$PATH in .ruby-env is not expanded

[betesh]

Description

When I put PATH=~/temp/bin:$PATH in a .ruby-env file, it treats $PATH as a literal, instead of expanding it. This is a change of behavior introduced in rvm 1.29.0.

git bisect helped me determine that this was introduced by 83edbd9

Steps to reproduce

~ $ mkdir -p ~/temp/bin && echo "2.4.0" >> ~/temp/.ruby-version && echo "PATH=~/temp/bin:\$PATH" >> ~/temp/.ruby-env

# With 1.28.0, this is valid: $PATH is the usual list of directores, including /bin, /sbin, etc
~ $ rvm get 1.28.0 && rvm reload && rvm in ~/temp do true 

# With all versions since 1.29.0, including stable and master, this blows up:
# $PATH is ~/temp/bin:$PATH, i.e. $PATH is not getting expanded when used recursively
~ $ rvm get master && rvm reload && rvm in ~/temp do true
/usr/bin/env: ‘bash’: No such file or directory
Command 'sed' is available in '/bin/sed'
The command could not be located because '/bin' is not included in the PATH environment variable.
sed: command not found

Expected behavior

$PATH should start with ~/temp/bin and then continue with the value of $PATH defined in ~/.bashrc

Actual behavior

$PATH is set to '~/temp/bin:$PATH', without $PATH being expanded

Environment info

rvm info:

ruby-2.4.0:

  system:
    uname:        "Linux my_machine_name 4.15.0-50-generic #54~16.04.1-Ubuntu SMP Wed May 8 15:55:19 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux"
    name:         "Ubuntu"
    version:      "16.04"
    architecture: "x86_64"
    bash:         "/bin/bash => GNU bash, version 4.3.48(1)-release (x86_64-pc-linux-gnu)"
    zsh:          " => not installed"
    remote_path:  "ubuntu/16.04/x86_64"

  rvm:
    version:      "1.29.8-next (master)"
    updated:      "1 minute 41 seconds ago"
    path:         "/home/me/.rvm"
    autolibs:     "[4] Allow RVM to use package manager if found, install missing dependencies, install package manager (only OS X)."

  ruby:
    interpreter:  "ruby"
    version:      "2.4.0p0"
    date:         "2016-12-24"
    platform:     "x86_64-linux"
    patchlevel:   "2016-12-24 revision 57164"
    full_version: "ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-linux]"

  homes:
    gem:          "/home/me/.rvm/gems/ruby-2.4.0"
    ruby:         "/home/me/.rvm/rubies/ruby-2.4.0"

  binaries:
    ruby:         "/home/me/.rvm/rubies/ruby-2.4.0/bin/ruby"
    irb:          "/home/me/.rvm/rubies/ruby-2.4.0/bin/irb"
    gem:          "/home/me/.rvm/rubies/ruby-2.4.0/bin/gem"
    rake:         "/home/me/.rvm/gems/ruby-2.4.0/bin/rake"

  environment:
    PATH:         "/home/me/.rvm/gems/ruby-2.4.0/bin:/home/me/.rvm/gems/ruby-2.4.0@global/bin:/home/me/.rvm/rubies/ruby-2.4.0/bin:/home/me/.rvm/bin:/home/me/.nvm/versions/node/v6.2.1/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin"
    GEM_HOME:     "/home/me/.rvm/gems/ruby-2.4.0"
    GEM_PATH:     "/home/me/.rvm/gems/ruby-2.4.0:/home/me/.rvm/gems/ruby-2.4.0@global"
    MY_RUBY_HOME: "/home/me/.rvm/rubies/ruby-2.4.0"
    IRBRC:        "/home/me/.rvm/rubies/ruby-2.4.0/.irbrc"
    RUBYOPT:      ""
    gemset:       ""

[betesh]

I just checked and this is still an issue in the latest master