unexpected result due to paths stripping trailing /

[lolbinarycat]

Describe the bug

the recommended way to convert a string to a path is by concatenating it with another path.

however, if you concatenate multiple strings together, you may not get the result you expect

Steps To Reproduce

1. $ nix repl
2. nix-repl> /bin + "/" + "sh"
3. /binsh

Expected behavior

the repl should print /bin/sh, or at the very least print a warning about the trailing / being ignored.

nix-env --version output
nix-env (Nix) 2.18.1

Additional context

the workaround it to parenthesize the rhs: /bin + ("/" + "sh")

i ran into this when trying to implement something similar to the nixpkgs by-name system.

Priorities

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[thufschmitt]

That is a quite annoying behaviour, but also something that can't be changed without breaking backwards-compatibility.

Extra motivation for NixOS/rfcs#137 I guess :/

[lolbinarycat]

@thufschmitt surely we can print a warning of some sort when just "/" is appended to a path?

[thufschmitt]

@thufschmitt surely we can print a warning of some sort when just "/" is appended to a path?

Right, that is something that would make a lot of sense.
It's kinda blocked on #10281 atm, but if you feel like helping there, that would be immensely appreciated.