annotation only fields first

HISTORY.rst

@@ -10,6 +10,7 @@ v0.4.0 (2017-XX-XX)
 * simplify error display
 * use unicode ellipsis in ``truncate``
 * add ``parse_obj``, ``parse_raw`` and ``parse_file`` helper functions #58
+* switch annotation only fields to come first in fields list not last
 
 v0.3.0 (2017-06-21)
 ...................

benchmarks/test_pydantic.py

@@ -10,9 +10,9 @@ class TestPydantic:
     def __init__(self, allow_extra):
 
         class Model(BaseModel):
-            id: int = ...
-            client_name: constr(max_length=255) = ...
-            sort_index: float = ...
+            id: int
+            client_name: constr(max_length=255)
+            sort_index: float
             # client_email: EmailStr = None
             client_phone: constr(max_length=255) = None
 
@@ -23,15 +23,15 @@ class TestPydantic:
 
             contractor: PositiveInt = None
             upstream_http_referrer: constr(max_length=1023) = None
-            grecaptcha_response: constr(min_length=20, max_length=1000) = ...
+            grecaptcha_response: constr(min_length=20, max_length=1000)
             last_updated: datetime = None
 
             class Skill(BaseModel):
-                subject: str = ...
-                subject_id: int = ...
-                category: str = ...
-                qual_level: str = ...
-                qual_level_id: int = ...
+                subject: str
+                subject_id: int
+                category: str
+                qual_level: str
+                qual_level_id: int
                 qual_level_ranking: float = 0
             skills: List[Skill] = []
 

docs/index.rst

@@ -234,7 +234,7 @@ The ellipsis notation ``...`` will not work with mypy, you need to use annotatio
 .. warning::
 
    Be aware that using annotation only fields will alter the order of your fields in metadata and errors:
-   annotation only fields will always come last, but still in the order they were defined.
+   annotation only fields will always come first, but still in the order they were defined.
 
 To get round this you can use the ``Required`` (via ``from pydantic import Required``) field as an alias for
 ellipses or annotation only.
@@ -247,8 +247,8 @@ a model.
 
 .. warning::
 
-   However be warned: immutability in python is never strict. If developers are determined/stupid they can always
-   modify a so called "immutable" object
+   Immutability in python is never strict. If developers are determined/stupid they can always
+   modify a so-called "immutable" object.
 
 .. literalinclude:: examples/mutation.py
 

pydantic/main.py

@@ -48,29 +48,18 @@ class MetaModel(type):
                 fields.update(base.__fields__)
                 config = inherit_config(base.config, config)
 
-        annotations = namespace.get('__annotations__')
         config = inherit_config(namespace.get('Config'), config)
-        class_validators = {n: f for n, f in namespace.items()
-                            if n.startswith('validate_') and isinstance(f, FunctionType)}
+        class_validators = {
+            n: f for n, f in namespace.items() if n.startswith('validate_') and isinstance(f, FunctionType)
+        }
 
         for f in fields.values():
             f.set_config(config)
 
-        for var_name, value in namespace.items():
-            if var_name.startswith('_') or isinstance(value, TYPE_BLACKLIST):
-                continue
-            fields[var_name] = Field.infer(
-                name=var_name,
-                value=value,
-                annotation=annotations.pop(var_name, None) if annotations else None,
-                class_validators=class_validators,
-                config=config,
-            )
-
-        if annotations:
-            for ann_name, ann_type in annotations.items():
-                if ann_name.startswith('_'):
-                    continue
+        annotations = namespace.get('__annotations__', {})
+        # annotation only fields need to come first in fields
+        for ann_name, ann_type in annotations.items():
+            if not ann_name.startswith('_') and ann_name not in namespace:
                 fields[ann_name] = Field.infer(
                     name=ann_name,
                     value=...,
@@ -79,6 +68,16 @@ class MetaModel(type):
                     config=config,
                 )
 
+        for var_name, value in namespace.items():
+            if not var_name.startswith('_') and not isinstance(value, TYPE_BLACKLIST):
+                fields[var_name] = Field.infer(
+                    name=var_name,
+                    value=value,
+                    annotation=annotations.get(var_name),
+                    class_validators=class_validators,
+                    config=config,
+                )
+
         new_namespace = {
             'config': config,
             '__fields__': fields,

tests/test_complex.py

@@ -397,16 +397,16 @@ _a:
 
 def test_annotation_config():
     class Model(BaseModel):
-        a: float
-        b: int = 10
+        b: float
+        a: int = 10
         _c: str
 
         class Config:
-            fields = {'a': 'foobar'}
+            fields = {'b': 'foobar'}
 
     assert list(Model.__fields__.keys()) == ['b', 'a']
-    assert [f.alias for f in Model.__fields__.values()] == ['b', 'foobar']
-    assert Model(foobar='123').a == 123.0
+    assert [f.alias for f in Model.__fields__.values()] == ['foobar', 'a']
+    assert Model(foobar='123').b == 123.0
 
 
 def test_success_values_include():

tests/test_main.py

@@ -285,7 +285,7 @@ def test_field_order():
         d: dict = {}
 
     # fields are ordered as defined except annotation-only fields come last
-    assert list(Model.__fields__.keys()) == ['b', 'd', 'c', 'a']
+    assert list(Model.__fields__.keys()) == ['c', 'a', 'b', 'd']
 
 
 def test_required():