Run mypy on Lib/test/libregrtest in CI

.github/workflows/mypy.yml

@@ -7,6 +7,7 @@ on:
       - main
   pull_request:
     paths:
+      - "Lib/test/libregrtest/**"
       - "Tools/clinic/**"
       - "Tools/cases_generator/**"
       - "Tools/peg_generator/**"
@@ -30,11 +31,11 @@ jobs:
   mypy:
     strategy:
       matrix:
-        target: [
-          "Tools/cases_generator",
-          "Tools/clinic",
-          "Tools/peg_generator",
-        ]
+        target:
+          - "Lib/test/libregrtest"
+          - "Tools/cases_generator"
+          - "Tools/clinic"
+          - "Tools/peg_generator"
     name: Run mypy on ${{ matrix.target }}
     runs-on: ubuntu-latest
     timeout-minutes: 10
@@ -46,4 +47,13 @@ jobs:
           cache: pip
           cache-dependency-path: Tools/requirements-dev.txt
       - run: pip install -r Tools/requirements-dev.txt
-      - run: mypy --config-file ${{ matrix.target }}/mypy.ini
+      - if: ${{ matrix.target != 'Lib/test/libregrtest' }}
+        run: mypy --config-file ${{ matrix.target }}/mypy.ini
+      - name: Run mypy on libregrtest
+        if: ${{ matrix.target == 'Lib/test/libregrtest' }}
+        # Mypy can't be run on libregrtest from the repo root,
+        # or it (amusingly) thinks that the entire Lib directory is "shadowing the stdlib",
+        # and refuses to do any type-checking at all
+        run: |
+          cd Lib/test
+          mypy --config-file libregrtest/mypy.ini

Lib/test/libregrtest/cmdline.py

@@ -3,6 +3,7 @@
 import shlex
 import sys
 from test.support import os_helper
+from typing import Literal
 
 
 USAGE = """\
@@ -157,11 +158,11 @@ def __init__(self, **kwargs) -> None:
         self.randomize = False
         self.fromfile = None
         self.fail_env_changed = False
-        self.use_resources = None
+        self.use_resources: list[str] | None = None
         self.trace = False
         self.coverdir = 'coverage'
         self.runleaks = False
-        self.huntrleaks = False
+        self.huntrleaks: tuple[int, int, str] | Literal[False] = False
         self.rerun = False
         self.verbose3 = False
         self.print_slow = False

Lib/test/libregrtest/findtests.py

@@ -24,7 +24,7 @@
 }
 
 
-def findtestdir(path=None):
+def findtestdir(path: StrPath | None = None) -> StrPath:
     return path or os.path.dirname(os.path.dirname(__file__)) or os.curdir
 
 

Lib/test/libregrtest/logger.py

@@ -14,7 +14,7 @@ def __init__(self, results: TestResults, quiet: bool, pgo: bool):
         self.start_time = time.perf_counter()
         self.test_count_text = ''
         self.test_count_width = 3
-        self.win_load_tracker = None
+        self.win_load_tracker: WindowsLoadTracker | None = None
         self._results: TestResults = results
         self._quiet: bool = quiet
         self._pgo: bool = pgo
@@ -32,9 +32,9 @@ def log(self, line: str = '') -> None:
 
         mins, secs = divmod(int(test_time), 60)
         hours, mins = divmod(mins, 60)
-        test_time = "%d:%02d:%02d" % (hours, mins, secs)
+        formatted_test_time = "%d:%02d:%02d" % (hours, mins, secs)
 
-        line = f"{test_time} {line}"
+        line = f"{formatted_test_time} {line}"
         if empty:
             line = line[:-1]
 

Lib/test/libregrtest/main.py

@@ -3,6 +3,7 @@
 import re
 import sys
 import time
+from typing import cast
 
 from test import support
 from test.support import os_helper
@@ -71,11 +72,11 @@ def __init__(self, ns: Namespace):
 
