typing fixes and improvements (#107)

* Add type parameters to Dict or List

* Use dict and list from builtins in type hints

Since we target Python 3.9, typing.Dict and typing.List are deprecated
and builtins can be used instead.

* Type windows_flag to fix 'call-overload' mypy error

* Add the error code about windows_flag's type ignore

This 'type ignore' is because mypy will raise an error on Linux as the
subprocess module does not have a CREATE_NO_WINDOW attribute defined.

* Re-use windows_flag in test

* Add a comment about 'type: ignore' for WindowsFlag

Author: dlax

pylsp_mypy/plugin.py

@@ -18,7 +18,7 @@
 import tempfile
 from configparser import ConfigParser
 from pathlib import Path
-from typing import IO, Any, Dict, List, Optional
+from typing import IO, Any, Optional, TypedDict
 
 try:
     import tomllib
@@ -47,9 +47,9 @@
 log = logging.getLogger(__name__)
 
 # A mapping from workspace path to config file path
-mypyConfigFileMap: Dict[str, Optional[str]] = {}
+mypyConfigFileMap: dict[str, Optional[str]] = {}
 
-settingsCache: Dict[str, Dict[str, Any]] = {}
+settingsCache: dict[str, dict[str, Any]] = {}
 
 tmpFile: Optional[IO[bytes]] = None
 
@@ -58,18 +58,25 @@
 # so store a cache of last diagnostics for each file a-la the pylint plugin,
 # so we can return some potentially-stale diagnostics.
 # https://github.com/python-lsp/python-lsp-server/blob/v1.0.1/pylsp/plugins/pylint_lint.py#L55-L62
-last_diagnostics: Dict[str, List[Dict[str, Any]]] = collections.defaultdict(list)
+last_diagnostics: dict[str, list[dict[str, Any]]] = collections.defaultdict(list)
+
 
 # Windows started opening opening a cmd-like window for every subprocess call
 # This flag prevents that.
 # This flag is new in python 3.7
-# This flag only exists on Windows
-windows_flag: Dict[str, int] = (
-    {"creationflags": subprocess.CREATE_NO_WINDOW} if os.name == "nt" else {}  # type: ignore
+# This flag only exists on Windows, hence the 'type: ignore[attr-defined]' below.
+class WindowsFlag(TypedDict, total=False):
+    creationflags: int
+
+
+windows_flag: WindowsFlag = (
+    {"creationflags": subprocess.CREATE_NO_WINDOW}  # type: ignore[attr-defined]
+    if os.name == "nt"
+    else {}
 )
 
 
-def parse_line(line: str, document: Optional[Document] = None) -> Optional[Dict[str, Any]]:
+def parse_line(line: str, document: Optional[Document] = None) -> Optional[dict[str, Any]]:
     """
     Return a language-server diagnostic from a line of the Mypy error report.
 
@@ -128,7 +135,7 @@ def parse_line(line: str, document: Optional[Document] = None) -> Optional[Dict[
     return diag
 
 
-def apply_overrides(args: List[str], overrides: List[Any]) -> List[str]:
+def apply_overrides(args: list[str], overrides: list[Any]) -> list[str]:
     """Replace or combine default command-line options with overrides."""
     overrides_iterator = iter(overrides)
     if True not in overrides_iterator:
@@ -140,7 +147,7 @@ def apply_overrides(args: List[str], overrides: List[Any]) -> List[str]:
     return overrides[: -(len(rest) + 1)] + args + rest
 
 
-def didSettingsChange(workspace: str, settings: Dict[str, Any]) -> None:
+def didSettingsChange(workspace: str, settings: dict[str, Any]) -> None:
     """Handle relevant changes to the settings between runs."""
     configSubPaths = settings.get("config_sub_paths", [])
     if settingsCache[workspace].get("config_sub_paths", []) != configSubPaths:
@@ -154,7 +161,7 @@ def didSettingsChange(workspace: str, settings: Dict[str, Any]) -> None:
         settingsCache[workspace] = settings.copy()
 
 
-def match_exclude_patterns(document_path: str, exclude_patterns: list) -> bool:
+def match_exclude_patterns(document_path: str, exclude_patterns: list[str]) -> bool:
     """Check if the current document path matches any of the configures exlude patterns."""
     document_path = document_path.replace(os.sep, "/")
 
@@ -169,14 +176,14 @@ def match_exclude_patterns(document_path: str, exclude_patterns: list) -> bool:
     return False
 
