The or_create for new GH teams does not create new teams

[MrMarvin]

Context

Given we have a Shipit instance that formerly only members of our orgs Github team admin had access to. We now added the handle myorg/developers to the github.oauth.teams config list.

Issue

All requests to Shipit now fail due to an exception raised:

NoMethodError (undefined method `each' for nil:NilClass)

Analysis

irb(main):005:0> team = Shipit::Team.find_or_create_by_handle('myorg/developers')
Traceback (most recent call last):
        1: from (irb):5
NoMethodError (undefined method `each' for nil:NilClass)


irb(main):006:0> team = Shipit::Team.find_or_create_by_handle('myorg/admins')
=> #<Shipit::Team id: 4, github_id: 54321, api_url: "https://api.github.com/organizations/12345/team/...", slug: "admins", name: "admins", organization: "myorg", created_at: "2020-02-21 09:35:32", updated_at: "2020-02-21 09:35:32">

Please note: The first case also seem to not reach out got Github, at least it returns instantly, too fast for a networked API call.

Workaround

Manually invoke

Shipit::Team.fetch_and_create_from_github('myorg','developers')

via rails console

[casperisfine]

It's documented in the setup guide:

github.oauth.teams optional, required only if you want to restrict access to a set of GitHub teams.

If it's missing, the Shipit installation will be public unless you setup another authentication method.

After you change the list of teams, you have to invoke bin/rake teams:fetch to prefetch the team members.

shipit-engine/docs/setup.md

Line 121 in 4411b81

**`github.oauth.teams`** optional, required only if you want to restrict access to a set of GitHub teams.

Maybe we could fetch the missing team on the fly though, not sure.

[casperisfine]

Also it certainly shouldn't fail with a NoMethodError on nil.

[MrMarvin]

The mentioned rake task ultimate invokes #find_or_create_by_handle, which then fails with the NoMethodError.

[MrMarvin]

After looking into the stacktrace for a little longer, it seems to be an issue in a different area: Caching.
It appears Shipit-engine has cached an empty response from Github (for whatever reason it was empty to begin with...) in the github api faraday cache:

irb(main):005:0> Shipit.github.api.org_teams('myorg', per_page: 100)
=> nil

irb(main):023:0> Rails.cache.clear
=> "OK"

irb(main):024:0> Shipit.github.api.org_teams('myorg', per_page: 100)
=> [{:name=>"some-team",
[...]

[casperisfine]

That's interesting. I'd need to investigate wether that comes from HTTP caching or from an application layer of cache.