Implement "code pr" opening an existing pull request if one exists

[begedin]

Description

Branching off of PR #8 to avoid potential trouble and to have something to make a PR out of (for testing). Nothing is implemented yet. In hindsight, this wasn't actually necessary.

The actuall changes are in

• Gemfile - new gem
• bin/code - new authorize command, modification of the publish command
• lib/github_api.rb - new class for communicating with the GitHub API via the octokit gem.

Unfortunately, there is no simple way to find a PR from the command-line or via hub. The only way this seems to be possible is through the GitHub API.

I actually contacted github and was promptly answered that this is exactly the case:

Yep, that's possible, but you need to use the API:

https://developer.github.com/v3/pulls/#list-pull-requests

Notice that you can specify the head and/or the base branch for that API endpoint in the query parameters, which allows you to fetch the list of pull requests for those branches.

E.g. here's the pull request for the push-changes branch in github/linguist

https://api.github.com/repos/github/linguist/pulls?head=github:push-changes

Does that help?

Since that would mean we'd have to handle authentication on code side instead of relying on hub authentication, I found a gem called github_api as well as one called octokit.

After some testing, I decided to go with the second one. It seems more developed and more robust than the first.

Issues

Unfortunately, I have difficulties with code due to using linux, which I haven't realized I had before.

• The open console command does something on linux different compared to mac. The correct command to be used on my system is ˙xdg-open, but some linux systems also havegnome-open` and other variations.
• When doing a code pr to create a new pull request, hub prompts for username and password, it seems, but there's no actual prompt in the console for me. It just hangs there, allowing input, but not indicating what that input is. If I try typing in my credentials, I get various errors, but I haven't yet figured out how and what to type in to get past it.

Basically, code has issues on linux :)

Flow

To elaborate, with this feature, the user is required to log in once, using

code authorize --username "username" --password "password"

After that an oauth token will be created and stored into the global .gitconfig file. The token will be used to fetch and the proper pull request url and open it in browser.

I don't see a way around this, but I'm thinking there should also be a prompt in that case, to ask for credentials if code pr was called before code authorize being called first. Either that, or we make code pr accept a --username and --password option to and call authorize internally if it's needed and the options are provided, displaying an error otherwise.

Basically

• User calls code pr
• PR doesn't exist -> PR is created
• PR exists
  • If code is already authorized, open PR
  • If code is not already authorized
  • Solution A - user needs to pass in --username and --password with code pr. Authorization runs. If options are not passed in, code shows an error with the instruction to pass them in.
  • Solution B - user is prompted for username and password directly and then authorize gets called before code pr is fetched and open. I'm not sure how simple this is to implement.

NOTE: I decided to go with Solution A for the time being. It's faster to implement and more typical of command line behavior.

[begedin]

@venkatd: I did some refactoring which was made possible by switching from using System.call to System.result (we don't want the configuration retrieval calls to get printed out to the standard output anyway, in my opinion).

I decided not to switch to the additional layer of a config object, for two simple reasons:

• we only have two properties to retrieve - origin url and auth token
• one of these two (auth token) now has a special case of throwing an error with further instructions if it's missing

If we end up having more in the future, then we'd have a case for adding a different layer, but for now, it seems like it would add complexity - mostly due to the special error case.

[venkatd]

@begedin do you prefer solution A or solution B? If you present several solutions, it will be a good habit to explain which option you prefer and why.

[begedin]

Sorry, I meant to add a comment. I went with solution A because it seems more straightforward and typical of command line behavior. The user is explained they need to call "code authorize" once, but isn't prompted for credentials directly.