feat: change method=profile:back to screen=previous

[aeneasr]

BREAKING CHANGE: When using two-step registration, it was previously possible to send method=profile:back to get to the previous screen. This feature was not documented in the SDK API yet. Going forward, please instead use screen=previous.

Checklist

• I have read the contributing guidelines.
• I have referenced an issue containing the design document if my change
  introduces a new feature.
• I am following the
  contributing code guidelines.
• I have read the security policy.
• I confirm that this pull request does not address a security
  vulnerability. If this pull request addresses a security vulnerability, I
  confirm that I got the approval (please contact
  [email protected]) from the maintainers to push
  the changes.
• I have added tests that prove my fix is effective or that my feature
  works.
• I have added or changed the documentation.

Further Comments

[mszekiel]

Would it be possible to additionally unify the behavior between login and registration? Right now login provides identifier_first node which has similar role than the profile:back if I understand that correctly.

But I believe this is some amount of additional work.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.

Project coverage is 78.65%. Comparing base (340f698) to head (d52215f).
Report is 9 commits behind head on master.

Files with missing lines	Patch %	Lines
...fservice/strategy/profile/two_step_registration.go	0.00%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4119      +/-   ##
==========================================
+ Coverage   78.63%   78.65%   +0.01%     
==========================================
  Files         377      377              
  Lines       26942    26942              
==========================================
+ Hits        21185    21190       +5     
+ Misses       4146     4142       -4     
+ Partials     1611     1610       -1     

Flag	Coverage Δ
	78.65% <0.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[aeneasr]

Would it be possible to additionally unify the behavior between login and registration? Right now login provides identifier_first node which has similar role than the profile:back if I understand that correctly.

That is kind of correct, I wanted to add a back button but decided against it due to time constraints, and used the identifier_first node as sort of a "workaround". But it's not good, because it adds an implicit dependency on this node.

I'm not entirely sure how to best handle this. Ideally we would have something like login_hint in the login flow object that is the identifier of the user, and maybe add a back button to identifier first auth.

@jonas-jonas wdyt?