[Bug]: Android: unable to connect to Uniswap using device browser

[Unik0rnMaggie]

Describe the bug

On Android Pixel 6 Pro, it's not possible to connect to Uniswap using the device's Chrome browser.
The connection modal gets stuck.

Unable to reproduce on iOS.

Unable to reproduce on other dapps like Relay or Sushi (not using wallet connect)

Expected behavior

Be able to connect to Uniswap using device chrome browser on Android

Screenshots/Recordings

Connect.uniswap.mp4

Steps to reproduce

1. Open chrome browser on Android
2. Go to Uniswap
3. Connect MetaMask
4. Notice it's not working

Error messages or log output

Where was this bug found?

Internal release testing

Version

8.3.0

Build number

6070

Build type

No response

Device

Pixel 6 Pro

Operating system

Android

Additional context

No response

Severity

No response

[metamask-ci]

Triage Agent -- Classification

Severity: Sev2 (confidence: 0.72) ⚠️ Advisory

This is a WalletConnect connection failure specific to Android when connecting to Uniswap via the device's Chrome browser (not the in-app browser). It affects a significant dApp (Uniswap) on one platform (Android), but workarounds exist (using the in-app browser, or using iOS). The connection modal gets stuck, meaning the feature is partially broken for a subset of users.
Not auto-applied -- confidence below threshold.

Size: size-M (confidence: 0.65) ⚠️ Advisory

WalletConnect connection issues involving the external browser → deeplink → WC2 pairing flow typically require investigation across multiple components (WC2Manager.connect, deeplink handling, session proposal flow). The issue could be related to Android-specific deeplink handling, WalletConnect pairing timing, or the loading state management. Multiple files may need changes.
Not auto-applied -- confidence below threshold.

Team: team-mobile-platform ✅

Matched via CODEOWNERS: @MetaMask/mobile-platform

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Root Cause Analysis

Affected component: WC2Manager (WalletConnectV2.ts) - connect() and onSessionProposal() flow

When connecting to Uniswap from Chrome on Android, the flow is: Chrome → WalletConnect deeplink → MetaMask app → WC2Manager.connect() → pairing → session_proposal → approval UI. The modal getting 'stuck' suggests the session_proposal event is either not being received, or the proposal handling is failing silently. Several potential root causes exist:

1. Deduplication over-filtering: The seenTopics Set with SEEN_TOPIC_TTL_MS = 5000 could be blocking legitimate retry attempts if Android delivers the deeplink multiple times with the same topic, causing the first attempt to fail silently and subsequent attempts to be deduplicated.

2. WC2Manager not initialized: The init() method has multiple early returns and waits (keychain unlock, 1-second delays). If getInstance() is called before init completes, the polling interval waits indefinitely. The showWCLoadingState is called in connect() but if the session_proposal never fires (e.g., pairing fails), hideWCLoadingState is never called, leaving the modal stuck.

3. Android-specific deeplink handling: The cleanUri transformation (wc:// → wc:) in connect() may not handle all Android deeplink URI formats correctly. Android may deliver the URI in a format that causes pairing to fail silently.

4. Proposal lock timeout: The PROPOSAL_LOCK_TIMEOUT_MS = 60_000 timeout could mask issues where a previous proposal is stuck, blocking new ones.

5. Navigation reference: The navigation reference obtained from NavigationService.navigation during init could be stale or undefined on Android when the app is cold-started via deeplink.

Evidence:

• Connection modal stuck - suggests showWCLoadingState called but hideWCLoadingState never reached
• Android-specific - deeplink URI handling differs between platforms
• Uniswap uses WalletConnect while other working dApps (Relay, Sushi) don't
• Version 8.3.0 reported - may be missing fixes in newer versions
• The connect() method has a seenTopics deduplication mechanism that could over-filter on Android

Suggested Fix

Confidence: medium: likely but needs investigation - the exact root cause among the several candidates needs to be confirmed with Android device debugging and WalletConnect relay logs

Investigate the WalletConnect deeplink → pairing → session_proposal flow on Android. The most likely issue is that the pairing succeeds but the session_proposal event is never received or is silently dropped, leaving the loading modal stuck. Add error handling and timeout for the loading state after pairing.

Target files: app/core/WalletConnect/WalletConnectV2.ts
Target functions: WC2Manager.connect, WC2Manager.onSessionProposal, WC2Manager._handleSessionProposal

Approach:

1. In connect(), after this.web3Wallet.core.pairing.pair(), add a timeout (e.g., 30 seconds) that will call hideWCLoadingState if no session_proposal is received, preventing the modal from being stuck indefinitely.
2. Add error handling around the pair() call to catch and log failures, and ensure hideWCLoadingState is called on error.
3. Verify the cleanUri transformation handles all Android deeplink URI formats (check if Android delivers URIs with different schemes like metamask://wc?uri=... that need additional parsing).
4. Add logging around the seenTopics deduplication to verify it's not over-filtering on Android.
5. Consider adding a pairing event listener (web3Wallet.core.pairing.events.on('pairing_expire', ...)) to detect when pairing fails and dismiss the loading state.
6. Ensure NavigationService.navigation is valid when the app is cold-started via deeplink on Android.

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Confidence threshold: 0.85. Labels marked ✅ were auto-applied. Labels marked ⚠️ are advisory only (below threshold).
To re-triage, remove the ta-bot-triage label and re-apply ta-needs-triage.
⚠️ Some dimensions could not be confidently classified. An engineer should review this issue.

[Unik0rnMaggie]

Unable to reproduce on Relay (not using wallet connect):

Connect.Relay.Pixel.6.Pro.mp4