fix: handle null trigger states in automation traces (#2203)

* fix: handle null trigger states in automation traces

* test: strengthen automation trace regression coverage

---------

Co-authored-by: kingpanther13 <kingpanther13@users.noreply.github.com>

Author: kingpanther13

src/ha_mcp/tools/tools_traces.py

@@ -782,13 +782,13 @@ def _populate_trigger_info(
             "description": trigger_vars.get("description"),
         }
         if "to_state" in trigger_vars:
-            result["trigger"]["to_state"] = trigger_vars.get("to_state", {}).get(
+            result["trigger"]["to_state"] = (trigger_vars.get("to_state") or {}).get(
                 "state"
             )
         if "from_state" in trigger_vars:
-            result["trigger"]["from_state"] = trigger_vars.get("from_state", {}).get(
-                "state"
-            )
+            result["trigger"]["from_state"] = (
+                trigger_vars.get("from_state") or {}
+            ).get("state")
         if "entity_id" in trigger_vars:
             result["trigger"]["entity_id"] = trigger_vars["entity_id"]
         if "error" in trigger_step:

tests/src/e2e/workflows/automation/test_traces.py

@@ -6,17 +6,19 @@
 """
 
 import logging
+import time
 from typing import Any
 
 import pytest
 
 from ...utilities.assertions import (
+    MCPAssertions,
     assert_mcp_success,
     parse_mcp_result,
     safe_call_tool,
 )
 from ...utilities.entity_finders import find_test_light_entity
-from ...utilities.wait_helpers import wait_for_condition
+from ...utilities.wait_helpers import wait_for_condition, wait_for_tool_result
 
 logger = logging.getLogger(__name__)
 
@@ -30,6 +32,67 @@ async def _find_test_light_entity(self, mcp_client) -> str:
         """Delegates to the suite-wide helper in utilities.entity_finders."""
         return await find_test_light_entity(mcp_client)
 
+    async def test_template_trace_with_null_trigger_states(
+        self,
+        mcp_client: Any,
+        test_data_factory: Any,
+    ) -> None:
+        """Return time-driven template traces whose HA states are null."""
+        trigger_after = int(time.time()) + 45
+        create_config = test_data_factory.automation_config(
+            "Template Null State Trace",
+            trigger=[
+                {
+                    "platform": "template",
+                    "value_template": (
+                        f"{{{{ as_timestamp(now()) >= {trigger_after} }}}}"
+                    ),
+                }
+            ],
+            action=[{"delay": {"seconds": 0}}],
+            initial_state=True,
+        )
+
+        automation_id: str | None = None
+        try:
+            async with MCPAssertions(mcp_client) as mcp:
+                create_data = await mcp.call_tool_success(
+                    "ha_config_set_automation", {"config": create_config}
+                )
+                automation_id = create_data.get("entity_id") or create_data.get(
+                    "automation_id"
+                )
+                assert automation_id is not None
+
+                traces_data = await wait_for_tool_result(
+                    mcp_client,
+                    tool_name="ha_get_automation_traces",
+                    arguments={"automation_id": automation_id},
+                    predicate=lambda data: data.get("trace_count", 0) > 0,
+                    timeout=120,
+                    poll_interval=1,
+                    description="time-driven template automation trace",
+                )
+                run_id = traces_data["traces"][0]["run_id"]
+                detailed_data = await mcp.call_tool_success(
+                    "ha_get_automation_traces",
+                    {"automation_id": automation_id, "run_id": run_id},
+                )
+
+            assert detailed_data["trigger"]["platform"] == "template"
+            assert detailed_data["trigger"]["from_state"] is None
+            assert detailed_data["trigger"]["to_state"] is None
+        finally:
+            if automation_id is not None:
+                cleanup_data = await safe_call_tool(
+                    mcp_client,
+                    "ha_config_remove_automation",
+                    {"identifier": automation_id},
+                )
+                assert cleanup_data.get("success") is True, (
+                    f"Failed to remove test automation: {cleanup_data}"
+                )
+
     async def test_automation_trace_after_trigger(
         self, mcp_client, cleanup_tracker, test_data_factory
     ):

tests/src/unit/test_tools_traces_detail.py

@@ -80,6 +80,62 @@ def test_format_flat_trace_structure(self):
         assert actions[0]["result"]["params"]["service"] == "turn_on"
         assert actions[1]["child_id"]["item_id"] == "set_brightness_chambre"
 
+    def test_format_template_trigger_with_null_states(self) -> None:
+        """Preserve null states from time-driven template trigger traces."""
+        trace_data = {
+            "state": "stopped",
+            "trace": {
+                "trigger/0": [
+                    {
+                        "path": "trigger/0",
+                        "changed_variables": {
+                            "trigger": {
+                                "platform": "template",
+                                "description": "time change or manual update via template",
+                                "entity_id": None,
+                                "from_state": None,
+                                "to_state": None,
+                            }
+                        },
+                    }
+                ]
+            },
+        }
+
+        result = _format_detailed_trace("automation.test", "run_123", trace_data)
+
+        assert result["success"] is True
+        assert result["trigger"] == {
+            "platform": "template",
+            "description": "time change or manual update via template",
+            "entity_id": None,
+            "from_state": None,
+            "to_state": None,
+        }
+
+    def test_format_template_trigger_with_state_objects(self) -> None:
+        """Preserve state strings from entity-driven template trigger traces."""
+        trace_data = {
+            "trace": {
+                "trigger/0": [
+                    {
+                        "changed_variables": {
+                            "trigger": {
+                                "platform": "template",
+                                "from_state": {"state": "off"},
+                                "to_state": {"state": "on"},
+                            }
+                        }
+                    }
+                ]
+            }
+        }
+
+        result = _format_detailed_trace("automation.test", "run_123", trace_data)
+
+        assert result["trigger"]["from_state"] == "off"
+        assert result["trigger"]["to_state"] == "on"
+
     def test_format_legacy_trace_structure(self):
         """Test fallback parsing of potential legacy trace structure (lists)."""