NixOS Build Failure: Sonarlint-ls Issue & Solution

Dec 3, 2025 by Alex Johnson 51 views

Experiencing build failures in NixOS can be frustrating, especially when working with essential tools like sonarlint-ls. This article delves into a specific build failure encountered with sonarlint-ls in NixOS, offering insights into the cause and potential solutions. If you're encountering a similar issue, this guide aims to provide clarity and help you resolve the problem efficiently.

Understanding the sonarlint-ls Build Failure in NixOS

The core issue revolves around a hash mismatch during the build process of sonarlint-ls. Let's break down the error message:

error: hash mismatch in fixed-output derivation '/nix/store/6yn6knx05cghc07xssc01d18zw974403-maven-deps-sonarlint-ls-3.25.0.76263.drv':
         specified: sha256-cRDrd2QysN3KCndfdnTn8/hXuJ1xd28GcE8vrd6ILuM=
            got:    sha256-Fk6JPMmzz7YnPWOdWKOXQ8z6bdYuXSgQdWBOaIlpd4A=
error: Cannot build '/nix/store/ncqpg4dwjbfnjl02d2l20n6dgr123gn8h-sonarlint-ls-3.25.0.76263.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/76ahqqix94kaa8xjkn7wp48s4wpv52yx-sonarlint-ls-3.25.0.76263

This error message indicates that the expected SHA256 hash of a dependency (maven-deps-sonarlint-ls-3.25.0.76263.drv) doesn't match the actual hash computed during the build. This discrepancy prevents Nix from building sonarlint-ls correctly.

Keywords are crucial here. When a NixOS build failure occurs, especially related to sonarlint-ls, it's often due to inconsistencies in dependency hashes. This hash mismatch tells us that the expected content of a dependency doesn't align with what's actually being downloaded or built. This could stem from various factors, including network issues, changes in upstream repositories, or even potential corruption during the download process. Understanding the root cause of this hash mismatch is the first step towards resolving the issue and getting sonarlint-ls up and running in your NixOS environment.

Possible Causes of the Hash Mismatch

Several factors can contribute to this hash mismatch, and it's essential to consider each one to diagnose the problem effectively:

Upstream Changes: The most common cause is that the upstream dependency has been updated, and its new version has a different hash. This means the hash stored in the Nixpkgs repository is outdated. When a sonarlint-ls build fails due to this, it indicates that the declared hash for a dependency no longer matches the actual hash of the downloaded file. This situation often arises when the maintainers of the upstream project release a new version or modify an existing one.
Network Issues: Intermittent network problems during the download of dependencies can lead to incomplete or corrupted files. If the file isn't fully downloaded or if there's corruption, the calculated hash will differ from the expected one. Therefore, troubleshooting NixOS build failures often involves checking your internet connection and ensuring that there are no disruptions during the build process.
Cache Corruption: While less frequent, corruption in the Nix store can also cause hash mismatches. The Nix store is where all packages and dependencies are stored, and if a file within the store becomes corrupted, it can lead to incorrect hash calculations. While Nix is designed to prevent corruption, it's a possibility worth considering, especially if other troubleshooting steps haven't resolved the issue. When NixOS reports a hash mismatch, cache corruption is a less common but still potential cause, and it may require more advanced solutions to address.
Nixpkgs Repository Issues: In rare cases, there might be an issue within the Nixpkgs repository itself, such as an incorrect hash being committed. While the Nixpkgs team is diligent in maintaining the repository, errors can sometimes occur. If you suspect this, it's worth checking the Nixpkgs issue tracker or contacting the maintainers to see if there's a known problem. Resolving NixOS package build errors sometimes requires checking for repository-specific issues.

These are the most common reasons for hash mismatches, and identifying the correct one is crucial to fixing the problem.

