fix: skip default nodeinfo upsert in handleReceivedUser for live packets (#3819)

Author: mdecourcy

app/src/main/java/com/geeksville/mesh/service/MeshService.kt

@@ -992,6 +992,17 @@ class MeshService : Service() {
         sessionPasskey = a.sessionPasskey
     }
 
+    /**
+     * Check if a User is a default/placeholder from firmware (node was evicted and re-created) and whether we should
+     * preserve existing user data instead of overwriting it.
+     */
+    private fun shouldPreserveExistingUser(existing: MeshProtos.User, incoming: MeshProtos.User): Boolean {
+        val isDefaultName = incoming.longName.matches(Regex("^Meshtastic [0-9a-fA-F]{4}$"))
+        val isDefaultHwModel = incoming.hwModel == MeshProtos.HardwareModel.UNSET
+        val hasExistingUser = existing.id.isNotEmpty() && existing.hwModel != MeshProtos.HardwareModel.UNSET
+        return hasExistingUser && isDefaultName && isDefaultHwModel
+    }
+
     private fun handleSharedContactImport(contact: AdminProtos.SharedContact) {
         handleReceivedUser(contact.nodeNum, contact.user, manuallyVerified = true)
     }
@@ -1006,22 +1017,37 @@ class MeshService : Service() {
         updateNodeInfo(fromNum) {
             val newNode = (it.isUnknownUser && p.hwModel != MeshProtos.HardwareModel.UNSET)
 
-            val keyMatch = !it.hasPKC || it.user.publicKey == p.publicKey
-            it.user =
-                if (keyMatch) {
-                    p
-                } else {
-                    p.copy {
-                        Timber.w("Public key mismatch from $longName ($shortName)")
-                        publicKey = NodeEntity.ERROR_BYTE_STRING
+            // Check if this is a default/unknown user from firmware (node was evicted and re-created)
+            val shouldPreserve = shouldPreserveExistingUser(it.user, p)
+
+            if (shouldPreserve) {
+                // Firmware sent us a placeholder - keep all our existing user data
+                Timber.d(
+                    "Preserving existing user data for node $fromNum: " +
+                        "kept='${it.user.longName}' (hwModel=${it.user.hwModel}), " +
+                        "skipped default='${p.longName}' (hwModel=UNSET)",
+                )
+                // Still update channel and verification status
+                it.channel = channel
+                it.manuallyVerified = manuallyVerified
+            } else {
+                val keyMatch = !it.hasPKC || it.user.publicKey == p.publicKey
+                it.user =
+                    if (keyMatch) {
+                        p
+                    } else {
+                        p.copy {
+                            Timber.w("Public key mismatch from $longName ($shortName)")
+                            publicKey = NodeEntity.ERROR_BYTE_STRING
+                        }
                     }
+                it.longName = p.longName
+                it.shortName = p.shortName
+                it.channel = channel
+                it.manuallyVerified = manuallyVerified
+                if (newNode) {
+                    serviceNotifications.showNewNodeSeenNotification(it)
                 }
-            it.longName = p.longName
-            it.shortName = p.shortName
-            it.channel = channel
-            it.manuallyVerified = manuallyVerified
-            if (newNode) {
-                serviceNotifications.showNewNodeSeenNotification(it)
             }
         }
     }
@@ -1723,14 +1749,9 @@ class MeshService : Service() {
         updateNodeInfo(info.num) {
             if (info.hasUser()) {
                 // Check if this is a default/unknown user from firmware (node was evicted and re-created)
-                val isDefaultName = info.user.longName.matches(Regex("^Meshtastic [0-9a-fA-F]{4}$"))
-                val isDefaultHwModel = info.user.hwModel == MeshProtos.HardwareModel.UNSET
-                val hasExistingUser = it.user.id.isNotEmpty() && it.user.hwModel != MeshProtos.HardwareModel.UNSET
-
-                // If firmware sends a default user (evicted node), preserve our existing user data
-                val shouldPreserveExisting = hasExistingUser && isDefaultName && isDefaultHwModel
+                val shouldPreserve = shouldPreserveExistingUser(it.user, info.user)
 
-                if (shouldPreserveExisting) {
+                if (shouldPreserve) {
                     // Firmware sent us a placeholder - keep all our existing user data
                     Timber.d(
                         "Preserving existing user data for node ${info.num}: " +