From a2cf1bb6e658a00cce93f375c083af1451c7e789 Mon Sep 17 00:00:00 2001
From: nikto_b <nikto_b@newt.team>
Date: Sat, 19 Jul 2025 20:35:27 +0300
Subject: [PATCH] Get rid of manual consumer fn unwrapping for callgraph
 generation

---
 src/breakshaft/graph_walker.py | 19 ++++++++-----------
 src/breakshaft/models.py       |  2 +-
 tests/test_basic.py            | 30 ++++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/src/breakshaft/graph_walker.py b/src/breakshaft/graph_walker.py
index 7c1d20c..0eb8918 100644
--- a/src/breakshaft/graph_walker.py
+++ b/src/breakshaft/graph_walker.py
@@ -14,19 +14,16 @@ class GraphWalker:
                            from_types: frozenset[type],
                            consumer_fn: Callable) -> Optional[Callgraph]:
 
-        into_types: frozenset[type] = extract_func_argtypes(consumer_fn)
-
         branches: frozenset[Callgraph] = frozenset()
 
-        for into_type in into_types:
-            cg = cls.generate_callgraph_singletype(injectors, from_types, into_type)
-            if cg is None:
-                return None
-            branches |= {cg}
-        variant = CallgraphVariant(
-            ConversionPoint.from_fn(consumer_fn, NoneType)[0],
-            branches, frozenset())
-        return Callgraph(frozenset({variant}))
+        # Хак, чтобы вынудить систему поставить первым преобразованием требуемый consumer
+        # Новый TypeAliasType каждый раз будет иметь эксклюзивный хэш, вне зависимости от содержимого
+        # При этом, TypeAliasType также выступает в роли ключа преобразования
+        # Это позволяет переложить обработку аргументов consumer на внутренние механизмы построения графа преобразований
+        type _tmp_type_for_consumer = object
+        injectors |= set(ConversionPoint.from_fn(consumer_fn, _tmp_type_for_consumer))
+
+        return cls.generate_callgraph_singletype(injectors, from_types, _tmp_type_for_consumer)
 
     @classmethod
     def generate_callgraph_singletype(cls,
diff --git a/src/breakshaft/models.py b/src/breakshaft/models.py
index 591c30d..fdd1012 100644
--- a/src/breakshaft/models.py
+++ b/src/breakshaft/models.py
@@ -39,7 +39,7 @@ class ConversionPoint:
         return inspect.iscoroutinefunction(self.fn) or is_async_context_manager_factory(self.fn)
 
     @classmethod
-    def from_fn(cls, func: Callable, rettype: Optional[type] = None):
+    def from_fn(cls, func: Callable, rettype: Optional[type] = None) -> list[ConversionPoint]:
         if rettype is None:
             annot = get_type_hints(func)
             rettype = annot.get('return')
diff --git a/tests/test_basic.py b/tests/test_basic.py
index b29a7df..e6f7972 100644
--- a/tests/test_basic.py
+++ b/tests/test_basic.py
@@ -38,3 +38,33 @@ def test_basic():
     fn2 = repo.get_conversion((int,), consumer, force_commutative=True, force_async=False, allow_async=False)
     dep = fn2(123)
     assert dep == 123
+
+
+def test_union_deps():
+    repo = ConvRepo()
+
+    @repo.mark_injector()
+    def b_to_a(b: B) -> A:
+        return A(int(b.b))
+
+    @repo.mark_injector()
+    def a_to_b(a: A) -> B:
+        return B(float(a.a))
+
+    @repo.mark_injector()
+    def int_to_a(i: int) -> A:
+        return A(i)
+
+    def consumer(dep: A | B) -> int:
+        if isinstance(dep, A):
+            return dep.a
+        else:
+            return int(dep.b)
+
+    fn1 = repo.get_conversion((B,), consumer, force_commutative=True, force_async=False, allow_async=False)
+    dep = fn1(B(42.1))
+    assert dep == 42
+
+    fn2 = repo.get_conversion((int,), consumer, force_commutative=True, force_async=False, allow_async=False)
+    dep = fn2(123)
+    assert dep == 123