Refactor string .format() to f-string syntax. Minor corrections. Blackened project.

Rebased to trigger ci.

Blackened project, due to Travis failures.

f-string formatting where applicable.
Minor corrections to language.

Corrected typo, missing parens.

Update test_structures.py to match updated phrasing.

Bowing to the wisdom of black.

As per black, adjusted line length in types/argument.py (line 67).

One  more kick in the pants by black.

More f-strings.

More blackening.

Author: changeling

UPGRADE-v2.0.md

@@ -379,10 +379,7 @@ class Base(ObjectType):
     id = ID()
 
     def resolve_id(self, info):
-        return "{type}_{id}".format(
-            type=self.__class__.__name__,
-            id=self.id
-        )
+        return f"{self.__class__.__name__}_{self.id}"
 ```
 
 ### UUID Scalar

docs/relay/nodes.rst

@@ -52,7 +52,7 @@ Example of a custom node:
 
         @staticmethod
         def to_global_id(type, id):
-            return '{}:{}'.format(type, id)
+            return f'{type}:{id}'
 
         @staticmethod
         def get_node_from_global_id(info, global_id, only_type=None):

docs/types/objecttypes.rst

@@ -26,7 +26,7 @@ This example model defines a Person, with a first and a last name:
         full_name = graphene.String()
 
         def resolve_full_name(root, info):
-            return '{} {}'.format(root.first_name, root.last_name)
+            return f'{root.first_name} {root.last_name}'
 
 **first\_name** and **last\_name** are fields of the ObjectType. Each
 field is specified as a class attribute, and each attribute maps to a
@@ -173,7 +173,7 @@ A field can use a custom resolver from outside the class:
     import graphene
 
     def resolve_full_name(person, info):
-        return '{} {}'.format(person.first_name, person.last_name)
+        return f'{person.first_name} {person.last_name}'
 
     class Person(graphene.ObjectType):
         first_name = graphene.String()

examples/complex_example.py

@@ -7,7 +7,7 @@ class GeoInput(graphene.InputObjectType):
 
     @property
     def latlng(self):
-        return "({},{})".format(self.lat, self.lng)
+        return f"({self.lat},{self.lng})"
 
 
 class Address(graphene.ObjectType):

graphene/pyutils/signature.py

@@ -54,7 +54,7 @@ def signature(obj):
     """Get a signature object for the passed callable."""
 
     if not callable(obj):
-        raise TypeError("{!r} is not a callable object".format(obj))
+        raise TypeError(f"{repr(obj)} is not a callable object")
 
     if isinstance(obj, types.MethodType):
         sig = signature(obj.__func__)
@@ -101,7 +101,7 @@ def signature(obj):
         try:
             ba = sig.bind_partial(*partial_args, **partial_keywords)
         except TypeError as ex:
-            msg = "partial object {!r} has incorrect arguments".format(obj)
+            msg = f"partial object {repr(obj)} has incorrect arguments"
             raise ValueError(msg)
 
         for arg_name, arg_value in ba.arguments.items():
@@ -171,10 +171,10 @@ def signature(obj):
 
     if isinstance(obj, types.BuiltinFunctionType):
         # Raise a nicer error message for builtins
-        msg = "no signature found for builtin function {!r}".format(obj)
+        msg = f"no signature found for builtin function {repr(obj)}"
         raise ValueError(msg)
 
-    raise ValueError("callable {!r} is not supported by signature".format(obj))
+    raise ValueError(f"callable {repr(obj)} is not supported by signature")
 
 
 class _void(object):
@@ -195,7 +195,7 @@ def __str__(self):
         return self._name
 
     def __repr__(self):
-        return "<_ParameterKind: {!r}>".format(self._name)
+        return f"<_ParameterKind: {repr(self._name)}>"
 
 
 _POSITIONAL_ONLY = _ParameterKind(0, name="POSITIONAL_ONLY")
@@ -249,7 +249,7 @@ def __init__(
 
         if default is not _empty:
             if kind in (_VAR_POSITIONAL, _VAR_KEYWORD):
-                msg = "{} parameters cannot have default values".format(kind)
+                msg = f"{kind} parameters cannot have default values"
                 raise ValueError(msg)
         self._default = default
         self._annotation = annotation
@@ -263,7 +263,7 @@ def __init__(
         else:
             name = str(name)
             if kind != _POSITIONAL_ONLY and not re.match(r"[a-z_]\w*$", name, re.I):
