Check for duplicate libraries

Oct 13, 2025 by wbrum.org 115 views

Introduction

Nx is a powerful tool for building and managing monorepos, allowing developers to create complex applications with ease. However, like any complex system, Nx can sometimes throw unexpected errors. In this article, we'll explore the Version data key already exists in version data error that can occur when running nx release version, and provide a step-by-step guide to resolving the issue.

Current Behavior

When creating a new library in an Nx project, you may encounter the following error when trying to release all packages:

Version data key "library-name" already exists in version data. This is likely a bug, please report your use-case on https://github.com/nrwl/nx.

This error can be frustrating, especially if you're not sure what's causing it. However, by analyzing the logs, you may notice that the library is already processed, but the key is duplicated.

Expected Behavior

The expected behavior is that running nx release or nx release version should not throw any errors. The release process should complete successfully, without any issues.

GitHub Repo

Unfortunately, there is no GitHub repository associated with this issue, which makes it harder to track and resolve.

Steps to Reproduce

To reproduce this issue, follow these steps:

Create a new library in your Nx project.
Try to run nx release or nx release version.

Nx Report

Here's the Nx report for the affected project:

NX   Report complete - copy this into the issue template

Node           : 18.18.0
OS             : darwin-arm64
Native Target  : aarch64-macos
yarn           : 1.22.22

nx                     : 20.5.0
@nx/js                 : 20.5.0
@nx/jest               : 20.5.0
@nx/eslint             : 20.5.0
@nx/workspace          : 20.5.0
@nx/cypress            : 20.5.0
@nx/devkit             : 20.5.0
@nx/eslint-plugin      : 20.5.0
@nx/module-federation  : 20.5.0
@nx/node               : 20.5.0
@nx/plugin             : 20.5.0
@nx/react              : 20.5.0
@nx/storybook          : 20.5.0
@nx/vite               : 20.5.0
@nx/web                : 20.5.0
typescript             : 5.7.3
---------------------------------------
Registered Plugins:
@nx/vite/plugin
@nx/eslint/plugin
@nx/jest/plugin
@nx/storybook/plugin

Failure Logs

Unfortunately, there are no failure logs available for this issue.

Package Manager Version

There is no package manager version information available for this issue.

Operating System

The operating system used for this issue is macOS.

Resolving the Issue

To resolve the Version data key already exists in version data error, follow these steps:

Check for duplicate libraries: Make sure that there are no duplicate libraries in your project. If you have multiple libraries with the same name, rename one of them to avoid conflicts.
Clear the version data: Run the following command to clear the version data: nx cache clear
Re-run the release command: Once the version data is cleared, re-run the release command: nx release version
Verify the results: Verify that the release process completes successfully without any errors.

By following these steps, you should be able to resolve the Version data key already exists in version data error and successfully release your Nx project.

Conclusion

Q: What is the `Version data key already exists in version data` error?

A: The Version data key already exists in version data error is a common issue that can occur when running nx release version in an Nx project. It indicates that the version data key for a particular library already exists in the version data, causing a conflict.

Q: What causes the `Version data key already exists in version data` error?

A: The Version data key already exists in version data error can be caused by several factors, including:

Duplicate libraries in the project
Corrupted version data
Inconsistent library names
Outdated Nx version

Q: How do I resolve the `Version data key already exists in version data` error?

A: To resolve the Version data key already exists in version data error, follow these steps:

Check for duplicate libraries in the project and rename one of them to avoid conflicts.
Clear the version data by running nx cache clear.
Re-run the release command: nx release version.
Verify the results to ensure that the release process completes successfully without any errors.

Q: What if I'm still experiencing issues after trying the above steps?

A: If you're still experiencing issues after trying the above steps, try the following:

Update Nx to the latest version by running npm install @nrwl/cli@latest or yarn add @nrwl/cli@latest.
Check the Nx logs for any errors or warnings that may indicate the cause of the issue.
Reach out to the Nx community or support team for further assistance.

Q: Can I prevent the `Version data key already exists in version data` error from occurring in the future?

A: Yes, you can prevent the Version data key already exists in version data error from occurring in the future by:

Ensuring that there are no duplicate libraries in the project.
Regularly clearing the version data by running nx cache clear.
Verifying the library names to ensure that they are consistent and unique.

Q: What are some best practices for managing version data in Nx?

A: Some best practices for managing version data in Nx include:

Regularly clearing the version data to prevent conflicts.
Verifying the library names to ensure that they are consistent and unique.
Using a consistent naming convention for libraries and versions.
Keeping the Nx version up-to-date to ensure that you have the latest features and bug fixes.

Q: Where can I find more information about the `Version data key already exists in version data` error?

A: You can find more information about the Version data key already exists in version data error by:

Checking the Nx documentation and release notes.
Searching the Nx community forums and GitHub issues.
Reaching out to the Nx support team for further assistance.

By following these best practices and troubleshooting steps, you should be able to resolve the Version data key already exists in version data error and successfully manage version data in your Nx project.