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Fixing Sphinx-Needs: Validation Issues With Variants

Alex Johnson
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Fixing Sphinx-Needs: Validation Issues With Variants

Hey everyone, let's dive into a pretty interesting bug I ran into while working with Sphinx-Needs. Specifically, it's about how the validation process handles variants. This can be a real headache if you're using them, so let's break it down.

The Problem: Pattern Validation and Variants

So, here's the deal. I was using Sphinx-Needs version 6.0.1, and I started getting this annoying warning: WARNING: Need 'SPEC_003' has validation errors: Severity: violation Field: complexity Need path: SPEC_003 Schema path: extra_options > schema > properties > complexity > pattern Schema message: '<<v1:high,high>>' does not match '^[a-zA-Z0-9:_]*(very_high|high|medium|low)(, (very_high|high|medium|low))*

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[sn_schema.extra_option_fail]. Not fun, right? Basically, Sphinx-Needs was complaining that the value of the complexity field didn't match the pattern I had defined.

To give you some context, in my reStructuredText (RST) code, I have something like this:

.. spec:: Shield Generator Specification
   :id: SPEC_003
   :complexity: <<v1:high, high>>

And in my ubproject.toml file, the complexity option is defined like this:

[[needs.extra_options]]
name = "complexity"
description = "Complexity level, very_high-low where very_high is highest and low is lowest"
schema = { type = "string", pattern = "^[a-zA-Z0-9:_]*(very_high|high|medium|low)(, (very_high|high|medium|low))*{{content}}quot; }

It looks like the schema pattern validation is happening before the variants (like <<v1:high, high>>) get resolved. This means the validator sees the raw variant syntax and freaks out because it doesn't match the pattern, which is designed for the resolved value. This bug is a pain in the butt, since it throws a warning for something that should work perfectly fine once the variants are resolved. This is where the bug is!

The crux of the issue is that Sphinx-Needs appears to be applying the schema pattern validation before it substitutes the variants. So, instead of validating against the resolved value (high, high), it's trying to validate the variant expression itself (<<v1:high, high>>). This mismatch causes the validation to fail and throw the warning.

Why is this a problem? Well, the whole point of variants is to make your documentation more flexible and adaptable. They allow you to reuse content, tailor it to different contexts, and avoid a ton of repetitive writing. If the validation system doesn't play nice with variants, you lose a lot of that flexibility. You might end up having to choose between using variants and having your documentation validated correctly. It's like choosing between two really good things and missing out on the benefits of both!

The Root Cause

This is a pretty common issue when you're working with complex documentation systems. It's important to understand the order of operations and how the tools you're using handle things like variants and validation. It's even more annoying because the underlying system works fine once it's done what it's supposed to do.

Why is this happening?

So, why does this happen? It seems that the schema pattern validation is happening before the variants are resolved. That means the validator is trying to match the raw variant syntax (<<v1:high, high>>) against the pattern. Obviously, that's not going to work. The pattern is designed to validate the final value, not the variant expression itself.

Here's a breakdown of why this order of operations matters:

This is a pretty common issue when you're working with complex documentation systems. It's important to understand the order of operations and how the tools you're using handle things like variants and validation. It's even more annoying because the underlying system works fine once it's done what it's supposed to do.

Workarounds and Expected Behavior

Here's the kicker: This only seems to be a problem for schema pattern validation. Other types of checks, like those for enums and number ranges, do work with variants. Go figure!

Workarounds

Expected Behavior

The expected behavior is that the pattern in the schema definition of extra_options should work with variants. Sphinx-Needs should resolve the variants before performing the pattern validation. This would allow you to use variants without getting validation errors, and it would make the whole process much smoother.

This is exactly the kind of thing that makes you want to understand how the tool works. You can't always change the world, but understanding what makes it tick can really help.

Implications and Impact

This bug can have several implications on your workflow and the quality of your documentation.

How to Fix This Bug?

Fixing this bug involves a few key steps to align the validation process with the expected behavior of variant resolution.

  1. Prioritize Variant Resolution: The core fix is to ensure that variant resolution occurs before schema pattern validation. This means modifying the Sphinx-Needs code to change the order of operations. The code needs to first process the RST, resolve any variants present in the fields, and then pass the resulting, resolved values to the validator.
  2. Adjust the Validation Logic: After ensuring that variants are resolved first, the validation logic needs to be adjusted to handle the resolved values properly. This means the pattern should be validated against the final, substituted content rather than the raw variant syntax. The key is to ensure the validator receives the expected input.
  3. Test Thoroughly: Once the fix is implemented, thorough testing is crucial. This includes:

Conclusion

So, there you have it. A pretty annoying bug in Sphinx-Needs. The key takeaway here is that the pattern validation is happening before the variants are resolved, which causes errors. This bug causes a disruption in the workflow and hinders documentation generation. Hopefully, this can be fixed in future versions of Sphinx-Needs. Until then, we'll have to use the workarounds.

I hope this article has been helpful, guys! If you have any questions, feel free to leave a comment below. Thanks for reading!

To keep up with the latest in Sphinx-Needs, I recommend checking out the official documentation, which will provide you with the most up-to-date information. Sphinx-Needs Documentation

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