bug#43081: diffutils always referrers to the native coreutils

[Mathieu Othacehe]

Hello,

The "diff" executable from diffutils stores a reference to the native,
canonical "pr" from coreutils. This is bad for two reasons:

* It makes the Guix System closure bigger by dragging the canonical
  coreutils.

* The cross-compiled diffutils drags the native coreutils to its
  closure, see:

--8<---------------cut here---------------start------------->8---
mathieu@cervin:~$ guix size 
/gnu/store/5bj91pfnm3z6qbpbl0hp07w12arzk93k-diffutils-3.7
store item                                                       total    self
/gnu/store/j48jp74s1j2mrh7nckg9asdyjv1hvi21-glibc-cross-aarch64-linux-gnu-2.31  
 158.9    71.4  34.8%
/gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31              38.4 36.7  
17.9%
/gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib           71.0    
32.6  15.9%
/gnu/store/xw23yv6fv0cb6n0sbc552l1mkc15yq3n-gcc-cross-aarch64-linux-gnu-7.5.0-lib
   186.8    27.9  13.6%
/gnu/store/57xj5gcy1jbl9ai2lnrqnpr0dald9i65-coreutils-8.32          88.0    
17.0   8.3%
/gnu/store/sl883skd8gbzcj4fl44w7dv1a5yaa3k4-gcc-cross-sans-libc-aarch64-linux-gnu-7.5.0-lib
    80.8     9.8   4.8%
/gnu/store/66m8j38495zdcy2iv55m5d1hj3pxayff-linux-libre-headers-cross-aarch64-linux-gnu-5.4.20
     5.1     5.1   2.5%
/gnu/store/bcjcd97xvh0qkvq1maqj6qab88xb30dv-bash-static-5.0.16       1.6     
1.6   0.8%
/gnu/store/mmhimfwmmidf09jw1plw3aw1g1zn2nkh-bash-static-5.0.16       1.6     
1.6   0.8%
--8<---------------cut here---------------end--------------->8---

The native version of glibc, gcc-lib, coreutils and bash-static are part
of the closure of the cross-compiled coreutils.

I hoped to fix it with the naive patch attached, but it fails for
obscure reasons while building acl:

--8<---------------cut here---------------start------------->8---
FAIL: test/malformed-restore
============================

[4] $ cp 
"/tmp/guix-build-acl-2.2.53.drv-0/acl-2.2.53/test/malformed-restore-double-owner.acl"
 tmp.acl -- ok
[5] $ sed -i "s/USER/30001/g" tmp.acl -- failed
ERROR: ld.so: object 
'/tmp/guix-build-acl-2.2.53.drv-0/acl-2.2.53/.libs/libtestlookup.so' from 
LD_PRELOAD cannot be preloaded: ignored. != ~
[6] $ sed -i "s/GROUP/30000/g" tmp.acl -- failed
ERROR: ld.so: object 
'/tmp/guix-build-acl-2.2.53.drv-0/acl-2.2.53/.libs/libtestlookup.so' from 
LD_PRELOAD cannot be preloaded: ignored. != ~
--8<---------------cut here---------------end--------------->8---

Any idea, what's going on?

Thanks,

Mathieu

>From 59ff84c360e25ac754cc17f285d9bbf077a5e6c3 Mon Sep 17 00:00:00 2001
From: Mathieu Othacehe <othacehe@gnu.org>
Date: Fri, 28 Aug 2020 09:32:17 +0200
Subject: [PATCH] gnu: diffutils: Do not refer to canonical coreutils.

* gnu/packages/base.scm (diffutils)[inputs]: Add "coreutils",
[arguments]: and use it by passing PR_PROGRAM.
---
 gnu/packages/base.scm | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/gnu/packages/base.scm b/gnu/packages/base.scm
index f22e4ab9cc..99f8aefb67 100644
--- a/gnu/packages/base.scm
+++ b/gnu/packages/base.scm
@@ -269,7 +269,13 @@ differences.")
              (base32
               "09isrg0isjinv8c535nxsi1s86wfdfzml80dbw41dj9x3hiad9xk"))))
    (build-system gnu-build-system)
+   (arguments
+    '(#:configure-flags
+      (list (string-append "PR_PROGRAM="
+                           (assoc-ref %build-inputs "coreutils*")
+                           "/bin/pr"))))
    (native-inputs `(("perl" ,perl)))
+   (inputs `(("coreutils*" ,coreutils)))
    (synopsis "Comparing and merging files")
    (description
     "GNU Diffutils is a package containing tools for finding the
-- 
2.24.0