Sign in with element classic final by bmarty · Pull Request #6296 · element-hq/element-x-android

bmarty · 2026-03-06T14:09:55Z

Content

Let Element X import details from any existing session from Element Classic to sign in and verify the session automatically.

Note: require element-hq/element-android#9136 to merged and released.

Motivation and context

Help users of Element Classic migrate smoothly to Element X.

Screenshots / GIFs

See recorded ones.

Demo of the happy path (case 5 below):

Screen_recording_20260413_145110.mp4

Demo of case 11:

Screen_recording_20260413_152344.mp4

Tests

There are several cases to consider, here is a summary:

Case	Element Classic state	Effect on Element X
1	Element Classic is not installed	No effect
2	Element Classic is installed, but no session exist	No effect
3	Element Classic is installed, a session exists, but the session is not verified, or some secrets (private keys) are missing	Pre-fill the homeserver and the userId, but will not be able to verify the session
4	Element Classic is installed, a session exists, is verified, all the secrets are known, but a session with the same userId exists on Element X.This can happen since Element X supports multi accounts.	No effect.
5	Happy path:Element Classic is installed, a session exists, is verified, all the secrets are known, and no session with the same userId exists on Element X	The flow to import a session from Element Classic is possible
6	Error in the communication between the 2 applications (Android) / accessing the shared storage (iOS) to retrieve the data.	No effect, no error displayed. Only logs.
7	Edge case:Element Classic is installed, a session exists, is verified, all the secrets are known, and no session with the same userId exists on Element X. But once on the MAS page displayed by Element X, user logs in to a different account	No effect, the regular login flow continues, i.e. the user will have to manually verify the session. The secrets exported by EC will not be used and just deleted.
8	Edge case:Element X provides the “mxid:” hint to MAS, but MAS just ignores it if it is connected to another account. It could warn the user. MAS issue: The login_hint is ignored when already logged in.	If the user continues, the secrets will not be used (mismatched userId) and the user will have to verify manually.
9	Edge case:The user does not use the button to sign in with Element Classic, but does a manual login. At the end the user signs in to the same account as the Element Classic one.	It is acceptable that EX requests the secret from EC to perform the verification step automatically.
10	Element Classic is installed, a session exists, is verified, all the secrets are known, and no session with the same userId exists on Element X. But EC is logged in using SSO that Element X does not support	No effect
11	Element Classic is installed, a session exists, is verified, the cross-signing keys are known but backups nor recovery have been set up. Running the migration will transfer the cross-signing keys but no backup key. Since EX is set up to automatically create a backup, it will do so. This in turn enables Element Classic to upload backups but not download. If the user decides to log out of EX it will not get a warning about setting up recovery since it is not the last device the user has. This would leave Classic in a broken state where it uploads to the backup but has no ability to download backups.	Display a dialog telling the user that they should first enable keybackup on Element Classic, before login using Element X. When the user is done with Element Classic, when Element X is resumed, the data are loaded again
12	Element Classic has a verified session, had a key backup, but key backup is now deleted. Element Classic still exports the old key backup key to Element X	Handle the same as 11.

Tested devices

Physical
Emulator
OS version(s):

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 · 2026-03-06T14:32:05Z

📱 Scan the QR code below to install the build (arm64 only) for this PR.

If you can't scan the QR code you can install the build via this link: https://i.diawi.com/X8bbcj

sonarqubecloud · 2026-03-06T16:07:04Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

codecov · 2026-03-06T16:43:46Z

Codecov Report

❌ Patch coverage is 72.30216% with 154 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.04%. Comparing base (c73d004) to head (fd3c4c2).
⚠️ Report is 29 commits behind head on develop.

Files with missing lines	Patch %	Lines
...res/login/impl/classic/ElementClassicConnection.kt	72.39%	34 Missing and 11 partials ⚠️
...atrix/impl/auth/RustMatrixAuthenticationService.kt	0.00%	36 Missing ⚠️
...ies/designsystem/components/avatar/BitmapAvatar.kt	25.64%	27 Missing and 2 partials ⚠️
.../features/login/impl/LoginFlowTransitionHandler.kt	0.00%	14 Missing ⚠️
...chitecture/appyx/FaderOrSliderTransitionHandler.kt	0.00%	14 Missing ⚠️
...s/classic/loginwithclassic/LoginWithClassicView.kt	95.32%	4 Missing and 1 partial ⚠️
...id/libraries/androidutils/service/ServiceBinder.kt	0.00%	4 Missing ⚠️
...s/classic/missingkeybackup/MissingKeyBackupView.kt	89.65%	0 Missing and 3 partials ⚠️
...t/android/features/login/impl/login/LoginHelper.kt	50.00%	1 Missing and 1 partial ⚠️
...ogin/impl/screens/classic/ClassicFlowNodeHelper.kt	96.00%	1 Missing ⚠️
... and 1 more