Solutions to Resolve the Build Failure

Now that we've explored the potential causes, let's discuss the solutions to get your sonarlint-ls build working again:

Update Nixpkgs: The first and often most effective solution is to update your Nixpkgs channel. This ensures you have the latest package definitions, including updated hashes. To update Nixpkgs, run the following command:
```
nix-channel --update
```
After updating, try building sonarlint-ls again:
```
nix build nixpkgs#sonarlint-ls
```
Updating Nixpkgs is a fundamental step in resolving NixOS build problems, as it synchronizes your system with the latest package information and fixes. This ensures that your system is using the most current definitions and hashes, which can resolve the mismatch and allow the build to proceed. By updating, you're essentially aligning your local system with the latest known good state, which is critical for resolving many common build errors. If a NixOS package fails to build, this should be the first troubleshooting step you take.
Override the Hash: If updating Nixpkgs doesn't resolve the issue, you can manually override the hash in your configuration.nix or through the command line. This approach is useful when you know the correct hash and want to bypass the outdated one in Nixpkgs. To override the hash, you'll need to determine the correct hash of the dependency. You can do this by trying to fetch the dependency directly using Nix:
```
nix-prefetch-url <dependency-url>
```
Replace <dependency-url> with the URL of the problematic dependency. Nix will download the file and output its hash. Once you have the correct hash, you can override it in your configuration. If you're building sonarlint-ls directly, you can use the --arg flag:
```
nix build nixpkgs#sonarlint-ls --arg overrideMavenDeps ''
```
Overriding the hash is a powerful technique for addressing NixOS hash mismatch errors, but it should be used with caution. It's essential to ensure that you're using the correct hash for the dependency, as using an incorrect hash can lead to further issues or even security vulnerabilities. This approach is particularly useful when you've verified that the upstream dependency has changed, and you have the new, correct hash. When you encounter a NixOS error message related to hash mismatches, overriding can provide a quick workaround while waiting for the official Nixpkgs repository to update.
Check Network Connectivity: Ensure you have a stable internet connection. Intermittent connectivity issues can lead to incomplete downloads and hash mismatches. Try downloading the dependency manually using wget or curl to verify your connection's stability.
Clean the Nix Store: Sometimes, cleaning the Nix store can resolve issues caused by corrupted files. Use the garbage collector to remove unused packages and free up space:
```
nix-collect-garbage -d
```
This command will remove any unreferenced packages from the Nix store, potentially resolving corruption issues. Performing a NixOS garbage collection is a good maintenance practice, as it removes unnecessary files and can sometimes resolve build issues caused by corrupted packages. By cleaning the Nix store, you ensure that your system is working with a fresh set of files, which can help resolve hash mismatches and other build-related errors. When you face a NixOS build failure, cleaning the store is a step that can help eliminate potential issues caused by corrupted data.
Report the Issue: If none of the above solutions work, it's possible that there's a genuine issue with the Nixpkgs package definition. In this case, report the problem to the Nixpkgs maintainers. Providing detailed information, including the error message, your system configuration, and steps to reproduce the issue, will help them diagnose and fix the problem.

As the original issue reporter did, you can notify the maintainers by tagging them in your issue report (e.g., @tricktron).

Reporting the issue is a crucial step in contributing to the NixOS community and ensuring that the problem is addressed for everyone. By providing detailed information about your NixOS build issue, you help the maintainers understand the problem and develop a fix. This collaborative approach is essential for maintaining the quality and stability of Nixpkgs. When you encounter a NixOS error that you can't resolve on your own, reporting it helps ensure that the community can work together to find a solution.

Conclusion

Build failures due to hash mismatches can be frustrating, but understanding the underlying causes and applying the appropriate solutions can help you overcome these challenges. In the case of sonarlint-ls in NixOS, updating Nixpkgs, overriding the hash, checking network connectivity, cleaning the Nix store, and reporting the issue are all valuable steps to consider.

By following this guide, you should be well-equipped to troubleshoot and resolve sonarlint-ls build failures and ensure a smooth development experience in NixOS.

For further information on NixOS and package management, you can refer to the official NixOS website.