Alias Paths Differ Only by Case

Two paths differ only in capitalization, which macOS and Windows treat as the same file.

Q-5-25 — Alias Paths Differ Only by Case

Two paths differ only in capitalization, which macOS and Windows treat as the same file.

What this means

Linux filesystems are usually case-sensitive: Deploy.html and deploy.html are two files. macOS and Windows, by default, are not — there, they are one file, and whichever is written second replaces the first.

This error fires when two aliases: entries resolve to paths that differ only in case, or when one does so against a page the project renders:

# one.qmd
aliases:
  - /Deploy.html

# two.qmd
aliases:
  - /deploy.html      # the same file on macOS and Windows

Why it is checked everywhere

The check runs on every platform, including case-sensitive ones. That is deliberate.

A site built on Linux CI where both files were written looks correct in the build log. Serve it from a case-insensitive filesystem — or let a contributor check it out on a Mac — and one redirect silently disappears. Catching it at build time on every platform is what makes the output portable.

How to fix it

Rename one of the two so they differ by more than capitalization. If both spellings need to work, pick one as the real alias; a case-insensitive host will serve it for either spelling anyway.

Difference from Quarto 1

Quarto 1 compares paths as exact strings, so it never notices. On a case-insensitive filesystem the redirects overwrite each other silently.