print_location: Add special support for minified documents

Replicates graphql/graphql-js@d8c1dfd

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 1.0.5 of GraphQL-core-next is up-to-date with GraphQL.js version
-14.3.1. All parts of the API are covered by an extensive test suite of currently 1880
+14.3.1. All parts of the API are covered by an extensive test suite of currently 1881
 unit tests.
 
 

graphql/language/print_location.py

@@ -1,5 +1,5 @@
 import re
-from typing import List, Optional, Tuple, cast
+from typing import Optional, Tuple, cast
 
 from .ast import Location
 from .location import SourceLocation, get_location
@@ -30,24 +30,40 @@ def print_source_location(source: Source, source_location: SourceLocation) -> st
 
     column_offset = first_line_column_offset if source_location.line == 1 else 0
     column_num = source_location.column + column_offset
+    location_str = f"{source.name}:{line_num}:{column_num}\n"
 
     lines = _re_newline.split(body)  # works a bit different from splitlines()
-    len_lines = len(lines)
-
-    def get_line(index: int) -> Optional[str]:
-        return lines[index] if 0 <= index < len_lines else None
-
-    return f"{source.name}:{line_num}:{column_num}\n" + print_prefixed_lines(
-        [
-            (f"{line_num - 1}", get_line(line_index - 1)),
-            (f"{line_num}", get_line(line_index)),
-            ("", " " * (column_num - 1) + "^"),
-            (f"{line_num + 1}", get_line(line_index + 1)),
-        ]
+    location_line = lines[line_index]
+
+    # Special case for minified documents
+    if len(location_line) > 120:
+        subline_index, subline_column_num = divmod(column_num, 80)
+        sublines = [location_line[i : i + 80] for i in range(0, len(location_line), 80)]
+
+        return location_str + print_prefixed_lines(
+            (str(line_num), sublines[0]),
+            *[("", subline) for subline in sublines[1 : subline_index + 1]],
+            (" ", " " * (subline_column_num - 1) + "^"),
+            (
+                "",
+                sublines[subline_index + 1]
+                if subline_index < len(sublines) - 1
+                else None,
+            ),
+        )
+
+    return location_str + print_prefixed_lines(
+        (f"{line_num - 1}", lines[line_index - 1] if line_index > 0 else None),
+        (f"{line_num}", location_line),
+        ("", " " * (column_num - 1) + "^"),
+        (
+            f"{line_num + 1}",
+            lines[line_index + 1] if line_index < len(lines) - 1 else None,
+        ),
     )
 
 
-def print_prefixed_lines(lines: List[Tuple[str, Optional[str]]]) -> str:
+def print_prefixed_lines(*lines: Tuple[str, Optional[str]]) -> str:
     """Print lines specified like this: ("prefix", "string")"""
     existing_lines = [
         cast(Tuple[str, str], line) for line in lines if line[1] is not None

tests/error/test_print_location.py

@@ -3,6 +3,55 @@
 
 
 def describe_print_location():
+    def prints_minified_documents():
+        minified_source = Source(
+            "query SomeMiniFiedQueryWithErrorInside("
+            "$foo:String!=FIRST_ERROR_HERE$bar:String)"
+            "{someField(foo:$foo bar:$bar baz:SECOND_ERROR_HERE)"
+            "{fieldA fieldB{fieldC fieldD...on THIRD_ERROR_HERE}}}"
+        )
+
+        first_location = print_source_location(
+            minified_source,
+            SourceLocation(1, minified_source.body.index("FIRST_ERROR_HERE") + 1),
+        )
+        assert first_location + "\n" == dedent(
+            """
+            GraphQL request:1:53
+            1 | query SomeMiniFiedQueryWithErrorInside($foo:String!=FIRST_ERROR_HERE$bar:String)
+              |                                                     ^
+              | {someField(foo:$foo bar:$bar baz:SECOND_ERROR_HERE){fieldA fieldB{fieldC fieldD.
+            """  # noqa: E501
+        )
+
+        second_location = print_source_location(
+            minified_source,
+            SourceLocation(1, minified_source.body.index("SECOND_ERROR_HERE") + 1),
+        )
+        assert second_location + "\n" == dedent(
+            """
+            GraphQL request:1:114
+            1 | query SomeMiniFiedQueryWithErrorInside($foo:String!=FIRST_ERROR_HERE$bar:String)
+              | {someField(foo:$foo bar:$bar baz:SECOND_ERROR_HERE){fieldA fieldB{fieldC fieldD.
+              |                                  ^
+              | ..on THIRD_ERROR_HERE}}}
+            """  # noqa: E501
+        )
+
+        third_location = print_source_location(
+            minified_source,
+            SourceLocation(1, minified_source.body.index("THIRD_ERROR_HERE") + 1),
+        )
+        assert third_location + "\n" == dedent(
+            """
+            GraphQL request:1:166
+            1 | query SomeMiniFiedQueryWithErrorInside($foo:String!=FIRST_ERROR_HERE$bar:String)
+              | {someField(foo:$foo bar:$bar baz:SECOND_ERROR_HERE){fieldA fieldB{fieldC fieldD.
+              | ..on THIRD_ERROR_HERE}}}
+              |      ^
+            """  # noqa: E501
+        )
+
     def prints_single_digit_line_number_with_no_padding():
         result = print_source_location(
             Source("*", "Test", SourceLocation(9, 1)), SourceLocation(1, 1)

tests/language/test_parser.py

@@ -94,7 +94,7 @@ def parse_provides_useful_error_when_using_source():
         assert str(error) + "\n" == dedent(
             """
             Syntax Error: Expected {, found <EOF>
-            
+
             MyQuery.graphql:1:6
             1 | query
               |      ^