Fix: ButtonItem callback compatibility - check parameter count before passing trigger

Fixes critical regression from v3.13.2 where all ButtonItem callbacks were
unconditionally passed a 5th parameter (trigger_auto_apply), breaking existing
callbacks that only accept 4 parameters.

Uses inspect.signature() to check callback parameter count at runtime:
- Callbacks with < 5 parameters: receive standard 4 args (backward compatible)
- Callbacks with >= 5 parameters: receive trigger_auto_apply as 5th arg

This maintains full backward compatibility while enabling the auto-apply feature
for DictItem/FloatArrayItem editors when callbacks opt-in by accepting the 5th
parameter.

Fixes: TypeError: callback() takes 4 positional arguments but 5 were given

Author: PierreRaybaut

CHANGELOG.md

@@ -1,5 +1,18 @@
 # Changelog #
 
+## Version 3.13.3 ##
+
+🛠️ Bug fixes:
+
+* **ButtonItem callbacks**: Fixed critical regression breaking callbacks with 4 parameters
+  * In v3.13.2, the auto-apply feature unconditionally passed a 5th parameter (`trigger_auto_apply`) to all ButtonItem callbacks
+  * This broke all existing callbacks expecting only 4 parameters (instance, item, value, parent)
+  * Now uses `inspect.signature()` to check callback parameter count at runtime
+  * Callbacks with fewer than 5 parameters receive only the standard 4 arguments
+  * Callbacks with 5+ parameters receive the additional `trigger_auto_apply` function
+  * Maintains full backward compatibility while supporting the new auto-apply feature
+  * Fixes `TypeError: callback() takes 4 positional arguments but 5 were given`
+
 ## Version 3.13.2 ##
 
 ✨ New features:

guidata/dataset/qtitemwidgets.py

@@ -18,6 +18,7 @@
 from __future__ import annotations
 
 import datetime
+import inspect
 import os
 import os.path as osp
 import sys
@@ -1555,14 +1556,24 @@ def clicked(self, *args) -> None:
         """
         self.parent_layout.update_dataitems()
         callback = self.item.get_prop_value("display", "callback")
-        # Pass auto-apply trigger function as optional 5th parameter
-        self.cb_value = callback(
-            self.item.instance,
-            self.item.item,
-            self.cb_value,
-            self.button.parent(),
-            self._trigger_auto_apply,
-        )
+        # Pass auto-apply trigger function as optional 5th parameter, only if callback
+        # takes 5 parameters:
+        sig = inspect.signature(callback)
+        if len(sig.parameters) < 5:
+            self.cb_value = callback(
+                self.item.instance,
+                self.item.item,
+                self.cb_value,
+                self.button.parent(),
+            )
+        else:
+            self.cb_value = callback(
+                self.item.instance,
+                self.item.item,
+                self.cb_value,
+                self.button.parent(),
+                self._trigger_auto_apply,
+            )
         self.set()
         self.parent_layout.update_widgets()
         self.notify_value_change()