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #6296      +/-   ##
===========================================
+ Coverage    81.02%   81.04%   +0.02%     
===========================================
  Files         2596     2608      +12     
  Lines        71726    72098     +372     
  Branches      9288     9337      +49     
===========================================
+ Hits         58114    58432     +318     
- Misses       10199    10236      +37     
- Partials      3413     3430      +17

☔ View full report in Codecov by Sentry.
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Ensure that the timeout has effect only in Idle state.

jmartinesp

Some minor comments about the code, just nitpicks so feel free to ignore them.

I'll give it another check with the IDE later and then test it. How should I test this, btw? Do I need versions of EXA and EA signed with some specific keys?

jmartinesp · 2026-04-13T14:29:24Z

+                // Do not emit error, else the regular on boarding flow will be displayed
+                // emitState(ElementClassicConnectionState.Error("The messenger is null, can't request data"))


Should this still be around?

jmartinesp · 2026-04-13T14:30:27Z

+@ContributesBinding(AppScope::class)
+@SingleIn(AppScope::class)
+class DefaultElementClassicConnection(


Maybe some diagram or explanation of how the flow should happen would be helpful as docs.

jmartinesp · 2026-04-13T14:30:53Z

+    }
+
+    override fun start() {
+        Timber.tag(loggerTag.value).w("start()")


Should this be a debug log now?

jmartinesp · 2026-04-13T14:32:48Z

+    private val mutableStateFlow = MutableStateFlow<ElementClassicConnectionState>(ElementClassicConnectionState.Idle)
+    override val stateFlow = mutableStateFlow.asStateFlow()


Nit: should this be at the start of this component?

Is using a getter better to you?
get() = mutableStateFlow.asStateFlow()

Oh, I just meant other properties are at the top of the component (~L75), so this should probably be there too?

Sure. I was confused because this class has a fun start() 😅

jmartinesp · 2026-04-13T14:35:22Z

+    private fun getElementClassicComponent() = ComponentName(
+        BuildConfig.elementClassicPackage,
+        ELEMENT_CLASSIC_SERVICE_FULL_CLASS_NAME,
+    )


Nit: this could probably be a val instead?

Oh yes, the function was different before.

bmarty · 2026-04-14T07:59:46Z

How should I test this, btw? Do I need versions of EXA and EA signed with some specific keys?

The code should run with debug versions and release version of the applications (EC debug <-> EX debug) and (EC release <-> EX release). But I need to check if nightly build could communicate together I do not think this is the case.

You can install Element Classic from develop (now that element-hq/element-android#9136 has been merged) and EX from this branch (using diawi QR code should be OK)

jmartinesp

It works really well! Just a couple of things I noticed:

I had a couple of sessions on EXA that I've been using for a while (so multi-account enabled). When I logged out of both accounts to test this, EXA wouldn't display the new screen to use EA's session data. After I cleared the app's data this was working, so maybe the logout didn't get rid of some data in the local DBs and case 4 happened, where EXA thought it didn't need to display anything because the same session already existed? Or maybe it was the force-kill that helped with this? It's not a blocking issue IMO, and I can't reproduce it anymore.
Another weird thing I experienced is I had EA with an account without key storage and EXA already opened in the initial screen. I then verified EA and went back to EXA, and when trying to log in it still asked me to verify my account, maybe because the session data had been shared before I verified EA (in the new initial screen)? Restarting the app used the right flow and I was logged in and verified directly.

bmarty · 2026-04-14T14:05:16Z

For point 1, I am not sure what happened.
For point 2, we EX is resumed on the Sign in with Classic screen, the data is not refreshed on this screen, only in the MissingKeyBackup screen (here). This could be changed and the data could be refreshed each time ClassicFlowNode is resumed maybe. Not sure if it could have some side effect, but I can give it a try

This ensure that Element X is always up to date regarding Element Classic state.

bmarty · 2026-04-14T15:03:23Z

Thanks @jmartinesp. I have added fd3c4c2 that should ensure that Element X is always up to date with Element Classic. So now:

start EX. The screen to login to Element Classic is displayed
go to background and to foreground. Nothing particular happen (in particular no glitch in the avatar that got fetched again)
switch to Element Classic
change the avatar of the account
switch to Element X: the avatar should be updated
switch to Element Classic
Sign out
switch to Element X: the screen to login with Classic is replaced by the on boarding screen

I have also checked that there is no regression when the screen to go and enable key backup on Element Classic is displayed.

