Fix regression with import resolver

ChangeLog

@@ -19,6 +19,10 @@ Release date: TBA
   Closes PyCQA/pylint#2462
   Closes #1208
 
+* Fix regression with the import resolver
+
+  Closes PyCQA/pylint#5131
+
 * Fix crash with invalid dataclass field call
 
   Closes PyCQA/pylint#5153

astroid/nodes/scoped_nodes.py

@@ -708,19 +708,16 @@ def import_module(self, modname, relative_only=False, level=None):
                 raise
         return AstroidManager().ast_from_module_name(modname)
 
-    def relative_to_absolute_name(self, modname, level):
+    def relative_to_absolute_name(self, modname: str, level: int) -> str:
         """Get the absolute module name for a relative import.
 
         The relative import can be implicit or explicit.
 
         :param modname: The module name to convert.
-        :type modname: str
 
         :param level: The level of relative import.
-        :type level: int
 
         :returns: The absolute module name.
-        :rtype: str
 
         :raises TooManyLevelsError: When the relative import refers to a
             module too far above this one.
@@ -734,8 +731,12 @@ def relative_to_absolute_name(self, modname, 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]
+            elif (
+                self.path
+                and not os.path.exists(os.path.dirname(self.path[0]) + "/__init__.py")
+                and os.path.exists(
+                    os.path.dirname(self.path[0]) + "/" + modname.split(".")[0]
+                )
             ):
                 level = level - 1
                 package_name = ""

tests/testdata/python3/data/beyond_top_level_three/module/sub_module/sub_sub_module/main.py

@@ -0,0 +1 @@
+from ...double_name import function

tests/unittest_inference.py

@@ -6547,5 +6547,13 @@ def test_namespace_package_same_name() -> None:
     resources.build_file("data/beyond_top_level_two/a.py")
 
 
+def test_relative_imports_init_package() -> None:
+    """check that relative imports within a package that uses __init__.py
+    still works"""
+    resources.build_file(
+        "data/beyond_top_level_three/module/sub_module/sub_sub_module/main.py"
+    )
+
+
 if __name__ == "__main__":
     unittest.main()