Pass the date value to the DateItem display callback

doc/release_notes/release_3.17.md

@@ -14,6 +14,7 @@
 * **Application startup blocked by a corrupted translation file** — when a `.mo` translation catalog was corrupted or unreadable (e.g. truncated during installation), importing guidata failed with an error such as `OSError: Bad magic number`. The same applied to any application relying on `guidata.configtools.get_translation`, like PlotPy, Sigima or DataLab, so the application could not start at all. The interface now falls back to English, and a `RuntimeWarning` identifies the faulty catalog (fixes [Issue #119](https://github.com/PlotPyStack/guidata/issues/119)).
 * **Error when editing a dictionary field in a JSON Schema based form** — in a form generated with `guidata.dataset.dataset_to_schema` (e.g. in a web frontend), editing a `DictItem` field failed with `TypeError: DictItem.__dictedit() missing 1 required positional argument: 'parent'`: the button opening the dictionary editor in the Qt interface was handled as a callback updating the other fields. `DictItem` fields are no longer flagged with `x-guidata-has-callback`, and `resolve_dataset_callbacks` returns an empty mapping for them (fixes [Issue #123](https://github.com/PlotPyStack/guidata/issues/123)).
 * **Date/time callback never called** — the `display` callback of a `DateTimeItem` was never called when the date or time was changed in a dataset editor, so that the values computed from it were not updated. The callback is now called on each change, with the new value of the item (a `datetime.datetime` object), like for the other items (fixes [Issue #123](https://github.com/PlotPyStack/guidata/issues/123)).
+* **Date callback received a Qt object** — the `display` callback of a `DateItem` received a Qt `QDateTime` object, whose type depends on the Qt binding (PyQt5, PyQt6 or PySide6), instead of the value of the item. It now receives the new value of the item (a `datetime.date` object), like the other items. Callbacks relying on the previous `QDateTime` argument must be updated (fixes [Issue #126](https://github.com/PlotPyStack/guidata/issues/126)).
 * **Plain-text "about" information** — `guidata.widgets.about.about(html=False)` (and `AboutInfo.about(html=False)`) failed with `UnboundLocalError` instead of returning the information about the package as plain text (fixes [Issue #123](https://github.com/PlotPyStack/guidata/issues/123)).
 * **French translations of the DataFrame editor** — when entering a number format not starting with `%`, the French error message stated the opposite of the actual rule ("must not start with '%'"), and the title of the export dialog box was shown in English. Both are now correctly translated (fixes [Issue #123](https://github.com/PlotPyStack/guidata/issues/123)).
 

guidata/dataset/qtitemwidgets.py

@@ -757,9 +757,10 @@ def __init__(
             qt_fmt = convert_date_format(fmt)
             self.dateedit.setDisplayFormat(qt_fmt)
 
-    def date_changed(self, value):
-        """Date changed"""
-        _display_callback(self, value)
+    def date_changed(self, _value) -> None:
+        """Date changed (the ``QDateTime`` argument is ignored: the callback
+        receives the Python value of the widget)"""
+        _display_callback(self, self.value())
         self.notify_value_change()
 
     def get(self) -> None:

guidata/tests/unit/test_datetime_display_callback.py

@@ -4,10 +4,11 @@
 # (see guidata/LICENSE for details)
 
 """
-Test the display callback of DateTimeItem
+Test the display callbacks of DateItem and DateTimeItem
 
-When the date/time is changed in a dataset editor, the ``display`` callback of a
-``DateTimeItem`` must be called with the Python value of the item (``datetime``).
+When the date (or date/time) is changed in a dataset editor, the ``display``
+callback of a ``DateItem`` (or ``DateTimeItem``) must be called with the Python
+value of the item (``date`` or ``datetime``), not with a Qt object.
 """
 
 from __future__ import annotations
@@ -18,11 +19,41 @@
 from qtpy import QtWidgets as QW
 
 from guidata.dataset import DataSet
-from guidata.dataset.dataitems import DateTimeItem
+from guidata.dataset.dataitems import DateItem, DateTimeItem
 from guidata.dataset.qtwidgets import DataSetEditLayout
 from guidata.qthelpers import qt_app_context
 
 
+def test_date_display_callback() -> None:
+    """Changing the date calls the display callback with a date"""
+    calls = []
+
+    def callback(instance: DataSet, _item: DateItem, value) -> None:
+        """Record the callback value and the dataset value"""
+        calls.append((value, instance.date))
+
+    class _DateDataSet(DataSet):
+        """Dataset with a date item having a display callback"""
+
+        date = DateItem("Date", default=datetime.date(2010, 10, 10)).set_prop(
+            "display", callback=callback
+        )
+
+    with qt_app_context():
+        dialog = QW.QDialog()
+        dataset = _DateDataSet()
+        layout = DataSetEditLayout(dialog, dataset, QW.QGridLayout(dialog))
+        try:
+            (widget,) = layout.get_terminal_widgets()
+            calls.clear()
+            widget.dateedit.setDate(QC.QDate(2024, 1, 2))
+            expected = datetime.date(2024, 1, 2)
+            assert calls == [(expected, expected)]
+            assert type(calls[0][0]) is datetime.date
+        finally:
+            dialog.deleteLater()
+
+
 def test_datetime_display_callback() -> None:
     """Changing the date/time calls the display callback with a datetime"""
     calls = []