NPV 120

NPV-120: Nix evaluation error

Description

Nix evaluation of the package set failed. This usually means there is a syntax error, missing dependency, or other evaluation-time failure in a pkgs/by-name package.

Error message

{stderr}
- Nix evaluation failed for some package in `pkgs/by-name`, see error above

The {stderr} portion contains the actual Nix error output.

Example

If a package.nix references an undefined variable:

error: undefined variable 'someDrv' at /path/to/package.nix:1:1
- Nix evaluation failed for some package in `pkgs/by-name`, see error above

How to fix

Read the Nix error output shown above the NPV-120 message. Fix the evaluation error in the referenced file — common causes include syntax errors, missing inputs, or incorrect attribute references.