Check the GitHub Workflow logs

Oct 13, 2025 by wbrum.org 43 views

Many Log Lines About "Nix Search Path Entry" Not Existing in @v31

Introduction

When updating from cachix/install-nix-action version 30 to version 31, many instances of the following warning message may appear in your GitHub Workflow logs:

warning: Nix search path entry '/home/runner/.nix-defexpr/channels' does not exist, ignoring

This issue is particularly frustrating, especially when it repeats multiple times during the Nix evaluation phase. In this article, we will delve into the possible causes of this problem and explore potential solutions to resolve it.

Understanding the Issue

The warning message indicates that the Nix search path entry /home/runner/.nix-defexpr/channels does not exist. This entry is part of the Nix search path, which is used to locate Nix packages and channels. The Nix search path is a list of directories that Nix searches for packages and channels.

In the context of GitHub Workflows, the cachix/install-nix-action is used to install Nix on the runner machine. The nix-path setting in nix.conf is used to specify the Nix search path. However, it seems that the nix-path setting is not being used correctly, resulting in the warning message.

Possible Causes

There are several possible causes for this issue:

NIX_PATH env var: The NIX_PATH env var is used to specify the Nix search path. However, it seems that the NIX_PATH env var is not being set correctly, resulting in the warning message.
nix-path setting in nix.conf: The nix-path setting in nix.conf is used to specify the Nix search path. However, it seems that the nix-path setting is not being used correctly, resulting in the warning message.
Interaction between NIX_PATH and nix-path: The interaction between the NIX_PATH env var and the nix-path setting in nix.conf may be causing the issue.

Potential Solutions

Here are some potential solutions to resolve this issue:

Specify NIX_PATH env var: Try specifying the NIX_PATH env var in your GitHub Workflow. You can do this by adding the following line to your workflow:

      - name: Set NIX_PATH env var
        run: |
          export NIX_PATH=/home/runner/.nix-defexpr/channels

Specify nix-path setting in nix.conf: Try specifying the nix-path setting in nix.conf. You can do this by adding the following line to your workflow:

      - name: Set nix-path setting in nix.conf
        run: |
          echo "nix-path = /home/runner/.nix-defexpr/channels" >> /etc/nix/nix.conf

Use nix-shell with --no-sandbox: Try using nix-shell with the --no-sandbox flag. This flag tells Nix to not use the sandbox, which may help resolve the issue.

      - name: cabal build in nix-shell
        run: |
          nix-shell --verbose --no-sandbox --command 'cabal build all'

Update cachix/install-nix-action to v32: Try updating cachix/install-nix-action to version 32. This version may have fixed the issue.

Conclusion

The warning message "Nix search path entry '/home/runner/.nix-defexpr/channels' does not exist, ignoring" is a common issue when updating from cachix/install-nix-action version 30 to version 31. The issue is caused by the interaction between the NIX_PATH env var and the nix-path setting in nix.conf. By specifying the NIX_PATH env var, specifying the nix-path setting in nix.conf, using nix-shell with the --no-sandbox flag, or updating cachix/install-nix-action to version 32, you may be able to resolve this issue.

Additional Information

The issue is related to NixOS/nix#11079.
The NIX_PATH env var is used to specify the Nix search path.
The nix-path setting in nix.conf is used to specify the Nix search path.
The interaction between the NIX_PATH env var and the nix-path setting in nix.conf may be causing the issue.

Related Issues

References

NixOS/nix
cachix/install-nix-action
cachix/cachix-action
Frequently Asked Questions (FAQs) About "Nix Search Path Entry" Not Existing in @v31

Q: What is the "Nix search path entry" warning message?

A: The "Nix search path entry" warning message is a common issue that appears in the GitHub Workflow logs when updating from cachix/install-nix-action version 30 to version 31. The message indicates that the Nix search path entry /home/runner/.nix-defexpr/channels does not exist.

Q: What causes the "Nix search path entry" warning message?

A: The "Nix search path entry" warning message is caused by the interaction between the NIX_PATH env var and the nix-path setting in nix.conf. The NIX_PATH env var is used to specify the Nix search path, but it seems that the NIX_PATH env var is not being set correctly, resulting in the warning message.

Q: How can I resolve the "Nix search path entry" warning message?

A: There are several ways to resolve the "Nix search path entry" warning message:

Specify NIX_PATH env var: Try specifying the NIX_PATH env var in your GitHub Workflow. You can do this by adding the following line to your workflow:

      - name: Set NIX_PATH env var
        run: |
          export NIX_PATH=/home/runner/.nix-defexpr/channels

Specify nix-path setting in nix.conf: Try specifying the nix-path setting in nix.conf. You can do this by adding the following line to your workflow:

      - name: Set nix-path setting in nix.conf
        run: |
          echo "nix-path = /home/runner/.nix-defexpr/channels" >> /etc/nix/nix.conf

Use nix-shell with --no-sandbox: Try using nix-shell with the --no-sandbox flag. This flag tells Nix to not use the sandbox, which may help resolve the issue.

      - name: cabal build in nix-shell
        run: |
          nix-shell --verbose --no-sandbox --command 'cabal build all'

Update cachix/install-nix-action to v32: Try updating cachix/install-nix-action to version 32. This version may have fixed the issue.

Q: Is the "Nix search path entry" warning message related to the NixOS/nix#11079 issue?

A: Yes, the "Nix search path entry" warning message is related to the NixOS/nix#11079 issue. The issue is caused by the interaction between the NIX_PATH env var and the nix-path setting in nix.conf.

Q: How can I prevent the "Nix search path entry" warning message from appearing in my GitHub Workflow logs?

A: To prevent the "Nix search path entry" warning message from appearing in your GitHub Workflow logs, you can try the following:

Specify NIX_PATH env var: Try specifying the NIX_PATH env var in your GitHub Workflow.
Specify nix-path setting in nix.conf: Try specifying the nix-path setting in nix.conf.
Use nix-shell with --no-sandbox: Try using nix-shell with the --no-sandbox flag.
Update cachix/install-nix-action to v32: Try updating cachix/install-nix-action to version 32.

Q: What are the benefits of resolving the "Nix search path entry" warning message?

A: Resolving the "Nix search path entry" warning message can help improve the reliability and performance of your GitHub Workflow. By resolving the issue, you can ensure that your workflow runs smoothly and efficiently, without any warning messages or errors.

Q: Can I ignore the "Nix search path entry" warning message?

A: While it is technically possible to ignore the "Nix search path entry" warning message, it is not recommended. Ignoring the warning message may cause other issues or problems in your workflow, and may lead to unexpected behavior or errors.

Q: How can I get help with resolving the "Nix search path entry" warning message?

A: If you are having trouble resolving the "Nix search path entry" warning message, you can try the following:

Check the GitHub Workflow logs: Check the GitHub Workflow logs to see if there are any other warning messages or errors.
Check the Nix documentation: Check the Nix documentation to see if there are any relevant resources or information.
Ask for help on GitHub: Ask for help on GitHub by creating a new issue or commenting on an existing issue.
Contact the Nix community: Contact the Nix community by joining the Nix mailing list or participating in the Nix community forum.