Add ruff linting

Configure ruff in pyproject.toml and apply its fixes: modern annotations
(X | None, builtin generics, collections.abc), sorted imports, explicit
stacklevel in test warnings.

pyproject.toml

@@ -57,6 +57,12 @@ warn_unused_ignores = true
 module = ["paramiko", "systemd", "dbus"]
 ignore_missing_imports = true
 
+[tool.ruff]
+line-length = 120
+
+[tool.ruff.lint]
+select = ["E", "F", "W", "I", "B", "UP"]
+
 [tool.pytest.ini_options]
 testpaths = ["tests"]
 # Import the repo copy, not an installed one

simple_backup/simple_backup.py

@@ -14,27 +14,27 @@ Classes:
 # Avoid evaluating annotations at definition time, as they reference optional modules (paramiko)
 from __future__ import annotations
 
-# Import libraries
-import sys
-import os
-import pwd
-import io
-import re
-from typing import Callable, Iterator, List, Optional, ParamSpec, TypedDict, TypeVar
-import warnings
-from functools import wraps
-from shutil import get_terminal_size, rmtree, which
-import shlex
 import argparse
 import configparser
+import io
 import logging
-from logging import StreamHandler
+import os
-from timeit import default_timer
+import pwd
-from subprocess import Popen, PIPE, STDOUT
+import re
+import shlex
+import sys
+import warnings
+from collections.abc import Callable, Iterator
 from datetime import datetime
-from tempfile import mkstemp
+from functools import wraps
 from getpass import GetPassWarning, getpass
 from glob import glob
+from logging import StreamHandler
+from shutil import get_terminal_size, rmtree, which
+from subprocess import PIPE, STDOUT, Popen
+from tempfile import mkstemp
+from timeit import default_timer
+from typing import ParamSpec, TypedDict, TypeVar
 
 try:
     import paramiko
@@ -204,9 +204,9 @@ class Backup:
             Perform the backup
     """
 
-    def __init__(self, inputs: Optional[List[str]], output: Optional[str], exclude: Optional[List[str]],
+    def __init__(self, inputs: list[str] | None, output: str | None, exclude: list[str] | None,
-                 keep: Optional[int], options: str,
+                 keep: int | None, options: str,
-                 ssh_host: Optional[str] = None, ssh_user: Optional[str] = None, ssh_keyfile: Optional[str] = None,
+                 ssh_host: str | None = None, ssh_user: str | None = None, ssh_keyfile: str | None = None,
                  remote_sudo: bool = False, remove_before: bool = False, verbose: bool = False,
                  progress: bool = False) -> None:
         # Missing values are reported by check_params()
@@ -228,7 +228,7 @@ class Backup:
         self._inputs_path = ''
         self._exclude_path = ''
         self._remote = False
-        self._ssh: Optional[paramiko.client.SSHClient] = None
+        self._ssh: paramiko.client.SSHClient | None = None
         self._password_auth = False
         self._removed_count = 0
 
@@ -281,7 +281,7 @@ class Backup:
 
         return 0
 
-    def _resolve_remote_path(self, path: str) -> Optional[str]:
+    def _resolve_remote_path(self, path: str) -> str | None:
         """Return the absolute path of a directory on the server, or None if it doesn't exist"""
 
         assert self._ssh is not None
@@ -450,7 +450,7 @@ class Backup:
             except IndexError:
                 logger.info('No previous backups available')
 
-    def _ssh_connect(self, homedir: str = '') -> Optional[paramiko.client.SSHClient]:
+    def _ssh_connect(self, homedir: str = '') -> paramiko.client.SSHClient | None:
         try:
             ssh = paramiko.SSHClient()
         except NameError:
@@ -469,7 +469,7 @@ class Backup:
             if connected is None:
                 ssh.close()
 
