Handle parentheses in variables in commands

[i7an]

Variables with parentheses are not handled correctly in commands:

FOO='passwo(rd'
BAR=$(echo '$FOO')

Result:

expected: {"BAR"=>"passwo(rd",           "FOO"=>"passwo(rd"}
     got: {"BAR"=>"$(echo 'passwo(rd')", "FOO"=>"passwo(rd"}

The solution I suggest is to parse commands first and expand variables before executing commands.

[i7an]

I think this is effectively private API. But kamal relies on it, which does not sound right to me. Please consider this.

I'll submit a patch to Kamal if this PR is ok.

Should I keep substitutions and call Variable from Command to reduce the chance of breaking something? 🤔

# lib/dotenv/substitutions/command.rb
def call(value, &block)
  # ...
  `#{Variable.call(command, env) }`.chomp
  # ...
end