Merge pull request #16 from erezsh/issue14

Bugfix: No longer changing ForwardRef._evaluate, that interfered with…

.github/workflows/tests.yml

@@ -3,7 +3,7 @@ on: [push, pull_request]
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04   # See https://github.com/actions/setup-python/issues/544
     strategy:
       matrix:
         python-version: [3.6, 3.7, 3.8, 3.9, 3.10.0-rc - 3.10, pypy3]

runtype/pytypes.py

@@ -14,6 +14,21 @@
 from . import base_types
 from . import datetime_parse
 
+
+if sys.version_info < (3, 9):
+    if sys.version_info < (3, 7):
+        # python 3.6 
+        _orig_eval = ForwardRef._eval_type
+    else:
+        _orig_eval = ForwardRef._evaluate
+
+    def _forwardref_evaluate(self, g, l, _):
+        return _orig_eval(self, g, l)
+else:
+    _forwardref_evaluate = ForwardRef._evaluate
+
+
+
 py38 = sys.version_info >= (3, 8)
 
 
@@ -342,7 +357,7 @@ def _to_canon(self, t):
             return t
 
         if isinstance(t, ForwardRef):
-            t = t._evaluate(self.frame.f_globals, self.frame.f_locals, set())
+            t = _forwardref_evaluate(t, self.frame.f_globals, self.frame.f_locals, set())
 
         if isinstance(t, tuple):
             return SumType([to_canon(x) for x in t])

runtype/utils.py

@@ -4,20 +4,9 @@
 if sys.version_info < (3, 7):
     # python 3.6 
     from typing import _ForwardRef as ForwardRef
-    _orig_eval = ForwardRef._eval_type
-elif sys.version_info < (3, 9):
-    from typing import ForwardRef
-    _orig_eval = ForwardRef._evaluate
 else:
     from typing import ForwardRef
 
-if sys.version_info < (3, 9):
-    def _evaluate(self, g, l, _):
-        return _orig_eval(self, g, l)
-    ForwardRef._evaluate = _evaluate
-
-
-
 def get_func_signatures(typesystem, f):
     sig = inspect.signature(f)
     typesigs = []