Regression: neovim and various plugins no longer build with nix 2.24.15

[xbreak]

Since #433055 some derivations end up with broken stdenv when using Nix 2.24.15:

$ nix build .#neovim --rebuild
error: builder for '/nix/store/9wrf9zcdc7qc7d5xp2ds96p8qg2viyj1-neovim-0.11.4.drv' failed with exit code 1;
       last 1 log lines:
       > /nix/store/l622p70vy8k5sh7y5wizi5f2mic6ynpg-source-stdenv.sh: line 2: /setup: No such file or directory
       For full logs, run 'nix log /nix/store/9wrf9zcdc7qc7d5xp2ds96p8qg2viyj1-neovim-0.11.4.drv'.
$ nix --version
nix (Nix) 2.24.15

with apparently $stdenv not being defined:

# /nix/store/l622p70vy8k5sh7y5wizi5f2mic6ynpg-source-stdenv.sh
if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; fi
source "$stdenv/setup"
source "$1"

The same issue occurs with various vimPlugins but e.g. not hello.

During git bisect run nix build .#vimPlugins.bufdelete-nvim --rebuild there were other unrelated build errors but outcome was:

# possible first bad commit: [5360dcde1f27b9c1e2d75eb3d52f53369973d6ab] Merge staging-next into staging
# possible first bad commit: [6ed3b21f759e1b135ca96344f91a13d2cf753ff8] stdenv: cleanup after bump of minver (#433055)

Details

git bisect start
# status: waiting for both good and bad commits
# good: [d0fc30899600b9b3466ddb260fd83deb486c32f1] perfect_dark: init at 0-unstable-2025-08-25 (#306767)
git bisect good d0fc30899600b9b3466ddb260fd83deb486c32f1
# bad: [b3d51a0365f6695e7dd5cdf3e180604530ed33b4] wheelwizard: init at 2.3.3 (#451649)
git bisect bad b3d51a0365f6695e7dd5cdf3e180604530ed33b4
# bad: [7d9f8fb0c12c32e035ee7c61ba5022a3a107f6f6] Merge staging-next into staging
git bisect bad 7d9f8fb0c12c32e035ee7c61ba5022a3a107f6f6
# bad: [481174a1e79672cae2272ff6db8d79571889b918] tektoncd-cli-pac: init at 0.37.0 (#411357)
git bisect bad 481174a1e79672cae2272ff6db8d79571889b918
# bad: [1779f9e0d8b45d88d7525665dd4d2a5b65041248] staging-next 2025-08-30 (#438642)
git bisect bad 1779f9e0d8b45d88d7525665dd4d2a5b65041248
# good: [9b20b4d9d99de64d5a661145c48300ab2c5113b7] ansible_2_18: add, fix version (#440639)
git bisect good 9b20b4d9d99de64d5a661145c48300ab2c5113b7
# good: [4baa6081530e84136bb4f21ee70d9e74f5e2c7f7] telepresence2: 2.24.0 -> 2.24.1 (#440770)
git bisect good 4baa6081530e84136bb4f21ee70d9e74f5e2c7f7
# bad: [6e8f5691dbddf7c5ec696a6b648dbb773487b760] meson: 1.8.3 -> 1.9.0
git bisect bad 6e8f5691dbddf7c5ec696a6b648dbb773487b760
# bad: [7099ae2a7e858c9c05b726c5048d1731fb79c214] Merge staging-next into staging
git bisect bad 7099ae2a7e858c9c05b726c5048d1731fb79c214
# bad: [fc627b6a75a8772c3502b60904829d98db387b91] Merge staging-next into staging
git bisect bad fc627b6a75a8772c3502b60904829d98db387b91
# bad: [555eba864d571d699e66522c4b2d18678dfb8a4a] Merge staging-next into staging
git bisect bad 555eba864d571d699e66522c4b2d18678dfb8a4a
# good: [9daeaddf2c2e6630a485caa77ade172204c7c6c2] python3Packages.llama-cpp-python: set cmakeFlags directly
git bisect good 9daeaddf2c2e6630a485caa77ade172204c7c6c2
# good: [cf4e81e3bccf9aaf8bb5baee020e77c4ab622559] buildGoModule: add buildTestBinaries option, add tests (#427334)
git bisect good cf4e81e3bccf9aaf8bb5baee020e77c4ab622559
# bad: [5360dcde1f27b9c1e2d75eb3d52f53369973d6ab] Merge staging-next into staging
git bisect bad 5360dcde1f27b9c1e2d75eb3d52f53369973d6ab
# good: [7e6ff957b79423c544fcbc21a1a672846c0c5435] modemmanager: 1.22.0 -> 1.24.0 / libmbim: 1.30.0 -> 1.32.0 (#414699)
git bisect good 7e6ff957b79423c544fcbc21a1a672846c0c5435
# good: [899c40e6f8ed0baee363a7a5d3be39241a40a1b7] stdenv: remove .attrs.sh fallback for structuredAttrs
git bisect good 899c40e6f8ed0baee363a7a5d3be39241a40a1b7
# good: [f7470c530e13c38d5b80c5602ab4266c2a33d33b] Merge master into staging-next
git bisect good f7470c530e13c38d5b80c5602ab4266c2a33d33b
# skip: [6ed3b21f759e1b135ca96344f91a13d2cf753ff8] stdenv: cleanup after bump of minver (#433055)
git bisect skip 6ed3b21f759e1b135ca96344f91a13d2cf753ff8
# good: [e821b847c62886c17cb7c4a3676f25f1140fb3cf] Merge staging-next into staging
git bisect good e821b847c62886c17cb7c4a3676f25f1140fb3cf
# only skipped commits left to test
# possible first bad commit: [5360dcde1f27b9c1e2d75eb3d52f53369973d6ab] Merge staging-next into staging
# possible first bad commit: [6ed3b21f759e1b135ca96344f91a13d2cf753ff8] stdenv: cleanup after bump of minver (#433055)