 
-def get_cmd(settings: Dict[str, Any], cmd: str) -> List[str]:
+def get_cmd(settings: dict[str, Any], cmd: str) -> list[str]:
     """
     Get the command to run from settings, falling back to searching the PATH.
     If the command is not found in the settings and is not available on the PATH, an
     empty list is returned.
     """
     command_key = f"{cmd}_command"
-    command: List[str] = settings.get(command_key, [])
+    command: list[str] = settings.get(command_key, [])
 
     if not (command and os.getenv("PYLSP_MYPY_ALLOW_DANGEROUS_CODE_EXECUTION")):
         # env var is required to allow command from settings
@@ -196,7 +203,7 @@ def get_cmd(settings: Dict[str, Any], cmd: str) -> List[str]:
 @hookimpl
 def pylsp_lint(
     config: Config, workspace: Workspace, document: Document, is_saved: bool
-) -> List[Dict[str, Any]]:
+) -> list[dict[str, Any]]:
     """
     Call the linter.
 
@@ -254,9 +261,9 @@ def pylsp_lint(
 def get_diagnostics(
     workspace: Workspace,
     document: Document,
-    settings: Dict[str, Any],
+    settings: dict[str, Any],
     is_saved: bool,
-) -> List[Dict[str, Any]]:
+) -> list[dict[str, Any]]:
     """
     Lints.
 
@@ -332,7 +339,7 @@ def get_diagnostics(
         args.extend(["--incremental", "--follow-imports", settings.get("follow-imports", "silent")])
         args = apply_overrides(args, overrides)
 
-        mypy_command: List[str] = get_cmd(settings, "mypy")
+        mypy_command: list[str] = get_cmd(settings, "mypy")
 
         if mypy_command:
             # mypy exists on PATH or was provided by settings
@@ -357,7 +364,7 @@ def get_diagnostics(
         # If daemon is dead/absent, kill will no-op.
         # In either case, reset to fresh state
 
-        dmypy_command: List[str] = get_cmd(settings, "dmypy")
+        dmypy_command: list[str] = get_cmd(settings, "dmypy")
 
         if dmypy_command:
             # dmypy exists on PATH or was provided by settings
@@ -449,7 +456,7 @@ def get_diagnostics(
 
 
 @hookimpl
-def pylsp_settings(config: Config) -> Dict[str, Dict[str, Dict[str, str]]]:
+def pylsp_settings(config: Config) -> dict[str, dict[str, dict[str, str]]]:
     """
     Read the settings.
 
@@ -468,7 +475,7 @@ def pylsp_settings(config: Config) -> Dict[str, Dict[str, Dict[str, str]]]:
     return {"plugins": {"pylsp_mypy": configuration}}
 
 
-def init(workspace: str) -> Dict[str, str]:
+def init(workspace: str) -> dict[str, str]:
     """
     Find plugin and mypy config files and creates the temp file should it be used.
 
@@ -509,7 +516,7 @@ def init(workspace: str) -> Dict[str, str]:
 
 
 def findConfigFile(
-    path: str, configSubPaths: List[str], names: List[str], mypy: bool
+    path: str, configSubPaths: list[str], names: list[str], mypy: bool
 ) -> Optional[str]:
     """
     Search for a config file.
@@ -580,9 +587,9 @@ def pylsp_code_actions(
     config: Config,
     workspace: Workspace,
     document: Document,
-    range: Dict,
-    context: Dict,
-) -> List[Dict]:
+    range: dict[str, Any],
+    context: dict[str, Any],
+) -> list[dict[str, Any]]:
     """
     Provide code actions to ignore errors.
 

test/test_plugin.py

@@ -1,10 +1,8 @@
 import collections
 import os
 import re
-import subprocess
 import sys
 from pathlib import Path
-from typing import Dict
 from unittest.mock import Mock, patch
 
 import pytest
@@ -31,10 +29,6 @@
     'test_plugin.py:124:1:129:77: note: Use "-> None" if function does not return a value'
 )
 
-windows_flag: Dict[str, int] = (
-    {"creationflags": subprocess.CREATE_NO_WINDOW} if os.name == "nt" else {}  # type: ignore
-)
-
 
 @pytest.fixture
 def last_diagnostics_monkeypatch(monkeypatch):
@@ -252,7 +246,7 @@ def test_option_overrides_dmypy(last_diagnostics_monkeypatch, workspace):
         "--no-pretty",
         document.path,
     ]
-    m.assert_called_with(expected, capture_output=True, **windows_flag, encoding="utf-8")
+    m.assert_called_with(expected, capture_output=True, **plugin.windows_flag, encoding="utf-8")
 
 
 def test_dmypy_status_file(tmpdir, last_diagnostics_monkeypatch, workspace):