Make print() break long List and Object Values over multiple line

Replicates graphql/graphql-js@ddd6a01

Author: Cito

src/graphql/language/printer.py

@@ -200,11 +200,19 @@ def leave_enum_value(node: PrintedNode, *_args: Any) -> str:
 
     @staticmethod
     def leave_list_value(node: PrintedNode, *_args: Any) -> str:
-        return f"[{join(node.values, ', ')}]"
+        values = node.values
+        values_line = f"[{join(values, ', ')}]"
+        return (
+            "\n".join(("[", indent(join(values, "\n")), "]"))
+            if len(values_line) > 80
+            else values_line
+        )
 
     @staticmethod
     def leave_object_value(node: PrintedNode, *_args: Any) -> str:
-        return f"{{ {join(node.fields, ', ')} }}"
+        fields = node.fields
+        fields_line = f"{{ {join(fields, ', ')} }}"
+        return block(fields) if len(fields_line) > MAX_LINE_LENGTH else fields_line
 
     @staticmethod
     def leave_object_field(node: PrintedNode, *_args: Any) -> str:

tests/language/test_printer.py

@@ -106,6 +106,75 @@ def puts_arguments_on_multiple_lines_if_line_has_more_than_80_chars():
             """
         )
 
+    def puts_large_object_values_on_multiple_lines_if_line_has_more_than_80_chars():
+        printed = print_ast(
+            parse(
+                "{trip(obj:{wheelchair:false,smallObj:{a: 1},largeObj:"
+                "{wheelchair:false,smallObj:{a: 1},arriveBy:false,"
+                "includePlannedCancellations:true,transitDistanceReluctance:2000,"
+                'anotherLongFieldName:"Lots and lots and lots and lots of text"},'
+                "arriveBy:false,includePlannedCancellations:true,"
+                "transitDistanceReluctance:2000,anotherLongFieldName:"
+                '"Lots and lots and lots and lots of text"}){dateTime}}'
+            )
+        )
+
+        assert printed == dedent(
+            """
+            {
+              trip(
+                obj: {
+                  wheelchair: false
+                  smallObj: { a: 1 }
+                  largeObj: {
+                    wheelchair: false
+                    smallObj: { a: 1 }
+                    arriveBy: false
+                    includePlannedCancellations: true
+                    transitDistanceReluctance: 2000
+                    anotherLongFieldName: "Lots and lots and lots and lots of text"
+                  }
+                  arriveBy: false
+                  includePlannedCancellations: true
+                  transitDistanceReluctance: 2000
+                  anotherLongFieldName: "Lots and lots and lots and lots of text"
+                }
+              ) {
+                dateTime
+              }
+            }
+            """
+        )
+
+    def puts_large_list_values_on_multiple_lines_if_line_has_more_than_80_chars():
+        printed = print_ast(
+            parse(
+                '{trip(list:[["small array", "small", "small"],'
+                ' ["Lots and lots and lots and lots of text",'
+                ' "Lots and lots and lots and lots of text",'
+                ' "Lots and lots and lots and lots of text"]]){dateTime}}'
+            )
+        )
+
+        assert printed == dedent(
+            """
+            {
+              trip(
+                list: [
+                  ["small array", "small", "small"]
+                  [
+                    "Lots and lots and lots and lots of text"
+                    "Lots and lots and lots and lots of text"
+                    "Lots and lots and lots and lots of text"
+                  ]
+                ]
+              ) {
+                dateTime
+              }
+            }
+            """
+        )
+
     def legacy_prints_fragment_with_variable_directives():
         query_ast_with_variable_directive = parse(
             "fragment Foo($foo: TestType @test) on TestType @testDirective { id }",