So the removal of fallback `.attrs.sh` seems plausible.

The same works derivations work fine on my NixOS 25.05 machine (nix 2.28).

Ping @wolfgangwalther

[wolfgangwalther]

cc @Ma27

[wolfgangwalther]

Observation: neovim has __structuredAttrs = true.

[wolfgangwalther]

Since Nix 2.24 isn't available anymore on unstable, I can't test this on my machine, I think.

It works with Lix.

[Ma27]

Cannot reproduce. Tried to build this with nix (Nix) 2.24.15 using the command

nix-build -A vimPlugins.bufdelete-nvim --store $(pwd)/../nixpkgs/testing --builders ''

such that the build doesn't get forwarded to any daemon.

Tested on nixpkgs rev c6fee01 (and on 25.05 rev b58bbfa to be extra sure).

Are you sure that the Nix used for building this is 2.24?
Remember, nix-build --version only tells you the version of the client, but the not of the daemon (or remote Nix in case of distributed builds) that actually does the building.

[xbreak]

Thanks for checking. So this is curious. Indeed this also works for me:

nix-build -A vimPlugins.bufdelete-nvim --store $(pwd)/../nixpkgs/testing --builders ''

But there are no remote builders and nix and nix-deamon are both 2.24.15

If something has been corrupted in /nix/store it is not found with nix-build -A vimPlugins.bufdelete-nvim --builders '' --repair which fails with same

...
       last 1 log lines:
> /nix/store/l622p70vy8k5sh7y5wizi5f2mic6ynpg-source-stdenv.sh: line 2: /setup: No such file or directory

[xbreak]

Some more data:

• I could build successfully on a very similar machine with same OS and Nix versions.

On first machine with observed failure:

• No corruption found with nix-store --verify --check-contents --repair.
• GC'd the entire /nix/store. Not a single file left. nix-build -A vimPlugins.bufdelete-nvim --builders '' still failed.
• Deleted ~/.cache/nix and GC'd the entire /nix/store. Not a single file left. nix-build -A vimPlugins.bufdelete-nvim --builders '' still failed with same error.

Any ideas?

[Ma27]

I could build successfully on a very similar machine with same OS and Nix versions.

just to be sure, did you test this with --store only or also with the default daemon installation?

[xbreak]

Without --store.

Uh, after making a recursive file diff which showed no file difference between stores I restarted nix-daemon and then it worked! So I guess there was some internal corruption - damn. Very peculiar in that it only hit some derivations but very systematically and git bisect quite clearly pointing to a relevant diff.

Sorry for the noise and thanks again for the feedback!

[xbreak]

Closing as unreproducible (some kind if Nix daemon bug fixed after restart).