input_date()'s input handler now handles None more gracefully (#1556)

Co-authored-by: Barret Schloerke <barret@posit.co>

Author: cpsievert

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Bug fixes
 
+* An empty `input_date()` value no longer crashes Shiny. (#1528)
+
 * Fixed bug where calling `.update_filter(None)` on a data frame renderer did not visually reset non-numeric column filters. (It did reset the column's filtering, just not the label). Now it resets filter's label. (#1557)
 
 * Require shinyswatch >= 0.7.0 and updated examples accordingly. (#1558)

shiny/input_handler.py

@@ -96,10 +96,10 @@ def _(value, name, session):
 
 @input_handlers.add("shiny.date")
 def _(
-    value: str | list[str], name: ResolvedId, session: Session
+    value: str | list[str] | None, name: ResolvedId, session: Session
 ) -> date | None | tuple[date | None, date | None]:
 
-    if isinstance(value, str):
+    if isinstance(value, str) or value is None:
         return _safe_strptime_date(value)
     else:
         return (