Page-to-page Markdown document links are not working

[markerikson]

🐛 Bug Report

Summary: In-page links such as [some link text](./SomeFile.md) are not getting turned into actual links to the final HTMl page.

Have you read the Contributing Guidelines on issues?

Yes

To Reproduce

A couple months ago, we set up the initial Docusaurus config for Redux. That's been sitting on a branch since then, and I'm just now poking around at it further.

The Redux docs have numerous inter-page links. Examples from the current docs:

• "Store" -> "Glossary" , using this link: [state tree](../Glossary.md#state).
• "Reducers" -> "Actions", using this link: [actions](Actions.md)

In our test deploy site at https://redux-docs.netlify.com , it looks like most or all of the internal links are broken.

1. Clone the Redux repo at https://github.com/reduxjs/redux
2. Check out the docs-rebuild branch, specifically as of commit reduxjs/redux@944df4a
3. Start Docusaurus
4. Inspect internal links such as those pages, and note that they point to something like /basics/Actions.md, instead of /basics/actions, even though the /docs/basics/Actions.md file has an ID, has been added to the sidebar, and is correctly linked from the sidebar.

Expected behavior

Simple Markdown file links would resolve correctly to the generated page URLs.

Actual Behavior

Markdown links are still pointing to the original file name in the brackets.

Note that this may be related to #1094 .

[reintroducing]

so i published my first docs page for an OSS project i'm doing and finally today pushed it out to production. ran into this as well, the sidebars seem to be linking fine but a path in the actual docs themselves did not. for instance, in tasks-home.md i'd have a link [creating](tasks-creating) which would then try to take me to tasks-home/tasks-creating. i even tried to disable cleanUrl in the siteConfig because I noticed if i went to tasks-home.html then the link worked correctly.

looking at the generated output in the build folder, docusaurus creates tasks-home.html and /tasks-home/index.html. Its within these index files that the linking is incorrect while the [page].html variants seem to work fine, but no matter what the setting is for cleanUrl, I can't get to those [page].html pages unless i 1) use the sidebar or 2) go directly to their URLs. every internal page to page link is broken, though.

its also worth noting that this all works locally before publishing, too.