Improved typing

Author: syrusakbary

graphql/error/format_error.py

@@ -10,7 +10,7 @@
 
 def format_error(error):
     # type: (Union[GraphQLError, GraphQLLocatedError]) -> Dict[str, Any]
-    formatted_error = {"message": text_type(error)}
+    formatted_error = {"message": text_type(error)}  # type: Dict[str, Any]
     if isinstance(error, GraphQLError):
         if error.locations is not None:
             formatted_error["locations"] = [

graphql/error/located_error.py

@@ -21,13 +21,12 @@ def __init__(
             try:
                 message = str(original_error)
             except UnicodeEncodeError:
-                message = original_error.message.encode("utf-8")
+                message = original_error.message.encode("utf-8")  # type: ignore
         else:
             message = "An unknown error occurred."
 
-        if hasattr(original_error, "stack"):
-            stack = original_error.stack
-        else:
+        stack = original_error and getattr(original_error, "stack", None)
+        if not stack:
             stack = sys.exc_info()[2]
 
         super(GraphQLLocatedError, self).__init__(

graphql/language/ast.py

@@ -462,9 +462,8 @@ def __eq__(self, other):
         # type: (Any) -> bool
         return self is other or (
             isinstance(other, Variable)
-            and
-            # self.loc == other.loc and
-            self.name == other.name
+            and self.name == other.name
+            # and self.loc == other.loc
         )
 
     def __repr__(self):

graphql/language/lexer.py

@@ -5,7 +5,7 @@
 from ..error import GraphQLSyntaxError
 
 if False:  # flake8: noqa
-    from typing import Optional
+    from typing import Optional, Any, List
     from .source import Source
 
 __all__ = ["Token", "Lexer", "TokenKind", "get_token_desc", "get_token_kind_desc"]
@@ -28,9 +28,10 @@ def __repr__(self):
         )
 
     def __eq__(self, other):
-        # type: (Token) -> bool
+        # type: (Any) -> bool
         return (
-            self.kind == other.kind
+            isinstance(other, Token)
+            and self.kind == other.kind
             and self.start == other.start
             and self.end == other.end
             and self.value == other.value
@@ -163,29 +164,33 @@ def read_token(source, from_position):
         return Token(TokenKind.EOF, position, position)
 
     code = char_code_at(body, position)
+    if code:
+        if code < 0x0020 and code not in (0x0009, 0x000A, 0x000D):
+            raise GraphQLSyntaxError(
+                source, position, u"Invalid character {}.".format(print_char_code(code))
+            )
 
-    if code < 0x0020 and code not in (0x0009, 0x000A, 0x000D):
-        raise GraphQLSyntaxError(
-            source, position, u"Invalid character {}.".format(print_char_code(code))
-        )
-
-    kind = PUNCT_CODE_TO_KIND.get(code)
-    if kind is not None:
-        return Token(kind, position, position + 1)
+        kind = PUNCT_CODE_TO_KIND.get(code)
+        if kind is not None:
+            return Token(kind, position, position + 1)
 
-    if code == 46:  # .
-        if char_code_at(body, position + 1) == char_code_at(body, position + 2) == 46:
-            return Token(TokenKind.SPREAD, position, position + 3)
+        if code == 46:  # .
+            if (
+                char_code_at(body, position + 1)
+                == char_code_at(body, position + 2)
+                == 46
+            ):
+                return Token(TokenKind.SPREAD, position, position + 3)
 
-    elif 65 <= code <= 90 or code == 95 or 97 <= code <= 122:
-        # A-Z, _, a-z
-        return read_name(source, position)
+        elif 65 <= code <= 90 or code == 95 or 97 <= code <= 122:
+            # A-Z, _, a-z
+            return read_name(source, position)
 
-    elif code == 45 or 48 <= code <= 57:  # -, 0-9
-        return read_number(source, position, code)
+        elif code == 45 or 48 <= code <= 57:  # -, 0-9
+            return read_number(source, position, code)
 
-    elif code == 34:  # "
-        return read_string(source, position)
+        elif code == 34:  # "
+            return read_string(source, position)
 
     raise GraphQLSyntaxError(
         source, position, u"Unexpected character {}.".format(print_char_code(code))
@@ -238,7 +243,7 @@ def position_after_whitespace(body, start_position):
 
 
 def read_number(source, start, first_code):
-    # type: (Source, int, int) -> Token
+    # type: (Source, int, Optional[int]) -> Token
     """Reads a number token from the source file, either a float
     or an int depending on whether a decimal point appears.
 
