Fix issue #969: Add support for single line exclusions

isort/main.py

@@ -422,6 +422,13 @@ def parse_args(argv: Optional[Sequence[str]] = None) -> Dict[str, Any]:
         action="store_true",
         help="Forces all from imports to appear on their own line",
     )
+    parser.add_argument(
+        "--nsl",
+        "--single-line-exclusions",
+        help="One or more modules to exclude from the single line rule.",
+        dest="single_line_exclusions",
+        action="append",
+    )
     parser.add_argument(
         "--sp",
         "--settings-path",

isort/output.py

@@ -239,7 +239,9 @@ def _with_from_imports(
 
         import_start = f"from {module} {import_type} "
         from_imports = list(parsed.imports[section]["from"][module])
-        if not config.no_inline_sort or config.force_single_line:
+        if not config.no_inline_sort or (
+            config.force_single_line and module not in config.single_line_exclusions
+        ):
             from_imports = sorting.naturally(
                 from_imports,
                 key=lambda key: sorting.module_key(
@@ -288,7 +290,7 @@ def _with_from_imports(
                     config,
                 )
                 from_imports = []
-            elif config.force_single_line:
+            elif config.force_single_line and module not in config.single_line_exclusions:
                 import_statement = ""
                 while from_imports:
                     from_import = from_imports.pop(0)

isort/profiles.py

@@ -15,7 +15,12 @@
     "line_length": 79,
 }
 pycharm = {"multi_line_output": 3, "force_grid_wrap": 2}
-google = {"force_single_line": True, "force_sort_within_sections": True, "lexicographical": True}
+google = {
+    "force_single_line": True,
+    "force_sort_within_sections": True,
+    "lexicographical": True,
+    "single_line_exclusions": ("typing",),
+}
 open_stack = {
     "force_single_line": True,
     "force_sort_within_sections": True,

isort/settings.py

@@ -142,6 +142,7 @@ class _Config:
     remove_imports: FrozenSet[str] = frozenset()
     reverse_relative: bool = False
     force_single_line: bool = False
+    single_line_exclusions: Tuple[str, ...] = ()
     default_section: str = "FIRSTPARTY"
     import_headings: Dict[str, str] = field(default_factory=dict)
     balanced_wrapping: bool = False

tests/test_isort.py

@@ -4702,3 +4702,23 @@ def test_noqa_issue_1065() -> None:
 from flask_security.signals import user_registered  # noqa
 """
     assert SortImports(file_contents=test_input).output == expected_output
+
+
+def test_single_line_exclusions():
+    test_input = """
+# start comment
+from os import path, system
+from typing import List, TypeVar
+"""
+    expected_output = """
+# start comment
+from os import path
+from os import system
+from typing import List, TypeVar
+"""
+    assert (
+        SortImports(
+            file_contents=test_input, force_single_line=True, single_line_exclusions=("typing",)
+        ).output
+        == expected_output
+    )