From 1437e73ce4bc386df76806da461f4dfc7388a0c3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dani=C3=ABl=20van=20Noord?=
 <13665637+DanielNoord@users.noreply.github.com>
Date: Tue, 5 Oct 2021 13:40:17 +0200
Subject: [PATCH] Fix ``relative-beyond-top-level`` false positive (#1186)

* Fix ``relative-beyond-top-level`` false positive
---
 ChangeLog                                            |  4 ++++
 astroid/nodes/scoped_nodes.py                        | 12 ++++++++++--
 .../python3/data/beyond_top_level/import_package.py  |  3 +++
 .../namespace_package/lower_level/helper_function.py |  5 +++++
 .../beyond_top_level/namespace_package/plugin_api.py |  2 ++
 .../namespace_package/top_level_function.py          |  5 +++++
 tests/unittest_inference.py                          |  5 +++++
 7 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 tests/testdata/python3/data/beyond_top_level/import_package.py
 create mode 100644 tests/testdata/python3/data/beyond_top_level/namespace_package/lower_level/helper_function.py
 create mode 100644 tests/testdata/python3/data/beyond_top_level/namespace_package/plugin_api.py
 create mode 100644 tests/testdata/python3/data/beyond_top_level/namespace_package/top_level_function.py

diff --git a/ChangeLog b/ChangeLog
index c80c57664a..0b55c004f5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -36,6 +36,10 @@ Release date: TBA
 
 * Improve brain for ``typing.Callable`` and ``typing.Type``.
 
+* Fix bug with importing namespace packages with relative imports
+
+  Closes PyCQA/pylint#5059
+
 
 What's New in astroid 2.8.0?
 ============================
diff --git a/astroid/nodes/scoped_nodes.py b/astroid/nodes/scoped_nodes.py
index e64f736e15..ba8fca0cfb 100644
--- a/astroid/nodes/scoped_nodes.py
+++ b/astroid/nodes/scoped_nodes.py
@@ -43,6 +43,7 @@
 import builtins
 import io
 import itertools
+import os
 import typing
 from typing import List, Optional, TypeVar
 
@@ -732,10 +733,17 @@ def relative_to_absolute_name(self, modname, level):
         if level:
             if self.package:
                 level = level - 1
+                package_name = self.name.rsplit(".", level)[0]
+            elif not os.path.exists("__init__.py") and os.path.exists(
+                modname.split(".")[0]
+            ):
+                level = level - 1
+                package_name = ""
+            else:
+                package_name = self.name.rsplit(".", level)[0]
             if level and self.name.count(".") < level:
                 raise TooManyLevelsError(level=level, name=self.name)
 
-            package_name = self.name.rsplit(".", level)[0]
         elif self.package:
             package_name = self.name
         else:
@@ -744,7 +752,7 @@ def relative_to_absolute_name(self, modname, level):
         if package_name:
             if not modname:
                 return package_name
-            return f"{package_name}.{modname}"
+            return f"{package_name}.{modname.split('.')[0]}"
         return modname
 
     def wildcard_import_names(self):
diff --git a/tests/testdata/python3/data/beyond_top_level/import_package.py b/tests/testdata/python3/data/beyond_top_level/import_package.py
new file mode 100644
index 0000000000..885d4c541a
--- /dev/null
+++ b/tests/testdata/python3/data/beyond_top_level/import_package.py
@@ -0,0 +1,3 @@
+from namespace_package import top_level_function
+
+top_level_function.do_something()
diff --git a/tests/testdata/python3/data/beyond_top_level/namespace_package/lower_level/helper_function.py b/tests/testdata/python3/data/beyond_top_level/namespace_package/lower_level/helper_function.py
new file mode 100644
index 0000000000..1d0b12b347
--- /dev/null
+++ b/tests/testdata/python3/data/beyond_top_level/namespace_package/lower_level/helper_function.py
@@ -0,0 +1,5 @@
+from ..plugin_api import top_message
+
+
+def plugin_message(msg):
+    return "plugin_message: %s" % top_message(msg)
\ No newline at end of file
diff --git a/tests/testdata/python3/data/beyond_top_level/namespace_package/plugin_api.py b/tests/testdata/python3/data/beyond_top_level/namespace_package/plugin_api.py
new file mode 100644
index 0000000000..3941f197ec
--- /dev/null
+++ b/tests/testdata/python3/data/beyond_top_level/namespace_package/plugin_api.py
@@ -0,0 +1,2 @@
+def top_message(msg):
+    return "top_message: %s" % msg
diff --git a/tests/testdata/python3/data/beyond_top_level/namespace_package/top_level_function.py b/tests/testdata/python3/data/beyond_top_level/namespace_package/top_level_function.py
new file mode 100644
index 0000000000..8342bd09f9
--- /dev/null
+++ b/tests/testdata/python3/data/beyond_top_level/namespace_package/top_level_function.py
@@ -0,0 +1,5 @@
+from .lower_level.helper_function import plugin_message
+
+
+def do_something():
+    return plugin_message("called by do_something")
diff --git a/tests/unittest_inference.py b/tests/unittest_inference.py
index ac52013836..dc662641bb 100644
--- a/tests/unittest_inference.py
+++ b/tests/unittest_inference.py
@@ -6535,5 +6535,10 @@ def play():
     assert next(node.infer()).pytype() == ".B"
 
 
+def test_namespace_package() -> None:
+    """check that a file using namespace packages and relative imports is parseable"""
+    resources.build_file("data/beyond_top_level/import_package.py")
+
+
 if __name__ == "__main__":
     unittest.main()