bug#39993: Guix report hash mismatch when underlying cause is ENOSPC

[Maxim Cournoyer]

Hello,

Ludovic Courtès <address@hidden> writes:

[...]

> Starting download of 
> /gnu/store/124q26gkdyls859sblabz3f60grfvvdl-tcpdump-4.9.3.tar.gz
> From 
> https://archive.softwareheritage.org/api/1/content/sha256:2cd47cb3d460b6ff75f4a9940f594317ad456cfbf2bd2c8e5151e16559db6410/raw/...
> In procedure fport_write: Ne haviĝas plu da spaco sur aparato
> failed to download 
> "/gnu/store/124q26gkdyls859sblabz3f60grfvvdl-tcpdump-4.9.3.tar.gz" from 
> "https://www.tcpdump.org/release/tcpdump-4.9.3.tar.gz";
> warning: rewriting hashes in 
> `/gnu/store/mv33j0si1n75q9kdimhvyrjn05pbxz5b-tcpdump-4.9.3.tar.gz'; cross 
> fingers
> sha256 hash mismatch for 
> /gnu/store/mv33j0si1n75q9kdimhvyrjn05pbxz5b-tcpdump-4.9.3.tar.gz:
>   expected hash: 0434vdcnbqaia672rggjzdn4bb8p8dchz559yiszzdk0sjrprm1c
>   actual hash:   0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
> hash mismatch for store item 
> '/gnu/store/mv33j0si1n75q9kdimhvyrjn05pbxz5b-tcpdump-4.9.3.tar.gz'
>
>> The root cause is that ‘false-if-exception*’ as used in (guix build
>> download) is too coarse-grain.
>
> I came up with a fix in 4a6ec23a9780bd75a7e527bd0dfb1943347869bb.
>
> Thanks,
> Ludo’.

That was quick!  Thank you! :-)

Maxim