Fix api key loading if RubyGems host is development

[jenshenny]

What was the end-user or developer problem that led to this PR?

From: #6624 (comment)

The gem signin fails with a warning if the host is localhost:3000

RUBYGEMS_HOST=http://localhost:3000 ruby -Ilib bin/gem signin
Failed to load /Users/jennyshen/.local/share/gem/credentials because it doesn't contain valid YAML hash
Failed to load /Users/jennyshen/.local/share/gem/credentials because it doesn't contain valid YAML hash
Enter your http://localhost:3000 credentials.
Don't have an account yet? Create one at http://localhost:3000/sign_up
   Email:   test2@example.com
Password:   

API Key name [Jennys-MacBook-Pro-2.local-jennyshen-20230516143333]:   
Please select scopes you want to enable for the API key (y/n)
index_rubygems [yN]  
...
Signed in with API key: Jennys-MacBook-Pro-2.local-jennyshen-20230516143333.
Failed to load /Users/jennyshen/.local/share/gem/credentials because it doesn't contain valid YAML hash
Failed to load /Users/jennyshen/.local/share/gem/credentials because it doesn't contain valid YAML hash

The original PR checks for invalid yaml like invalid: foo: bar by checking if there is : in the key. It is possible to have : as a part of the key like http://localhost:3000.

What is your fix for the problem, implemented in this PR?

Change the includes?(":") to includes?(": ") as that would prompt invalid yaml.

Furthermore, after the warning was fixed, keys with http://localhost:3000 still aren't successfully loaded. This is because

When the api keys gets loaded, the localhost key has a trailing / causing Gem.configuration.api_keys.key?(host) to fail.

[41, 50] in /Users/jennyshen/src/github.com/Shopify/rubygems/lib/rubygems/gemcutter_utilities.rb
   41:   ##
   42:   # The API key from the command options or from the user's configuration.
   43: 
   44:   def api_key
   45:     byebug
=> 46:     if ENV["GEM_HOST_API_KEY"]
   47:       ENV["GEM_HOST_API_KEY"]
   48:     elsif options[:key]
   49:       verify_api_key options[:key]
   50:     elsif Gem.configuration.api_keys.key?(host)
(byebug) Gem.configuration.api_keys
{"http://localhost:3000/"=>"rubygems_"}
(byebug) Gem.configuration.api_keys.key?(host)
false

The serialized key gets converted back here

• If the key contains __, it gets replaced with . and removes the trailing forward slash.

In the case of localhost:3000, since there aren't any __ because the original host doesn't contain any . , the forward slash never gets removed. I changed the elsif to remove any trailing forward slash.

cc: @hsbt

Make sure the following tasks are checked

• Describe the problem / feature
• Write tests for features and bug fixes
• Write code to solve the problem
• Make sure you follow the current code style and write meaningful commit messages without tags

[ericherscovich]

Looks good thank you!

[indirect]

looks good to me, let's get a review from @hsbt or @deivid-rodriguez to double check 👍🏻

[deivid-rodriguez]

It looks good to me!

[jenshenny]

Would anyone be able to merge this in? I don't have merge access for this repo 😄

[indirect]

done!