🐞 Fix: Initial imports from sys.modules #127 (#136)

docs/CHANGELOG.md

@@ -4,6 +4,7 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased] - ././2020
 
+- [🐞 Fix: Initial imports from sys.modules by @hakancelik96](https://github.com/hakancelik96/unimport/pull/136)
 - [🐞 Fix: import and name matcher by @hakancelik96](https://github.com/hakancelik96/unimport/pull/133)
 - [🐞 Fix: type comment by @hakancelik96](https://github.com/hakancelik96/unimport/pull/130)
 - [💪 Support type variable by @hakancelik96](https://github.com/hakancelik96/unimport/pull/128)

tests/test_refactor.py

@@ -242,6 +242,18 @@ def test_get_star_imp_none(self):
             self.session.refactor(action),
         )
 
+    def test_initial_imports(self):
+        from unimport.constants import INITIAL_IMPORTS
+
+        actions = [
+            (f"import {imp_name}\n{imp_name.split('.')[0]}\n")
+            for imp_name in INITIAL_IMPORTS
+        ]
+        self.assertListEqual(
+            actions,
+            [self.session.refactor(action) for action in actions],
+        )
+
 
 class TestDuplicateUnusedRefactor(RefactorTestCase):
     def test_full_unused(self):

unimport/constants.py

@@ -56,3 +56,20 @@
     SUBSCRIPT_TYPE_VARIABLE.extend(["Literal", "OrderedDict"])
 elif PY37_PLUS:
     SUBSCRIPT_TYPE_VARIABLE.append("Literal")
+
+INITIAL_IMPORTS = frozenset(
+    # https://docs.python.org/3/library/sys.html#sys.modules
+    # The first thing Python will do is look up the name of import in sys.modules.
+    # Initial modules are below.
+    {
+        "encodings.utf_8",
+        "encodings.aliases",
+        "encodings.latin_1",
+        "importlib._bootstrap",
+        "importlib.abc",
+        "importlib.machinery",
+        "importlib._bootstrap_external",
+        "importlib.util",
+        "os.path",
+    }
+)

unimport/scan.py

@@ -17,7 +17,11 @@
 )
 
 from unimport import color
-from unimport.constants import PY38_PLUS, SUBSCRIPT_TYPE_VARIABLE
+from unimport.constants import (
+    INITIAL_IMPORTS,
+    PY38_PLUS,
+    SUBSCRIPT_TYPE_VARIABLE,
+)
 from unimport.relate import first_occurrence, get_parents, relate
 from unimport.statement import Import, ImportFrom, Name
 from unimport.utils import get_dir, get_source, is_std
@@ -103,6 +107,8 @@ def visit_Import(self, node: ast.Import) -> None:
             return
         for column, alias in enumerate(node.names):
             name = alias.asname or alias.name
+            if name in INITIAL_IMPORTS:
+                name = name.split(".")[0]
             self.imports.append(
                 Import(
                     lineno=node.lineno,