Retry section lookup for from+import statements, if defaulted

isort/deprecated/finders.py

@@ -377,12 +377,12 @@ def __init__(
                     )
         self.finders: Tuple[BaseFinder, ...] = tuple(finders)
 
-    def find(self, module_name: str) -> Optional[str]:
+    def find(self, module_name: str) -> Tuple[Optional[str], str]:
         for finder in self.finders:
             try:
                 section = finder.find(module_name)
                 if section is not None:
-                    return section
+                    return section, ""
             except Exception as exception:
                 # isort has to be able to keep trying to identify the correct
                 # import section even if one approach fails
@@ -391,4 +391,4 @@ def find(self, module_name: str) -> Optional[str]:
                         f"{finder.__class__.__name__} encountered an error ({exception}) while "
                         f"trying to identify the {module_name} module"
                     )
-        return None
+        return None, ""

isort/parse.py

@@ -155,7 +155,7 @@ def file_contents(contents: str, config: Config = DEFAULT_CONFIG) -> ParsedConte
 
         finder = FindersManager(config=config).find
     else:
-        finder = partial(place.module, config=config)
+        finder = partial(place.module_with_reason, config=config)
 
     line_count = len(in_lines)
 
@@ -438,7 +438,13 @@ def file_contents(contents: str, config: Config = DEFAULT_CONFIG) -> ParsedConte
 
             if type_of_import == "from":
                 import_from = just_imports.pop(0)
-                placed_module = finder(import_from)
+                placed_module, reason = finder(import_from)
+                if placed_module == config.default_section and reason.startswith("Default"):
+                    # The imported name might be a submodule of `import_from`, in which case
+                    # it might be specified in the config.
+                    # See https://github.com/PyCQA/isort/issues/2167.
+                    placed_module, reason = finder(".".join([import_from] + just_imports))
+
                 if config.verbose and not config.only_modified:
                     print(f"from-type place_module for {import_from} returned {placed_module}")
 
@@ -552,7 +558,7 @@ def file_contents(contents: str, config: Config = DEFAULT_CONFIG) -> ParsedConte
                             import_index -= len(
                                 categorized_comments["above"]["straight"].get(module, [])
                             )
-                    placed_module = finder(module)
+                    placed_module, reason = finder(module)
                     if config.verbose and not config.only_modified:
                         print(f"else-type place_module for {module} returned {placed_module}")
 

tests/unit/test_isort.py

@@ -5671,3 +5671,14 @@ def test_reexport_not_last_line() -> None:
     meme = "rickroll"
 """
     assert isort.code(test_input, config=Config(sort_reexports=True)) == expd_output
+
+
+def test_import_submodule_both_ways() -> None:
+    """See https://github.com/PyCQA/isort/issues/2167."""
+    test_input = "import requests\n" "\n" "from subdir import fileA\n"
+    test_output = isort.code(code=test_input, known_first_party=["subdir.fileA"])
+    assert test_output == ("import requests\n" "\n" "from subdir import fileA\n")
+
+    test_input = "import requests\n" "\n" "import subdir.fileA\n"
+    test_output = isort.code(code=test_input, known_first_party=["subdir.fileA"])
+    assert test_output == ("import requests\n" "\n" "import subdir.fileA\n")