The emission of `NIX_CONFIG` into post-build-hooks breaks post-build-hooks if they use config values incompatible with CppNix #739

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opened 2025-03-14 23:23:21 +00:00 by jade · 2 comments

jade commented

2025-03-14 23:23:21 +00:00

Owner

This was, of course, found at work. What happens is that the post-build-hook receives NIX_CONFIG as an environment variable:

https://git.lix.systems/lix-project/lix/src/f21fd6b7e653230c01b454f486cc51d5cc999667/lix/libstore/build/derivation-goal.cc#L977-L980

This is then a config parse failure on CppNix since they did not adopt consensual accept-flake-config yet, and so their accept-flake-config remains a boolean rather than our tristate (which naturally defaults to a non-boolean value. whelp).

Mercury issue: DUX-3152

*** found package.yaml. Using hpack...
post-build-hook: error: Boolean setting 'accept-flake-config' has invalid value 'ask'
post-build-hook: Try 'nix --help' for more information.
error:
       … while evaluating 'strict' to select 'drvPath' on it
         at /builtin/derivation.nix:1:552:
       … while calling the 'derivationStrict' builtin
         at /builtin/derivation.nix:1:208:
       (stack trace truncated; use '--show-trace' to show the full trace)

       error: program '/nix/store/aaaaaaaaaaaaaaaaaaaaaaa-cache-hook/bin/cache-hook' failed with exit code 123

Yeah I am not fixing this (and I don't even think it should be fixed because what on earth are you supposed to do about it, we probably need to nuke this entire infrastructure, and I don't think we should stop causing bugs like it either), but I am documenting it. This was, of course, found at work. What happens is that the post-build-hook receives NIX_CONFIG as an environment variable: https://git.lix.systems/lix-project/lix/src/f21fd6b7e653230c01b454f486cc51d5cc999667/lix/libstore/build/derivation-goal.cc#L977-L980 This is then a config parse failure on CppNix since they did not adopt consensual accept-flake-config yet, and so their accept-flake-config remains a boolean rather than our tristate (which naturally defaults to a non-boolean value. whelp). Mercury issue: DUX-3152 ``` *** found package.yaml. Using hpack... post-build-hook: error: Boolean setting 'accept-flake-config' has invalid value 'ask' post-build-hook: Try 'nix --help' for more information. error: … while evaluating 'strict' to select 'drvPath' on it at /builtin/derivation.nix:1:552: … while calling the 'derivationStrict' builtin at /builtin/derivation.nix:1:208: (stack trace truncated; use '--show-trace' to show the full trace) error: program '/nix/store/aaaaaaaaaaaaaaaaaaaaaaa-cache-hook/bin/cache-hook' failed with exit code 123 ```

jade added the

bug

E/requires rearchitecture

Status

wontfix

Area/store

labels

2025-03-14 23:23:21 +00:00

jade commented

2025-03-15 00:02:18 +00:00

Author

Owner

Okay, on one hand this is a ridiculous issue, but on the other hand we can only output overridden settings into the build hook, like we do with the protocol.

jade removed the

Status

wontfix

E/requires rearchitecture

labels

2025-03-15 00:02:24 +00:00

lix-bot commented

2025-03-15 00:24:00 +00:00

Member

This issue was mentioned on Gerrit on the following CLs:

commit message in cl/2800 ("post-build-hook: don't emit config settings that aren't overridden")

This issue was mentioned on Gerrit on the following CLs: * commit message in [cl/2800](https://gerrit.lix.systems/c/lix/+/2800) ("post-build-hook: don't emit config settings that aren't overridden")

jade referenced this issue from a commit

2025-03-15 00:31:33 +00:00

post-build-hook: don't emit config settings that aren't overridden