fetchGit is flaky: sometimes cannot find git revision #10431
Description
Describe the bug
The problem only occurs since nix 2.21.x
fetchGit is flaky on an empty ~/.cache/nix/gitv3 and can often crash like that:
error: Cannot find Git revision '43c751b41d74f96cbbd4e07b7aec9675651e2951' in [...]
Steps To Reproduce
- Evaluate
fetchGit { url="https://github.com/sebastianbergmann/environment.git"; rev = "43c751b41d74f96cbbd4e07b7aec9675651e2951";}on an empty~/.cache/nix/gitv3several times in a row. - notice that sometimes the fetching works and sometimes it crashes.
- To speed up the evaluation, you can set
shallow=true. It does not affect the outcome.
Here an example with 3 evaluations of the same expression, succeeding 2 times and failing one time.
❯ rm -rf ~/.cache/nix/gitv3
~
❯ nix repl
Nix 2.21.2
Type :? for help.
nix-repl> fetchGit { url="https://github.com/sebastianbergmann/environment.git"; rev = "43c751b41d74f96cbbd4e07b7aec9675651e2951"; }
fatal: unable to access 'https://github.com/sebastianbergmann/environment.git/': Could not resolve host: github.com
warning: could not read HEAD ref from repo at 'https://github.com/sebastianbergmann/environment.git', using 'master'
warning: could not update mtime for file '/home/grmpf/.cache/nix/gitv3/0da421j037zz3w3qxl31dc3r7s84xsrgr7hs25yn3ic0h6iqald1/refs/heads/master': No such file or directory
fatal: Refusing to point HEAD outside of refs/
warning: could not update cached head 'master' for 'https://github.com/sebastianbergmann/environment.git'
{
lastModified = 1681191566;
lastModifiedDate = "20230411053926";
narHash = "sha256-Ttez88NVbtHeT/4AglFTEdsGqLgkKTuvqP7uR4tP7BI=";
outPath = "/nix/store/391g2lyf8f1014riqpfdbn93s9gjv42h-source";
rev = "43c751b41d74f96cbbd4e07b7aec9675651e2951";
revCount = 448;
shortRev = "43c751b";
submodules = false;
}
~ took 13s
❯ rm -rf ~/.cache/nix/gitv3
~
❯ nix repl
Nix 2.21.2
Type :? for help.
nix-repl> fetchGit { url="https://github.com/sebastianbergmann/environment.git"; rev = "43c751b41d74f96cbbd4e07b7aec9675651e2951"; }
warning: could not update mtime for file '/home/grmpf/.cache/nix/gitv3/0da421j037zz3w3qxl31dc3r7s84xsrgr7hs25yn3ic0h6iqald1/refs/heads/main': No such file or directory
{
lastModified = 1681191566;
lastModifiedDate = "20230411053926";
narHash = "sha256-Ttez88NVbtHeT/4AglFTEdsGqLgkKTuvqP7uR4tP7BI=";
outPath = "/nix/store/391g2lyf8f1014riqpfdbn93s9gjv42h-source";
rev = "43c751b41d74f96cbbd4e07b7aec9675651e2951";
revCount = 448;
shortRev = "43c751b";
submodules = false;
}
~ took 49s
❯ rm -rf ~/.cache/nix/gitv3
~
❯ nix repl
Nix 2.21.2
Type :? for help.
nix-repl> fetchGit { url="https://github.com/sebastianbergmann/environment.git"; rev = "43c751b41d74f96cbbd4e07b7aec9675651e2951"; }
fatal: unable to access 'https://github.com/sebastianbergmann/environment.git/': Could not resolve host: github.com
warning: could not update mtime for file '/home/grmpf/.cache/nix/gitv3/0da421j037zz3w3qxl31dc3r7s84xsrgr7hs25yn3ic0h6iqald1/refs/heads/main': No such file or directory
error:
… while calling the 'fetchGit' builtin
at «string»:1:1:
1| fetchGit { url="https://github.com/sebastianbergmann/environment.git"; rev = "43c751b41d74f96cbbd4e07b7aec9675651e2951"; }
| ^
… while fetching the input 'git+https://github.com/sebastianbergmann/environment.git?exportIgnore=1&rev=43c751b41d74f96cbbd4e07b7aec9675651e2951'
error: Cannot find Git revision '43c751b41d74f96cbbd4e07b7aec9675651e2951' in ref 'refs/heads/main' of repository 'https://github.com/sebastianbergmann/environment.git'! Please make sure that the rev exists on the ref you've specified or add allRefs = true; to fetchGit.
What can be observed is that the warnings raised by nix are not reproducible as well. Though, I could not determine any correlation between the warnings and the outcome.
Expected behavior
nix-env --version output
Additional context
Add any other context about the problem here.
Priorities
Add 👍 to issues you find important.