-    def _ssh_login(self, ssh: paramiko.client.SSHClient, homedir: str) -> Optional[paramiko.client.SSHClient]:
+    def _ssh_login(self, ssh: paramiko.client.SSHClient, homedir: str) -> paramiko.client.SSHClient | None:
         try:
             ssh.load_host_keys(filename=f'{homedir}/.ssh/known_hosts')
         except FileNotFoundError:
@@ -553,7 +553,7 @@ class Backup:
 
         return ssh
 
-    def _load_ssh_key(self) -> Optional[paramiko.PKey]:
+    def _load_ssh_key(self) -> paramiko.PKey | None:
         try:
             return paramiko.PKey.from_path(self.ssh_keyfile)
         except TypeError:
@@ -808,7 +808,7 @@ def _read_records(stream: io.BufferedIOBase) -> Iterator[str]:
         yield buffer.decode('utf-8', errors='replace')
 
 
-def _detect_user() -> Optional[str]:
+def _detect_user() -> str | None:
     if os.geteuid() == 0:
         return os.getenv('SUDO_USER') or os.getenv('DOAS_USER')
 
@@ -873,8 +873,8 @@ def _expand_home(path: str, user: str) -> str:
     return os.path.expanduser(path)
 
 
-def _expand_inputs(inputs: List[str], user: Optional[str] = None) -> List[str]:
+def _expand_inputs(inputs: list[str], user: str | None = None) -> list[str]:
-    expanded_inputs: List[str] = []
+    expanded_inputs: list[str] = []
 
     for i in inputs:
         if i == '':
@@ -900,13 +900,13 @@ def _expand_inputs(inputs: List[str], user: Optional[str] = None) -> List[str]:
 class ConfigArgs(TypedDict):
     """Values read from the configuration file"""
 
-    inputs: Optional[List[str]]
+    inputs: list[str] | None
-    output: Optional[str]
+    output: str | None
-    exclude: Optional[List[str]]
+    exclude: list[str] | None
     keep: int
-    ssh_host: Optional[str]
+    ssh_host: str | None
-    ssh_user: Optional[str]
+    ssh_user: str | None
-    ssh_keyfile: Optional[str]
+    ssh_keyfile: str | None
     remote_sudo: bool
     numeric_ids: bool
 
@@ -919,7 +919,7 @@ def _get_bool(config: configparser.ConfigParser, key: str) -> bool:
     return config.getboolean('server', key)
 
 
-def _read_config(config_file: str, user: Optional[str] = None) -> ConfigArgs:
+def _read_config(config_file: str, user: str | None = None) -> ConfigArgs:
     config_args: ConfigArgs = {'inputs': None,
                                'output': None,
                                'exclude': None,

tests/conftest.py

@@ -1,7 +1,7 @@
 """Shared fixtures for the simple_backup tests"""
 
 import sys
-from typing import Callable
+from collections.abc import Callable
 
 import pytest
 

tests/test_cli.py

@@ -2,8 +2,9 @@
 
 import os
 import pwd
+from collections.abc import Callable
 from pathlib import Path
-from typing import Any, Callable, Optional
+from typing import Any
 
 import pytest
 
@@ -25,8 +26,8 @@ class FakeBackup:
     check_code = 0
 
     def __init__(self, inputs: Any, output: Any, exclude: Any, keep: Any, options: str,
-                 ssh_host: Optional[str] = None, ssh_user: Optional[str] = None,
+                 ssh_host: str | None = None, ssh_user: str | None = None,
-                 ssh_keyfile: Optional[str] = None, remote_sudo: bool = False,
+                 ssh_keyfile: str | None = None, remote_sudo: bool = False,
                  remove_before: bool = False, verbose: bool = False, progress: bool = False) -> None:
         self.inputs = inputs
         self.output = output
@@ -40,7 +41,7 @@ class FakeBackup:
         self.remove_before = remove_before
         self.verbose = verbose
         self.progress = progress
-        self.homedir: Optional[str] = None
+        self.homedir: str | None = None
         self.ran = False
         self.closed = False
         FakeBackup.instances.append(self)
@@ -86,13 +87,13 @@ def as_root(monkeypatch: pytest.MonkeyPatch) -> None:
 
