Teletype subcommand creation causes nil reference error

[jschank]

Reposted from tty-file, by request.

Thanks, John for reporting!

Does the contacts command already exist when you're trying to create contacts phonelist subcommand? Would it be possible for you to report this issue at https://github.com/piotrmurach/tty since that's where the teletype tool is developed?

I cannot use teletype to create a subcommand of a command.
When I do I get an exception

> teletype add contacts phonelist --force                                                                                                                                    136ms
      create  spec/integration/contacts/phonelist_spec.rb
      create  spec/unit/contacts/phonelist_spec.rb
      create  lib/ddca/commands/contacts/phonelist.rb
      create  lib/ddca/templates/contacts/phonelist/.gitkeep
Traceback (most recent call last):
	10: from /Users/jschank/.asdf/installs/ruby/2.5.1/bin/teletype:23:in `<main>'
	 9: from /Users/jschank/.asdf/installs/ruby/2.5.1/bin/teletype:23:in `load'
	 8: from /Users/jschank/.asdf/installs/ruby/2.5.1/lib/ruby/gems/2.5.0/gems/tty-0.8.1/exe/teletype:14:in `<top (required)>'
	 7: from /Users/jschank/.asdf/installs/ruby/2.5.1/lib/ruby/gems/2.5.0/gems/thor-0.20.0/lib/thor/base.rb:466:in `start'
	 6: from /Users/jschank/.asdf/installs/ruby/2.5.1/lib/ruby/gems/2.5.0/gems/thor-0.20.0/lib/thor.rb:387:in `dispatch'
	 5: from /Users/jschank/.asdf/installs/ruby/2.5.1/lib/ruby/gems/2.5.0/gems/thor-0.20.0/lib/thor/invocation.rb:126:in `invoke_command'
	 4: from /Users/jschank/.asdf/installs/ruby/2.5.1/lib/ruby/gems/2.5.0/gems/thor-0.20.0/lib/thor/command.rb:27:in `run'
	 3: from /Users/jschank/.asdf/installs/ruby/2.5.1/lib/ruby/gems/2.5.0/gems/tty-0.8.1/lib/tty/cli.rb:88:in `add'
	 2: from /Users/jschank/.asdf/installs/ruby/2.5.1/lib/ruby/gems/2.5.0/gems/tty-0.8.1/lib/tty/commands/add.rb:131:in `execute'
	 1: from /Users/jschank/.asdf/installs/ruby/2.5.1/lib/ruby/gems/2.5.0/gems/tty-file-0.6.0/lib/tty/file.rb:512:in `inject_into_file'
/Users/jschank/.asdf/installs/ruby/2.5.1/lib/ruby/gems/2.5.0/gems/tty-file-0.6.0/lib/tty/file.rb:512:in `escape': no implicit conversion of nil into String (TypeError)

It doesn't matter if I try to define parameters or not. I met this problem when I tried a more complex call:

> teletype add contacts phone_list --desc "Color code the phone extension list" --args contacts_file extension_xslx

Ultimately resulted in the same exception, from the same place

[jschank]

Answer - from tty-file:

Yep, contacts already existed. Created with add command earlier.

[jayjlawrence]

What might not be clear is - are we permitted to add a sub command to an existing command? It does not appear this is supported:

teletype add main
teletype add main sub

I made a small script to show the issue:

#!/bin/bash

VER=2.5.1

rm -rf works || true
rm -rf issue || true
echo $VER > .ruby-version

echo "**** NEW PROJECT works ****"
teletype new works

cd works
echo $VER > .ruby-version
echo "**** ADD main sub ****"
teletype add main sub
cd ..

echo "**** NEW PROJECT issue ****"
teletype new issue
cd issue
echo $VER > .ruby-version
echo "**** ADD main ****"
teletype add main
echo "**** ADD sub ****"
teletype add main sub

I using the latest tty gem this is what I see for output:

**** NEW PROJECT works ****
Creating gem 'works'...
Code of conduct enabled in config
      create  works/Gemfile
      create  works/lib/works.rb
      create  works/lib/works/version.rb
      create  works/works.gemspec
      create  works/Rakefile
      create  works/README.md
      create  works/bin/console
      create  works/bin/setup
      create  works/.gitignore
      create  works/.travis.yml
      create  works/.rspec
      create  works/spec/spec_helper.rb
      create  works/spec/works_spec.rb
      create  works/CODE_OF_CONDUCT.md
      append  works/README.md
      inject  works/works.gemspec
      create  works/lib/works/cli.rb
      create  works/lib/works/command.rb
      create  works/exe/works
      create  works/LICENSE.txt
      create  works/lib/works/commands/.gitkeep
      create  works/lib/works/templates/.gitkeep
      create  works/spec/integration/.gitkeep
      create  works/spec/support/.gitkeep
      create  works/spec/unit/.gitkeep
Initializing git repo in /Users/jaylawrence/Projects/PwCmd/TTYissue/works

Your teletype project has been created successfully.

Run "teletype help" for more commands.

