remain in the reference
>> graph alongside their non-bootstrap counterparts.
>
> On a related note, Haskell packages retain needless references to *all*
> other Haskell packages at build time.  That’s because we *copy* their
> .conf files at build time to create a package cache, and these .conf
> files thus propagate even to unrelated packages.

Weren’t these files eventually superseded by the
‘ghc-package-cache-file’ profile hook?  Or are these two different
things?

Ludo’.

bug#41451: Haskell packages retain references to bootstrap variants

[Ricardo Wurmus]

Ludovic Courtès <ludo@gnu.org> writes:

> Ricardo Wurmus <rekado@elephly.net> skribis:
>
>> Ricardo Wurmus <rekado@elephly.net> writes:
>>
>>> Some Haskell packages have a “-bootstrap” variant to cut dependency
>>> cycles.  Unfortunately, these bootstrap variants remain in the reference
>>> graph alongside their non-bootstrap counterparts.
>>
>> On a related note, Haskell packages retain needless references to *all*
>> other Haskell packages at build time.  That’s because we *copy* their
>> .conf files at build time to create a package cache, and these .conf
>> files thus propagate even to unrelated packages.
>
> Weren’t these files eventually superseded by the
> ‘ghc-package-cache-file’ profile hook?  Or are these two different
> things?

That hook also operates on the .conf.d directory containing all .conf
files that have been copied from Haskell inputs.

-- 
Ricardo