Add linting for CODEOWNERS

[dhruvkb]

Goal

The CODEOWNERS file frequently goes out of sync with the codebase.

We need to ensure two things:

• Every file/folder in the repo has a CODEOWNERS entry.
• Every entry in CODEOWNERS must be a real, existing file/folder.

[gmottajr]

Hello Dhruv (@dhruvkb),

I Just came across your issue report and at first quickly read an idea lighted up in my mind.
This is about tackling your CODEOWNERS file synchronization request programmatically by creating a Python function. Here's a high-level overview of the Python function approach:

Step 1: List All Files/Folders in the Repository:
    We'll start by getting a list of all the files and folders in our repo.

Step 2: Parse the CODEOWNERS File:
    Next, we'll look at the CODEOWNERS file to see what's currently listed there.

Step 3: Compare Entries:
    We'll then compare these two lists to find out if there are any mismatches.

Step 4: Generate a Synchronization Report:
    If we find any discrepancies, we'll create a report to list what's missing and what shouldn't be there.

Step 5: Logging (optional):
    In case you think it would be a good idea, we can log this report to a file so that we can review it later for reference.

Optional 6: Update CODEOWNERS File:
    Depending on what we find, we can decide whether or not to automatically update the CODEOWNERS file.

Benefits:
Automation: The Python function automates the process, reducing the need for manual checks and updates, which can be time-consuming, especially in large repositories

Proactive Issue Identification: By running the synchronization function before any potential problems arise, we proactively identify discrepancies or misconfigurations between the CODEOWNERS file and the codebase. These issues might not yet have caused any problems, but they have the potential to do so in the future.

Preventing Future Errors: Identifying and addressing these discrepancies early on helps prevent future errors and complications. For example, if an important file or folder lacks an entry in CODEOWNERS, this might not immediately impact the project, but it could lead to confusion or security concerns later.

Maintaining Codebase Integrity: Keeping the CODEOWNERS file in sync ensures the integrity of the codebase's ownership and responsibility structure. This can be crucial for collaboration and code review processes.

Efficiency: This approach streamlines the synchronization process, making it more efficient and consistent across projects.

Transparency: The synchronization report provides transparency by clearly outlining what's missing or incorrectly specified in the CODEOWNERS file, making it easier to understand and address.

Documentation: It contributes to maintaining a well-documented codebase by ensuring that every file and folder has a corresponding entry in CODEOWNERS, which can be especially valuable for onboarding new team members.

Customization: The Python function can be customized to fit specific project needs and can be integrated into existing workflows, such as CI/CD pipelines.

Logging: By logging the synchronization report, we create a historical record of changes and can easily review the state of CODEOWNERS at different points in time.

So basically, this is the plan in a nutshell. If needed, how does that sound? I can dive deeper into the specifics and actually write the Python function though.
Let me know your thoughts!
Cheers,

[dhruvkb]

There is a package https://github.com/mszostok/codeowners-validator that already does the checking for us. We need to integrate it into our lint hooks (managed by pre-commit in the .pre-commit-config.yaml file). pre-commit supports Docker hooks so we can use the Docker approach to add this our repo.

Would you like to add it to our Git hooks? If so I can assign the issue to you.

[gmottajr]

Yeah, sure, I'll give it a try.
Please assign the issue to me.

[dhruvkb]

This change was completed by #3570.