Make Index Default Key

docs/source/escape-hatches/_examples/super_simple_chart/app.py

@@ -4,7 +4,13 @@
 
 
 file = Path(__file__).parent / "super-simple-chart.js"
-ssc = web.module_from_file("super-simple-chart", file, fallback="⌛")
+ssc = web.module_from_file(
+    "super-simple-chart",
+    file,
+    fallback="⌛",
+    # normally this option is not required
+    replace_existing=True,
+)
 SuperSimpleChart = web.export(ssc, "SuperSimpleChart")
 
 

docs/source/reference-material/_examples/matplotlib_plot.py

@@ -71,6 +71,7 @@ def poly_coef_input(index, callback):
                 "onChange": callback,
             },
         ),
+        key=index,
     )
 
 

docs/source/reference-material/_examples/snake_game.py

@@ -18,7 +18,12 @@ def GameView():
     game_state, set_game_state = idom.hooks.use_state(GameState.init)
 
     if game_state == GameState.play:
-        return GameLoop(grid_size=6, block_scale=50, set_game_state=set_game_state)
+        return GameLoop(
+            grid_size=6,
+            block_scale=50,
+            set_game_state=set_game_state,
+            key="game loop",
+        )
 
     start_button = idom.html.button(
         {"onClick": lambda event: set_game_state(GameState.play)},
@@ -40,7 +45,12 @@ def GameView():
         """
     )
 
-    return idom.html.div({"className": "snake-game-menu"}, menu_style, menu)
+    return idom.html.div(
+        {"className": "snake-game-menu"},
+        menu_style,
+        menu,
+        key="menu",
+    )
 
 
 class Direction(enum.Enum):
@@ -154,14 +164,18 @@ def create_grid(grid_size, block_scale):
         [
             idom.html.div(
                 {"style": {"height": f"{block_scale}px"}},
-                [create_grid_block("black", block_scale) for i in range(grid_size)],
+                [
+                    create_grid_block("black", block_scale, key=i)
+                    for i in range(grid_size)
+                ],
+                key=i,
             )
             for i in range(grid_size)
         ],
     )
 
 
-def create_grid_block(color, block_scale):
+def create_grid_block(color, block_scale, key):
     return idom.html.div(
         {
             "style": {
@@ -170,7 +184,8 @@ def create_grid_block(color, block_scale):
                 "backgroundColor": color,
                 "outline": "1px solid grey",
             }
-        }
+        },
+        key=key,
     )
 
 

src/idom/config.py

@@ -5,7 +5,6 @@
 
 from pathlib import Path
 from tempfile import TemporaryDirectory
-from warnings import warn
 
 from ._option import Option as _Option
 
@@ -58,25 +57,16 @@
 
 IDOM_FEATURE_INDEX_AS_DEFAULT_KEY = _Option(
     "IDOM_FEATURE_INDEX_AS_DEFAULT_KEY",
-    default=False,
+    default=True,
     mutable=False,
     validator=lambda x: bool(int(x)),
 )
 """Use the index of elements/components amongst their siblings as the default key.
 
-In a future release this flag's default value will be set to true, and after that, this
-flag will be removed entirely and the indices will always be the default key.
+The flag's default value is set to true. To return to legacy behavior set
+``IDOM_FEATURE_INDEX_AS_DEFAULT_KEY=0``. In a future release, this flag will be removed
+entirely and the indices will always be the default key.
 
-For more information on changes to this feature flag see: https://github.com/idom-team/idom/issues/351
+For more information on changes to this feature flag see:
+https://github.com/idom-team/idom/issues/351
 """
-
-if not IDOM_FEATURE_INDEX_AS_DEFAULT_KEY.current:
-    warn(
-        "In the next release, the feature flag IDOM_FEATURE_INDEX_AS_DEFAULT_KEY will "
-        "be activated by default. To try this out before the next release simply set "
-        "IDOM_FEATURE_INDEX_AS_DEFAULT_KEY=1 as an environment variable. After this "
-        "change, you can revert to the old behavior by setting it to 0 instead. If you "
-        "have questions or issues with this change report them here: "
-        "https://github.com/idom-team/idom/issues/351",
-        DeprecationWarning,
-    )

src/idom/core/layout.py

@@ -698,10 +698,10 @@ def _process_child_type_and_key(
 
 if IDOM_FEATURE_INDEX_AS_DEFAULT_KEY.current:
 
