improve typing

linuxnamespaces/__init__.py:
 * linuxnamespaces.filedescriptor only exports FileDescriptor. By
   importing *, we re-export it implicitly.

linuxnamespaces/atlocation.py:
 * PathLike should be parameterized and we no longer allow bytes there.

linuxnamespaces/tarutils.py:
 * Resolve dict vs Mapping.

tests/test_simple.py:
 * Establish expected type to mypy.

examples/unschroot.py:
 * pidfd is first an int and later a FileDescriptor, but we always use
   it as int.
 * Also tell mypy that we cannot get NULL from waitid.

5 files changed, 12 insertions, 4 deletions

diff --git a/examples/unschroot.py b/examples/unschroot.py
index 682b5b0..5f644fc 100755
--- a/examples/unschroot.py
+++ b/examples/unschroot.py
@@ -207,6 +207,7 @@ def do_run_session(args: argparse.Namespace) -> None:
     gidmap = linuxnamespaces.IDAllocation.loadsubid("gid").allocatemap(65536)
     mainsock, childsock = socket.socketpair()
     pid = os.fork()
+    pidfd: int
     if pid == 0:
         mainsock.close()
         os.chdir(session.path)
@@ -281,7 +282,9 @@ def do_run_session(args: argparse.Namespace) -> None:
     os.waitpid(pid, 0)
     linuxnamespaces.prctl_set_child_subreaper(False)
     mainsock.send(b"\0")
-    sys.exit(os.waitid(os.P_PIDFD, pidfd, os.WEXITED).si_status)
+    wres = os.waitid(os.P_PIDFD, pidfd, os.WEXITED)
+    assert wres is not None
+    sys.exit(wres.si_status)
 
 
 def do_end_session(args: argparse.Namespace) -> None:
diff --git a/linuxnamespaces/__init__.py b/linuxnamespaces/__init__.py
index 65dfc8d..5a9ef39 100644
--- a/linuxnamespaces/__init__.py
+++ b/linuxnamespaces/__init__.py
@@ -16,7 +16,7 @@ import stat
 import subprocess
 import typing
 
-from .filedescriptor import FileDescriptor
+from .filedescriptor import *
 from .atlocation import *
 from .syscalls import *
 
diff --git a/linuxnamespaces/atlocation.py b/linuxnamespaces/atlocation.py
index 8a38650..20d402a 100644
--- a/linuxnamespaces/atlocation.py
+++ b/linuxnamespaces/atlocation.py
@@ -21,7 +21,7 @@ from .filedescriptor import FileDescriptor
 AT_FDCWD = FileDescriptor(-100)
 
 
-PathConvertible = typing.Union[str, os.PathLike]
+PathConvertible = typing.Union[str, os.PathLike[str]]
 
 
 class AtFlags(enum.IntFlag):
diff --git a/linuxnamespaces/tarutils.py b/linuxnamespaces/tarutils.py
index facb537..6285d5a 100644
--- a/linuxnamespaces/tarutils.py
+++ b/linuxnamespaces/tarutils.py
@@ -19,7 +19,11 @@ TarPath = str | bytes | os.PathLike[str] | os.PathLike[bytes]
 class ZstdTarFile(tarfile.TarFile):
     """Subclass of tarfile.TarFile that can read zstd compressed archives."""
 
-    OPEN_METH = {"zst": "zstopen"} | tarfile.TarFile.OPEN_METH
+    # mypy types OPEN_METH as Mapping rather than dict while it really is a
+    # dict. Hence, it complains that there is no __or__ for dict and Mapping.
+    OPEN_METH = {
+        "zst": "zstopen",
+    } | tarfile.TarFile.OPEN_METH  # type: ignore[operator]
 
     @classmethod
     def zstopen(
diff --git a/tests/test_simple.py b/tests/test_simple.py
index 878e985..e971e22 100644
--- a/tests/test_simple.py
+++ b/tests/test_simple.py
@@ -161,6 +161,7 @@ class AsnycioTest(unittest.IsolatedAsyncioTestCase):
             self.assertTrue(fut.done())
         exc = fut.exception()
         self.assertIsInstance(exc, OSError)
+        assert isinstance(exc, OSError)  # also tell mypy
         self.assertEqual(exc.errno, errno.EPIPE)