Also this change is simplifying the code, so all good!

sonarqubecloud · 2026-04-14T15:12:45Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

ElementBot · 2026-04-14T15:18:44Z

+    private val slider: ModifierTransitionHandler<LoginFlowNode.NavTarget, BackStack.State>,
+    private val fader: ModifierTransitionHandler<LoginFlowNode.NavTarget, BackStack.State>,
+) : ModifierTransitionHandler<LoginFlowNode.NavTarget, BackStack.State>() {
+    override fun createModifier(


⚠️ Modifier factory functions should be extensions on Modifier

ElementBot · 2026-04-14T15:18:44Z

+     * Handler of incoming messages from service.
+     */
+    @Suppress("DEPRECATION")
+    inner class IncomingHandler : Handler() {


⚠️ This Handler class should be static or leaks might occur (io.element.android.features.login.impl.classic.DefaultElementClassicConnection.IncomingHandler)

ElementBot · 2026-04-14T15:18:44Z

+    private val slider: ModifierTransitionHandler<NavTarget, BackStack.State>,
+    private val fader: ModifierTransitionHandler<NavTarget, BackStack.State>,
+) : ModifierTransitionHandler<NavTarget, BackStack.State>() {
+    override fun createModifier(


⚠️ Modifier factory functions should be extensions on Modifier

bmarty added the PR-Feature For a new feature label Mar 6, 2026

bmarty force-pushed the feature/bma/signInWithElementClassicFinal branch from 01673ce to 8abb802 Compare March 6, 2026 14:23

bmarty added the Record-Screenshots Runs the 'Record Screenshots' CI job and adds a commit with any new screenshots found. label Mar 6, 2026

bmarty added Record-Screenshots Runs the 'Record Screenshots' CI job and adds a commit with any new screenshots found. and removed Record-Screenshots Runs the 'Record Screenshots' CI job and adds a commit with any new screenshots found. labels Mar 6, 2026

bmarty force-pushed the feature/bma/signInWithElementClassicFinal branch from 10f8556 to 7927b17 Compare March 16, 2026 17:27

bmarty force-pushed the feature/bma/signInWithElementClassicFinal branch 2 times, most recently from 52a59e8 to 436113a Compare April 9, 2026 12:55

bmarty added Record-Screenshots Runs the 'Record Screenshots' CI job and adds a commit with any new screenshots found. and removed Record-Screenshots Runs the 'Record Screenshots' CI job and adds a commit with any new screenshots found. labels Apr 9, 2026

github-actions Bot removed the Record-Screenshots Runs the 'Record Screenshots' CI job and adds a commit with any new screenshots found. label Apr 9, 2026

bmarty and others added 4 commits April 13, 2026 11:16

Fix typo

683b1fe

Sign in with Classic

8c5caab

Update screenshots

62f2251

Ignore secrets when the bundle does not contain the room keys version.

73e1a09

bmarty force-pushed the feature/bma/signInWithElementClassicFinal branch from f39687d to 73e1a09 Compare April 13, 2026 09:16

bmarty marked this pull request as ready for review April 13, 2026 12:42

bmarty requested a review from a team as a code owner April 13, 2026 12:42

bmarty requested review from jmartinesp and removed request for a team April 13, 2026 12:42

Fix navigation issue.

f5e1cbe

Ensure that the timeout has effect only in Idle state.

bmarty force-pushed the feature/bma/signInWithElementClassicFinal branch from 676c11c to f5e1cbe Compare April 13, 2026 13:37

jmartinesp reviewed Apr 13, 2026

View reviewed changes

bmarty added 3 commits April 14, 2026 10:12

Improve log and reduce severity.

1962b96

Make elementClassicComponent a val.

53c20f3

Move vals at the top of the class.

76de9db

jmartinesp approved these changes Apr 14, 2026

View reviewed changes

Refresh Element Classic state each time ClassicFlowNode is resumed.

fd3c4c2

This ensure that Element X is always up to date regarding Element Classic state.

ElementBot reviewed Apr 14, 2026

View reviewed changes

bmarty merged commit 4b8368f into develop Apr 14, 2026
32 of 34 checks passed

bmarty deleted the feature/bma/signInWithElementClassicFinal branch April 14, 2026 21:00

This was referenced Apr 15, 2026

Take into account the value of FeatureFlags.SignInWithClassic #6586

Merged

[Task] Sign in with Element Classic #6143

Closed

		// Do not emit error, else the regular on boarding flow will be displayed
		// emitState(ElementClassicConnectionState.Error("The messenger is null, can't request data"))

		private val mutableStateFlow = MutableStateFlow<ElementClassicConnectionState>(ElementClassicConnectionState.Idle)
		override val stateFlow = mutableStateFlow.asStateFlow()

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