[Bug] runBlocking calls from inside coroutine

[bbrockbernd]

Describe the bug

There are two instances where a runBlocking builder is called from within a coroutine. Although there are rare occasions where blocking a coroutine is desired, in general this should be avoided. Since it can hurt performance and in bad cases result in deadlocks.

Instance 1
Function didJoinWaitList containing a runBlocking call:

Android/network-protection/network-protection-impl/src/main/java/com/duckduckgo/networkprotection/impl/waitlist/NetworkProtectionWaitlistImpl.kt

Lines 110 to 112 in dd6fbf0

	private fun didJoinWaitlist(): Boolean {
	return runBlocking { netPWaitlistRepository.getWaitlistToken() != null }
	}

Is called from isTreated, which is a suspend function:

Android/network-protection/network-protection-impl/src/main/java/com/duckduckgo/networkprotection/impl/waitlist/NetworkProtectionWaitlistImpl.kt

Lines 94 to 101 in dd6fbf0

	private suspend fun isTreated(): Boolean {
	if (appBuildConfig.isInternalBuild()) {
	// internal users are always treated
	return true
	}
	// User is in beta already
	if (didJoinBeta() || didJoinWaitlist()) {
	return netPRemoteFeature.isWaitlistActive()

Fix 1
The didJoinWaitList can be turned into a suspend function since it is only called from other suspend functions, which in turn allows the runBlocking builder to be removed.

Instance 2
runBlocking call from within a flow operation (Flow.combine). The passed lambda is a suspend function.

Android/app-tracking-protection/vpn-impl/src/main/java/com/duckduckgo/mobile/android/vpn/apps/TrackingProtectionAppsRepository.kt

Lines 91 to 106 in 4d756eb

	.combine(appTrackerRepository.getManualAppExclusionListFlow()) { ddgExclusionList, manualList ->
	logcat { "getProtectedApps flow" }
	installedApps
	.map {
	val isExcluded = isExcludedFromAppTP(it, ddgExclusionList, manualList)
	runBlocking {
	TrackingProtectionAppInfo(
	packageName = it.packageName,
	name = packageManager.getApplicationLabel(it).toString(),
	category = it.parseAppCategory(),
	isExcluded = networkProtectionExclusionList.isExcluded(it.packageName) || isExcluded,
	knownProblem = hasKnownIssue(it, ddgExclusionList),
	userModified = isUserModified(it.packageName, manualList),
	)
	}
	}

Fix 2
InstalledApps can be handled as a flow with Sequence.asFlow() allowing runBlocking to be removed.

How to Reproduce

Goto:
https://github.com/duckduckgo/Android/blob/dd6fbf0df4911ba085d2c37c05f861fb1e2958f3/network-protection/network-protection-impl/src/main/java/com/duckduckgo/networkprotection/impl/waitlist/NetworkProtectionWaitlistImpl.kt
and
https://github.com/duckduckgo/Android/blob/4d756eb80aa88e334db91951156783a0b0562383/app-tracking-protection/vpn-impl/src/main/java/com/duckduckgo/mobile/android/vpn/apps/TrackingProtectionAppsRepository.kt

Expected behavior

Unblocked coroutines ;)

Environment

- DDG App Version:
- Device:
- OS:

[github-actions]

Thank you for opening an Issue in our Repository.
The issue has been forwarded to the team and we'll follow up as soon as we have time to investigate.
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[marcosholgado]

Thanks, we are actually removing some of this code soon and will be cleaning this out.