 
 @pytest.fixture
-def config_calls(monkeypatch: pytest.MonkeyPatch) -> list[tuple[str, Optional[str]]]:
+def config_calls(monkeypatch: pytest.MonkeyPatch) -> list[tuple[str, str | None]]:
     """Record the config file path and user instead of reading the file"""
 
-    calls: list[tuple[str, Optional[str]]] = []
+    calls: list[tuple[str, str | None]] = []
     read_config = sb._read_config
 
-    def record(config_file: str, user: Optional[str] = None) -> sb.ConfigArgs:
+    def record(config_file: str, user: str | None = None) -> sb.ConfigArgs:
         calls.append((config_file, user))
 
         return read_config('/nonexistent/simple_backup.conf', user)
@@ -249,20 +250,20 @@ ssh_keyfile=/keys/id
 
 class TestUser:
     @pytest.mark.usefixtures('as_user')
-    def test_current_user(self, run_cli: RunCli, config_calls: list[tuple[str, Optional[str]]]) -> None:
+    def test_current_user(self, run_cli: RunCli, config_calls: list[tuple[str, str | None]]) -> None:
         assert run_cli() == 0
         assert config_calls == [(f'{HOME}/.config/simple_backup/simple_backup.conf', USER)]
         assert last_backup().homedir == HOME
 
     @pytest.mark.usefixtures('as_root')
-    def test_explicit_user(self, run_cli: RunCli, config_calls: list[tuple[str, Optional[str]]]) -> None:
+    def test_explicit_user(self, run_cli: RunCli, config_calls: list[tuple[str, str | None]]) -> None:
         assert run_cli('-u', USER, '-c', '~/other.conf') == 0
         assert config_calls == [(f'{HOME}/other.conf', USER)]
         assert last_backup().homedir == HOME
 
     @pytest.mark.usefixtures('as_root')
     @pytest.mark.parametrize('var', ['SUDO_USER', 'DOAS_USER'])
-    def test_sudo_or_doas_user(self, run_cli: RunCli, config_calls: list[tuple[str, Optional[str]]],
+    def test_sudo_or_doas_user(self, run_cli: RunCli, config_calls: list[tuple[str, str | None]],
                                monkeypatch: pytest.MonkeyPatch, var: str) -> None:
         monkeypatch.setenv(var, USER)
 
@@ -271,7 +272,7 @@ class TestUser:
         assert last_backup().homedir == HOME
 
     @pytest.mark.usefixtures('as_root')
-    def test_root_without_user(self, run_cli: RunCli, config_calls: list[tuple[str, Optional[str]]],
+    def test_root_without_user(self, run_cli: RunCli, config_calls: list[tuple[str, str | None]],
                                caplog: pytest.LogCaptureFixture) -> None:
         assert run_cli() == 0
         # '~' is left to expanduser, i.e. $HOME

tests/test_local.py

@@ -2,9 +2,10 @@
 
 import io
 import os
+from collections.abc import Callable, Iterator
 from datetime import datetime, timedelta
 from pathlib import Path
-from typing import Any, Callable, Iterator, Optional
+from typing import Any
 
 import pytest
 
@@ -52,7 +53,7 @@ def out(tmp_path: Path) -> Path:
     return out
 
 
-def make_backup(out: Path, inputs: list[str], keep: int = -1, exclude: Optional[list[str]] = None,
+def make_backup(out: Path, inputs: list[str], keep: int = -1, exclude: list[str] | None = None,
                 remove_before: bool = False, progress: bool = False) -> sb.Backup:
     backup = sb.Backup(inputs, str(out), exclude or [], keep, OPTIONS, remove_before=remove_before,
                        progress=progress)

tests/test_remote.py

@@ -10,7 +10,7 @@ import warnings
 from getpass import GetPassWarning
 from pathlib import Path
 from shutil import which
-from typing import Any, Optional
+from typing import Any
 
