alias doesn't work in fish shell on macOS

Question

I've been struggling with an issue that I cannot find mentioned anywhere and I cannot trace down. I can't leverage any of the alias command functionality in fish, which also breaks fish integrations that rely on that command (like zoxide init fish). I can manually define aliases fine (they're just functions after all), but commands like alias ls "ls -lah" don't work.

My suspicion is that somehow it's prefering to interpret alias as the macOS executable rather than the fish built-in:

> alias foo="echo foo"
> foo
fish: Unknown command: foo
> type -a alias
alias is /usr/bin/alias
> alias --help
/usr/bin/alias: line 4: alias: --: invalid option
alias: usage: alias [-p] [name[=value] ... ]

I have many fish aliases defined manually in my configs and they work, just the alias built-in itself seems to be broken.

Follow-up

Some requested additional details that don't fit in a comment:

> fish --version
fish, version 3.7.0
> set -S fish_function_path
$fish_function_path: set in global scope, unexported, with 6 elements
$fish_function_path[1]: |/Users/<REDACTED>/.config/fish/functions|
$fish_function_path[2]: |/opt/homebrew/etc/fish/functions|
$fish_function_path[3]: |/Users/<REDACTED>/.local/share/fish/vendor_functions.d|
$fish_function_path[4]: |/opt/homebrew/Cellar/fish/3.7.0/share/fish/vendor_functions.d|
$fish_function_path[5]: |/opt/homebrew/share/fish/vendor_functions.d|
$fish_function_path[6]: |/opt/homebrew/Cellar/fish/3.7.0/share/fish/functions|

Answer 1

I would simply use abbr instead:

abbr -a ls ls -lah

Abbreviations are better for multiple reasons:

• if you overwrite a basic command like ls, they let you skip the auto-expansion at times, if needed. It's not unikely to encounter such situations and you won't have to temporarily remove the alias if they occur.
• they work much better with autocompletions
• they save the original expanded command in the history. Which could be a slight disadvantage if it's your own machine and you prefer to save aliases instead to e.g. remember them. But otherwise, if working with multiple people especially, saving the original commands makes debugging easier.

Answer 2

It turns out the issue was with function auto-loading - I had a file ~/.config/fish/functions/alias.fish with some aliases in it, but this caused fish not to read the main definition at /opt/homebrew/Cellar/fish/3.7.0/share/fish/functions/alias.fish because fish explicitly looks for the first file whose name matches the function name. Renaming the file solved the issue.