Fields order are preserved by @autofields even in the case of a field with just a type annotation. Fixed #76

Author: Sylvain MARIE

pyfields/autofields_.py

@@ -179,7 +179,12 @@ def v_gen():
                     # optional field : copy the default value by default
                     new_field = field(check_type=need_to_check_type, default_factory=copy_value(default_value))
 
-                # Attach the newly created field to the class
+                # Attach the newly created field to the class. Delete attr first so that order is preserved
+                # even if one of them had only an annotation.
+                try:
+                    delattr(cls, member_name)
+                except AttributeError:
+                    pass
                 setattr(cls, member_name, new_field)
                 new_field.set_as_cls_member(cls, member_name, type_hint=type_hint)
 

pyfields/helpers.py

@@ -207,12 +207,12 @@ def get_fields(cls_or_obj,
                ):
     # type: (...) -> T
     """
-    Utility method to collect all fields defined in a class, including all inherited or not.
+    Utility method to collect all fields defined in a class, including all inherited or not, in definition order.
 
     By default duplicates are removed and ancestor fields are included and appear first. If a field is overridden,
     it will appear at the position of the overridden field in the order.
 
-    If an object is provided, `getfields` will be executed on its class.
+    If an object is provided, `get_fields` will be executed on its class.
 
     :param cls_or_obj:
     :param include_inherited:

pyfields/tests/issues/_test_py36.py

@@ -1,6 +1,8 @@
 #  Authors: Sylvain Marie <[email protected]>
 #
 #  Copyright (c) Schneider Electric Industries, 2019. All right reserved.
+from typing import Optional, List
+
 from pyfields import field, init_fields, autofields
 
 
@@ -44,3 +46,21 @@ def test_issue_73_cross_ref():
     # note: we have to define the classes outside the function for the cross-ref to work
     # indeed typing.get_type_hints() will only access the globals of the defining module
     return A, B
+
+
+def test_issue_74():
+    @autofields
+    class City:
+        name: Optional[str]
+        buildings: List[str] = []
+
+    return City
+
+
+def test_issue_76():
+    @autofields
+    class Foo:
+        c: int
+        b: str = "hello"
+
+    return Foo

pyfields/tests/issues/test_issue_74_76.py

@@ -0,0 +1,22 @@
+import sys
+
+import pytest
+
+from pyfields import get_fields
+
+
+@pytest.mark.skipif(sys.version_info < (3, 6), reason="Annotations not supported in python < 3.6")
+def test_issue_74():
+    """test associated with the non-issue 74"""
+    from ._test_py36 import test_issue_74
+    City = test_issue_74()
+    c = City(name=None)
+    assert c.name is None
+    assert c.buildings == []
+
+
+def test_issue_76():
+    """ issue 76 is fixed """
+    from ._test_py36 import test_issue_76
+    Foo = test_issue_76()
+    assert [f.name for f in get_fields(Foo)] == ['c', 'b']