Correctly handle custom inspect fn that returns object value

Replicates graphql/graphql-js@1632bd6

Author: Cito

README.md

@@ -13,7 +13,7 @@ a query language for APIs created by Facebook.
 [![Code Style](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)
 
 The current version 1.0.1 of GraphQL-core-next is up-to-date with GraphQL.js version
-14.0.2. All parts of the API are covered by an extensive test suite of currently 1681
+14.0.2. All parts of the API are covered by an extensive test suite of currently 1682
 unit tests.
 
 

graphql/language/ast.py

@@ -81,6 +81,13 @@ class Location(NamedTuple):
     def __str__(self):
         return f"{self.start}:{self.end}"
 
+    def __repr__(self):
+        """Print a simplified form when appearing in repr() or inspect()."""
+        return "<Location {}:{}>".format(self.start, self.end)
+
+    def __inspect__(self):
+        return repr(self)
+
     def __eq__(self, other):
         if isinstance(other, Location):
             return self.start == other.start and self.end == other.end

graphql/language/lexer.py

@@ -56,10 +56,15 @@ def __init__(
         self.next: Optional[Token] = None
         self.value: Optional[str] = value
 
+    def __str__(self):
+        return self.desc
+
     def __repr__(self):
-        return "<Token {} at {}-{} ({}/{})>".format(
-            self.desc, self.start, self.end, self.line, self.column
-        )
+        """Print a simplified form when appearing in repr() or inspect()."""
+        return "<Token {} {}/{}>".format(self.desc, self.line, self.column)
+
+    def __inspect__(self):
+        return repr(self)
 
     def __eq__(self, other):
         if isinstance(other, Token):

graphql/pyutils/inspect.py

@@ -24,6 +24,14 @@ def inspect(value: Any) -> str:
     """
     if isinstance(value, (bool, int, float, str)) or value in (None, INVALID):
         return repr(value)
+    # check if we have a custom inspect method
+    try:
+        inspect_method = value.__inspect__
+        if callable(inspect_method):
+            value = inspect_method()
+            return value if isinstance(value, str) else inspect(value)
+    except AttributeError:
+        pass
     if isinstance(value, list):
         return f"[{', '.join(map(inspect, value))}]"
     if isinstance(value, tuple):
@@ -71,15 +79,6 @@ def inspect(value: Any) -> str:
             value, (GraphQLNamedType, GraphQLScalarType, GraphQLWrappingType)
         ):
             return str(value)
-        # check if we have a custom inspect method
-        try:
-            inspect_method = value.__inspect__
-            if not callable(inspect_method):
-                raise AttributeError
-        except AttributeError:
-            pass
-        else:
-            return inspect_method()
         try:
             name = type(value).__name__
             if not name or "<" in name or ">" in name:

tests/language/test_lexer.py

@@ -2,7 +2,7 @@
 
 from graphql.error import GraphQLSyntaxError
 from graphql.language import Lexer, Source, SourceLocation, Token, TokenKind
-from graphql.pyutils import dedent
+from graphql.pyutils import dedent, inspect
 
 
 def lex_one(s: str) -> Token:
@@ -40,10 +40,12 @@ def records_line_and_column():
         token = lex_one("\n \r\n \r  foo\n")
         assert token == Token(TokenKind.NAME, 8, 11, 4, 3, None, "foo")
 
-    def can_be_stringified():
+    def can_be_stringified_or_pyutils_inspected():
         token = lex_one("foo")
-        assert repr(token) == "<Token Name 'foo' at 0-3 (1/1)>"
         assert token.desc == "Name 'foo'"
+        assert str(token) == token.desc
+        assert repr(token) == "<Token Name 'foo' 1/1>"
+        assert inspect(token) == repr(token)
 
     # noinspection PyArgumentEqualDefault
     def skips_whitespace_and_comments():

tests/language/test_parser.py

@@ -2,7 +2,7 @@
 
 from pytest import raises
 
-from graphql.pyutils import dedent
+from graphql.pyutils import dedent, inspect
 from graphql.error import GraphQLSyntaxError
 from graphql.language import (
     ArgumentNode,
@@ -367,6 +367,8 @@ def experimental_allows_parsing_fragment_defined_variables():
     def contains_location_information_that_only_stringifies_start_end():
         result = parse("{ id }")
         assert str(result.loc) == "0:6"
+        assert repr(result.loc) == "<Location 0:6>"
+        assert inspect(result.loc) == repr(result.loc)
 
     def contains_references_to_source():
         source = Source("{ id }")

tests/pyutils/test_inspect.py

@@ -167,3 +167,12 @@ def __inspect__():
                 return "<custom magic method inspect>"
 
         assert inspect(TestClass()) == "<custom magic method inspect>"
+
+    def custom_inspect_that_uses_self():
+        class TestClass:
+            str = "Hello World!"
+
+            def __inspect__(self):
+                return self.str
+
+        assert inspect(TestClass()) == "Hello World!"