inert is not treated as a boolean attribute

[JoeMorgan]

Astro Info

Astro                    v5.0.5
Node                     v22.1.0
System                   macOS (x64)
Package Manager          npm
Output                   server
Adapter                  @astrojs/netlify
Integrations             @astrojs/solid-js
                         @astrojs/mdx
                         @astrojs/sitemap

If this issue only occurs in one browser, which browser is a problem?

No response

Describe the Bug

Same as 12023, but in this case it's the inert attribute. When resolving the inert attribute Astro preserves the full attribute with its value: inert="true" or inert="false". This causes the relevant portion of the UI to become inert (can't interact with it via keyboard or mouse) in both true and false conditions.

On v4.X, inert="true" was output when true, and nothing was when false.

inert is not part of the list of boolean attributes at: https://github.com/withastro/astro/blob/astro%405.0.0-beta.1/packages/astro/src/runtime/server/render/util.ts#L9

What's the expected result?

As per https://5-0-0-beta.docs.astro.build/en/guides/upgrade-to/v5/#changed-non-boolean-html-attribute-values, I expect the output of inert={true} should be inert, inert={false} should not output anything.

See the specification for more details concerning this attribute.

Link to Minimal Reproducible Example

https://stackblitz.com/edit/github-s2pipusj?file=src%2Fcomponents%2FWelcome.astro

Participation

• I am willing to submit a pull request for this issue.

[JoeMorgan]

PR here: #12729