Multi-instance docs with baseUrl doesn't work

[semoal]

🐛 Bug Report

Prerequisites

• I'm using the latest version of Docusaurus.
• I have tried the npm run clear or yarn clear command.
• I have tried rm -rf node_modules yarn.lock package-lock.json and re-installing packages.
• I have tried creating a repro with https://new.docusaurus.io
• I have read the console error message carefully (if applicable)

Description

Basically adding a baseUrl to our config, and two docs one pointing to "/" and other to "/example", "/example" won't work.

Have you read the Contributing Guidelines on issues?

Yes

Steps to reproduce

https://stackblitz.com/edit/github-fjbw7h?file=docusaurus.config.js

Here it is a reproducible repo, you can check that chaning baseUrl to "/" will make it work, or keeping the "/latest/" but adding a baseUrl to "/" docs path.

Expected behavior

(Write what you thought would happen.)

• It should accept a baseUrl like: /latest/
• One doc, should be able to navigate to root: /latest/{docURL} (without /docs/ prefix)
• Other doc, should be able to navigate to basePath passed: latest/{routeBasePath}/{docUrl}

I entered on debug mode and I think the problem is that the router since it is not exact, it tries to navigate to the first group to routes, but on there isn't the /latest/forms/.

Not sure how we can fix this ^^

Actual behavior

It should navigate correctly.

Reproducible demo

https://stackblitz.com/edit/github-fjbw7h?file=docusaurus.config.js

[slorber]

Agree, it seems our route ordering logic does not handle baseUrl and /baseUrl/ could end-up being before /baseUrl/someDocPluginInstance.

Related to #5645

@lex111 do you want to fix it?

Note I found some interesting route ranking algo in ReachUI recently: https://reach.tech/router/ranking
https://github.com/zoontek/react-chicane/blob/main/src/matcher.ts#L7

[lex111]

Do you mean just add support for baseUrl or implement route ranking algo? Apparently as a quick fix, it would be better to add baseUrl instead simply slash as now?

[semoal]

An easy and fast fix (if introducing router ranking it's complex) could be:

server.ts file on @docusaurus/core

-    sortConfig(pluginsRouteConfigs)
+    sortConfig(pluginsRouteConfigs, context.siteConfig.baseUrl);

SortConfig url checking with baseUrl:

- if (a.path === "/" && b.path !== "/") {
-   return 1;
- }
- if (a.path !== "/" && b.path === "/") {
-   return -1;
- }
+ if (a.path === baseUrl && b.path !== baseUrl) {
+   return 1;
+ }
+ if (a.path !== baseUrl && b.path === baseUrl) {
+   return +1;
+ }

[lex111]

Yes, that's what I meant, it should work.