[remote_base] Reject unknown protocol names and log a dropped secondary dumper

esphome/components/remote_base/__init__.py

@@ -136,15 +136,19 @@ def protocol_define(name: str) -> str:
     return f"USE_REMOTE_PROTOCOL_{_protocol_stem(name).upper()}"
 
 
-def request_protocol(name: str) -> None:
-    """Keep a protocol's source file in the build; components using it from C++ must call this."""
-    cg.add_define(protocol_define(name))
-
-
 _PROTOCOL_STEMS = sorted(
     path.name.removesuffix("_protocol.cpp")
     for path in Path(__file__).parent.glob("*_protocol.cpp")
 )
+
+
+def request_protocol(name: str) -> None:
+    """Keep a protocol's source file in the build; components using it from C++ must call this."""
+    if _protocol_stem(name) not in _PROTOCOL_STEMS:
+        raise ValueError(f"Unknown remote protocol {name!r}")
+    cg.add_define(protocol_define(name))
+
+
 # Only the protocol sources a configuration uses are compiled
 FILTER_SOURCE_FILES = filter_source_files_from_defines(
     {f"{stem}_protocol.cpp": protocol_define(stem) for stem in _PROTOCOL_STEMS}

esphome/components/remote_base/remote_base.cpp

@@ -114,15 +114,16 @@ void RemoteReceiverBase::register_listener(RemoteReceiverListener *listener) {
 #ifdef REMOTE_BASE_DUMPER_COUNT
 void RemoteReceiverBase::register_dumper(RemoteReceiverDumperBase *dumper) {
   if (dumper->is_secondary()) {
-    this->secondary_dumper_ = dumper;
+    if (this->secondary_dumper_ == nullptr) {
+      this->secondary_dumper_ = dumper;
+      return;
+    }
+  } else if (this->dumpers_.size() < REMOTE_BASE_DUMPER_COUNT) {
+    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);
+  ESP_LOGE(TAG, "No %s slot: register it from to_code() with remote_base.add_%s", LOG_STR_LITERAL("dumper"),
+           LOG_STR_LITERAL("dumper"));
 }
 #endif
 

tests/component_tests/remote_receiver/test_slot_counts.py

@@ -71,6 +71,12 @@ def test_every_registry_name_maps_to_a_protocol_source() -> None:
         assert f"{stem}_protocol.cpp" in sources, name
 
 
+def test_request_protocol_rejects_unknown_names() -> None:
+    """A misspelled protocol would otherwise surface only as a link error."""
+    with pytest.raises(ValueError, match="toshiba"):
+        remote_base.request_protocol("toshiba")
+
+
 def test_dump_list_is_deduplicated_across_forms() -> None:
     dumpers = remote_base.validate_dumpers(["raw", {"raw": None}, "nec", "nec"])
     assert [name for name, _ in dumpers] == ["raw", "nec"]