[arp242]

Plus shells also behave different depending on how it's invoked (e.g. as "sh" rather than "zsh" or "bash") which can affect the output of these builtins.

My own preference these days is to explicitly use /bin/zsh and just rely on zsh behaviour (e.g. "$+commands[ls]"). It's not "compatible" in the sense of "POSIX compatible", but it's more compatible in the sense of "much higher chance everything will work on a random system", with the only downside that people will need to install zsh. I think that's a fair trade-off for many (though obviously not all) cases.