-    def _default_key(index: int) -> Any:  # pragma: no cover
+    def _default_key(index: int) -> Any:
         return index
 
 else:
 
-    def _default_key(index: int) -> Any:
+    def _default_key(index: int) -> Any:  # pragma: no cover
         return object()

src/idom/core/proto.py

@@ -22,11 +22,14 @@
 """Simple function returning a new component"""
 
 
+Key = Union[str, int]
+
+
 @runtime_checkable
 class ComponentType(Protocol):
     """The expected interface for all component-like objects"""
 
-    key: Optional[Any]
+    key: Key | None
     """An identifier which is unique amongst a component's immediate siblings"""
 
     def render(self) -> VdomDict:
@@ -74,7 +77,7 @@ def __exit__(
 
 
 class _VdomDictOptional(TypedDict, total=False):
-    key: str
+    key: Key | None
     children: Sequence[
         # recursive types are not allowed yet:
         # https://github.com/python/mypy/issues/731
@@ -101,7 +104,7 @@ class ImportSourceDict(TypedDict):
 
 
 class _OptionalVdomJson(TypedDict, total=False):
-    key: str
+    key: Key
     error: str
     children: List[Any]
     attributes: Dict[str, Any]

src/idom/core/vdom.py

@@ -129,7 +129,7 @@ def is_vdom(value: Any) -> bool:
 def vdom(
     tag: str,
     *attributes_and_children: VdomAttributesAndChildren,
-    key: str = "",
+    key: str | int | None = None,
     event_handlers: Optional[EventHandlerMapping] = None,
     import_source: Optional[ImportSourceDict] = None,
 ) -> VdomDict:
@@ -169,7 +169,7 @@ def vdom(
     if event_handlers:
         model["eventHandlers"] = event_handlers
 
-    if key != "":
+    if key is not None:
         model["key"] = key
 
     if import_source is not None:
@@ -182,7 +182,7 @@ class _VdomDictConstructor(Protocol):
     def __call__(
         self,
         *attributes_and_children: VdomAttributesAndChildren,
-        key: str = ...,
+        key: str | int | None = ...,
         event_handlers: Optional[EventHandlerMapping] = ...,
         import_source: Optional[ImportSourceDict] = ...,
     ) -> VdomDict:
@@ -200,7 +200,7 @@ def make_vdom_constructor(
 
     def constructor(
         *attributes_and_children: VdomAttributesAndChildren,
-        key: str = "",
+        key: str | int | None = None,
         event_handlers: Optional[EventHandlerMapping] = None,
         import_source: Optional[ImportSourceDict] = None,
     ) -> VdomDict:
@@ -333,7 +333,11 @@ def _is_single_child(value: Any) -> bool:
                     logger.error(f"Key not specified for child in list {child}")
                 elif isinstance(child, Mapping) and "key" not in child:
                     # remove 'children' to reduce log spam
-                    child_copy = {**child, "children": ...}
+                    child_copy = {**child, "children": _EllipsisRepr()}
                     logger.error(f"Key not specified for child in list {child_copy}")
 
         return False
+
+    class _EllipsisRepr:
+        def __repr__(self) -> str:
+            return "..."

src/idom/testing.py

@@ -14,6 +14,7 @@
     Generic,
     Iterator,
     List,
+    NoReturn,
     Optional,
     Tuple,
     Type,
@@ -173,6 +174,10 @@ def __exit__(
         return None
 
 
+class LogAssertionError(AssertionError):
+    """An assertion error raised in relation to log messages."""
+
+
 @contextmanager
 def assert_idom_logged(
     match_message: str = "",
@@ -192,11 +197,13 @@ def assert_idom_logged(
     error_pattern = re.compile(match_error)
 
     try:
-        with capture_idom_logs() as handler:
+        with capture_idom_logs(yield_existing=clear_matched_records) as log_records:
             yield None
-    finally:
+    except Exception:
+        raise
+    else:
         found = False
-        for record in list(handler.records):
+        for record in list(log_records):
             if (
                 # record message matches
                 message_pattern.findall(record.getMessage())
@@ -222,36 +229,85 @@ def assert_idom_logged(
             ):
                 found = True
                 if clear_matched_records:
-                    handler.records.remove(record)
+                    log_records.remove(record)
 
         if not found:  # pragma: no cover
-            conditions = []
-            if match_message:
-                conditions.append(f"log message pattern {match_message!r}")
-            if error_type:
-                conditions.append(f"exception type {error_type}")
-            if match_error:
-                conditions.append(f"error message pattern {match_error!r}")
-            raise AssertionError(
-                "Could not find a log record matching the given "
-                + " and ".join(conditions)
+            _raise_log_message_error(
+                "Could not find a log record matching the given",
+                match_message,
+                error_type,
+                match_error,
             )
 
