add debug logs

- "children" key not allowed in attributes
- key required for dynamic children

src/idom/client/app/package.json

@@ -4,7 +4,9 @@
   "version": "0.1.0",
   "author": "Ryan Morshead",
   "main": "index.js",
-  "workspaces": [ "./packages/*" ],
+  "workspaces": [
+    "./packages/*"
+  ],
   "license": "MIT",
   "repository": {
     "type": "git",

src/idom/core/vdom.py

@@ -5,15 +5,21 @@
 
 from __future__ import annotations
 
+import logging
 from typing import Any, Iterable, List, Mapping, Optional, Sequence, Tuple, Union
 
 from fastjsonschema import compile as compile_json_schema
 from mypy_extensions import TypedDict
 from typing_extensions import Protocol
 
+from idom.config import IDOM_DEBUG_MODE
+
 from .events import EventHandler
 
 
+logger = logging.getLogger()
+
+
 VDOM_JSON_SCHEMA = {
     "$schema": "http://json-schema.org/draft-07/schema",
     "$ref": "#/definitions/element",
@@ -209,15 +215,59 @@ def coalesce_attributes_and_children(
 
     children_or_iterables: Sequence[Any]
     attributes, *children_or_iterables = values
-    if not isinstance(attributes, Mapping) or "tagName" in attributes:
+    if not _is_attributes(attributes):
         attributes = {}
         children_or_iterables = values
 
     children: List[Any] = []
     for child in children_or_iterables:
-        if isinstance(child, (str, Mapping)) or not hasattr(child, "__iter__"):
+        if _is_single_child(child):
             children.append(child)
         else:
             children.extend(child)
 
     return attributes, children
+
+
+def _is_attributes(value: Any) -> bool:
+    return isinstance(value, Mapping) and "tagName" not in value
+
+
+if IDOM_DEBUG_MODE.current:
+
+    _debug_is_attributes = _is_attributes
+
+    def _is_attributes(value: Any) -> bool:
+        result = _debug_is_attributes(value)
+        if result and "children" in value:
+            logger.error(f"Reserved key 'children' found in attributes {value}")
+        return result
+
+
+def _is_single_child(value: Any) -> bool:
+    return isinstance(value, (str, Mapping)) or not hasattr(value, "__iter__")
+
+
+if IDOM_DEBUG_MODE.current:
+
+    _debug_is_single_child = _is_single_child
+
+    def _is_single_child(value: Any) -> bool:
+        if _debug_is_single_child(value):
+            return True
+
+        from .component import AbstractComponent
+
+        if hasattr(value, "__iter__") and not hasattr(value, "__len__"):
+            logger.error(
+                f"Did not verify key-path integrity of children in generator {value} "
+                "- pass a sequence (i.e. list of finite length) in order to verify"
+            )
+        else:
+            for child in value:
+                if (isinstance(child, AbstractComponent) and child.key is None) or (
+                    isinstance(child, Mapping) and "key" not in child
+                ):
+                    logger.error(f"Key not specified for dynamic child {child}")
+
+        return False

tests/test_core/test_vdom.py

@@ -2,6 +2,7 @@
 from fastjsonschema import JsonSchemaException
 
 import idom
+from idom.config import IDOM_DEBUG_MODE
 from idom.core.vdom import make_vdom_constructor, validate_vdom
 
 
@@ -256,3 +257,40 @@ def test_valid_vdom(value):
 def test_invalid_vdom(value, error_message_pattern):
     with pytest.raises(JsonSchemaException, match=error_message_pattern):
         validate_vdom(value)
+
+
+@pytest.mark.skipif(not IDOM_DEBUG_MODE.current, reason="Only logs in debug mode")
+def test_debug_log_if_children_in_attributes(caplog):
+    idom.vdom("div", {"children": ["hello"]})
+    assert len(caplog.records) == 1
+    assert caplog.records[0].message.startswith(
+        "Reserved key 'children' found in attributes"
+    )
+    caplog.records.clear()
+
+
+@pytest.mark.skipif(not IDOM_DEBUG_MODE.current, reason="Only logs in debug mode")
+def test_debug_log_cannot_verify_keypath_for_genereators(caplog):
+    idom.vdom("div", (1 for i in range(10)))
+    assert len(caplog.records) == 1
+    assert caplog.records[0].message.startswith(
+        "Did not verify key-path integrity of children in generator"
+    )
+    caplog.records.clear()
+
+
+@pytest.mark.skipif(not IDOM_DEBUG_MODE.current, reason="Only logs in debug mode")
+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")
+
+    caplog.records.clear()
+
+    @idom.component
+    def MyComponent():
+        return idom.vdom("div")
+
+    idom.vdom("div", [MyComponent()])
+    assert len(caplog.records) == 1
+    assert caplog.records[0].message.startswith("Key not specified for dynamic child")