Poetry2nix Flake Build Error: Missing `poetry2nix.overrides` Attribute

What Will You Learn?

Discover how to address the Poetry2nix flake build error resulting from a missing poetry2nix.overrides attribute.

Introduction to the Problem and Solution

Encountering errors during software development is a common occurrence. In this scenario, the Poetry2nix tool throws an error due to a crucial attribute being absent. The solution lies in defining this attribute correctly within our project configuration.

To tackle this issue effectively, it is imperative to ensure that the poetry2nix.overrides attribute is accurately set in our project configuration. By providing the necessary override values, we can eliminate the build error and successfully create our project environment.


# Ensure poetry2nix.overrides attribute is defined in your project configuration file

# Example of setting overrides in pyproject.toml file:
python = "^3.8"

pytest = "^6.0"

dev = ["pytest"]

# Add poetry2nix overrides section at the end of pyproject.toml file:
requires = ["poetry-core>=1.0.0"]
build-backend = "poetry.core.masonry.api"

# Define overrides for poetry2nix as needed:
overrides = '''
  { my-package =
    { src = pkgs.fetchFromGitHub {
        owner  ="my-owner"
        repo   ="my-repo"
        rev    ="my-rev"
        sha256 ="my-sha256";

# Copyright PHD


  • pyproject.toml: Centralized location for defining project metadata and dependencies.
  • overrides: Allows customization of package configurations for Poetry packages through the poetry-to-nix plugin.
  • fetchFromGitHub: Function used to retrieve package source code from GitHub based on specified parameters.
  • By incorporating these configurations in pyproject.toml, we instruct Poetry on handling dependencies during builds using Poetry2nix.
  1. How do I locate my project’s pyproject.toml file?

  2. You can typically find your project’s pyproject.toml file in the root directory of your Python project.

  3. What does the ‘overrides’ section do in Poetry?

  4. The ‘overrides’ section enables customization of package configurations when utilizing tools like Poetry2NIX for dependency management.

  5. Can I use different sources besides GitHub with fetchFromGitHub function?

  6. No, fetchFromGitHub specifically fetches source code from GitHub repositories based on provided details.

  7. Do all projects require setting up overrides for dependencies?

  8. Not all projects may necessitate custom overrides; it depends on specific requirements or configurations unique to your project setup.

  9. Is it necessary to include dev-dependencies in overrides block too?

  10. While not mandatory, including dev-dependencies in the overrides block is recommended if there are dev-specific customizations or additional dependencies required only during development.

  11. How does specifying revisions (rev) impact package fetching from GitHub?

  12. Specifying revisions ensures that your dependency always retrieves a specific version of code associated with that revision number from GitHub.


Resolving build errors such as missing attributes demands meticulous attention while configuring development environments using tools like Poetry and NIX plugins. Understanding these interactions facilitates smoother software deployment processes.

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