Only offer to verify if a cross-signed device is available

[uhoreg]

Fixes #4864

Content

Currently, on logging in, it will offer to verify against another device if the user has any other devices, even if they are not cross-signed. This change uses the function introduced in matrix-org/matrix-rust-sdk#5699 to check whether the user has any cross-signed devices, and will only offer to verify if one is available.

Motivation and context

#4864

Screenshots / GIFs

No "Use another device" button

Tests

• Signed in a test user with Element Web, but did not verify
• Ensured that the user had no other devices
• Signed in to Element X, and check that "Confirm your dentity" screen did not offer to "Use another device"
• Signed out of Element X
• Reset cross-signing in Element Web
• Signed in to Element X, and check that "Confirm your identity" screen now offers to "Use another device"

Tested devices

• Physical
• Emulator
• OS version(s): Android 16 (API 36.0)

Checklist

• Changes have been tested on an Android device or Android emulator with API 24
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
• Pull request is based on the develop branch
• Pull request title will be used in the release note, it clearly define what will change for the user
• Pull request includes screenshots or videos if containing UI changes
• You've made a self review of your PR

[github-actions]

Thank you for your contribution! Here are a few things to check in the PR to ensure it's reviewed as quickly as possible:

• Your branch should be based on origin/develop, at least when it was created.
• The title of the PR will be used for release notes, so it needs to describe the change visible to the user.
• The test pass locally running ./gradlew test.
• The code quality check suite pass locally running ./gradlew runQualityChecks.
• If you modified anything related to the UI, including previews, you'll have to run the Record screenshots GH action in your forked repo: that will generate compatible new screenshots. However, given Github Actions limitations, it will prevent the CI from running temporarily, until you upload a new commit after that one. To do so, just pull the latest changes and push an empty commit.

[codecov]

Codecov Report

❌ Patch coverage is 86.95652% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.02%. Comparing base (43ad874) to head (d43e3da).
⚠️ Report is 95 commits behind head on develop.

Files with missing lines	Patch %	Lines
...es/matrix/impl/encryption/RustEncryptionService.kt	72.72%	1 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #5433      +/-   ##
===========================================
- Coverage    81.03%   81.02%   -0.01%     
===========================================
  Files         2312     2312              
  Lines        63450    63463      +13     
  Branches      8012     8014       +2     
===========================================
+ Hits         51414    51419       +5     
- Misses        9099     9106       +7     
- Partials      2937     2938       +1     

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[uhoreg]

Trying to get Maestro running locally so I can look into the failure, because the CI log isn't very helpful. The code coverage seems to be complaining about missing a test on the mapRecoveryException line. Otherwise, I think this is pretty much ready for review.

[bmarty]

Thanks!

isLastDevice is also used in LogoutView, to warn the user if this is the last session. I am wondering if the new hasDevicesToVerifyAgainst could be used there too. What do you think?

Also, having this screen:

with actually no options to confirm seems a bit annoying for the user. We may want to iterate on the design in this case.
Can't we enter the recovery key?

[bmarty]

For clarity / reduce tech debt, I think ChooseSelfVerificationModeState.isLastDevice could be renamed to canUseAnotherDevice. Do not forget to negate the boolean wherever this is necessary.

[bmarty]

Maybe add the same TODO than in the KDoc of isLastDevice. It is a bit annoying to request this value every 5s, when it's only used in the session verification screen.

[uhoreg]

Also, having this screen:

with actually no options to confirm seems a bit annoying for the user. We may want to iterate on the design in this case. Can't we enter the recovery key?

Yes, if the user has a recovery key set up, they should have a button to use the recovery key. In this case, my test user did not have a recovery key, so no button was shown, and the user's only option was "Can't confirm?", which resets the user's cross-signing keys (which is the only thing that can be done in this case).

[uhoreg]

isLastDevice is also used in LogoutView, to warn the user if this is the last session. I am wondering if the new hasDevicesToVerifyAgainst could be used there too. What do you think?

I'm not sure. I just checked what Element Web did here, and it looks like it's only checking the backup status. As far as I can tell, it doesn't seem to check at all whether there are any other devices. So we might need to make a new issue to make the clients consistent, and figure out what criteria we should use to warn the user. Anyways, I don't think hasDevicesToVerifyAgainst will be quite right, because it specifically excludes dehydrated devices, and if the user has a dehydrated device, they shouldn't be shown a warning on logout.

[uhoreg]

Tried to reproduce the CI failures. For Test / Runs unit tests the failing task succeeds on my machine. For Maestro (local) / Maestro test suite I'm having trouble getting the Maestro suite to complete, but it gets past the login section, which is the only place my PR should affect.

[bmarty]

The failing tests are related to the screenshot test, which are not run by default when running the test locally.
To avoid this problem, I think you need to use the opposite values for all boolean assigned to canUseAnotherDevice, and so the screenshot will be identical to the current version.

[bmarty]

Thanks!