Fix: Using --import-mode=importlib, a directory with the same name in the namespace package causes a KeyError.（#12592）

Author: dongfangtianyu

changelog/12592.bugfix.rst

@@ -0,0 +1 @@
+Fixed the issue of  causes ``KeyError`` when using the parameter ``--import-mode=importlib`` in pytest>=8.2 .

src/_pytest/pathlib.py

@@ -629,6 +629,15 @@ def _import_module_using_spec(
 
     if spec_matches_module_path(spec, module_path):
         assert spec is not None
+
+        # Find spec and import this module.
+        mod = importlib.util.module_from_spec(spec)
+        sys.modules[module_name] = mod
+        spec.loader.exec_module(mod)  # type: ignore[union-attr]
+
+        if insert_modules:
+            insert_missing_modules(sys.modules, module_name)
+
         # Attempt to import the parent module, seems is our responsibility:
         # https://github.com/python/cpython/blob/73906d5c908c1e0b73c5436faeff7d93698fc074/Lib/importlib/_bootstrap.py#L1308-L1311
         parent_module_name, _, name = module_name.rpartition(".")
@@ -655,17 +664,9 @@ def _import_module_using_spec(
                     insert_modules=insert_modules,
                 )
 
-        # Find spec and import this module.
-        mod = importlib.util.module_from_spec(spec)
-        sys.modules[module_name] = mod
-        spec.loader.exec_module(mod)  # type: ignore[union-attr]
-
         # Set this module as an attribute of the parent module (#12194).
         if parent_module is not None:
             setattr(parent_module, name, mod)
-
-        if insert_modules:
-            insert_missing_modules(sys.modules, module_name)
         return mod
 
     return None

testing/test_pathlib.py

@@ -1505,6 +1505,44 @@ def test_full_ns_packages_without_init_files(
             tmp_path / "src/dist2/ns/a/core/foo/m.py", consider_namespace_packages=True
         ) == (tmp_path / "src/dist2", "ns.a.core.foo.m")
 
+    def test_ns_multiple_levels_import_same_name_directory(
+        self,
+        tmp_path: Path,
+        monkeypatch: MonkeyPatch,
+        pytester: Pytester,
+    ) -> None:
+        """Check KeyError with `--import-mode=importlib` (#12592)."""
+        self.setup_directories(tmp_path, monkeypatch, pytester)
+        code = dedent("""
+        def test():
+            assert "four lights" == "five lights"
+        """)
+
+        # a subdirectories with the same name in the namespace package,
+        # along with a tests file
+        test_base_path = tmp_path / "src/dist2/com/company"
+        test_py = test_base_path / "a/b/c/test_demo.py"
+        test_dir = test_base_path / "a/b/c/c"
+
+        test_dir.mkdir(parents=True)
+        test_py.write_text(code, encoding="UTF-8")
+
+        pkg_root, module_name = resolve_pkg_root_and_module_name(
+            test_py, consider_namespace_packages=True
+        )
+        assert (pkg_root, module_name) == (
+            tmp_path / "src/dist2",
+            "com.company.a.b.c.test_demo",
+        )
+
+        result = pytester.runpytest("--import-mode=importlib", test_py)
+
+        result.stdout.no_fnmatch_line(
+            "E   KeyError: 'test_ns_multiple_levels_import1.src.dist2.com.company.a.b'"
+        )
+
+        assert "KeyError" not in result.stdout.str()
+
 
 def test_is_importable(pytester: Pytester) -> None:
     pytester.syspathinsert()