Fixing bug with Google emails containing capital letters (SCP-6061)

[bistline]

BACKGROUND & CHANGES

This fixes a long-standing bug with some users not being able to sign back into SCP after initially creating an account. The problem lies with Devise (our main auth handler) and the fact that these users have capitalization in their emails according to their Google profiles. Since all modern email providers do not recognize capitalization, this is not normally an issue, but SCP has custom handling to decode the email from their profile and then do a lookup based on that value. If there are capital letters, the query fails. This leads to SCP trying to create a new user account (which is what happens the first time anyone logs in). This always works the first time and will fail every time after because the email address is taken, but the query will never find the correct account. This explains the infinite loop because we redirect back to the sign in page as the user hasn't successfully signed into SCP. Now, the account lookup correctly uses the downcased email, as this is what is saved by Devise.

MANUAL TESTING

If you do not have access to an email account with capitalization of the email in the Google profile, it is not possible to test this manually. The new UserTest should correctly find user if profile has capital letters covers this sufficiently. You can prove that it works by doing the following:

1. Change line 126 in app/models/user.rb back to the original:

user = User.create(email: data['email'],

2. Run the test manually and confirm it fails:

bin/rails test test/models/user_test.rb -n /capital/
...
  1) Failure:
UserTest#test_should_correctly_find_user_if_profile_has_capital_letters [test/models/user_test.rb:183]:
Expected false to be truthy.

[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 71.55%. Comparing base (ee78d40) to head (ac324b1).
⚠️ Report is 12 commits behind head on development.

Files with missing lines	Patch %	Lines
app/models/user.rb	80.00%	1 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           development    #2319      +/-   ##
===============================================
- Coverage        71.55%   71.55%   -0.01%     
===============================================
  Files              340      340              
  Lines            29129    29130       +1     
  Branches          2651     2651              
===============================================
  Hits             20844    20844              
- Misses            8144     8145       +1     
  Partials           141      141              

Files with missing lines	Coverage Δ
app/models/user.rb	78.32% <80.00%> (+5.55%)	⬆️

... and 3 files with indirect coverage changes

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[eweitz]

Thanks -- helpful maintenance context.