Caused by 1d3696f0fb
Without this fix the kept build directory is readable only by root
```
$ sudo ls -ld /comp-temp/nix-build-openssh-static-x86_64-unknown-linux-musl-9.8p1.drv-5
drwx------ root root 60 B Wed Sep 11 00:09:48 2024 /comp-temp/nix-build-openssh-static-x86_64-unknown-linux-musl-9.8p1.drv-5/
$ sudo ls -ld /comp-temp/nix-build-openssh-static-x86_64-unknown-linux-musl-9.8p1.drv-5/build
drwxr-xr-x nixbld1 nixbld 80 B Wed Sep 11 00:09:58 2024 /comp-temp/nix-build-openssh-static-x86_64-unknown-linux-musl-9.8p1.drv-5/build/
```
When `nix fmt` is called without an argument, Nix appends the "." argument before calling the formatter. The comment in the code is:
> Format the current flake out of the box
This also happens when formatting sub-folders.
This means that the formatter is now unable to distinguish, as an interface, whether the "." argument is coming from the flake or the user's intent to format the current folder. This decision should be up to the formatter.
Treefmt, for example, will automatically look up the project's root and format all the files. This is the desired behaviour. But because the "." argument is passed, it cannot function as expected.
This fixes the warning
$ nix eval --store /tmp/nix --expr 'builtins.fetchTree { type = "git"; url = "https://github.com/DeterminateSystems/attic"; ref = "fixups-for-magic-nix-cache"; rev = "635753a2069d4b8228e846dc5c09ad361c75cd1a"; }'
warning: could not update mtime for file '/home/eelco/.cache/nix/gitv3/09788h9zgba5lbfkaa6ija2dvi004jwsqjf5ln21i2njs07cz766/refs/heads/fixups-for-magic-nix-cache': error: changing modification time of '"/home/eelco/.cache/nix/gitv3/09788h9zgba5lbfkaa6ija2dvi004jwsqjf5ln21i2njs07cz766/refs/heads/fixups-for-magic-nix-cache"': No such file or directory
When we're fetching by rev, that file doesn't necessarily exist, and we
don't care about it anyway.
Fixes
$ nix flake metadata --store /tmp/nix nixpkgs
error: path '/tmp/nix/nix/store/65xpqkz92d9j7k5ric4z8lzhiigxsfbg-source/flake.nix' is not in the Nix store
This has been broken since 598deb2b23.
On macOS, `mkdir("x/')` behaves differently than `mkdir("x")` if `x` is
a dangling symlink (the formed succeed while the latter fails). So make
sure we always strip the trailing slash.
/tmp/ecstatic-euler-mAFGV7
% /home/joerg/git/nix/build/subprojects/nix/nix repl
Nix 2.25.0
Type :? for help.
after doing rm /tmp/ecstatic-euler-mAFGV7 this will result in:
nix-repl> :lf .
error: cannot determine current working directory: No such file or directory
Before it would make the repl crash
/tmp/clever-hermann-MCm7A9
% /home/joerg/git/nix/build/subprojects/nix/nix repl
Nix 2.25.0
Type :? for help.
nix-repl> :lf .
error: filesystem error: cannot get current path: No such file or directory
Before:
nix-env % ./src/nix/nix eval --impure --expr 'let f = builtins.readDir "/nix/store/hs3yxdq9knimwdm51gvbs4dvncz46f9d-hello-2.12.1/foo"; in f' --show-trace
error: filesystem error: directory iterator cannot open directory: No such file or directory [/nix/store/hs3yxdq9knimwdm51gvbs4dvncz46f9d-hello-2.12.1/foo]
After:
error:
… while calling the 'readDir' builtin
at «string»:1:9:
1| let f = builtins.readDir "/nix/store/hs3yxdq9knimwdm51gvbs4dvncz46f9d-hello-2.12.1/foo"; in f
| ^
error: reading directory '/nix/store/hs3yxdq9knimwdm51gvbs4dvncz46f9d-hello-2.12.1/foo': No such file or directory
this should make it more obvious how things are related to each other, and also
hopefully expose the historical context without having to say on every
corner that these details are accounting for legacy decisions.
