Unify print_ast and print_schema output for block strings

Replicates graphql/graphql-js@ded3261

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 1.0.2 of GraphQL-core-next is up-to-date with GraphQL.js version
-14.1.1. All parts of the API are covered by an extensive test suite of currently 1725
+14.1.1. All parts of the API are covered by an extensive test suite of currently 1737
 unit tests.
 
 

graphql/language/block_string_value.py

@@ -1,4 +1,4 @@
-__all__ = ["dedent_block_string_value"]
+__all__ = ["dedent_block_string_value", "print_block_string"]
 
 
 def dedent_block_string_value(raw_string: str) -> str:
@@ -37,3 +37,31 @@ def leading_whitespace(s):
     while i < n and s[i] in " \t":
         i += 1
     return i
+
+
+def print_block_string(
+    value: str, indentation: str = "", prefer_multiple_lines: bool = False
+) -> str:
+    """Print a block string in the indented block form.
+
+    Prints a block string in the indented block form by adding a leading and
+    trailing blank line. However, if a block string starts with whitespace and
+    is a single-line, adding a leading blank line would strip that whitespace.
+    """
+    is_single_line = "\n" not in value
+    has_leading_space = value.startswith(" ") or value.startswith("\t")
+    has_trailing_quote = value.endswith('"')
+    print_as_multiple_lines = (
+        not is_single_line or has_trailing_quote or prefer_multiple_lines
+    )
+
+    # Format a multi-line block quote to account for leading space.
+    if print_as_multiple_lines and not (is_single_line and has_leading_space):
+        result = "\n" + indentation
+    else:
+        result = ""
+    result += value.replace("\n", "\n" + indentation) if indentation else value
+    if print_as_multiple_lines:
+        result += "\n"
+
+    return '"""' + result.replace('"""', '\\"""') + '"""'

graphql/language/printer.py

@@ -4,6 +4,7 @@
 
 from .ast import Node, OperationType
 from .visitor import visit, Visitor
+from .block_string_value import print_block_string
 
 __all__ = ["print_ast"]
 
@@ -113,7 +114,7 @@ def leave_float_value(self, node, *_args):
 
     def leave_string_value(self, node, key, *_args):
         if node.block:
-            return print_block_string(node.value, key == "description")
+            return print_block_string(node.value, "" if key == "description" else "  ")
         return dumps(node.value)
 
     def leave_boolean_value(self, node, *_args):
@@ -301,24 +302,6 @@ def leave_input_object_type_extension(self, node, *_args):
         )
 
 
-def print_block_string(value: str, is_description: bool = False) -> str:
-    """Print a block string.
-
-    Prints a block string in the indented block form by adding a leading and trailing
-    blank line. However, if a block string starts with whitespace and is a single-line,
-    adding a leading blank line would strip that whitespace.
-    """
-    escaped = value.replace('"""', '\\"""')
-    if is_multiline(value) or not value.startswith((" ", "\t")):
-        if not is_description:
-            escaped = indent(escaped)
-        return f'"""\n{escaped}\n"""'
-    else:
-        if escaped.endswith('"'):
-            escaped += "\n"
-        return f'"""{escaped}"""'
-
-
 def join(strings: Optional[Sequence[str]], separator: str = "") -> str:
     """Join strings in a given sequence.
 

graphql/utilities/schema_printer.py

@@ -3,6 +3,7 @@
 from typing import Any, Callable, Dict, List, Optional, Union, cast
 
 from ..language import print_ast
+from ..language.block_string_value import print_block_string
 from ..pyutils import inspect
 from ..type import (
     DEFAULT_DEPRECATION_REASON,
@@ -254,34 +255,21 @@ def print_deprecated(field_or_enum_value: Union[GraphQLField, GraphQLEnumValue])
 
 
 def print_description(
-    type_: Union[GraphQLArgument, GraphQLDirective, GraphQLEnumValue, GraphQLNamedType],
+    def_: Union[GraphQLArgument, GraphQLDirective, GraphQLEnumValue, GraphQLNamedType],
     indentation="",
     first_in_block=True,
 ) -> str:
-    if not type_.description:
+    if not def_.description:
         return ""
-    lines = description_lines(type_.description, 120 - len(indentation))
-
-    description = []
-    if indentation and not first_in_block:
-        description.append("\n")
-    description.extend([indentation, '"""'])
-
-    if len(lines) == 1 and len(lines[0]) < 70 and not lines[0].endswith('"'):
-        # In some circumstances, a single line can be used for the description.
-        description.extend([escape_quote(lines[0]), '"""\n'])
-    else:
-        # Format a multi-line block quote to account for leading space.
-        has_leading_space = lines and lines[0].startswith((" ", "\t"))
-        if not has_leading_space:
-            description.append("\n")
-        for i, line in enumerate(lines):
-            if i or not has_leading_space:
-                description.append(indentation)
-            description.extend([escape_quote(line), "\n"])
-        description.extend([indentation, '"""\n'])
-
-    return "".join(description)
+
+    lines = description_lines(def_.description, 120 - len(indentation))
+
+    text = '\n'.join(lines)
+    prefer_multiple_lines = len(text) > 70
+    block_string = print_block_string(text, '', prefer_multiple_lines)
+    prefix = '\n' + indentation if indentation and not first_in_block else indentation
+
+    return prefix + block_string.replace('\n', '\n' + indentation) + '\n'
 
