[Backport maintenance/2.17.x] Fix incorrect preferred-modules matches

doc/whatsnew/fragments/8453.bugfix

@@ -0,0 +1,3 @@
+Fix a regression of ``preferred-modules`` where a partial match was used instead of the required full match.
+
+Closes #8453

pylint/checkers/imports.py

@@ -922,7 +922,15 @@ def _check_preferred_module(self, node: ImportNode, mod_path: str) -> None:
             mod_compare = [f"{node.modname}.{name[0]}" for name in node.names]
 
         # find whether there are matches with the import vs preferred_modules keys
-        matches = [k for k in self.preferred_modules for mod in mod_compare if k in mod]
+        matches = [
+            k
+            for k in self.preferred_modules
+            for mod in mod_compare
+            # exact match
+            if k == mod
+            # checks for base module matches
+            or k in mod.split(".")[0]
+        ]
 
         # if we have matches, add message
         if matches:

tests/checkers/unittest_imports.py

@@ -192,6 +192,23 @@ def test_preferred_module(capsys: CaptureFixture[str]) -> None:
         # assert there were no errors
         assert len(errors) == 0
 
+        # Test for challenges with preferred modules indefinite matches
+        Run(
+            [
+                f"{os.path.join(REGR_DATA, 'preferred_module/unpreferred_submodule.py')}",
+                "-d all",
+                "-e preferred-module",
+                # prefer pathlib instead of random (testing to avoid regression)
+                # pathlib shouldn't match with path, which is in the test file
+                "--preferred-modules=random:pathlib",
+            ],
+            exit=False,
+        )
+        _, errors = capsys.readouterr()
+
+        # Assert there were no errors
+        assert len(errors) == 0
+
     @staticmethod
     def test_allow_reexport_package(capsys: CaptureFixture[str]) -> None:
         """Test --allow-reexport-from-package option."""