CHANGELOG.md

@@ -7,6 +7,7 @@ Find out more about isort's release policy [here](https://pycqa.github.io/isort/
 ### 5.9.0 TBD
   - Fixed (https://github.com/PyCQA/isort/pull/1695) added imports being added to doc string in some cases.
   - Implemented #1697: Provisional support for PEP 582: skip `__pypackages__` directories by default.
+  - Implemented #1208: Support `from` imports being identified from `known_{section}` setting.
 
 ### 5.8.0 March 20th 2021
   - Fixed #1631: as import comments can in some cases be duplicated.

isort/place.py

@@ -23,7 +23,7 @@ def module_with_reason(name: str, config: Config = DEFAULT_CONFIG) -> Tuple[str,
     return (
         _forced_separate(name, config)
         or _local(name, config)
-        or _known_pattern(name, config)
+        or known_pattern(name, config)
         or _src_path(name, config)
         or (config.default_section, "Default option in Config or universal default.")
     )
@@ -49,7 +49,8 @@ def _local(name: str, config: Config) -> Optional[Tuple[str, str]]:
     return None
 
 
-def _known_pattern(name: str, config: Config) -> Optional[Tuple[str, str]]:
+@lru_cache(maxsize=1000)
+def known_pattern(name: str, config: Config) -> Optional[Tuple[str, str]]:
     parts = name.split(".")
     module_names_to_check = (".".join(parts[:first_k]) for first_k in range(len(parts), 0, -1))
     for module_name_to_check in module_names_to_check:

tests/unit/test_ticketed_features.py

@@ -1082,3 +1082,17 @@ def test_isort_can_push_star_imports_above_others_issue_1504():
 from ._bar import All, Any, Not
 """
     )
+
+
+def test_isort_identifies_from_imports_against_known_section_issue_1208():
+    """isort should provide a way to identify x from y, within known sections.
+    see: https://github.com/PyCQA/isort/issues/1208
+    """
+    assert isort.check_code(
+        """
+import namespace.mymodule
+from namespace import mymodule
+""",
+        known_first_party=["namespace.mymodule"],
+        show_diff=True,
+    )