Fix duplicate fields Pyreverse bug

doc/whatsnew/fragments/8189.bugfix

@@ -0,0 +1,3 @@
+Don't show class fields more than once in Pyreverse diagrams.
+
+Closes #8189

pylint/pyreverse/diagrams.py

@@ -121,16 +121,19 @@ def get_relationship(
     def get_attrs(self, node: nodes.ClassDef) -> list[str]:
         """Return visible attributes, possibly with class name."""
         attrs = []
-        properties = [
-            (n, m)
-            for n, m in node.items()
-            if isinstance(m, nodes.FunctionDef) and decorated_with_property(m)
-        ]
-        for node_name, associated_nodes in (
-            list(node.instance_attrs_type.items())
-            + list(node.locals_type.items())
-            + properties
+        properties = {
+            local_name: local_node
+            for local_name, local_node in node.items()
+            if isinstance(local_node, nodes.FunctionDef)
+            and decorated_with_property(local_node)
+        }
+        for attr_name, attr_type in list(node.locals_type.items()) + list(
+            node.instance_attrs_type.items()
         ):
+            if attr_name not in properties:
+                properties[attr_name] = attr_type
+
+        for node_name, associated_nodes in properties.items():
             if not self.show_attr(node_name):
                 continue
             names = self.class_names(associated_nodes)

tests/pyreverse/functional/class_diagrams/attributes/duplicates.mmd

@@ -8,12 +8,9 @@ classDiagram
   }
   class DuplicateArrows {
     a
-    a
   }
   class DuplicateFields {
     example1 : int
-    example1 : int
-    example2 : int
     example2 : int
   }
   A --* DuplicateArrows : a

tests/pyreverse/functional/class_diagrams/attributes/duplicates.py

@@ -1,4 +1,4 @@
-# OPEN BUG: https://github.com/pylint-dev/pylint/issues/8189
+# Test for https://github.com/pylint-dev/pylint/issues/8189
 class DuplicateFields():
     example1: int
     example2: int