Fix scheduler crash when cancelling items with NULL names (#9444)

tests/integration/fixtures/scheduler_null_name.yaml

@@ -0,0 +1,43 @@
+esphome:
+  name: scheduler-null-name
+
+host:
+
+logger:
+  level: DEBUG
+
+api:
+  services:
+    - service: test_null_name
+      then:
+        - lambda: |-
+            // First, create a scenario that would trigger the crash
+            // The crash happens when defer() is called with a name that would be cancelled
+
+            // Test 1: Create a defer with a valid name
+            App.scheduler.set_timeout(nullptr, "test_defer", 0, []() {
+              ESP_LOGI("TEST", "First defer should be cancelled");
+            });
+
+            // Test 2: Create another defer with the same name - this triggers cancel_item_locked_
+            // In the unfixed code, this would crash if the name was NULL
+            App.scheduler.set_timeout(nullptr, "test_defer", 0, []() {
+              ESP_LOGI("TEST", "Second defer executed");
+            });
+
+            // Test 3: Now test with nullptr - this is the actual crash scenario
+            // Create a defer item without a name (like voice assistant does)
+            const char* null_name = nullptr;
+            App.scheduler.set_timeout(nullptr, null_name, 0, []() {
+              ESP_LOGI("TEST", "Defer with null name executed");
+            });
+
+            // Test 4: Create another defer with null name - this would trigger the crash
+            App.scheduler.set_timeout(nullptr, null_name, 0, []() {
+              ESP_LOGI("TEST", "Second null defer executed");
+            });
+
+            // Test 5: Verify scheduler still works
+            App.scheduler.set_timeout(nullptr, "valid_timeout", 50, []() {
+              ESP_LOGI("TEST", "Test completed successfully");
+            });

tests/integration/test_scheduler_null_name.py

@@ -0,0 +1,59 @@
+"""Test that scheduler handles NULL names safely without crashing."""
+
+import asyncio
+import re
+
+import pytest
+
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+@pytest.mark.asyncio
+async def test_scheduler_null_name(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test that scheduler handles NULL names safely without crashing."""
+
+    loop = asyncio.get_running_loop()
+    test_complete_future: asyncio.Future[bool] = loop.create_future()
+
+    # Pattern to match test completion
+    test_complete_pattern = re.compile(r"Test completed successfully")
+
+    def check_output(line: str) -> None:
+        """Check log output for test completion."""
+        if not test_complete_future.done() and test_complete_pattern.search(line):
+            test_complete_future.set_result(True)
+
+    async with run_compiled(yaml_config, line_callback=check_output):
+        async with api_client_connected() as client:
+            # Verify we can connect
+            device_info = await client.device_info()
+            assert device_info is not None
+            assert device_info.name == "scheduler-null-name"
+
+            # List services
+            _, services = await asyncio.wait_for(
+                client.list_entities_services(), timeout=5.0
+            )
+
+            # Find our test service
+            test_null_name_service = next(
+                (s for s in services if s.name == "test_null_name"), None
+            )
+            assert test_null_name_service is not None, (
+                "test_null_name service not found"
+            )
+
+            # Execute the test
+            client.execute_service(test_null_name_service, {})
+
+            # Wait for test completion
+            try:
+                await asyncio.wait_for(test_complete_future, timeout=10.0)
+            except asyncio.TimeoutError:
+                pytest.fail(
+                    "Test did not complete within timeout - likely crashed due to NULL name"
+                )