Preserve used imports during filtered import cleanup

CHANGELOG.md

@@ -1,6 +1,6 @@
 # **Upcoming release**
 
-- ...
+- #811 Preserve still-used imports when moving globals with filtered import cleanup
 
 # Release 1.15.0
 

rope/refactor/importutils/actions.py

@@ -175,6 +175,11 @@ def visitFromImport(self, import_stmt, import_info):
         ):
             if import_info.is_star_import():
                 return True
+            if import_stmt.readonly:
+                return not self.import_info.is_star_import() and all(
+                    pair in import_info.names_and_aliases
+                    for pair in self.import_info.names_and_aliases
+                )
             if self.import_info.is_star_import():
                 import_stmt.import_info = self.import_info
                 return True

ropetest/refactor/importutilstest.py

@@ -1948,6 +1948,30 @@ def import_filter(import_stmt):
 
         return import_filter
 
+    def test_filtered_duplicate_removal_preserves_distinct_from_imports(self):
+        for imported in ("mod3", "mod3 as other", "*"):
+            with self.subTest(imported=imported):
+                source = "from pkg2 import mod2\nfrom pkg2 import " + imported + "\n"
+                self.mod.write(source)
+                pymod = self.project.get_pymodule(self.mod)
+                module_imports = self.import_tools.module_imports(
+                    pymod, self._line_filter(2)
+                )
+                module_imports.remove_duplicates()
+                self.assertEqual(source, module_imports.get_changed_source())
+
+    def test_filtered_duplicate_removal_still_removes_covered_imports(self):
+        for imported in ("mod2", "mod2, mod3", "*"):
+            with self.subTest(imported=imported):
+                expected = "from pkg2 import " + imported + "\n"
+                self.mod.write(expected + "from pkg2 import mod2\n")
+                pymod = self.project.get_pymodule(self.mod)
+                module_imports = self.import_tools.module_imports(
+                    pymod, self._line_filter(2)
+                )
+                module_imports.remove_duplicates()
+                self.assertEqual(expected, module_imports.get_changed_source())
+
     def test_filtered_expand_stars(self):
         self.pkg1.get_child("__init__.py").write("var1 = 1\n")
         self.pkg2.get_child("__init__.py").write("var2 = 1\n")

ropetest/refactor/movetest.py

@@ -73,6 +73,29 @@ def test_move_constant(self) -> None:
         self.assertEqual("", self.origin_module.read())
         self.assertEqual("foo = 123\n", self.destination_module.read())
 
+    def test_move_constant_preserves_used_module_alias(self) -> None:
+        self.project.prefs["prefer_module_from_imports"] = True
+        self.mod4.write("def keep():\n    return 1\n\nvalue = 2\n")
+        self.mod5.write("def existing():\n    return 3\n")
+        self.mod3.write(
+            "from pkg import mod5\n"
+            "from pkg import mod4 as utils_module\n"
+            "\n"
+            "def run():\n"
+            "    return mod5.existing(), utils_module.keep(), utils_module.value\n"
+        )
+        self._move(self.mod4, self.mod4.read().index("value"), self.mod5)
+        self.assertEqual(
+            "from pkg import mod5\n"
+            "from pkg import mod4 as utils_module\n"
+            "\n"
+            "def run():\n"
+            "    return mod5.existing(), utils_module.keep(), mod5.value\n",
+            self.mod3.read(),
+        )
+        self.assertEqual("def keep():\n    return 1\n\n", self.mod4.read())
+        self.assertIn("value = 2\n", self.mod5.read())
+
     def test_move_constant_2(self) -> None:
         self.origin_module.write("bar = 321\nfoo = 123\n")
         self._move(self.origin_module, self.origin_module.read().index("foo") + 1, self.destination_module)