[remote_base] Log an error for registrations without a codegen slot, dedupe mapped dumpers

esphome/components/remote_base/__init__.py

@@ -233,11 +233,16 @@ def validate_dumpers(value):
         return validate_dumpers(list(DUMPER_REGISTRY.keys()))
     if isinstance(value, list):
         # a dumper listed twice would register twice; the receiver holds one secondary dumper
-        value = (
-            list(dict.fromkeys(value))
-            if all(isinstance(v, str) for v in value)
-            else value
-        )
+        seen: set[str] = set()
+        deduped = []
+        for item in value:
+            key = item if isinstance(item, str) else next(iter(item), None)
+            if isinstance(key, str):
+                if key in seen:
+                    continue
+                seen.add(key)
+            deduped.append(item)
+        value = deduped
     return cv.validate_registry("dumper", DUMPER_REGISTRY)(value)
 
 

esphome/components/remote_base/remote_base.cpp

@@ -99,13 +99,30 @@ bool RemoteReceiverBinarySensorBase::on_receive(RemoteReceiveData src) {
 
 /* RemoteReceiverBase */
 
+// Slots are counted at code generation; a registration from C++ setup() has none
+#ifdef REMOTE_BASE_LISTENER_COUNT
+void RemoteReceiverBase::register_listener(RemoteReceiverListener *listener) {
+  if (this->listeners_.size() == REMOTE_BASE_LISTENER_COUNT) {
+    ESP_LOGE(TAG, "No %s slot: register it from to_code() with remote_base.add_%s", LOG_STR_LITERAL("listener"),
+             LOG_STR_LITERAL("listener"));
+    return;
+  }
+  this->listeners_.push_back(listener);
+}
+#endif
+
 #ifdef REMOTE_BASE_DUMPER_COUNT
 void RemoteReceiverBase::register_dumper(RemoteReceiverDumperBase *dumper) {
   if (dumper->is_secondary()) {
     this->secondary_dumper_ = dumper;
-  } else {
-    this->dumpers_.push_back(dumper);
+    return;
   }
+  if (this->dumpers_.size() == REMOTE_BASE_DUMPER_COUNT) {
+    ESP_LOGE(TAG, "No %s slot: register it from to_code() with remote_base.add_%s", LOG_STR_LITERAL("dumper"),
+             LOG_STR_LITERAL("dumper"));
+    return;
+  }
+  this->dumpers_.push_back(dumper);
 }
 #endif
 

esphome/components/remote_base/remote_base.h

@@ -213,7 +213,7 @@ class RemoteReceiverBase : public RemoteComponentBase {
  public:
   RemoteReceiverBase(InternalGPIOPin *pin) : RemoteComponentBase(pin) {}
 #ifdef REMOTE_BASE_LISTENER_COUNT
-  void register_listener(RemoteReceiverListener *listener) { this->listeners_.push_back(listener); }
+  void register_listener(RemoteReceiverListener *listener);
 #endif
 #ifdef REMOTE_BASE_DUMPER_COUNT
   void register_dumper(RemoteReceiverDumperBase *dumper);

tests/components/remote_receiver/bare-common.yaml

@@ -1,4 +1,6 @@
-# A receiver with no dumpers and no listeners compiles both lists out
+# A receiver with no dumpers and no listeners compiles both lists out.
+# Only built while remote_receiver is tested in isolation: the counts are global defines,
+# so this variant cannot be merged with configs that register any.
 remote_receiver:
   - id: rcvr_bare
     pin: ${pin}