Fix broken links, and make them an error

[huonw]

Currently running a build shows a lot of warnings about broken links, that can't be resolved. It'd be nifty to fix them, and make them an error:

pantsbuild.org/docusaurus.config.js

Lines 43 to 45 in 38e1bda

	// @TODO: This should throw on prod
	onBrokenLinks: isDev ? "warn" : "warn",
	onBrokenMarkdownLinks: isDev ? "warn" : "warn",

e.g.

$ NODE_OPTIONS="--max-old-space-size=6144" npm run build
...
[WARNING] Docs markdown link couldn't be resolved: (../../using-pants/key-concepts-to-know-about-pants/targets-and-build-files.mdx) in "/Users/huon/projects/pantsbuild/pantsbuild.org/versioned_docs/version-2.8/docs/getting-started/create-initial-build-files.mdx" for version 2.8
[WARNING] Docs markdown link couldn't be resolved: (../../using-pants/key-concepts-to-know-about-pants/targets-and-build-files.mdx) in "/Users/huon/projects/pantsbuild/pantsbuild.org/versioned_docs/version-2.8/docs/getting-started/create-initial-build-files.mdx" for version 2.8
[WARNING] Docs markdown link couldn't be resolved: (../../using-pants/resources-and-archives.mdx) in "/Users/huon/projects/pantsbuild/pantsbuild.org/versioned_docs/version-2.8/docs/getting-started/create-initial-build-files.mdx" for version 2.8
...

Before we make it an error, we'll likely also want to have validation on the Pants side, or else we'll only find out about new broken links when doing a doc sync here for a new release, and that would block merging that new release's docs.

[thejcannon]

I agree, and in general I'd love for us to keep the docs material in there pants repo "healthy"

[thejcannon]

josh@cephandrius:~/work/pantsbuild.org$ NODE_OPTIONS='--max-old-space-size=6144' npm run build

> pantsbuild.org@0.0.0 build
> docusaurus build


    ------------------------------------------------------------------------------------------------------------------------------------------------------------ 
                                                                                                                                                                 
                                                                   Update available 3.0.1 → 3.1.0                                                                
                                                                                                                                                                 
                                         To upgrade Docusaurus packages with the latest version, run the following command:                                      
        `yarn upgrade @docusaurus/core@latest @docusaurus/plugin-client-redirects@latest @docusaurus/preset-classic@latest @docusaurus/eslint-plugin@latest      
                                                              @docusaurus/module-type-aliases@latest`                                                            
                                                                                                                                                                 
    ------------------------------------------------------------------------------------------------------------------------------------------------------------ 

[INFO] [en] Creating an optimized production build...

✔ Client
  

✔ Server
  Compiled successfully in 14.53m

(node:62066) ExperimentalWarning: The Fetch API is an experimental feature. This feature could change at any time
(Use `node --trace-warnings ...` to show where the warning was created)

✔ Client
  

● Server █████████████████████████ cache (99%) shutdown IdleFileCachePlugin
 stored

[SUCCESS] Generated static files in "build".
[INFO] Use `npm run serve` command to test your build locally.
josh@cephandrius:~/work/pantsbuild.org$

I'm gonna leave this open though since making these an error wouldn't fly, as someone can introduce a broken link in the pantsbuild/pants repo :/

[kaos]

Does this cover the docs links on https://www.pantsbuild.org/versions ?

I noticed they point at /2.14.x rather than just /2.14 etc.

[thejcannon]

It should cover everything. Something must be wrong with my local setup since those are bad links, yet bumping the build to throw doesn't throw or warn 😨