pylibfdt: Support copy.copy() and copy.deepcopy() on Property

`libfdt.Property` subclasses `bytearray` and has a two-argument
`__init__(self, name, value)` constructor. Because `bytearray`'s default
copy/reduce protocol passes only the raw byte buffer to the constructor
(and does not copy instance attributes), calling `copy.copy()` or
`copy.deepcopy()` on a `Property` fails with `TypeError:
Property.__init__() missing 1 required positional argument: 'value'`.

Implement `__copy__()` and `__deepcopy__()` on `Property` so shallow and
deep copies preserve both `name` and the byte contents, and add a unit
test in `tests/pylibfdt_tests.py`.

Assisted-by: Gemini:gemini-pro-prerelease
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Message-ID: <20261101220224.1436242-7-dianders@chromium.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

pylibfdt/libfdt.i

@@ -908,6 +908,12 @@ class Property(bytearray):
         bytearray.__init__(self, value)
         self.name = name
 
+    def __copy__(self):
+        return type(self)(self.name, self)
+
+    def __deepcopy__(self, memo):
+        return type(self)(self.name, self)
+
     def as_cell(self, fmt):
         return struct.unpack('>' + fmt, self)[0]
 

tests/pylibfdt_tests.py

@@ -4,6 +4,7 @@
 # Written by Simon Glass <sjg@chromium.org>
 #
 
+import copy
 import struct
 import sys
 import types
@@ -192,6 +193,11 @@ class PyLibfdtBasicTests(unittest.TestCase):
         prop = self.fdt.get_property_by_offset(poffset)
         self.assertEqual(prop.name, 'compatible')
         self.assertEqual(prop, b'test_tree1\0')
+        for copied in (copy.copy(prop), copy.deepcopy(prop)):
+            self.assertIsInstance(copied, libfdt.Property)
+            self.assertIsNot(copied, prop)
+            self.assertEqual(copied.name, 'compatible')
+            self.assertEqual(copied, b'test_tree1\0')
 
         with self.assertRaises(FdtException) as e:
             self.fdt.get_property_by_offset(-2)