-                msg = "{!r} is not a valid parameter name".format(name)
+                msg = f"{repr(name)} is not a valid parameter name"
                 raise ValueError(msg)
             self._name = name
 
@@ -325,14 +325,14 @@ def __str__(self):
         if kind == _POSITIONAL_ONLY:
             if formatted is None:
                 formatted = ""
-            formatted = "<{}>".format(formatted)
+            formatted = f"<{formatted}>"
 
         # Add annotation and default value
         if self._annotation is not _empty:
-            formatted = "{}:{}".format(formatted, formatannotation(self._annotation))
+            formatted = f"{formatted}:{formatannotation(self._annotation)}"
 
         if self._default is not _empty:
-            formatted = "{}={}".format(formatted, repr(self._default))
+            formatted = f"{formatted}={repr(self._default)}"
 
         if kind == _VAR_POSITIONAL:
             formatted = "*" + formatted
@@ -342,10 +342,10 @@ def __str__(self):
         return formatted
 
     def __repr__(self):
-        return "<{} at {:#x} {!r}>".format(self.__class__.__name__, id(self), self.name)
+        return f"<{self.__class__.__name__} at {id(self):#x} {repr(self.name)}>"
 
     def __hash__(self):
-        msg = "unhashable type: '{}'".format(self.__class__.__name__)
+        msg = f"unhashable type: '{self.__class__.__name__}'"
         raise TypeError(msg)
 
     def __eq__(self, other):
@@ -442,7 +442,7 @@ def kwargs(self):
         return kwargs
 
     def __hash__(self):
-        msg = "unhashable type: '{}'".format(self.__class__.__name__)
+        msg = f"unhashable type: '{self.__class__.__name__}'"
         raise TypeError(msg)
 
     def __eq__(self, other):
@@ -501,8 +501,7 @@ def __init__(
                 for idx, param in enumerate(parameters):
                     kind = param.kind
                     if kind < top_kind:
-                        msg = "wrong parameter order: {0} before {1}"
-                        msg = msg.format(top_kind, param.kind)
+                        msg = f"wrong parameter order: {top_kind} before {param.kind}"
                         raise ValueError(msg)
                     else:
                         top_kind = kind
@@ -513,7 +512,7 @@ def __init__(
                         param = param.replace(name=name)
 
                     if name in params:
-                        msg = "duplicate parameter name: {!r}".format(name)
+                        msg = f"duplicate parameter name: {repr(name)}"
                         raise ValueError(msg)
                     params[name] = param
             else:
@@ -527,7 +526,7 @@ def from_function(cls, func):
         """Constructs Signature for the given python function"""
 
         if not isinstance(func, types.FunctionType):
-            raise TypeError("{!r} is not a Python function".format(func))
+            raise TypeError(f"{repr(func)} is not a Python function")
 
         Parameter = cls._parameter_cls
 
@@ -631,7 +630,7 @@ def replace(self, parameters=_void, return_annotation=_void):
         return type(self)(parameters, return_annotation=return_annotation)
 
     def __hash__(self):
-        msg = "unhashable type: '{}'".format(self.__class__.__name__)
+        msg = f"unhashable type: '{self.__class__.__name__}'"
         raise TypeError(msg)
 
     def __eq__(self, other):
@@ -708,10 +707,9 @@ def _bind(self, args, kwargs, partial=False):
                     elif param.name in kwargs:
                         if param.kind == _POSITIONAL_ONLY:
                             msg = (
-                                "{arg!r} parameter is positional only, "
+                                f"{repr(param.name)} parameter is positional only, "
                                 "but was passed as a keyword"
                             )
-                            msg = msg.format(arg=param.name)
                             raise TypeError(msg)
                         parameters_ex = (param,)
                         break
@@ -726,8 +724,7 @@ def _bind(self, args, kwargs, partial=False):
                             parameters_ex = (param,)
                             break
                         else:
