chore(gdb): cast fallback, NULL string handling, order-independent widget discovery

- Widget __init__ cast fallback to self when type missing in debug info
- safe_string: NULL returns None (normal), CorruptedValue returns marker
- parse_widgets: two-pass inheritance resolution, remove hardcoded list

scripts/gdb/lvglgdb/lvgl/widgets/_helpers.py

@@ -8,16 +8,16 @@ from lvglgdb.lvgl.data_utils import ptr_or_none  # noqa: F401
 
 
 def safe_string(obj, field_name):
-    """Read a char* field as string or corrupted marker. Never returns None."""
+    """Read a char* field as string, corrupted marker, or None (NULL/missing)."""
     from lvglgdb.value import CorruptedValue
     val = obj.safe_field(field_name)
     if val is None:
-        return str(CorruptedValue(0, ValueError("field not found")))
+        return None
     if not getattr(val, 'is_ok', True):
         return str(val)
     addr = int(val)
     if not addr:
-        return str(CorruptedValue(0, ValueError("NULL pointer")))
+        return None
     return val.string(fallback=str(CorruptedValue(addr, MemoryError("unreadable"))))
 
 

scripts/gdb/lvglgdb/lvgl/widgets/lv_3dtexture.py

@@ -13,7 +13,7 @@ class LV3dtexture(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_3dtexture_t", ptr=True)
+        self._wv = self.cast("lv_3dtexture_t", ptr=True) or self
 
     @property
     def id(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_animimg.py

@@ -14,7 +14,7 @@ class LVAnimimg(LVImage):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_animimg_t", ptr=True)
+        self._wv = self.cast("lv_animimg_t", ptr=True) or self
 
     @property
     def anim(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_arc.py

@@ -13,7 +13,7 @@ class LVArc(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_arc_t", ptr=True)
+        self._wv = self.cast("lv_arc_t", ptr=True) or self
 
     @property
     def rotation(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_arclabel.py

@@ -14,7 +14,7 @@ class LVArclabel(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_arclabel_t", ptr=True)
+        self._wv = self.cast("lv_arclabel_t", ptr=True) or self
 
     @property
     def text(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_bar.py

@@ -14,7 +14,7 @@ class LVBar(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_bar_t", ptr=True)
+        self._wv = self.cast("lv_bar_t", ptr=True) or self
 
     @property
     def cur_value(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_button.py

@@ -13,7 +13,7 @@ class LVButton(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_button_t", ptr=True)
+        self._wv = self.cast("lv_button_t", ptr=True) or self
 
     def snapshot(self, include_children=False, include_styles=False):
         """Snapshot with widget-specific fields in widget_data."""

scripts/gdb/lvglgdb/lvgl/widgets/lv_buttonmatrix.py

@@ -14,7 +14,7 @@ class LVButtonmatrix(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_buttonmatrix_t", ptr=True)
+        self._wv = self.cast("lv_buttonmatrix_t", ptr=True) or self
 
     @property
     def map_p(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_calendar.py

@@ -14,7 +14,7 @@ class LVCalendar(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_calendar_t", ptr=True)
+        self._wv = self.cast("lv_calendar_t", ptr=True) or self
 
     @property
     def btnm(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_canvas.py

@@ -14,7 +14,7 @@ class LVCanvas(LVImage):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_canvas_t", ptr=True)
+        self._wv = self.cast("lv_canvas_t", ptr=True) or self
 
     @property
     def draw_buf(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_chart.py

@@ -14,7 +14,7 @@ class LVChart(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_chart_t", ptr=True)
+        self._wv = self.cast("lv_chart_t", ptr=True) or self
 
     @property
     def series_ll(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_checkbox.py

@@ -14,7 +14,7 @@ class LVCheckbox(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_checkbox_t", ptr=True)
+        self._wv = self.cast("lv_checkbox_t", ptr=True) or self
 
     @property
     def txt(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_dropdown.py

@@ -14,7 +14,7 @@ class LVDropdown(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_dropdown_t", ptr=True)
+        self._wv = self.cast("lv_dropdown_t", ptr=True) or self
 
     @property
     def list(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_dropdown_list.py

@@ -14,7 +14,7 @@ class LVDropdownList(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_dropdown_list_t", ptr=True)
+        self._wv = self.cast("lv_dropdown_list_t", ptr=True) or self
 
     @property
     def dropdown(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_image.py

@@ -14,7 +14,7 @@ class LVImage(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_image_t", ptr=True)
+        self._wv = self.cast("lv_image_t", ptr=True) or self
 
     @property
     def src(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_imagebutton.py

@@ -13,7 +13,7 @@ class LVImagebutton(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_imagebutton_t", ptr=True)
+        self._wv = self.cast("lv_imagebutton_t", ptr=True) or self
 
     def snapshot(self, include_children=False, include_styles=False):
         """Snapshot with widget-specific fields in widget_data."""

scripts/gdb/lvglgdb/lvgl/widgets/lv_ime_pinyin.py

@@ -14,7 +14,7 @@ class LVImePinyin(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_ime_pinyin_t", ptr=True)
+        self._wv = self.cast("lv_ime_pinyin_t", ptr=True) or self
 
     @property
     def kb(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_keyboard.py

@@ -14,7 +14,7 @@ class LVKeyboard(LVButtonmatrix):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_keyboard_t", ptr=True)
+        self._wv = self.cast("lv_keyboard_t", ptr=True) or self
 
     @property
     def ta(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_label.py

@@ -14,7 +14,7 @@ class LVLabel(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_label_t", ptr=True)
+        self._wv = self.cast("lv_label_t", ptr=True) or self
 
     @property
     def text(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_led.py

@@ -14,7 +14,7 @@ class LVLed(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_led_t", ptr=True)
+        self._wv = self.cast("lv_led_t", ptr=True) or self
 
     @property
     def color(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_line.py

@@ -13,7 +13,7 @@ class LVLine(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_line_t", ptr=True)
+        self._wv = self.cast("lv_line_t", ptr=True) or self
 
     @property
     def point_num(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_menu.py

@@ -14,7 +14,7 @@ class LVMenu(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_menu_t", ptr=True)
+        self._wv = self.cast("lv_menu_t", ptr=True) or self
 
     @property
     def storage(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_menu_page.py

@@ -14,7 +14,7 @@ class LVMenuPage(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_menu_page_t", ptr=True)
+        self._wv = self.cast("lv_menu_page_t", ptr=True) or self
 
     @property
     def title(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_msgbox.py

@@ -14,7 +14,7 @@ class LVMsgbox(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_msgbox_t", ptr=True)
+        self._wv = self.cast("lv_msgbox_t", ptr=True) or self
 
     @property
     def header(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_roller.py

@@ -13,7 +13,7 @@ class LVRoller(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_roller_t", ptr=True)
+        self._wv = self.cast("lv_roller_t", ptr=True) or self
 
     @property
     def option_cnt(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_scale.py

@@ -14,7 +14,7 @@ class LVScale(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_scale_t", ptr=True)
+        self._wv = self.cast("lv_scale_t", ptr=True) or self
 
     @property
     def section_ll(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_slider.py

@@ -14,7 +14,7 @@ class LVSlider(LVBar):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_slider_t", ptr=True)
+        self._wv = self.cast("lv_slider_t", ptr=True) or self
 
     @property
     def left_knob_area(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_spangroup.py

@@ -14,7 +14,7 @@ class LVSpangroup(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_spangroup_t", ptr=True)
+        self._wv = self.cast("lv_spangroup_t", ptr=True) or self
 
     @property
     def lines(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_spinbox.py

@@ -13,7 +13,7 @@ class LVSpinbox(LVTextarea):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_spinbox_t", ptr=True)
+        self._wv = self.cast("lv_spinbox_t", ptr=True) or self
 
     @property
     def value(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_spinner.py

@@ -13,7 +13,7 @@ class LVSpinner(LVArc):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_spinner_t", ptr=True)
+        self._wv = self.cast("lv_spinner_t", ptr=True) or self
 
     @property
     def duration(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_switch.py

@@ -13,7 +13,7 @@ class LVSwitch(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_switch_t", ptr=True)
+        self._wv = self.cast("lv_switch_t", ptr=True) or self
 
     @property
     def anim_state(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_table.py

@@ -14,7 +14,7 @@ class LVTable(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_table_t", ptr=True)
+        self._wv = self.cast("lv_table_t", ptr=True) or self
 
     @property
     def col_cnt(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_tabview.py

@@ -13,7 +13,7 @@ class LVTabview(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_tabview_t", ptr=True)
+        self._wv = self.cast("lv_tabview_t", ptr=True) or self
 
     @property
     def tab_cur(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_textarea.py

@@ -14,7 +14,7 @@ class LVTextarea(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_textarea_t", ptr=True)
+        self._wv = self.cast("lv_textarea_t", ptr=True) or self
 
     @property
     def label(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_tileview.py

@@ -14,7 +14,7 @@ class LVTileview(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_tileview_t", ptr=True)
+        self._wv = self.cast("lv_tileview_t", ptr=True) or self
 
     @property
     def tile_act(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_tileview_tile.py

@@ -13,7 +13,7 @@ class LVTileviewTile(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_tileview_tile_t", ptr=True)
+        self._wv = self.cast("lv_tileview_tile_t", ptr=True) or self
 
     @property
     def dir(self):

scripts/gdb/lvglgdb/lvgl/widgets/lv_win.py

@@ -13,7 +13,7 @@ class LVWin(LVObject):
 
     def __init__(self, obj):
         super().__init__(obj)
-        self._wv = self.cast("lv_win_t", ptr=True)
+        self._wv = self.cast("lv_win_t", ptr=True) or self
 
     def snapshot(self, include_children=False, include_styles=False):
         """Snapshot with widget-specific fields in widget_data."""

scripts/gdb/scripts/generators/gen_widget_wrappers.py

@@ -190,36 +190,44 @@ def _find_structs(text: str):
 
 
 def parse_widgets() -> dict[str, WidgetDef]:
-    widgets = {}
+    # Pass 1: collect all structs with parent type
+    candidates = []
     for private_h in sorted(WIDGETS_DIR.glob("*/lv_*_private.h")):
         text = private_h.read_text()
         widget_dir = private_h.parent.name
-
         for raw_name, body in _find_structs(text):
             struct_name = f"lv_{raw_name}_t"
-
             first_line = ""
             for line in body.splitlines():
                 line = line.strip()
                 if line and not line.startswith(("/*", "//", "*", "#")):
                     first_line = line.rstrip(";").strip()
                     break
-
             parent_match = re.match(r"(lv_\w+_t)\s+\w+", first_line)
-            if not parent_match:
-                continue
+            if parent_match:
+                candidates.append((struct_name, parent_match.group(1), body, widget_dir))
 
-            parent_type = parent_match.group(1)
-            if parent_type == "lv_obj_t" or parent_type in widgets or parent_type in (
-                "lv_bar_t", "lv_image_t", "lv_arc_t", "lv_textarea_t", "lv_buttonmatrix_t",
-            ):
-                all_fields = parse_struct_fields(body)
-                widgets[struct_name] = WidgetDef(
-                    struct_name=struct_name, c_type=struct_name,
-                    parent_type=parent_type,
-                    fields=all_fields[1:] if all_fields else [],
-                    widget_dir=widget_dir,
-                )
+    # Pass 2: resolve inheritance from lv_obj_t (order-independent)
+    widget_types = {"lv_obj_t"}
+    changed = True
+    while changed:
+        changed = False
+        for name, parent, _, _ in candidates:
+            if name not in widget_types and parent in widget_types:
+                widget_types.add(name)
+                changed = True
+
+    # Pass 3: build WidgetDef for discovered widgets
+    widgets = {}
+    for struct_name, parent_type, body, widget_dir in candidates:
+        if struct_name in widget_types and struct_name != "lv_obj_t":
+            all_fields = parse_struct_fields(body)
+            widgets[struct_name] = WidgetDef(
+                struct_name=struct_name, c_type=struct_name,
+                parent_type=parent_type,
+                fields=all_fields[1:] if all_fields else [],
+                widget_dir=widget_dir,
+            )
     return widgets
 
 
@@ -284,16 +292,16 @@ from lvglgdb.lvgl.data_utils import ptr_or_none  # noqa: F401
 
 
 def safe_string(obj, field_name):
-    """Read a char* field as string or corrupted marker. Never returns None."""
+    """Read a char* field as string, corrupted marker, or None (NULL/missing)."""
     from lvglgdb.value import CorruptedValue
     val = obj.safe_field(field_name)
     if val is None:
-        return str(CorruptedValue(0, ValueError("field not found")))
+        return None
     if not getattr(val, 'is_ok', True):
         return str(val)
     addr = int(val)
     if not addr:
-        return str(CorruptedValue(0, ValueError("NULL pointer")))
+        return None
     return val.string(fallback=str(CorruptedValue(addr, MemoryError("unreadable"))))
 
 
@@ -396,7 +404,7 @@ def gen_widget_file(wdef: WidgetDef, widgets: dict[str, WidgetDef]) -> str:
     lines.append("")
     lines.append(f"    def __init__(self, obj):")
     lines.append(f"        super().__init__(obj)")
-    lines.append(f'        self._wv = self.cast("{wdef.c_type}", ptr=True)')
+    lines.append(f'        self._wv = self.cast("{wdef.c_type}", ptr=True) or self')
     lines.append("")
 
     # Properties