How do I remap a trailing slash?

[AndrewKvalheim]

I’d like to perform this transformation, which I believe requires matching the trailing slash:

/     → /index.html
/a    → /a.html
/a/   → /a/index.html
/a/a  → /a/a.html
/a/a/ → /a/a/index.html

Surprisingly, something in lychee eats the trailing slash before I have a chance:

$ echo '<a href='{/,/a,/a/,/a/a,/a/a/}'>' > a.html
$ lychee --dump --base . a.html
file:///tmp/demo
file:///tmp/demo/a
file:///tmp/demo/a/a

Five distinct paths went in, but only three came out. Is there some default remapping rule I need to disable first?

[mre]

I haven't looked into it, but I think it's because of incorrect path concatenation when providing a base.
There are similar issues in the issue tracker. I think this part needs more tests to fix edge-cases. It is a somewhat ad-hoc implementation that was hand-rolled for lychee's needs, and it's not my best work, I'm afraid.

At least the url crate is not the culprit. It keeps the trailing slash, as can be seen in this Rust playground example.

[mre]

Dropping a note to myself here to try https://github.com/danreeves/path-clean for path handling.