-                            msg = "{arg!r} parameter lacking default value"
-                            msg = msg.format(arg=param.name)
+                            msg = f"{repr(param.name)} parameter lacking default value"
                             raise TypeError(msg)
             else:
                 # We have a positional argument to process
@@ -752,8 +749,7 @@ def _bind(self, args, kwargs, partial=False):
 
                     if param.name in kwargs:
                         raise TypeError(
-                            "multiple values for argument "
-                            "{arg!r}".format(arg=param.name)
+                            f"multiple values for argument {repr(param.name)}"
                         )
 
                     arguments[param.name] = arg_val
@@ -767,8 +763,8 @@ def _bind(self, args, kwargs, partial=False):
                 # Signature object (but let's have this check here
                 # to ensure correct behaviour just in case)
                 raise TypeError(
-                    "{arg!r} parameter is positional only, "
-                    "but was passed as a keyword".format(arg=param.name)
+                    f"{repr(param.name)} parameter is positional only, "
+                    "but was passed as a keyword"
                 )
 
             if param.kind == _VAR_KEYWORD:
@@ -790,7 +786,7 @@ def _bind(self, args, kwargs, partial=False):
                     and param.default is _empty
                 ):
                     raise TypeError(
-                        "{arg!r} parameter lacking default value".format(arg=param_name)
+                        f"{repr(param_name)} parameter lacking default value"
                     )
 
             else:
@@ -841,10 +837,10 @@ def __str__(self):
 
             result.append(formatted)
 
-        rendered = "({})".format(", ".join(result))
+        rendered = f"({', '.join(result)})"
 
         if self.return_annotation is not _empty:
             anno = formatannotation(self.return_annotation)
-            rendered += " -> {}".format(anno)
+            rendered += f" -> {anno}"
 
         return rendered

graphene/relay/connection.py

@@ -52,16 +52,14 @@ class Meta:
     @classmethod
     def __init_subclass_with_meta__(cls, node=None, name=None, **options):
         _meta = ConnectionOptions(cls)
-        assert node, "You have to provide a node in {}.Meta".format(cls.__name__)
+        assert node, f"You have to provide a node in {cls.__name__}.Meta"
         assert isinstance(node, NonNull) or issubclass(
             node, (Scalar, Enum, ObjectType, Interface, Union, NonNull)
-        ), ('Received incompatible node "{}" for Connection {}.').format(
-            node, cls.__name__
-        )
+        ), f'Received incompatible node "{node}" for Connection {cls.__name__}.'
 
         base_name = re.sub("Connection$", "", name or cls.__name__) or node._meta.name
         if not name:
-            name = "{}Connection".format(base_name)
+            name = f"{base_name}Connection"
 
         edge_class = getattr(cls, "Edge", None)
         _node = node
@@ -71,11 +69,9 @@ class EdgeBase(object):
             cursor = String(required=True, description="A cursor for use in pagination")
 
         class EdgeMeta:
-            description = "A Relay edge containing a `{}` and its cursor.".format(
-                base_name
-            )
+            description = f"A Relay edge containing a `{base_name}` and its cursor."
 
-        edge_name = "{}Edge".format(base_name)
+        edge_name = f"{base_name}Edge"
         if edge_class:
             edge_bases = (edge_class, EdgeBase, ObjectType)
         else:
@@ -132,9 +128,9 @@ def type(self):
                 "Read more: https://github.com/graphql-python/graphene/blob/v2.0.0/UPGRADE-v2.0.md#node-connections"
             )
 
-        assert issubclass(connection_type, Connection), (
-            '{} type have to be a subclass of Connection. Received "{}".'
-        ).format(self.__class__.__name__, connection_type)
+        assert issubclass(
+            connection_type, Connection
+        ), f'{self.__class__.__name__} type have to be a subclass of Connection. Received "{connection_type}".'
         return type
 
     @classmethod