 
 def escape_quote(line: str) -> str:

tests/language/test_block_string_value.py

@@ -1,11 +1,14 @@
-from graphql.language.block_string_value import dedent_block_string_value
+from graphql.language.block_string_value import (
+    dedent_block_string_value,
+    print_block_string,
+)
 
 
 def join(*args):
     return "\n".join(args)
 
 
-def describe_block_string_value():
+def describe_dedent_block_string_value():
     def removes_uniform_indentation_from_a_string():
         raw_value = join(
             "", "    Hello,", "      World!", "", "    Yours,", "      GraphQL."
@@ -67,3 +70,69 @@ def does_not_alter_trailing_spaces():
         assert dedent_block_string_value(raw_value) == join(
             "Hello,     ", "  World!   ", "           ", "Yours,     ", "  GraphQL. "
         )
+
+
+def describe_print_block_string():
+    def describe_single_line():
+        def simple():
+            assert print_block_string("single line") == '"""single line"""'
+
+        def with_leading_whitespace():
+            assert print_block_string("  single line") == '"""  single line"""'
+
+        def with_indentation():
+            assert (
+                print_block_string("single line", indentation=" ")
+                == '"""single line"""'
+            )
+
+        def with_indentation_and_leading_whitespace():
+            assert (
+                print_block_string(" single line", indentation="  ")
+                == '""" single line"""'
+            )
+
+        def with_trailing_quote():
+            assert (
+                print_block_string('single "line"')
+                == '"""\nsingle "line"\n"""'
+            )
+
+        def prefer_multiple_lines():
+            assert (
+                print_block_string("single line", prefer_multiple_lines=True)
+                == '"""\nsingle line\n"""'
+            )
+
+    def describe_multiple_lines():
+        def simple():
+            assert print_block_string("multiple\nlines") == '"""\nmultiple\nlines\n"""'
+
+        def with_leading_whitespace():
+            assert (
+                print_block_string(" multiple\nlines") == '"""\n multiple\nlines\n"""'
+            )
+
+        def with_indentation():
+            assert (
+                print_block_string("multiple\nlines", indentation="  ")
+                == '"""\n  multiple\n  lines\n"""'
+            )
+
+        def with_indentation_and_leading_whitespace():
+            assert (
+                print_block_string(" multiple\nlines", indentation="  ")
+                == '"""\n   multiple\n  lines\n"""'
+            )
+
+        def with_trailing_quote():
+            assert (
+                print_block_string('multiple\n"line"')
+                == '"""\nmultiple\n"line"\n"""'
+            )
+
+        def do_not_prefer_multiple_lines():
+            assert (
+                print_block_string("multiple\nlines", prefer_multiple_lines=False)
+                == '"""\nmultiple\nlines\n"""'
+            )

tests/language/test_schema_printer.py

@@ -48,18 +48,12 @@ def prints_kitchen_sink(kitchen_sink_sdl):  # noqa: F811
             type Foo implements Bar & Baz {
               "Description of the `one` field."
               one: Type
-              """
-              This is a description of the `two` field.
-              """
+              """This is a description of the `two` field."""
               two(
-                """
-                This is a description of the `argument` argument.
-                """
+                """This is a description of the `argument` argument."""
                 argument: InputType!
               ): Type
-              """
-              This is a description of the `three` field.
-              """
+              """This is a description of the `three` field."""
               three(argument: InputType, other: String): Int
               four(argument: String = "string"): String
               five(argument: [String] = ["string", "string"]): String
@@ -115,13 +109,9 @@ def prints_kitchen_sink(kitchen_sink_sdl):  # noqa: F811
             extend scalar CustomScalar @onScalar
 
             enum Site {
-              """
-              This is a description of the `DESKTOP` value
-              """
+              """This is a description of the `DESKTOP` value"""
               DESKTOP
-              """
-              This is a description of the `MOBILE` value
-              """
+              """This is a description of the `MOBILE` value"""
               MOBILE
               "This is a description of the `WEB` value"
               WEB
@@ -157,9 +147,7 @@ def prints_kitchen_sink(kitchen_sink_sdl):  # noqa: F811
 
             extend input InputType @onInputObject
 
-            """
-            This is a description of the `@skip` directive
-            """
+            """This is a description of the `@skip` directive"""
             directive @skip(if: Boolean! @onArgumentDefinition) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT
 
             directive @include(if: Boolean!) on FIELD | FRAGMENT_SPREAD | INLINE_FRAGMENT