@@ -341,26 +346,23 @@ def read_string(source, start):
 
     position = start + 1
     chunk_start = position
-    code = 0
-    value = []
+    code = 0  # type: Optional[int]
+    value = []  # type: List[str]
     append = value.append
 
     while position < body_length:
         code = char_code_at(body, position)
-        if not (
-            code is not None
-            and code
-            not in (
-                # LineTerminator
-                0x000A,
-                0x000D,
-                # Quote
-                34,
-            )
+        if code in (
+            None,
+            # LineTerminator
+            0x000A,
+            0x000D,
+            # Quote
+            34,
         ):
             break
 
-        if code < 0x0020 and code != 0x0009:
+        if code < 0x0020 and code != 0x0009:  # type: ignore
             raise GraphQLSyntaxError(
                 source,
                 position,
@@ -372,7 +374,7 @@ def read_string(source, start):
             append(body[chunk_start : position - 1])
 
             code = char_code_at(body, position)
-            escaped = ESCAPED_CHAR_CODES.get(code)
+            escaped = ESCAPED_CHAR_CODES.get(code)  # type: ignore
             if escaped is not None:
                 append(escaped)
 
@@ -399,7 +401,9 @@ def read_string(source, start):
                 raise GraphQLSyntaxError(
                     source,
                     position,
-                    u"Invalid character escape sequence: \\{}.".format(unichr(code)),
+                    u"Invalid character escape sequence: \\{}.".format(
+                        unichr(code)  # type: ignore
+                    ),
                 )
 
             position += 1

graphql/language/printer.py

@@ -56,15 +56,15 @@ class PrintingVisitor(Visitor):
 
     def leave_Name(self, node, *args):
         # type: (Name, *Any) -> str
-        return node.value
+        return node.value  # type: ignore
 
     def leave_Variable(self, node, *args):
         # type: (Variable, *Any) -> str
-        return "$" + node.name
+        return "$" + node.name  # type: ignore
 
     def leave_Document(self, node, *args):
         # type: (Document, *Any) -> str
-        return join(node.definitions, "\n\n") + "\n"
+        return join(node.definitions, "\n\n") + "\n"  # type: ignore
 
     def leave_OperationDefinition(self, node, *args):
         # type: (OperationDefinition, *Any) -> str

graphql/language/tests/test_ast.py

@@ -1,6 +1,6 @@
 import copy
 
-from graphql.language.visitor_meta import QUERY_DOCUMENT_KEYS, VisitorMeta
+from graphql.language.visitor_meta import QUERY_DOCUMENT_KEYS
 
 
 def test_ast_is_hashable():

graphql/language/tests/test_visitor.py

@@ -28,7 +28,7 @@
 from typing import Union
 from graphql.language.ast import Field
 from graphql.language.ast import Name
-from graphql.language.visitor import Falsey
+from graphql.language.visitor import _Falsey
 from typing import List
 from graphql.language.ast import Argument
 from graphql.language.ast import IntValue

graphql/language/visitor.py

@@ -13,7 +13,7 @@
     from .printer import PrintingVisitor
 
 
-class Falsey(object):
+class _Falsey(object):
     def __nonzero__(self):
         return False
 
@@ -22,15 +22,19 @@ def __bool__(self):
         return False
 
 
-BREAK = object()
-REMOVE = Falsey()
+class _Break(object):
+    pass
+
+
+BREAK = _Break()
+REMOVE = _Falsey()
 
 
 class Stack(object):
     __slots__ = "in_array", "index", "keys", "edits", "prev"
 
     def __init__(self, in_array, index, keys, edits, prev):
-        # type: (bool, int, Any, List[Tuple[str, str]], Optional[Stack]) -> None
+        # type: (bool, int, Any, List[Tuple[Union[str, int], Any]], Optional[Stack]) -> None
         self.in_array = in_array
         self.index = index
         self.keys = keys
@@ -46,7 +50,7 @@ def visit(root, visitor, key_map=None):
     in_array = isinstance(root, list)
     keys = [root]
     index = -1
-    edits = []  # type: List[Tuple[int, Any]]
+    edits = []  # type: List[Tuple[Union[str, int], Any]]
     parent = None  # type: Optional[Node]
     path = []  # type: List
     ancestors = []  # type: List[Node]
@@ -75,7 +79,7 @@ def visit(root, visitor, key_map=None):
                 edit_offset = 0
                 for edit_key, edit_value in edits:
                     if in_array:
-                        edit_key -= edit_offset
+                        edit_key -= edit_offset  # type: ignore
 
