File.expand_path should resolve ~/ using /etc/passwd when HOME is not set
I would expect a call like File.expand_path('~/.ssh/known_hosts') to work even though HOME is not set.
A reason this is important to fix is that libraries (in my use case Net::SSH) do calls like File.expand_path('~/.ssh/known_hosts'), but this will often fail when the code is run in a unix service, since HOME often isn't set then.
I considered reporting this as a bug, but the current behaviour is actually documented.
Updated by knu (Akinori MUSHA) about 6 years ago
Bash seems to do that:
% bash -c 'unset HOME; echo ~'
As far as I tested most other known shells like tcsh, zsh, ash, dash and pdksh do not, but we could follow the best.
Through my testing, I found fish unique in that it automatically defines a missing HOME on startup and then expands ~ simply to $HOME. While it would keep things simple and efficient, Ruby is not a shell after all, and altering the environment would clearly be something unasked for.
I think following Bash should be the way to go.
Updated by pabs (Paul Wise) over 5 years ago
Does anyone know if this also fixes the Dir.home value? Currently (in 2.3) that doesn't work when HOME is unset either.
pabs@chianamo ~ $ unset HOME pabs@chianamo /home/pabs $ ruby -e 'print Dir.home' -e:1:in `home': couldn't find HOME environment -- expanding `~' (ArgumentError) from -e:1:in `<main>'