 import pytest
 
@@ -30,7 +30,7 @@ class FakeSSH:
         self.home = home
         self.bin_dir = bin_dir
         self.commands: list[str] = []
-        self.fail_on: Optional[str] = None
+        self.fail_on: str | None = None
         self.closed = False
 
     def exec_command(self, command: str) -> tuple[None, io.BytesIO, io.BytesIO]:
@@ -186,7 +186,7 @@ class TestRemoveOldBackups:
         assert [c for c in ssh.commands if 'rm -r' in c][0].startswith('sudo rm -r ')
 
     @pytest.mark.parametrize('names', [[], None])
-    def test_nothing_to_remove(self, remote_home: Path, names: Optional[list[str]]) -> None:
+    def test_nothing_to_remove(self, remote_home: Path, names: list[str] | None) -> None:
         if names is not None:
             make_backups(remote_home, *names)
 
@@ -348,11 +348,11 @@ class TestRsyncArgs:
 class FakeClient:
     """paramiko.SSHClient stand-in; connect() takes its outcomes from a list"""
 
-    def __init__(self, outcomes: list[Optional[BaseException]]) -> None:
+    def __init__(self, outcomes: list[BaseException | None]) -> None:
         self.outcomes = outcomes
         self.connects: list[dict[str, Any]] = []
         self.policies: list[str] = []
-        self.known_hosts: Optional[str] = None
+        self.known_hosts: str | None = None
         self.closed = False
 
     def load_host_keys(self, filename: str) -> None:
@@ -370,7 +370,7 @@ class FakeClient:
 
         if isinstance(outcome, UserWarning):
             # Like WarningPolicy for an unknown host key
-            warnings.warn(outcome)
+            warnings.warn(outcome, stacklevel=2)
         elif outcome is not None:
             raise outcome
 
@@ -462,7 +462,7 @@ class TestLogin:
     def test_password_no_terminal(self, client: FakeClient, monkeypatch: pytest.MonkeyPatch,
                                   caplog: pytest.LogCaptureFixture) -> None:
         def no_tty(prompt: str) -> str:
-            warnings.warn('Can not control echo on the terminal.', GetPassWarning)
+            warnings.warn('Can not control echo on the terminal.', GetPassWarning, stacklevel=2)
 
             return ''
 
@@ -474,7 +474,7 @@ class TestLogin:
 
     @pytest.mark.parametrize('outcome, connected', [(None, True), ('error', False)])
     def test_keyfile(self, client: FakeClient, monkeypatch: pytest.MonkeyPatch,
-                     outcome: Optional[str], connected: bool) -> None:
+                     outcome: str | None, connected: bool) -> None:
         pkey = object()
         client.outcomes = [ssh_error(), ssh_error(), ssh_error() if outcome else None]
         monkeypatch.setattr(sb.Backup, '_load_ssh_key', lambda self: pkey)
@@ -548,7 +548,7 @@ class TestLoadKey:
     def test_no_terminal(self, keys: Path, monkeypatch: pytest.MonkeyPatch,
                          caplog: pytest.LogCaptureFixture) -> None:
         def no_tty(prompt: str) -> str:
-            warnings.warn('Can not control echo on the terminal.', GetPassWarning)
+            warnings.warn('Can not control echo on the terminal.', GetPassWarning, stacklevel=2)
 
             return ''
 
@@ -558,7 +558,7 @@ class TestLoadKey:
         assert 'Unable to get passphrase' in caplog.text
 
     @pytest.mark.parametrize('content', [None, 'not a key\n'])
-    def test_bad_file(self, tmp_path: Path, caplog: pytest.LogCaptureFixture, content: Optional[str]) -> None:
+    def test_bad_file(self, tmp_path: Path, caplog: pytest.LogCaptureFixture, content: str | None) -> None:
         keyfile = tmp_path / 'id'
 
         if content is not None: