chore: review-cleanup fleet (audit + fix + hardening) (#5158)

core/prefs/src/commonMain/kotlin/org/meshtastic/core/prefs/FlowCache.kt

@@ -19,19 +19,31 @@ package org.meshtastic.core.prefs
 import kotlinx.atomicfu.AtomicRef
 import kotlinx.collections.immutable.PersistentMap
 
-internal inline fun <K, V> cachedFlow(cache: AtomicRef<PersistentMap<K, V>>, key: K, build: () -> V): V {
-    var resolved = cache.value[key]
-    if (resolved == null) {
-        val newValue = build()
-        while (resolved == null) {
-            val current = cache.value
-            val currentValue = current[key]
-            if (currentValue != null) {
-                resolved = currentValue
-            } else if (cache.compareAndSet(current, current.put(key, newValue))) {
-                resolved = newValue
-            }
+/**
+ * Look up [key] in [cache]; if absent, construct a value via [build] and insert it atomically.
+ *
+ * [build] is wrapped in a [Lazy] before being published to [cache], so concurrent first-access of the same key never
+ * invokes [build] more than once — only the winner of the CAS has its [Lazy] evaluated, and all readers share that same
+ * result. This matters when [build] eagerly launches a coroutine (e.g. `Flow.stateIn(scope, Eagerly, …)`): the naive
+ * approach would leak the losing coroutine into a never-cancelled scope.
+ */
+@Suppress("ReturnCount")
+internal inline fun <K, V> cachedFlow(
+    cache: AtomicRef<PersistentMap<K, Lazy<V>>>,
+    key: K,
+    crossinline build: () -> V,
+): V {
+    cache.value[key]?.let {
+        return it.value
+    }
+    val newLazy = lazy(LazyThreadSafetyMode.SYNCHRONIZED) { build() }
+    while (true) {
+        val current = cache.value
+        current[key]?.let {
+            return it.value
+        }
+        if (cache.compareAndSet(current, current.put(key, newLazy))) {
+            return newLazy.value
         }
     }
-    return checkNotNull(resolved)
 }

core/prefs/src/commonMain/kotlin/org/meshtastic/core/prefs/map/MapConsentPrefsImpl.kt

@@ -42,7 +42,7 @@ class MapConsentPrefsImpl(
 ) : MapConsentPrefs {
     private val scope = CoroutineScope(SupervisorJob() + dispatchers.default)
 
-    private val consentFlows = atomic(persistentMapOf<Int?, StateFlow<Boolean>>())
+    private val consentFlows = atomic(persistentMapOf<Int?, Lazy<StateFlow<Boolean>>>())
 
     override fun shouldReportLocation(nodeNum: Int?): StateFlow<Boolean> = cachedFlow(consentFlows, nodeNum) {
         val key = booleanPreferencesKey(nodeNum.toString())

core/prefs/src/commonMain/kotlin/org/meshtastic/core/prefs/mesh/MeshPrefsImpl.kt

@@ -18,7 +18,6 @@ package org.meshtastic.core.prefs.mesh
 
 import androidx.datastore.core.DataStore
 import androidx.datastore.preferences.core.Preferences
-import androidx.datastore.preferences.core.booleanPreferencesKey
 import androidx.datastore.preferences.core.edit
 import androidx.datastore.preferences.core.intPreferencesKey
 import androidx.datastore.preferences.core.stringPreferencesKey
@@ -45,8 +44,7 @@ class MeshPrefsImpl(
 ) : MeshPrefs {
     private val scope = CoroutineScope(SupervisorJob() + dispatchers.default)
 
-    private val locationFlows = atomic(persistentMapOf<Int?, StateFlow<Boolean>>())
-    private val storeForwardFlows = atomic(persistentMapOf<String?, StateFlow<Int>>())
+    private val storeForwardFlows = atomic(persistentMapOf<String?, Lazy<StateFlow<Int>>>())
 
     override val deviceAddress: StateFlow<String?> =
         dataStore.data
@@ -65,15 +63,6 @@ class MeshPrefsImpl(
         }
     }
 
-    override fun shouldProvideNodeLocation(nodeNum: Int?): StateFlow<Boolean> = cachedFlow(locationFlows, nodeNum) {
-        val key = booleanPreferencesKey(provideLocationKey(nodeNum))
-        dataStore.data.map { it[key] ?: false }.stateIn(scope, SharingStarted.Eagerly, false)
-    }
-
-    override fun setShouldProvideNodeLocation(nodeNum: Int?, provide: Boolean) {
-        scope.launch { dataStore.edit { prefs -> prefs[booleanPreferencesKey(provideLocationKey(nodeNum))] = provide } }
-    }
-
     override fun getStoreForwardLastRequest(address: String?): StateFlow<Int> = cachedFlow(storeForwardFlows, address) {
         val key = intPreferencesKey(storeForwardKey(address))
         dataStore.data.map { it[key] ?: 0 }.stateIn(scope, SharingStarted.Eagerly, 0)
@@ -92,8 +81,6 @@ class MeshPrefsImpl(
         }
     }
 
-    private fun provideLocationKey(nodeNum: Int?) = "provide-location-$nodeNum"
-
     private fun storeForwardKey(address: String?): String = "store-forward-last-request-${normalizeAddress(address)}"
 
     companion object {

core/prefs/src/commonMain/kotlin/org/meshtastic/core/prefs/ui/UiPrefsImpl.kt

@@ -46,7 +46,7 @@ class UiPrefsImpl(
     private val scope = CoroutineScope(SupervisorJob() + dispatchers.default)
 
     // Maps nodeNum to a flow for the for the "provide-location-nodeNum" pref
-    private val provideNodeLocationFlows = atomic(persistentMapOf<Int, StateFlow<Boolean>>())
+    private val provideNodeLocationFlows = atomic(persistentMapOf<Int, Lazy<StateFlow<Boolean>>>())
 
     override val appIntroCompleted: StateFlow<Boolean> =
         dataStore.data.map { it[KEY_APP_INTRO_COMPLETED] ?: false }.stateIn(scope, SharingStarted.Eagerly, false)