def determine_install_method
return :http if @options[:force_http]
best = @base_command.environment.best_install_method?
@method = @@default_method if best == :http and @method == :export
case
when (best == :http and @method != :http)
msg = "Cannot install using subversion because `svn' cannot be found in your PATH"
when (best == :export and (@method != :export and @method != :http))
msg = "Cannot install using #{@method} because this project is not under subversion."
when (best != :externals and @method == :externals)
msg = "Cannot install using externals because vendor/plugins is not under subversion."
end
if msg
puts msg
exit 1
end
@method
end