**** ADD main sub ****
      create  spec/integration/main_spec.rb
      create  spec/integration/main/sub_spec.rb
      create  spec/unit/main/sub_spec.rb
      create  lib/works/commands/main.rb
      create  lib/works/commands/main/sub.rb
      create  lib/works/templates/main/sub/.gitkeep
      inject  lib/works/cli.rb
      inject  lib/works/commands/main.rb
**** NEW PROJECT issue ****
Creating gem 'issue'...
Code of conduct enabled in config
      create  issue/Gemfile
      create  issue/lib/issue.rb
      create  issue/lib/issue/version.rb
      create  issue/issue.gemspec
      create  issue/Rakefile
      create  issue/README.md
      create  issue/bin/console
      create  issue/bin/setup
      create  issue/.gitignore
      create  issue/.travis.yml
      create  issue/.rspec
      create  issue/spec/spec_helper.rb
      create  issue/spec/issue_spec.rb
      create  issue/CODE_OF_CONDUCT.md
      append  issue/README.md
      inject  issue/issue.gemspec
      create  issue/lib/issue/cli.rb
      create  issue/lib/issue/command.rb
      create  issue/exe/issue
      create  issue/LICENSE.txt
      create  issue/lib/issue/commands/.gitkeep
      create  issue/lib/issue/templates/.gitkeep
      create  issue/spec/integration/.gitkeep
      create  issue/spec/support/.gitkeep
      create  issue/spec/unit/.gitkeep
Initializing git repo in /Users/jaylawrence/Projects/PwCmd/TTYissue/issue

Your teletype project has been created successfully.

Run "teletype help" for more commands.

**** ADD main ****
      create  spec/integration/main_spec.rb
      create  spec/unit/main_spec.rb
      create  lib/issue/commands/main.rb
      create  lib/issue/templates/main/.gitkeep
      inject  lib/issue/cli.rb
**** ADD sub ****
      create  spec/integration/main/sub_spec.rb
      create  spec/unit/main/sub_spec.rb
      create  lib/issue/commands/main/sub.rb
      create  lib/issue/templates/main/sub/.gitkeep
/Users/jaylawrence/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/tty-file-0.6.0/lib/tty/file.rb:512:in `escape': no implicit conversion of nil into String (TypeError)
	from /Users/jaylawrence/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/tty-file-0.6.0/lib/tty/file.rb:512:in `inject_into_file'
	from /Users/jaylawrence/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/tty-0.8.1/lib/tty/commands/add.rb:131:in `execute'
	from /Users/jaylawrence/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/tty-0.8.1/lib/tty/cli.rb:88:in `add'
	from /Users/jaylawrence/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/thor-0.20.3/lib/thor/command.rb:27:in `run'
	from /Users/jaylawrence/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/thor-0.20.3/lib/thor/invocation.rb:126:in `invoke_command'
	from /Users/jaylawrence/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/thor-0.20.3/lib/thor.rb:387:in `dispatch'
	from /Users/jaylawrence/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/thor-0.20.3/lib/thor/base.rb:466:in `start'
	from /Users/jaylawrence/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/tty-0.8.1/exe/teletype:14:in `<top (required)>'
	from /Users/jaylawrence/.rbenv/versions/2.5.1/bin/teletype:23:in `load'
	from /Users/jaylawrence/.rbenv/versions/2.5.1/bin/teletype:23:in `<main>'

[piotrmurach]

This is not supported. Why is that? It is impossible to distinguish between command argument and subcommand name. To make it more concrete:

mytool main arg  # the arg is the argument to command main
mytool main subcmd # the subcmd is a sub command name  

How would mytool reconcile this situation? The answer is it cannot. Basically when you run:

tty add main

This will genearte a command main. When you run mytool main it will call method called main with everything else passed as arguments or options. Then if you wished your command main to provide meaning for your arguments, you would need specify logic yourself like so:

def main(arg1)
  if arg1 == 'subcmd'
    # invoke subcmd
  end
end

The teleteype executable cannot do this for you because your main can have plenty of logic already and figuring out arguments maybe hard or impossible to automate. The one thing teletype could do is to create these commands but hooking them up with your main command would be a rather hard thing to do elegantly.

On the other hand if you wish main to support subcommands you wouldn't actually need to generate the main command first. The act of generating subcommand creates the main command as well as a namespace for all the other subcommands. The main itself would become the list of all subcommands:

tty add main subcmd1
tty add main subcmd2
...

Then you can run:

mytool main # lists all subcommands
mytool main subcmd1
mytool main subcmd2

Does that make sense? It probably would be beneficial to provide automatic explanation for this when generating commands or improve documentation?

[jayjlawrence]

As I get to know the toolkit better I see what you mean. It might be helpful in section 2.8 to specifically address this point. The way it flows is here's how to do a command called "config" and how it can do a few things, then let's (also) add a subcommand called "config set".

If you would like I could make a PR with some documentation edits that might help the new user. (because I am one right now so I know what's got me puzzled here and there).

I think that there's a case that could be made for section 2.9 which would be the kitchen sink example. In fact It think I'll build one now for myself and would be happy to add to the above edit.

I would recommend that if a command is detected when adding a subcommand that it fail and advise the user as such.

[piotrmurach]

I view documentation as essential to tty adoption. So I'm always happy to receive PRs improving the docs! If you can chunk your changes into smaller PRs that will be even better so I can review them quicker and merge. Thanks!

I will have to see what is the best approach in handling the subcommand generation when the command is already present, whether an error message gets displayed or the teletype will figure out how to and generate additional commands and let the user to manually wire them into their command.