nix-shell fails to open with a derivation symlink on macOS

[fson]

Specifying a drv file path that is a symlink causes nix-shell to fail with a syntax error on macOS.

This works and starts the shell successfully:

$ nix-shell /nix/store/zng8s969fmbcyany3b3nxx9nn5g4vxa7-nix-shell.drv

[nix-shell:~]$ 

This fails:

$ ln -s /nix/store/zng8s969fmbcyany3b3nxx9nn5g4vxa7-nix-shell.drv shell.drv
$ nix-shell shell.drv
error: syntax error, unexpected ',', expecting ')', at /nix/store/zng8s969fmbcyany3b3nxx9nn5g4vxa7-nix-shell.drv:1:15

I'm using Nix 2.0 on macOS 10.13.3.

The contents of /nix/store/zng8s969fmbcyany3b3nxx9nn5g4vxa7-nix-shell.drv are:

Derive([("out","/nix/store/qbb27qj7sf4xpali6z8b3s385p24n17m-nix-shell","","")],[("/nix/store/9swhg6583n478dmn4ax45wd9lv31xks3-git-crypt-scripts.drv",["out"]),("/nix/store/adbmcrygzwlpsw05x5gid2ky0d01lydd-stdenv-darwin.drv",["out"]),("/nix/store/mjg92sy9bs1zdsbf3zj55kc06ghpfs7y-bash-4.4-p12.drv",["out"]),("/nix/store/sypfk3kb48zfnkiqisb4q04ydql5v7sr-git-crypt-0.5.0.drv",["out"])],["/nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh"],"x86_64-darwin","/nix/store/19cc89zq5n68ibr53izy4zgcr5qg2rza-bash-4.4-p12/bin/bash",["-e","/nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh"],[("__impureHostDeps","/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation /bin/sh /usr/lib/libSystem.B.dylib /usr/lib/system/libunc.dylib /dev/zero /dev/random /dev/urandom /bin/sh"),("__propagatedImpureHostDeps",""),("__propagatedSandboxProfile",""),("__sandboxProfile",""),("buildInputs","/nix/store/ifmfjdnb2pc20i4hb7523k78wiln64w0-git-crypt-0.5.0 /nix/store/ajmxkq1py0gb1gnp5pqmva64gcy6r9ra-git-crypt-scripts"),("builder","/nix/store/19cc89zq5n68ibr53izy4zgcr5qg2rza-bash-4.4-p12/bin/bash"),("configureFlags",""),("depsBuildBuild",""),("depsBuildBuildPropagated",""),("depsBuildTarget",""),("depsBuildTargetPropagated",""),("depsHostBuild",""),("depsHostBuildPropagated",""),("depsTargetTarget",""),("depsTargetTargetPropagated",""),("name","nix-shell"),("nativeBuildInputs",""),("nobuildPhase","echo\necho \"This derivation is not meant to be built, aborting\";\necho\nexit 1\n"),("out","/nix/store/qbb27qj7sf4xpali6z8b3s385p24n17m-nix-shell"),("phases","nobuildPhase"),("propagatedBuildInputs",""),("propagatedNativeBuildInputs",""),("stdenv","/nix/store/vp6la88iirygv8gcfmqmsamdmgh5nf9p-stdenv-darwin"),("system","x86_64-darwin")])

[MDeltaX]

Same on NixOS master.

[LnL7]

Have you tried nix-shell $PWD/shell.drv, I think it requires a full path.

[fson]

Tried with the full path, still fails when using the symlink.

[regnat]

I think this is the intended behavior (although that wasn't the case in Nix 1.11 and could have been documented): nix-shell interprets is argument as a derivation only when it is a store path (which imho is a good thing since it makes the heuristic less fragile)

[dtzWill]

For purposes of nix-shell, would it be problematic to just readlink the argument?

If this is desired behavior we can still do much better in terms of the error reported-- "derivations must be store paths" or whatever instead of blaming the poor comma :D.

[simoncarpinter]

I encountered this bug using direnv as documented here; I've updated that page to use readlink. Cheers @dtzWill :).

[hussein-aitlahcen]

Having the same issue after updating to Nix 2.0

[Profpatsch]

I think that was mostly fixed by

https://github.com/NixOS/nix/commit/12913ccf454c1bc82a51c59872f8185b40c533c5

and we can close this issue. (It shouldn’t happen from 2.1 onwards.)

[stefandeml]

Still have the same issue on Catalina. Also the readlink workaround does not work.

[Profpatsch]

We now hit the very same issue on NixOS (!) with nix 2.3.1: https://github.com/target/lorri/issues/357

This here is the showcase of nix’s misbehavior: https://github.com/target/lorri/issues/357#issuecomment-603729686