fix(respond): keep platform-specific components when checking for empty chains

astrbot/core/pipeline/respond/stage.py

@@ -142,12 +142,11 @@ async def _is_empty_message_chain(self, chain: list[BaseMessageComponent]) -> bo
             return True
 
         for comp in chain:
-            comp_type = type(comp)
-
-            # 检查组件类型是否在字典中
-            if comp_type in self._component_validators:
-                if self._component_validators[comp_type](comp):
-                    return False
+            validator = self._component_validators.get(type(comp))
+            # Platform-specific components (e.g. Discord embeds) have no
+            # validator here; leave them for the platform adapter to handle.
+            if validator is None or validator(comp):
+                return False
 
         # 如果所有组件都为空
         return True

tests/unit/test_respond_stage_empty_chain.py

@@ -0,0 +1,34 @@
+import pytest
+
+import astrbot.core.message.components as Comp
+from astrbot.core.message.components import BaseMessageComponent
+from astrbot.core.pipeline.respond.stage import RespondStage
+
+
+class _PlatformCard(BaseMessageComponent):
+    type: str = "platform_card"
+    title: str = ""
+
+
+@pytest.mark.asyncio
+async def test_platform_specific_component_is_not_empty():
+    stage = RespondStage()
+
+    assert await stage._is_empty_message_chain([_PlatformCard(title="t")]) is False
+    assert (
+        await stage._is_empty_message_chain([Comp.Plain(text=" "), _PlatformCard()])
+        is False
+    )
+
+
+@pytest.mark.asyncio
+async def test_builtin_empty_components_are_still_empty():
+    stage = RespondStage()
+
+    assert await stage._is_empty_message_chain([]) is True
+    assert (
+        await stage._is_empty_message_chain(
+            [Comp.Plain(text="  "), Comp.Image(file="")]
+        )
+        is True
+    )