fix(api): emit disconnected directly from didCompleteWithError to trigger auto-retry

[thisisabhash]

Issue #

#4220

Description

fix(api): emit disconnected directly from didCompleteWithError to trigger auto-retry

Summary

Fixes #4220. Resolves GraphQL subscriptions getting permanently stuck in connecting state after repeated iOS background/foreground transitions.

Problem

When iOS suspends the app process, the kernel defuncts TCP flows bound to the WebSocket connection. On foreground return, didCompleteWithError fires with NSPOSIXErrorDomain Code=53 "Software caused connection abort". The old code handled this by calling networkMonitor.updateState(.offline), expecting NWPathMonitor to later fire .online to trigger reconnection. But NWPathMonitor only fires on path changes — if the network path never actually changed (the socket just died from process suspension), no .online event arrives and the client stays dead permanently.

Root Cause

Reconnection after connection abort depends on NWPathMonitor firing .online:

case (NSPOSIXErrorDomain.self, Int(ECONNABORTED)):
    subject.send(.error(WebSocketClient.Error.connectionLost))
    Task { await self?.networkMonitor.updateState(.offline) }

This pushes .offline to the network monitor scan, but reconnection only happens when NWPathMonitor fires .online to produce (.offline, .online). If the network path never changed (process suspension doesn't change the network path), no .online arrives and the client is permanently stuck.

Fix

File: WebSocketClient.swift

Instead of going through the network monitor, directly cancel the stale connection and emit .disconnected(.invalid, nil). This triggers the existing auto-retry mechanism (retryOnCloseCode(.invalid)) which creates a new connection — no dependency on NWPathMonitor.

case (NSPOSIXErrorDomain.self, Int(ECONNABORTED)),
     (NSPOSIXErrorDomain.self, 57):
    subject.send(.error(WebSocketClient.Error.connectionLost))
    Task { [weak self] in
        await connection?.cancel(with: .invalid, reason: nil)
        subject.send(.disconnected(.invalid, nil))
    }

Verification

Unit test — AWSPluginsCoreTests/WebSocketClientTests (1 new test)

Test	What it verifies
testWebSocketClient_whenConnectionAborts_shouldEmitDisconnectedAndReconnect	Connection abort emits .disconnected and auto-retry reconnects

Test plan

swift test --filter "WebSocketClientTests"  # 9/9 pass (8 existing + 1 new, no regressions)

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 66.87%. Comparing base (7428f64) to head (6699e47).
⚠️ Report is 41 commits behind head on main.

Files with missing lines	Patch %	Lines
...ore/AWSPluginsCore/WebSocket/WebSocketClient.swift	50.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4222      +/-   ##
==========================================
+ Coverage   66.72%   66.87%   +0.14%     
==========================================
  Files        1151     1151              
  Lines       43817    43796      -21     
==========================================
+ Hits        29239    29289      +50     
+ Misses      14578    14507      -71     

Flag	Coverage Δ
API_plugin_unit_test	68.33% <ø> (-0.07%)	⬇️
AWSPluginsCore	68.05% <50.00%> (-0.43%)	⬇️
Amplify	47.47% <ø> (ø)
Amplify_Foundation_Bridge_unit_test	62.28% <ø> (ø)
Amplify_Foundation_unit_test	67.64% <ø> (ø)
Analytics_plugin_unit_test	83.43% <ø> (ø)
Auth_plugin_unit_test	72.30% <ø> (+0.01%)	⬆️
DataStore_plugin_unit_test	82.71% <ø> (+1.01%)	⬆️
Firehose_plugin_unit_test	53.15% <ø> (ø)
Geo_plugin_unit_test	73.39% <ø> (ø)
Kinesis_plugin_unit_test	52.17% <ø> (ø)
Logging_plugin_unit_test	64.86% <ø> (ø)
Predictions_plugin_unit_test	33.89% <ø> (ø)
PushNotifications_plugin_unit_test	85.66% <ø> (ø)
RecordCache_unit_test	76.40% <ø> (ø)
Storage_plugin_unit_test	78.67% <ø> (ø)
unit_tests	66.87% <50.00%> (+0.14%)	⬆️

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[jvh-aws]

nit: can we run swiftformat?