address comments

charmcraft.yaml

@@ -109,14 +109,14 @@ parts:
 config:
   options:
     always_enable_zipkin:
-      description: force enable a receiver for Tempo's 'zipkin' protocol.
+      description: Force-enable the receiver for the 'zipkin' protocol in Tempo, even if there is no integration currently requesting it.
       type: boolean
       default: false
     always_enable_otlp_grpc:
-      description: force enable a receiver for Tempo's 'otlp_grpc' protocol.
+      description: Force-enable the receiver for the 'otlp_grpc' protocol in Tempo, even if there is no integration currently requesting it.
       type: boolean
       default: false
     always_enable_otlp_http:
-      description: force enable a receiver for Tempo's 'otlp_http' protocol.
+      description: Force-enable the receiver for the 'otlp_http' protocol in Tempo, even if there is no integration currently requesting it.
       type: boolean
       default: false

src/tempo.py

@@ -265,8 +265,8 @@ def is_ready(self):
 
     def _build_receivers_config(self, receivers: Sequence[ReceiverProtocol]):  # noqa: C901
         # receivers: the receivers we have to enable because the requirers we're related to
-        # intend to use them
-        # it already includes self.enabled_receivers: receivers we have to enable because *this charm* will use them.
+        # intend to use them. It already includes receivers that are always enabled
+        # through config or because *this charm* will use them.
         receivers_set = set(receivers)
 
         if not receivers_set:

tests/scenario/test_enabled_receivers.py

@@ -28,7 +28,7 @@ def test_receivers_with_relations(context, s3, all_worker):
     with context.manager(tracing.changed_event, state) as mgr:
         charm: TempoCoordinatorCharm = mgr.charm
         # extra receivers should only include default otlp_http
-        assert charm.enabled_receivers == set(["otlp_http"])
+        assert charm.enabled_receivers == {"otlp_http"}
         out = mgr.run()
 
     tracing_out = out.get_relations(tracing.endpoint)[0]
@@ -69,7 +69,7 @@ def test_receivers_with_relations_and_config(context, s3, all_worker):
     with context.manager("config-changed", state) as mgr:
         charm: TempoCoordinatorCharm = mgr.charm
         # extra receivers should only include default otlp_http
-        assert charm.enabled_receivers == set(["otlp_http", "zipkin"])
+        assert charm.enabled_receivers == {"otlp_http", "zipkin"}
 
     # run action
     action_out = context.run_action("list-receivers", state)