Fixed #1721: repeat noqa comments on separate from lines with force-s…

…ingle-line set, sometimes get dropped.

CHANGELOG.md

@@ -10,6 +10,7 @@ Find out more about isort's release policy [here](https://pycqa.github.io/isort/
   - Fixed (https://github.com/PyCQA/isort/pull/1726): isort ignores reverse_sort when force_sort_within_sections is true.
   - Fixed #1741: comments in hanging indent modes can lead to invalid code.
   - Fixed #1744: repeat noqa comments dropped when * import and non * imports exist from the same package.
+  - Fixed #1721: repeat noqa comments on separate from lines with force-single-line set, sometimes get dropped.
   - Implemented #1697: Provisional support for PEP 582: skip `__pypackages__` directories by default.
   - Implemented #1705: More intuitive handling of isort:skip_file comments on streams.
 

isort/parse.py

@@ -455,6 +455,20 @@ def file_contents(contents: str, config: Config = DEFAULT_CONFIG) -> ParsedConte
                         ] = associated_comment
                         if associated_comment in comments:
                             comments.pop(comments.index(associated_comment))
+                if (
+                    config.force_single_line
+                    and comments
+                    and attach_comments_to is None
+                    and len(just_imports) == 1
+                ):
+                    nested_from_comments = categorized_comments["nested"].setdefault(
+                        import_from, {}
+                    )
+                    existing_comment = nested_from_comments.get(just_imports[0], "")
+                    nested_from_comments[
+                        just_imports[0]
+                    ] = f"{existing_comment}{'; ' if existing_comment else ''}{'; '.join(comments)}"
+                    comments = []
 
                 if comments and attach_comments_to is None:
                     attach_comments_to = categorized_comments["from"].setdefault(import_from, [])

tests/unit/test_regressions.py

@@ -1780,3 +1780,19 @@ def test_isort_should_keep_multi_noqa_with_star_issue_1744():
 from typing import *  # noqa
 """
     )
+
+
+def test_isort_should_keep_multiple_noqa_comments_force_single_line_mode_issue_1721():
+    assert isort.check_code(
+        """
+from some_very_long_filename_to_import_from_that_causes_a_too_long_import_row import (  # noqa: E501
+    CONSTANT_1,
+)
+from some_very_long_filename_to_import_from_that_causes_a_too_long_import_row import (  # noqa: E501
+    CONSTANT_2,
+)
+""",
+        show_diff=True,
+        profile="black",
+        force_single_line=True,
+    )