insert_into_file fails with "`merge': no implicit conversion of nil into Hash (TypeError)" when given no config

[technicalpickles]

I ran into this while writing a Rails template. Consider this small template:

# insert_into_file_test.rb
insert_into_file "some_file" do
  "hello this is content for some_file"
end

Running rails new -m insert_into_file_test.rb test-insert-into-file-test fails with:

       apply  /Users/technicalpickles/src/insert_into_file_test.rb
/Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/actions/inject_into_file.rb:35:in `merge': no implicit conversion of nil into Hash (TypeError)
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/actions/inject_into_file.rb:35:in `initialize'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/actions/inject_into_file.rb:27:in `new'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/actions/inject_into_file.rb:27:in `insert_into_file'
	from /Users/technicalpickles/src/insert_into_file_test.rb:1:in `apply'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/actions.rb:224:in `instance_eval'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/actions.rb:224:in `apply'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/generators/app_base.rb:162:in `apply_rails_template'
	from (eval):1:in `apply_rails_template'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/command.rb:27:in `run'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/invocation.rb:126:in `invoke_command'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/invocation.rb:133:in `block in invoke_all'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/invocation.rb:133:in `each'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/invocation.rb:133:in `map'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/invocation.rb:133:in `invoke_all'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/group.rb:232:in `dispatch'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/base.rb:444:in `start'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/commands/application/application_command.rb:24:in `perform'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/command.rb:27:in `run'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor/invocation.rb:126:in `invoke_command'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/thor-0.19.4/lib/thor.rb:369:in `dispatch'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/command/base.rb:63:in `perform'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/command.rb:44:in `invoke'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/railties-5.1.2/lib/rails/cli.rb:16:in `<top (required)>'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:68:in `require'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/lib/ruby/gems/2.4.0/gems/railties-5.1.2/exe/rails:9:in `<top (required)>'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/bin/rails:22:in `load'
	from /Users/technicalpickles/.rbenv/versions/2.4.1/bin/rails:22:in `<main>'

Clearly a developer error, since most uses of this require the use of :after to indicate where to insert the content. It looks like :before or :after are required, so if there is neither, that should be an error.

Rails is using the most recent thor, 0.19.4, and the same code seems to be in master.

[enigmatt-pl]

This branch fixes it, unless you meant something else?