Incorrectly builds urls for Github Enterprise API endpoints

[toddmohney]

The default Github Enterprise installation exposes its API at endpoints
prefixed with /api/v3. The current version of Octokit, however, has a bug
where when configuring the api_endpoint, as recommended, results in requests to an
incorrect url.

Expected behavior

Configuring the Octokit client's api_endpoint value as

client = Octokit::Client.new(
  api_endpoint: "https://somedomain.com/api/v3",
  client_id: "123"
)

then calling client.check_application_authorization("some-token")

should result in a request to

https://somedomain.com/api/v3/applications/abc/tokens/some-token

Actual behavior

A request is made to

https://somedomain.com/applications/abc/tokens/some-token

Notice the omitted /api/v3

Steps to reproduce

We've put together a repository with a simple demonstration of this bug. Run rspec spec/test.rb from the root of this repository

Investigation

The problem can be traced down to where the request url is built in Faraday

On these lines, base is a URI instance and the + operator is defined on URI as an alias to merge which does not exhibit the same behavior as concatenation and is why the /api/v3 portion of the path gets lost.

Proposed resolution

At the moment, I'm not certain how to correct this issue from Octokit's point of view, but am happy to help.

[jrockks]

Liucevse

[gdiggs]

@tarebyte any thoughts here?

[tarebyte]

@toddmohney @gordondiggs let me take a look to see if I can help you resolve this issue, apologies for the delay.

[tarebyte]

@toddmohney @gordondiggs after playing around with this for a bit, I think the patch is going to have to be upstream to Faraday.

Without some serious hackery I don't see how we can fix this on the Octokit side of things.

[gdiggs]

Thanks @pengwynn @tarebyte!