Keep overlong star imports stable with Black

isort/wrap.py

@@ -68,6 +68,8 @@ def import_statement(
     return statement
 
 
+# Ignore DeepSource cyclomatic complexity check for this function.
+# skipcq: PY-R1000
 def line(content: str, line_separator: str, config: Config = DEFAULT_CONFIG) -> str:
     """Returns a line wrapped to the specified line-length, if possible."""
     if len(content) <= config.line_length:
@@ -84,15 +86,11 @@ def line(content: str, line_separator: str, config: Config = DEFAULT_CONFIG) ->
     if "#" in content:
         line_without_comment, comment = content.split("#", 1)
 
-    # A ``from ... import *`` / ``from ... cimport *`` statement cannot use
-    # parenthesis-based wrapping because the wildcard ``*`` has no valid
-    # continuation in that mode. Use a backslash continuation instead so the
-    # statement is split across lines while remaining valid Python.
-    # See https://github.com/PyCQA/isort/issues/2267
-    if line_without_comment.rstrip().endswith("*"):
-        prefix, keyword, _ = line_without_comment.rstrip().rsplit(" ", 2)
-        comment_suffix = f"  #{comment}" if comment else ""
-        return f"{prefix} {keyword} \\{line_separator}{config.indent}*{comment_suffix}"
+    # Star imports cannot use parenthesized wrapping, while backslash wrapping
+    # conflicts with Black. Leave them intact even when they exceed line length.
+    # See https://github.com/PyCQA/isort/issues/2267 and issue #2649.
+    if line_without_comment.rstrip().endswith("import *"):
+        return content
 
     for splitter in ("import ", "cimport ", ".", "as "):
         exp = r"\b" + re.escape(splitter) + r"\b"

tests/unit/test_wrap.py

@@ -50,33 +50,25 @@ def test_line__comment_with_brackets__expects_unchanged_comment(multi_line_outpu
     assert wrap.line(content=content, line_separator="\n", config=config) == expected
 
 
-def test_line_star_import_wrapped_with_backslash() -> None:
-    """Star imports cannot use parenthesis-based wrapping, so should use backslashes.
-
-    See issue #2267.
-    """
+def test_line_star_import_is_not_wrapped() -> None:
+    """Star imports cannot be split in a way that Black accepts (issue #2649)."""
     content = "from very.very.very.very.very.very.very.very.very.long.line import *"
-    expected = "from very.very.very.very.very.very.very.very.very.long.line import \\\n    *"
     config = Config(line_length=20)
-    assert wrap.line(content=content, line_separator="\n", config=config) == expected
+    assert wrap.line(content=content, line_separator="\n", config=config) == content
 
 
-def test_line_star_cimport_wrapped_with_backslash() -> None:
-    """Star cimports should also use backslashes."""
+def test_line_star_cimport_is_not_wrapped() -> None:
+    """Star cimports have the same syntactic wrapping restriction."""
     content = "from very.very.very.very.very.very.very.very.very.long.line cimport *"
-    expected = "from very.very.very.very.very.very.very.very.very.long.line cimport \\\n    *"
     config = Config(line_length=20)
-    assert wrap.line(content=content, line_separator="\n", config=config) == expected
+    assert wrap.line(content=content, line_separator="\n", config=config) == content
 
 
-def test_line_star_import_with_comment_wrapped_with_backslash() -> None:
-    """When falling back to backslashes for start imports, comments should be preserved."""
+def test_line_star_import_with_comment_is_not_wrapped() -> None:
+    """Comments remain on an over-long star import that cannot be wrapped."""
     content = "from very.very.very.very.very.very.very.very.very.long.line import *  # noqa: F401"
     config = Config(line_length=20)
-    expected = (
-        "from very.very.very.very.very.very.very.very.very.long.line import \\\n    *  # noqa: F401"
-    )
-    assert wrap.line(content=content, line_separator="\n", config=config) == expected
+    assert wrap.line(content=content, line_separator="\n", config=config) == content
 
 
 def test_line_star_import_in_noqa_mode_is_not_backslash_wrapped() -> None:
@@ -88,8 +80,7 @@ def test_line_star_import_in_noqa_mode_is_not_backslash_wrapped() -> None:
     )
 
 
-def test_star_import_wrapped_end_to_end() -> None:
-    """New lines should be preserved at the end of too long start imports."""
+def test_star_import_is_not_wrapped_end_to_end() -> None:
+    """Long star imports remain stable across isort and Black (issue #2649)."""
     source = "from very.very.very.very.very.very.very.very.very.long.line import *\n"
-    expected = "from very.very.very.very.very.very.very.very.very.long.line import \\\n    *\n"
-    assert code(source, line_length=20, force_single_line=True) == expected
+    assert code(source, profile="black") == source