Subject: Re: bug#42327: Offload build to Childhurd selects linux-libre-headers
From: Ludovic Courtès <[email-masked]>
To: Jan Nieuwenhuizen <[email-masked]>
Cc: [email-masked]
Date: Mon, 13 Jul 2020 16:52:02 +0200
List-Id: <debbugs-submit.debbugs.gnu.org>

Hi!

Jan Nieuwenhuizen <[email-masked]> skribis:

> With static-bash-for-glibc, however, it goes off track
>
> $ ./pre-inst-env guix build --system=i586-gnu \
>    -e '(@@ (gnu packages commencement) static-bash-for-glibc)'
> The following derivations will be built:
>    /gnu/store/gv40jpz4g0hbia28wa6d50z9x6ncgdlh-bash-static-5.0.16.drv
>    /gnu/store/apj2ihazv6x3anhvfvmmqrkyak05p9yc-gcc-cross-boot0-wrapped-7.5.0.drv
>    /gnu/store/yfpy5b3xqkarxchyhi339fw2ldwczj1d-linux-libre-headers-5.4.20.drv
>
>
> ...oops!  Note that a native build on the Childhurd works all the way up
> to "hello".
>
> The "glibc-final-with-bootstrap-bash" has a propagated-inputs that looks
> like this
>
> (define* (kernel-headers-boot0 #:optional (system (%current-system)))
>   (match system
>     ("i586-gnu" hurd-core-headers-boot0)
>     (_ linux-libre-headers-boot0)))
>
> (define glibc-final-with-bootstrap-bash
>    [..]
>    (propagated-inputs `(("kernel-headers" ,(kernel-headers-boot0))))
>    [..])
>
> In KERNEL-HEADERS-BOOT0, SYSTEM is "x86_64-linux".  Passing SYSTEM from
> a LET-SYSTEM clause (see attached patch) seems to fix this...but i'm
> afraid that triggers a world rebuild.  Our offload Childhurds can only
> run master, right?  Is there any way around this?  Thoughts?

Here’s my powerful debugging trick for such dynamic binding issues (it’s
not related to offloading):

diff --git a/gnu/packages/commencement.scm b/gnu/packages/commencement.scm
index d0393ebe25..5ec7facd02 100644
--- a/gnu/packages/commencement.scm
+++ b/gnu/packages/commencement.scm
@@ -3116,6 +3116,9 @@ memoized as a function of '%current-system'."
               ,@(%boot0-inputs)))))
 
 (define* (kernel-headers-boot0 #:optional (system (%current-system)))
+  (when (string=? system "x86_64-linux")
+    (pk system)
+    (display-backtrace (make-stack #t) (current-error-port) #f 80))
   (match system
     ("i586-gnu" hurd-core-headers-boot0)
     (_ linux-libre-headers-boot0)))

That gives me this:

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix build -s i586-gnu hello -d --no-grafts

;;; ("x86_64-linux")
In ice-9/boot-9.scm:
  1736:10 30 (with-exception-handler _ _ #:unwind? _ #:unwind-for-type _)
In unknown file:
          29 (apply-smob/0 #<thunk 7f59f45ab580>)
In ice-9/boot-9.scm:
    718:2 28 (call-with-prompt _ _ #<procedure default-prompt-handler (k proc)>)
In ice-9/eval.scm:
    619:8 27 (_ #(#(#<directory (guile-user) 7f59f41e8f00>)))
In guix/ui.scm:
  1953:12 26 (run-guix-command _ . _)
    663:2 25 (call-with-error-handling _)
In ice-9/boot-9.scm:
  1736:10 24 (with-exception-handler _ _ #:unwind? _ #:unwind-for-type _)
  1731:15 23 (with-exception-handler #<procedure 7f59f1f734b0 at ice-9/boot-9.scm:1815:7 (exn)> _ #:unwind? _ # _)
In guix/status.scm:
    776:4 22 (call-with-status-report _ _)
In ice-9/boot-9.scm:
  1736:10 21 (with-exception-handler _ _ #:unwind? _ #:unwind-for-type _)
In guix/store.scm:
   631:22 20 (thunk)
   1299:8 19 (call-with-build-handler #<procedure 7f59f1f8c930 at guix/ui.scm:1069:2 (continue store things mod…> …)
In guix/scripts/build.scm:
    925:2 18 (_)
In ice-9/boot-9.scm:
  1731:15 17 (with-exception-handler #<procedure 7f59e300e750 at ice-9/boot-9.scm:1815:7 (exn)> _ #:unwind? _ # _)
  1736:10 16 (with-exception-handler _ _ #:unwind? _ #:unwind-for-type _)
In guix/ui.scm:
    440:6 15 (_)
In guix/scripts/build.scm:
    927:5 14 (_)
In srfi/srfi-1.scm:
   673:15 13 (append-map #<procedure 7f59e3015dc0 at guix/scripts/build.scm:927:17 (system)> ("i586-gnu"))
   586:17 12 (map1 ("i586-gnu"))
In guix/scripts/build.scm:
   929:20 11 (_ _)
In guix/store.scm:
   1340:2 10 (map/accumulate-builds #<store-connection 256.99 7f59f1fb09b0> _ _)
In srfi/srfi-1.scm:
   586:17  9 (map1 (#<package [email-masked] gnu/packages/base.scm:74 7f59e57f0820>))
In guix/store.scm:
   1299:8  8 (call-with-build-handler #<procedure build-accumulator (continue store things mode)> _)
In guix/scripts/build.scm:
   888:18  7 (_ _)
In guix/packages.scm:
  1075:16  6 (package-derivation _ #<package [email-masked] gnu/packages/base.scm:74 7f59e57f0820> _ #:graft? _)
  1393:22  5 (thunk)
    927:4  4 (bag->derivation #<store-connection 256.99 7f59f1fb09b0> #<<bag> name: "hello-2.10" system: "i586-…> …)
   812:23  3 (transitive-inputs _)
In gnu/packages/commencement.scm:
  3304:44  2 (propagated-inputs #<package [email-masked] gnu/packages/commencement.scm:3263 7f59e6856d20>)
  3121:23  1 (kernel-headers-boot0 _)
In unknown file:
           0 (make-stack #t)
--8<---------------cut here---------------end--------------->8---

At that point, it looks like a déjà-vu to me.  :-)

Should be fixed with efb10f175fa6323024aa471c58ea1da445085298.

Thanks,
Ludo’.