Fix determination of propset in multimodule compilation

Author: p-sawicki

mypyc/codegen/emitfunc.py

@@ -484,7 +484,7 @@ def visit_set_attr(self, op: SetAttr) -> None:
         rtype = op.class_type
         cl = rtype.class_ir
         attr_rtype, decl_cl = cl.attr_details(op.attr)
-        if op.is_propset:
+        if cl.get_method(op.attr):
             # Again, use vtable access for properties...
             assert not op.is_init and op.error_kind == ERR_FALSE, "%s %d %d %s" % (
                 op.attr,

mypyc/ir/ops.py

@@ -31,6 +31,7 @@ class to enable the new behavior. Sometimes adding a new abstract
 
 from mypy_extensions import trait
 
+from mypyc.common import PROPSET_PREFIX
 from mypyc.ir.deps import Dependency
 from mypyc.ir.rtypes import (
     RArray,
@@ -926,8 +927,14 @@ def __init__(self, obj: Value, attr: str, src: Value, line: int) -> None:
         self.is_init = False
 
         cl = self.class_type.class_ir
+        is_propset = False
+        for ir in cl.mro:
+            propset = ir.method_decls.get(PROPSET_PREFIX + attr)
+            if propset is not None:
+                is_propset = not propset.implicit
+                break
         # If True, this op represents calling a property setter.
-        self.is_propset = cl.get_method(self.attr) is not None
+        self.is_propset = is_propset
 
     def mark_as_initializer(self) -> None:
         self.is_init = True

mypyc/test-data/run-classes.test

@@ -2164,6 +2164,21 @@ import gc
 
 from native import A, B, C, D, E, F, Foo, G
 
+def test_leaks() -> None:
+    a = A()
+
+    gc.collect()
+    before = gc.get_objects()
+    for _ in range(100):
+        a.foo = Foo()
+    gc.collect()
+    after = gc.get_objects()
+
+    diff = len(after) - len(before)
+    # Small difference is expected, if the property setter call was leaking objects
+    # we would get a difference similar to the number of iterations above.
+    assert diff <= 2, diff
+
 def set_foo(foo: Foo) -> None:
     a = A()
     a.foo = foo
@@ -2212,6 +2227,7 @@ g = G(4)
 g.x = 20
 assert g.x == 20
 
+test_leaks()
 test_use_after_passing_to_prop_setter()
 
 [file driver.py]