                     if in_array and edit_value is REMOVE:
                         node.pop(edit_key)  # type: ignore
@@ -84,7 +88,6 @@ def visit(root, visitor, key_map=None):
                     else:
                         if isinstance(node, list):
                             node[edit_key] = edit_value
-
                         else:
                             setattr(node, edit_key, edit_value)  # type: ignore
 
@@ -99,7 +102,6 @@ def visit(root, visitor, key_map=None):
                 key = index if in_array else keys[index]
                 if isinstance(parent, list):
                     node = parent[key]
-
                 else:
                     node = getattr(parent, key, None)
 
@@ -148,7 +150,11 @@ def visit(root, visitor, key_map=None):
         if not is_leaving:
             stack = Stack(in_array, index, keys, edits, stack)
             in_array = isinstance(node, list)
-            keys = node if in_array else visitor_keys.get(type(node), None) or []
+            keys = (
+                node
+                if in_array
+                else visitor_keys.get(type(node), None) or []  # type: ignore
+            )  # type: ignore
             index = -1
             edits = []
 
@@ -178,10 +184,11 @@ def enter(
         path,  # type: List[Union[int, str]]
         ancestors,  # type: List[Any]
     ):
-        # type: (...) -> Optional[Any]
-        method = self._get_enter_handler(type(node))
+        # type: (...) -> Any
+        method = self._get_enter_handler(type(node))  # type: ignore
         if method:
             return method(self, node, key, parent, path, ancestors)
+        return None
 
     def leave(
         self,
@@ -191,10 +198,11 @@ def leave(
         path,  # type: List[Union[int, str]]
         ancestors,  # type: List[Any]
     ):
-        # type: (...) -> Optional[Any]
-        method = self._get_leave_handler(type(node))
+        # type: (...) -> Any
+        method = self._get_leave_handler(type(node))  # type: ignore
         if method:
             return method(self, node, key, parent, path, ancestors)
+        return None
 
 
 class ParallelVisitor(Visitor):
@@ -203,7 +211,10 @@ class ParallelVisitor(Visitor):
     def __init__(self, visitors):
         # type: (List[Any]) -> None
         self.visitors = visitors
-        self.skipping = [None] * len(visitors)
+        self.skipping = [None] * len(
+            visitors
+        )  # type: List[Union[Node, _Break, _Falsey, None]]
+        return None
 
     def enter(
         self,
@@ -213,7 +224,7 @@ def enter(
         path,  # type: List[Union[int, str]]
         ancestors,  # type: List[Any]
     ):
-        # type: (...) -> Optional[Any]
+        # type: (...) -> Any
         for i, visitor in enumerate(self.visitors):
             if not self.skipping[i]:
                 result = visitor.enter(node, key, parent, path, ancestors)
@@ -223,6 +234,7 @@ def enter(
                     self.skipping[i] = BREAK
                 elif result is not None:
                     return result
+        return None
 
     def leave(
         self,
@@ -232,7 +244,7 @@ def leave(
         path,  # type: List[Union[int, str]]
         ancestors,  # type: List[Any]
     ):
-        # type: (...) -> Optional[Any]
+        # type: (...) -> Any
         for i, visitor in enumerate(self.visitors):
             if not self.skipping[i]:
                 result = visitor.leave(node, key, parent, path, ancestors)
@@ -242,17 +254,14 @@ def leave(
                     return result
             elif self.skipping[i] == node:
                 self.skipping[i] = REMOVE
+        return None
 
 
 class TypeInfoVisitor(Visitor):
     __slots__ = "visitor", "type_info"
 
-    def __init__(
-        self,
-        type_info,  # type: TypeInfo
-        visitor,  # type: Union[TestVisitor, ParallelVisitor, UsageVisitor]
-    ):
-        # type: (...) -> None
+    def __init__(self, type_info, visitor):
+        # type: (TypeInfo, Visitor) -> None
         self.type_info = type_info
         self.visitor = visitor