@@ -143,9 +139,9 @@ def resolve_connection(cls, connection_type, args, resolved):
             return resolved
 
         assert isinstance(resolved, Iterable), (
-            "Resolved value from the connection field have to be iterable or instance of {}. "
-            'Received "{}"'
-        ).format(connection_type, resolved)
+            f"Resolved value from the connection field has to be iterable or instance of {connection_type}. "
+            f'Received "{resolved}"'
+        )
         connection = connection_from_list(
             resolved,
             args,

graphene/relay/mutation.py

@@ -28,7 +28,7 @@ def __init_subclass_with_meta__(
             input_fields = {}
 
         cls.Input = type(
-            "{}Input".format(base_name),
+            f"{base_name}Input",
             bases,
             OrderedDict(
                 input_fields, client_mutation_id=String(name="clientMutationId")
@@ -42,12 +42,12 @@ def __init_subclass_with_meta__(
         mutate_and_get_payload = getattr(cls, "mutate_and_get_payload", None)
         if cls.mutate and cls.mutate.__func__ == ClientIDMutation.mutate.__func__:
             assert mutate_and_get_payload, (
-                "{name}.mutate_and_get_payload method is required"
+                f"{name or cls.__name__}.mutate_and_get_payload method is required"
                 " in a ClientIDMutation."
-            ).format(name=name or cls.__name__)
+            )
 
         if not name:
-            name = "{}Payload".format(base_name)
+            name = f"{base_name}Payload"
 
         super(ClientIDMutation, cls).__init_subclass_with_meta__(
             output=None, arguments=arguments, name=name, **options
@@ -61,8 +61,8 @@ def on_resolve(payload):
                 payload.client_mutation_id = input.get("client_mutation_id")
             except Exception:
                 raise Exception(
-                    ("Cannot set client_mutation_id in the payload object {}").format(
-                        repr(payload)
+                    (
+                        f"Cannot set client_mutation_id in the payload object {repr(payload)}"
                     )
                 )
             return payload

graphene/relay/node.py

@@ -98,9 +98,9 @@ def get_node_from_global_id(cls, info, global_id, only_type=None):
             return None
 
         if only_type:
-            assert graphene_type == only_type, ("Must receive a {} id.").format(
-                only_type._meta.name
-            )
+            assert (
+                graphene_type == only_type
+            ), f"Must receive a {only_type._meta.name} id."
 
         # We make sure the ObjectType implements the "Node" interface
         if cls not in graphene_type._meta.interfaces:

graphene/types/argument.py

@@ -64,18 +64,17 @@ def to_arguments(args, extra_args=None):
 
         if isinstance(arg, (InputField, Field)):
             raise ValueError(
-                "Expected {} to be Argument, but received {}. Try using Argument({}).".format(
-                    default_name, type(arg).__name__, arg.type
-                )
+                f"Expected {default_name} to be Argument, but received {type(arg).__name__}. "
+                f"Try using Argument({arg.type})."
             )
 
         if not isinstance(arg, Argument):
-            raise ValueError('Unknown argument "{}".'.format(default_name))
+            raise ValueError(f'Unknown argument "{default_name}".')
 
         arg_name = default_name or arg.name
         assert (
             arg_name not in arguments
-        ), 'More than one Argument have same name "{}".'.format(arg_name)
+        ), f'More than one Argument have same name "{arg_name}".'
         arguments[arg_name] = arg
 
     return arguments

graphene/types/base.py

@@ -20,10 +20,10 @@ def __setattr__(self, name, value):
         if not self._frozen:
             super(BaseOptions, self).__setattr__(name, value)
         else:
-            raise Exception("Can't modify frozen Options {}".format(self))
+            raise Exception(f"Can't modify frozen Options {self}")
 
     def __repr__(self):
-        return "<{} name={}>".format(self.__class__.__name__, repr(self.name))
+        return f"<{self.__class__.__name__} name={repr(self.name)}>"
 
 
 class BaseType(SubclassWithMeta):