Feature #12695


File.expand_path should resolve ~/ using /etc/passwd when HOME is not set

Added by fursten (Mårten Svantesson) over 7 years ago. Updated over 6 years ago.

Target version:


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.

Related issues 1 (0 open1 closed)

Related to Ruby master - Bug #16787: [patch] allow Dir.home to work for non-login procs when $HOME not setClosedActions

Updated by shyouhei (Shyouhei Urabe) over 7 years ago

+1 it makes sense to me.

Updated by nobu (Nobuyoshi Nakada) over 7 years ago

Why doesn't your service launcher set HOME?

Updated by akr (Akira Tanaka) about 7 years ago

I think its good idea.

Although POSIX doesn't specify it for shell, we can define it in Ruby.

Updated by knu (Akinori MUSHA) about 7 years ago

Makes sense. Ruby knows how to resolve ~user, so you may well expect it to resolve ~ as well given that the login name is identified.

Updated by knu (Akinori MUSHA) about 7 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 matz (Yukihiro Matsumoto) about 7 years ago



Actions #8

Updated by nobu (Nobuyoshi Nakada) about 7 years ago

  • Status changed from Open to Closed

Applied in changeset r56902.

file.c: home directory from system

  • file.c (rb_default_home_dir): resolve home directory from the
    system database when HOME is not set. [Feature #12695]

Updated by pabs (Paul Wise) over 6 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>'

Updated by nobu (Nobuyoshi Nakada) over 6 years ago

This is a new feature of 2.4.

Actions #11

Updated by shyouhei (Shyouhei Urabe) over 3 years ago

  • Related to Bug #16787: [patch] allow Dir.home to work for non-login procs when $HOME not set added

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