Replace ClassProperty with metaclass properties

Python 3.10+ doesn't have a built-in class property decorator (the
@classmethod + @Property chaining was deprecated in 3.11). The modern
approach is to define properties on the metaclass, which automatically
makes them work at the class level.

- Move connection, table_name, full_table_name properties to TableMeta
- Create PartMeta subclass with overridden properties for Part tables
- Remove ClassProperty class from utils.py

Co-authored-by: dimitri-yatsenko <[email protected]>

Author: claude

src/datajoint/user_tables.py

@@ -7,7 +7,7 @@
 from .autopopulate import AutoPopulate
 from .errors import DataJointError
 from .table import Table
-from .utils import ClassProperty, from_camel_case
+from .utils import from_camel_case
 
 _base_regexp = r"[a-z][a-z0-9]*(_[a-z][a-z0-9]*)*"
 
@@ -78,6 +78,26 @@ def __add__(cls, arg):
     def __iter__(cls):
         return iter(cls())
 
+    # Class properties - defined on metaclass to work at class level
+    @property
+    def connection(cls):
+        """The database connection for this table."""
+        return cls._connection
+
+    @property
+    def table_name(cls):
+        """The table name formatted for MySQL."""
+        if cls._prefix is None:
+            raise AttributeError("Class prefix is not defined!")
+        return cls._prefix + from_camel_case(cls.__name__)
+
+    @property
+    def full_table_name(cls):
+        """The fully qualified table name (`database`.`table`)."""
+        if cls.database is None:
+            return None
+        return r"`{0:s}`.`{1:s}`".format(cls.database, cls.table_name)
+
 
 class UserTable(Table, metaclass=TableMeta):
     """
@@ -101,27 +121,6 @@ def definition(self):
         """
         raise NotImplementedError('Subclasses of Table must implement the property "definition"')
 
-    @ClassProperty
-    def connection(cls):
-        return cls._connection
-
-    @ClassProperty
-    def table_name(cls):
-        """
-        :return: the table name of the table formatted for mysql.
-        """
-        if cls._prefix is None:
-            raise AttributeError("Class prefix is not defined!")
-        return cls._prefix + from_camel_case(cls.__name__)
-
-    @ClassProperty
-    def full_table_name(cls):
-        if cls not in {Manual, Imported, Lookup, Computed, Part, UserTable}:
-            # for derived classes only
-            if cls.database is None:
-                raise DataJointError("Class %s is not properly declared (schema decorator not applied?)" % cls.__name__)
-            return r"`{0:s}`.`{1:s}`".format(cls.database, cls.table_name)
-
 
 class Manual(UserTable):
     """
@@ -163,7 +162,28 @@ class Computed(UserTable, AutoPopulate):
     tier_regexp = r"(?P<computed>" + _prefix + _base_regexp + ")"
 
 
-class Part(UserTable):
+class PartMeta(TableMeta):
+    """Metaclass for Part tables with overridden class properties."""
+
+    @property
+    def table_name(cls):
+        """The table name for a Part is derived from its master table."""
+        return None if cls.master is None else cls.master.table_name + "__" + from_camel_case(cls.__name__)
+
+    @property
+    def full_table_name(cls):
+        """The fully qualified table name (`database`.`table`)."""
+        if cls.database is None or cls.table_name is None:
+            return None
+        return r"`{0:s}`.`{1:s}`".format(cls.database, cls.table_name)
+
+    @property
+    def master(cls):
+        """The master table for this Part table."""
+        return cls._master
+
+
+class Part(UserTable, metaclass=PartMeta):
     """
     Inherit from this class if the table's values are details of an entry in another table
     and if this table is populated by the other table. For example, the entries inheriting from
@@ -184,24 +204,6 @@ class Part(UserTable):
         + ")"
     )
 
-    @ClassProperty
-    def connection(cls):
-        return cls._connection
-
-    @ClassProperty
-    def full_table_name(cls):
-        return (
-            None if cls.database is None or cls.table_name is None else r"`{0:s}`.`{1:s}`".format(cls.database, cls.table_name)
-        )
-
-    @ClassProperty
-    def master(cls):
-        return cls._master
-
-    @ClassProperty
-    def table_name(cls):
-        return None if cls.master is None else cls.master.table_name + "__" + from_camel_case(cls.__name__)
-
     def delete(self, force=False):
         """
         unless force is True, prohibits direct deletes from parts.

src/datajoint/utils.py

@@ -7,14 +7,6 @@
 from .errors import DataJointError
 
 
-class ClassProperty:
-    def __init__(self, f):
-        self.f = f
-
-    def __get__(self, obj, owner):
-        return self.f(owner)
-
-
 def user_choice(prompt, choices=("yes", "no"), default=None):
     """
     Prompts the user for confirmation.  The default value, if any, is capitalized.