From 75c098843a2a9da348a24bdd94cd7675dfa51ea0 Mon Sep 17 00:00:00 2001
From: "Laurent Mignon (ACSONE)" <laurent.mignon@acsone.eu>
Date: Tue, 3 Oct 2023 18:42:45 +0200
Subject: [PATCH] Fix: inheritance

Fix error when a class is extended to add others aggregated classes as parent
classes. Before this fix, the builder used the list of all base classes of
the final class as base classes for every class into the hierarchy.
---
 news/15.bugfix             |  3 +++
 src/extendable/main.py     |  4 +++-
 src/extendable/registry.py |  7 ++++++-
 tests/test_simple.py       | 29 +++++++++++++++++++++++++++++
 4 files changed, 41 insertions(+), 2 deletions(-)
 create mode 100644 news/15.bugfix

diff --git a/news/15.bugfix b/news/15.bugfix
new file mode 100644
index 0000000..d28742e
--- /dev/null
+++ b/news/15.bugfix
@@ -0,0 +1,3 @@
+Fix error when a class is extended to add others aggregated classes as base
+classes. Before this fix, the builder used the list of all base classes
+the final class should have as base classes for every class into the hierarchy.
diff --git a/src/extendable/main.py b/src/extendable/main.py
index 0638288..2360bbc 100644
--- a/src/extendable/main.py
+++ b/src/extendable/main.py
@@ -24,6 +24,7 @@
 class ExtendableClassDef:
     name: str
     base_names: List[str]
+    original_base_names: List[str]
     namespace: Dict[str, Any]
     original_name: str
     others_bases: List[Any]
@@ -44,7 +45,8 @@ def __init__(
         self.name = namespace["__xreg_name__"]
         self.original_name = original_name
         self.others_bases = bases
-        self.base_names = namespace["__xreg_base_names__"] or []
+        self.base_names = namespace["__xreg_base_names__"].copy() or []
+        self.original_base_names = self.base_names.copy()
         self.hierarchy = [self]
         self.metaclass = metaclass
         self.kwargs = kwargs
diff --git a/src/extendable/registry.py b/src/extendable/registry.py
index afd1e46..5092048 100644
--- a/src/extendable/registry.py
+++ b/src/extendable/registry.py
@@ -121,13 +121,18 @@ def build_extendable_class(
             # determine all the classes the component should inherit from
             bases = LastOrderedSet[main.ExtendableMeta]()
             for base_name in cls_def.base_names:
+                # the base_names contains all the bases for the final aggregated
+                # class. Here we check that all the base required to build the
+                # current hierarchy are already build.
                 if base_name not in self:
                     if idx != 0 or base_name != cls_def.name:
                         raise TypeError(
                             f"Pydnatic class '{name}' extends an non-existing "
                             f"extendable class '{base_name}'."
                         )
-                else:
+                elif base_name in cls_def.original_base_names:
+                    # The bases to inherit for the current class are the one
+                    # defined into the original class definition.
                     parent_class = self[base_name]
                     bases.add(parent_class)
             for other_base in class_def.others_bases:
diff --git a/tests/test_simple.py b/tests/test_simple.py
index 7691550..6ae6e3a 100644
--- a/tests/test_simple.py
+++ b/tests/test_simple.py
@@ -258,6 +258,35 @@ class MyExt(metaclass=MyMeta):
     assert MyMeta._is_extendable(MyExt)
 
 
+def test_mixin_inheritance(test_registry):
+    class BaseMixin(metaclass=ExtendableMeta):
+        def test(self):
+            return "base"
+
+    class MixinA(BaseMixin):
+        def test_a(self):
+            return "A"
+
+    class MixinB(BaseMixin):
+        def test_b(self):
+            return "B"
+
+    class ExtendedB(MixinB, extends=True):
+        def test_b(self):
+            res = super().test_b()
+            return res + " extended"
+
+    class Mixin(MixinA, MixinB, extends=MixinB):
+        pass
+
+    test_registry.init_registry()
+
+    obj = Mixin()
+    assert obj.test() == "base"
+    assert obj.test_a() == "A"
+    assert obj.test_b() == "B extended"
+
+
 def test_issubclass_multi_level(test_registry):
     class A(metaclass=ExtendableMeta):
         pass