build fails on my machines, but not [for] others: martinvonz/jj

[colemickens]

Describe the bug

Hi,

All of the sudden, on various machines of mine, I'm unable to build jj, due to test failures:

❯ nix build github:martinvonz/jj/32d622863a773e4826a35e2a6da0f696f68f06df -L &> /tmp/log                                                                   

and then looking at the relevant snippet of log:

jujutsu-unstable> --- STDERR:              jj-lib::test_bad_locking test_bad_locking_children::git_backend ---                                             
jujutsu-unstable> thread 'test_bad_locking_children::git_backend' panicked at 'called `Result::unwrap()` on an `Err` value: Os { code: 5, kind: Uncategoriz
ed, message: "Input/output error" }', lib/tests/test_bad_locking.rs:48:54  

Some sort of generic Input/output error...

However, other users on the jj repo report they're able to build it. (jj-vcs/jj#2103). And sure enough, if I pin a revision from last week that I know was building... it does not build for me.

Did something happen with the nix sandbox (I do use unstable), possibly?

❯ nix --version
nix (Nix) 2.17.0

[tomberek]

Worked on mine. Perhaps number of cores? Look at the locking mechanism used in the test?

[colemickens]

nu─▶  $env.NIX_BUILD_CORES = 1
nu─▶  nix build -L github:martinvonz/jj --option 'cores' '1' -j1 

got it to build, surely a flakey-tests issue, not a nix issue. Closing. Thanks!