fix: retry send tasks stuck in Entry state

logos_delivery/messaging/delivery_service/send_service/send_processor.nim

@@ -32,5 +32,10 @@ method process*(
     currentProcessor = currentProcessor.fallbackProcessor
     keepTrying = task.state == DeliveryState.FallbackRetry
 
-  if task.state == DeliveryState.FallbackRetry:
+  # A task still in `FallbackRetry` exhausted the chain without delivering, and
+  # one still in `Entry` was never attempted because no processor had a usable
+  # peer yet (e.g. a lightpush peer that finishes registering right after the
+  # first send). Both must be queued for the next round so the service loop
+  # retries them; otherwise the task would sit untouched until it ages out.
+  if task.state == DeliveryState.FallbackRetry or task.state == DeliveryState.Entry:
     task.state = DeliveryState.NextRoundRetry

tests/api/test_api_send.nim

@@ -352,6 +352,43 @@ suite "Waku API - Send":
     (await node.stop()).isOkOr:
       raiseAssert "Failed to stop node: " & error
 
+  asyncTest "Edge sender delivers via lightpush (no relay)":
+    ## Reproduces issue #3847: an Edge node (no relay mounted) that is only
+    ## connected to a lightpush-capable peer must deliver through lightpush.
+    var node: Waku
+    lockNewGlobalBrokerContext:
+      node = (await createNode(createApiNodeConf(cli_args.WakuMode.Edge))).valueOr:
+        raiseAssert error
+      node.mountMessagingClient().isOkOr:
+        raiseAssert "Failed to mount messaging: " & error
+      (await node.start()).isOkOr:
+        raiseAssert "Failed to start Waku node: " & error
+
+      # Edge node has no relay; its only path to the network is the
+      # lightpush peer it is connected to.
+      await node.node.connectToNodes(@[lightpushNodePeerInfo])
+
+    check node.node.wakuRelay.isNil()
+
+    let eventManager = newSendEventListenerManager(node.brokerCtx)
+    defer:
+      await eventManager.teardown()
+
+    let envelope = MessageEnvelope.init(
+      ContentTopic("/waku/2/default-content/proto"), "test payload"
+    )
+
+    let requestId = (await node.send(envelope)).valueOr:
+      raiseAssert error
+
+    const eventTimeout = 10.seconds
+    discard await eventManager.waitForEvents(eventTimeout)
+
+    eventManager.validate({SendEventOutcome.Propagated}, requestId)
+
+    (await node.stop()).isOkOr:
+      raiseAssert "Failed to stop node: " & error
+
   asyncTest "Send fully validates fallback to lightpush":
     var node: LogosDelivery
     lockNewGlobalBrokerContext: