chore(gdb): fix safe_string corrupted markers, safe_color struct read, ptr_or_none null check, char** detection

- safe_string: use CorruptedValue for consistent corrupted markers, never returns None
- safe_color: read lv_color_t {red, green, blue} sub-fields instead of int()
- ptr_or_none: handle None input from safe_field
- Generator: char** (multi-level pointer) no longer marked as is_string

scripts/gdb/lvglgdb/lvgl/data_utils.py

@@ -16,8 +16,8 @@ def fmt_cb(cb) -> str:
 
 
 def ptr_or_none(val) -> Optional[str]:
-    """Convert pointer to hex string or None if NULL."""
-    if not val.is_ok:
+    """Convert pointer to hex string or None if NULL/missing."""
+    if val is None or not val.is_ok:
         return None
     addr = int(val)
     return hex(addr) if addr else None

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

@@ -8,19 +8,28 @@ from lvglgdb.lvgl.data_utils import ptr_or_none  # noqa: F401
 
 
 def safe_string(obj, field_name):
-    """Read a char* field as string, or None."""
+    """Read a char* field as string or corrupted marker. Never returns None."""
+    from lvglgdb.value import CorruptedValue
     val = obj.safe_field(field_name)
-    if val is None or not getattr(val, 'is_ok', True) or not int(val):
-        return None
-    return val.string(fallback=None)
+    if val is None:
+        return str(CorruptedValue(0, ValueError("field not found")))
+    if not getattr(val, 'is_ok', True):
+        return str(val)
+    addr = int(val)
+    if not addr:
+        return str(CorruptedValue(0, ValueError("NULL pointer")))
+    return val.string(fallback=str(CorruptedValue(addr, MemoryError("unreadable"))))
 
 
 def safe_color(obj, field_name):
-    """Read lv_color_t as hex string."""
+    """Read lv_color_t {red, green, blue} as hex string."""
     val = obj.safe_field(field_name)
     if val is None or not getattr(val, 'is_ok', True):
         return None
-    return f"#{int(val):06x}"
+    r = int(val.safe_field("red", 0))
+    g = int(val.safe_field("green", 0))
+    b = int(val.safe_field("blue", 0))
+    return f"#{r:02x}{g:02x}{b:02x}"
 
 
 def safe_area(obj, field_name):

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

@@ -6,7 +6,7 @@ Do not edit manually. Regenerate from the GDB script root with:
 """
 
 from lvglgdb.lvgl.core.lv_obj import LVObject
-from ._helpers import ptr_or_none, safe_string
+from ._helpers import ptr_or_none
 
 
 class LVButtonmatrix(LVObject):
@@ -19,7 +19,7 @@ class LVButtonmatrix(LVObject):
     @property
     def map_p(self):
         """Pointer to the current map"""
-        return safe_string(self._wv, "map_p")
+        return ptr_or_none(self._wv.safe_field("map_p"))
 
     @property
     def button_areas(self):

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

@@ -6,7 +6,7 @@ Do not edit manually. Regenerate from the GDB script root with:
 """
 
 from lvglgdb.lvgl.core.lv_obj import LVObject
-from ._helpers import safe_string, safe_wrapper
+from ._helpers import ptr_or_none, safe_wrapper
 
 
 class LVScale(LVObject):
@@ -23,7 +23,7 @@ class LVScale(LVObject):
 
     @property
     def txt_src(self):
-        return safe_string(self._wv, "txt_src")
+        return ptr_or_none(self._wv.safe_field("txt_src"))
 
     @property
     def mode(self):

scripts/gdb/scripts/generators/gen_widget_wrappers.py

@@ -165,7 +165,7 @@ def parse_struct_fields(body: str) -> list[StructField]:
                 name=name, c_type=c_type,
                 is_pointer=is_ptr,
                 is_obj_pointer=is_ptr and "lv_obj_t" in c_type,
-                is_string=is_ptr and "char" in c_type,
+                is_string=is_ptr and "char" in c_type and c_type.count("*") <= 1,
                 comment=comment,
             ))
 
@@ -284,19 +284,28 @@ from lvglgdb.lvgl.data_utils import ptr_or_none  # noqa: F401
 
 
 def safe_string(obj, field_name):
-    """Read a char* field as string, or None."""
+    """Read a char* field as string or corrupted marker. Never returns None."""
+    from lvglgdb.value import CorruptedValue
     val = obj.safe_field(field_name)
-    if val is None or not getattr(val, 'is_ok', True) or not int(val):
-        return None
-    return val.string(fallback=None)
+    if val is None:
+        return str(CorruptedValue(0, ValueError("field not found")))
+    if not getattr(val, 'is_ok', True):
+        return str(val)
+    addr = int(val)
+    if not addr:
+        return str(CorruptedValue(0, ValueError("NULL pointer")))
+    return val.string(fallback=str(CorruptedValue(addr, MemoryError("unreadable"))))
 
 
 def safe_color(obj, field_name):
-    """Read lv_color_t as hex string."""
+    """Read lv_color_t {red, green, blue} as hex string."""
     val = obj.safe_field(field_name)
     if val is None or not getattr(val, 'is_ok', True):
         return None
-    return f"#{int(val):06x}"
+    r = int(val.safe_field("red", 0))
+    g = int(val.safe_field("green", 0))
+    b = int(val.safe_field("blue", 0))
+    return f"#{r:02x}{g:02x}{b:02x}"
 
 
 def safe_area(obj, field_name):