 
 @contextmanager
-def capture_idom_logs() -> Iterator[_LogRecordCaptor]:
-    """Capture logs from IDOM"""
-    if _LOG_RECORD_CAPTOR_SINGLTON in ROOT_LOGGER.handlers:
-        # this is being handled by an outer capture context
-        yield _LOG_RECORD_CAPTOR_SINGLTON
-        return None
+def assert_idom_did_not_log(
+    match_message: str = "",
+    error_type: type[Exception] | None = None,
+    match_error: str = "",
+    clear_matched_records: bool = False,
+) -> Iterator[None]:
+    """Assert the inverse of :func:`assert_idom_logged`"""
+    try:
+        with assert_idom_logged(
+            match_message, error_type, match_error, clear_matched_records
+        ):
+            yield None
+    except LogAssertionError:
+        pass
+    else:
+        _raise_log_message_error(
+            "Did find a log record matching the given",
+            match_message,
+            error_type,
+            match_error,
+        )
 
-    ROOT_LOGGER.addHandler(_LOG_RECORD_CAPTOR_SINGLTON)
+
+def _raise_log_message_error(
+    prefix: str,
+    match_message: str = "",
+    error_type: type[Exception] | None = None,
+    match_error: str = "",
+) -> NoReturn:
+    conditions = []
+    if match_message:
+        conditions.append(f"log message pattern {match_message!r}")
+    if error_type:
+        conditions.append(f"exception type {error_type}")
+    if match_error:
+        conditions.append(f"error message pattern {match_error!r}")
+    raise LogAssertionError(prefix + " " + " and ".join(conditions))
+
+
+@contextmanager
+def capture_idom_logs(
+    yield_existing: bool = False,
+) -> Iterator[list[logging.LogRecord]]:
+    """Capture logs from IDOM
+
+    Parameters:
+        yield_existing:
+            If already inside an existing capture context yield the same list of logs.
+            This is useful if you need to mutate the list of logs to affect behavior in
+            the outer context.
+    """
+    if yield_existing:
+        for handler in reversed(ROOT_LOGGER.handlers):
+            if isinstance(handler, _LogRecordCaptor):
+                yield handler.records
+                return None
+
+    handler = _LogRecordCaptor()
+    original_level = ROOT_LOGGER.level
+
+    ROOT_LOGGER.setLevel(logging.DEBUG)
+    ROOT_LOGGER.addHandler(handler)
     try:
-        yield _LOG_RECORD_CAPTOR_SINGLTON
+        yield handler.records
     finally:
-        ROOT_LOGGER.removeHandler(_LOG_RECORD_CAPTOR_SINGLTON)
-        _LOG_RECORD_CAPTOR_SINGLTON.records = []
+        ROOT_LOGGER.removeHandler(handler)
+        ROOT_LOGGER.setLevel(original_level)
 
 
 class _LogRecordCaptor(logging.NullHandler):
@@ -264,9 +320,6 @@ def handle(self, record: logging.LogRecord) -> bool:
         return True
 
 
-_LOG_RECORD_CAPTOR_SINGLTON = _LogRecordCaptor()
-
-
 class HookCatcher:
     """Utility for capturing a LifeCycleHook from a component
 

src/idom/web/module.py

@@ -195,8 +195,8 @@ def module_from_file(
             Using this option has negative performance consequences since all DOM
             elements must be changed on each render. See :issue:`461` for more info.
         replace_existing:
-            Whether to replace the source for a module with the same name if
-            if already exists. Otherwise raise an error.
+            Whether to replace the source for a module with the same name if it already
+            exists. Otherwise raise an error.
     """
     source_file = Path(file)
     target_file = _web_module_path(name)