Revert "Do not append namespace packages to sys.path (#6405)" (#6548)

This reverts commit 603be8408a5d2d98283f41cfd9a94998fd7cfd3c.

7 files changed, 0 insertions, 74 deletions

diff --git a/ChangeLog b/ChangeLog
index 245910e58..d03570e33 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -25,16 +25,6 @@ Release date: TBA
 
   Closes #4301
 
-* By default the similarity checker will now ignore imports and ignore function signatures when computing
-  duplication. If you want to keep the previous behaviour set ``ignore-imports`` and ``ignore-signatures`` to ``False``.
-
-* Improved recognition of namespace packages. They should no longer be added to ``sys.path``
-  which should prevent various issues with false positives.
-  Because of the difficulties with mirroring the python import mechanics we would gladly
-  hear feedback on this change.
-
-  Closes #5226, Closes #2648
-
 * ``BaseChecker`` classes now require the ``linter`` argument to be passed.
 
 * Fix a failure to respect inline disables for ``fixme`` occurring on the last line
diff --git a/doc/whatsnew/2.14.rst b/doc/whatsnew/2.14.rst
index 4f8d8a126..b532e1dd1 100644
--- a/doc/whatsnew/2.14.rst
+++ b/doc/whatsnew/2.14.rst
@@ -129,13 +129,6 @@ Other Changes
 
   Closes #4301
 
-* Improved recognition of namespace packages. They should no longer be added to ``sys.path``
-  which should prevent various issues with false positives.
-  Because of the difficulties with mirroring the python import mechanics we would gladly
-  hear feedback on this change.
-
-  Closes #5226, Closes #2648
-
 * Update ``invalid-slots-object`` message to show bad object rather than its inferred value.
 
   Closes #6101
diff --git a/pylint/lint/utils.py b/pylint/lint/utils.py
index a08cd6d2a..30694c25c 100644
--- a/pylint/lint/utils.py
+++ b/pylint/lint/utils.py
@@ -11,8 +11,6 @@ from collections.abc import Iterator, Sequence
 from datetime import datetime
 from pathlib import Path
 
-from astroid import modutils
-
 from pylint.config import PYLINT_HOME
 from pylint.lint.expand_modules import get_python_path
 
@@ -73,29 +71,12 @@ def get_fatal_error_message(filepath: str, issue_template_path: Path) -> str:
     )
 
 
-def _is_part_of_namespace_package(filename: str) -> bool:
-    """Check if a file is part of a namespace package."""
-    try:
-        modname = modutils.modpath_from_file(filename)
-    except ImportError:
-        modname = [Path(filename).stem]
-
-    try:
-        spec = modutils.file_info_from_modpath(modname)
-    except ImportError:
-        return False
-
-    return modutils.is_namespace(spec)
-
-
 def _patch_sys_path(args: Sequence[str]) -> list[str]:
     original = list(sys.path)
     changes = []
     seen = set()
     for arg in args:
         path = get_python_path(arg)
-        if _is_part_of_namespace_package(path):
-            continue
         if path not in seen:
             changes.append(path)
             seen.add(path)
diff --git a/tests/lint/test_namespace_packages.py b/tests/lint/test_namespace_packages.py
deleted file mode 100644
index 6ac96f09e..000000000
--- a/tests/lint/test_namespace_packages.py
+++ /dev/null
@@ -1,25 +0,0 @@
-# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
-# For details: https://github.com/PyCQA/pylint/blob/main/LICENSE
-# Copyright (c) https://github.com/PyCQA/pylint/blob/main/CONTRIBUTORS.txt
-
-"""Tests related to linting of namespace packages."""
-
-from io import StringIO
-
-from pylint.reporters.text import TextReporter
-from pylint.testutils._run import _Run as Run
-
-
-def test_namespace_package_sys_path() -> None:
-    """Test that we do not append namespace packages to sys.path.
-
-    The test package is based on https://github.com/PyCQA/pylint/issues/2648.
-    """
-    pylint_output = StringIO()
-    reporter = TextReporter(pylint_output)
-    runner = Run(
-        ["tests/regrtest_data/namespace_import_self/"],
-        reporter=reporter,
-        exit=False,
-    )
-    assert not runner.linter.stats.by_msg
diff --git a/tests/lint/unittest_expand_modules.py b/tests/lint/unittest_expand_modules.py
index 1ce5b6c4e..15f72d0c5 100644
--- a/tests/lint/unittest_expand_modules.py
+++ b/tests/lint/unittest_expand_modules.py
@@ -77,13 +77,6 @@ test_caching = {
     "path": str(TEST_DIRECTORY / "lint/test_caching.py"),
 }
 
-test_namespace_packages = {
-    "basename": "lint",
-    "basepath": INIT_PATH,
-    "isarg": False,
-    "name": "lint.test_namespace_packages",
-    "path": str(TEST_DIRECTORY / "lint/test_namespace_packages.py"),
-}
 
 init_of_package = {
     "basename": "lint",
@@ -115,7 +108,6 @@ class TestExpandModules(CheckerTestCase):
                 [
                     init_of_package,
                     test_caching,
-                    test_namespace_packages,
                     test_pylinter,
                     test_utils,
                     this_file_from_init,
diff --git a/tests/regrtest_data/namespace_import_self/else/__init__.py b/tests/regrtest_data/namespace_import_self/else/__init__.py
deleted file mode 100644
index e69de29bb..000000000
--- a/tests/regrtest_data/namespace_import_self/else/__init__.py
+++ /dev/null
diff --git a/tests/regrtest_data/namespace_import_self/pylint/__init__.py b/tests/regrtest_data/namespace_import_self/pylint/__init__.py
deleted file mode 100644
index cce5e5302..000000000
--- a/tests/regrtest_data/namespace_import_self/pylint/__init__.py
+++ /dev/null
@@ -1,5 +0,0 @@
-"""Module that imports from its own namespace."""
-
-from pylint import run_pylint
-
-run_pylint()