Subject: Re: bug#61853: ‘guix pack’ shell tests fail

From: Ludovic Courtès <[email-masked]>
Date: Tue, 28 Feb 2023 00:07:31 +0100

Ludovic Courtès <[email-masked]> skribis:

> In both cases this is because $test_directory is read-only:

This in turn is due to a permission change in generated tarballs:

--8<---------------cut here---------------start------------->8---
$ guix describe
Generation 248  Feb 27 2023 16:36:12    (current)
  guix cf9e050
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: cf9e0508b26196dc985302776d860a0359652c59
$ guix pack hello
/gnu/store/k0mjzvv76s0yn4r4mwzy6mvf71wxpbg2-hello-tarball-pack.tar.gz
ludo@ribbon ~/src/guix$ tar tzvf /gnu/store/k0mjzvv76s0yn4r4mwzy6mvf71wxpbg2-hello-tarball-pack.tar.gz |head
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/include/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/gcc/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/gcc/x86_64-unknown-linux-gnu/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/gcc/x86_64-unknown-linux-gnu/10.3.0/
-r--r--r-- root/root      2056 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/gcc/x86_64-unknown-linux-gnu/10.3.0/crtbegin.o
--8<---------------cut here---------------end--------------->8---

Compared to:

--8<---------------cut here---------------start------------->8---
$ guix time-machine --commit=v1.4.0 -- pack hello
/gnu/store/vjjavmn16mxzgrlfawjcgq5j4iqm7609-hello-tarball-pack.tar.gz
$ tar tzvf /gnu/store/vjjavmn16mxzgrlfawjcgq5j4iqm7609-hello-tarball-pack.tar.gz | head
drwxr-xr-x root/root         0 1970-01-01 01:00 ./
drwxr-xr-x root/root         0 1970-01-01 01:00 ./gnu/
drwxrwxr-t root/root         0 1970-01-01 01:00 ./gnu/store/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/include/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/gcc/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/gcc/x86_64-unknown-linux-gnu/
dr-xr-xr-x root/root         0 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/gcc/x86_64-unknown-linux-gnu/10.3.0/
-r--r--r-- root/root      2056 1970-01-01 01:00 ./gnu/store/094bbaq6glba86h1d4cj16xhdi6fk2jl-gcc-10.3.0-lib/lib/gcc/x86_64-unknown-linux-gnu/10.3.0/crtbegin.o
tar: stdout: write error
--8<---------------cut here---------------end--------------->8---

That’s an acceptable change IMO, introduced in
68380db4c40a2ee1156349a87254fd7b1f1a52d5.  However, the tests were
evidently not run after that change, which is problematic.

Anyway, fixed in 92a0e60a963a54230e400c5c2ae585205489bf35.  Both tests
now pass for me.

One issue with 68380db4c40a2ee1156349a87254fd7b1f1a52d5, though, is that
it introduces a copy of the profile being built to the store
(“profile-directory”).  This was purposefully avoided before because
it’s very I/O-intensive, space-consuming, and puts more pressure on the
store.  It’s a pattern we avoided for system images too, having noticed
its cost (commit 7f75a7ec08975eb6d6e01db61bd6b91f447f655e for instance.)

We may need to come back to a single derivation well or creating packs
for big profiles will be too costly.

Ludo’.