fix false possitive key warning

Author: rmorshea

src/idom/core/vdom.py

@@ -174,7 +174,7 @@ def vdom(
     if event_handlers:
         model["eventHandlers"] = event_handlers
 
-    if key:
+    if key != "":
         model["key"] = key
 
     if import_source is not None:
@@ -337,6 +337,6 @@ def _is_single_child(value: Any) -> bool:
                 if (isinstance(child, ComponentType) and child.key is None) or (
                     isinstance(child, Mapping) and "key" not in child
                 ):
-                    logger.error(f"Key not specified for dynamic child {child}")
+                    logger.error(f"Key not specified for child in list {child}")
 
         return False

tests/test_core/test_vdom.py

@@ -336,7 +336,7 @@ def test_debug_log_cannot_verify_keypath_for_genereators(caplog):
 def test_debug_log_dynamic_children_must_have_keys(caplog):
     idom.vdom("div", [idom.vdom("div")])
     assert len(caplog.records) == 1
-    assert caplog.records[0].message.startswith("Key not specified for dynamic child")
+    assert caplog.records[0].message.startswith("Key not specified for child")
 
     caplog.records.clear()
 
@@ -346,4 +346,4 @@ def MyComponent():
 
     idom.vdom("div", [MyComponent()])
     assert len(caplog.records) == 1
-    assert caplog.records[0].message.startswith("Key not specified for dynamic child")
+    assert caplog.records[0].message.startswith("Key not specified for child")