         # Select tests
         if ns.match_tests:
-            self.match_tests: FilterTuple = tuple(ns.match_tests)
+            self.match_tests: FilterTuple | None = tuple(ns.match_tests)
         else:
             self.match_tests = None
         if ns.ignore_tests:
-            self.ignore_tests: FilterTuple = tuple(ns.ignore_tests)
+            self.ignore_tests: FilterTuple | None = tuple(ns.ignore_tests)
         else:
             self.ignore_tests = None
         self.exclude: bool = ns.exclude
@@ -105,16 +106,16 @@ def __init__(self, ns: Namespace):
         if ns.huntrleaks:
             warmups, runs, filename = ns.huntrleaks
             filename = os.path.abspath(filename)
-            self.hunt_refleak: HuntRefleak = HuntRefleak(warmups, runs, filename)
+            self.hunt_refleak: HuntRefleak | None = HuntRefleak(warmups, runs, filename)
         else:
             self.hunt_refleak = None
         self.test_dir: StrPath | None = ns.testdir
         self.junit_filename: StrPath | None = ns.xmlpath
         self.memory_limit: str | None = ns.memlimit
         self.gc_threshold: int | None = ns.threshold
-        self.use_resources: tuple[str] = tuple(ns.use_resources)
+        self.use_resources: tuple[str, ...] = tuple(ns.use_resources or ())
         if ns.python:
-            self.python_cmd: tuple[str] = tuple(ns.python)
+            self.python_cmd: tuple[str, ...] | None = tuple(ns.python)
         else:
             self.python_cmd = None
         self.coverage: bool = ns.trace
@@ -139,6 +140,7 @@ def log(self, line=''):
         self.logger.log(line)
 
     def find_tests(self, tests: TestList | None = None) -> tuple[TestTuple, TestList | None]:
+        assert self.tmp_dir is not None
         if self.single_test_run:
             self.next_single_filename = os.path.join(self.tmp_dir, 'pynexttest')
             try:
@@ -183,6 +185,7 @@ def find_tests(self, tests: TestList | None = None) -> tuple[TestTuple, TestList
             else:
                 selected = alltests
         else:
+            assert tests is not None
             selected = tests
 
         if self.single_test_run:
@@ -389,7 +392,7 @@ def create_run_tests(self, tests: TestTuple):
             match_tests=self.match_tests,
             ignore_tests=self.ignore_tests,
             match_tests_dict=None,
-            rerun=None,
+            rerun=False,
             forever=self.forever,
             pgo=self.pgo,
             pgo_extended=self.pgo_extended,
@@ -457,6 +460,7 @@ def _run_tests(self, selected: TestTuple, tests: TestList | None) -> int:
                                          self.fail_rerun)
 
     def run_tests(self, selected: TestTuple, tests: TestList | None) -> int:
+        assert self.tmp_dir is not None
         os.makedirs(self.tmp_dir, exist_ok=True)
         work_dir = get_work_dir(self.tmp_dir)
 

Lib/test/libregrtest/mypy.ini

@@ -0,0 +1,43 @@
+# Config file for running mypy on libregrtest.
+#
+# Note: mypy can't be run on libregrtest from the CPython repo root.
+# If you try to do so, mypy will complain
+# about the entire `Lib/` directory "shadowing the stdlib".
+# Instead, `cd` into `Lib/test`, then run `mypy --config-file libregrtest/mypy.ini`.
+
+[mypy]
+packages = libregrtest
+python_version = 3.11
+platform = linux
+pretty = True
+
+# Enable most stricter settings
+enable_error_code = ignore-without-code
+strict = True
+
+# Various stricter settings that we can't yet enable
+# Try to enable these in the following order:
+disallow_incomplete_defs = False
+disallow_untyped_calls = False
+disallow_untyped_defs = False
+check_untyped_defs = False
+warn_return_any = False
+
+# Various internal modules that typeshed deliberately doesn't have stubs for:
+[mypy-_abc.*]
+ignore_missing_imports = True
+
+[mypy-_opcode.*]
+ignore_missing_imports = True
+
+[mypy-_overlapped.*]
+ignore_missing_imports = True
+
+[mypy-_testcapi.*]
+ignore_missing_imports = True
+
+[mypy-_testinternalcapi.*]
+ignore_missing_imports = True
+
+[mypy-test.*]
+ignore_missing_imports = True

Lib/test/libregrtest/refleak.py

@@ -1,6 +1,7 @@
 import sys
 import warnings
 from inspect import isabstract
+from typing import Any, Callable
 
 from test import support
 from test.support import os_helper
@@ -45,12 +46,13 @@ def runtest_refleak(test_name, test_func,
     fs = warnings.filters[:]
     ps = copyreg.dispatch_table.copy()
     pic = sys.path_importer_cache.copy()
+    zdc: dict[str, Any] | None
     try:
         import zipimport
     except ImportError:
         zdc = None # Run unmodified on platforms without zipimport support
     else:
-        zdc = zipimport._zip_directory_cache.copy()
+        zdc = zipimport._zip_directory_cache.copy()  # type: ignore[attr-defined]
     abcs = {}
     for abc in [getattr(collections.abc, a) for a in collections.abc.__all__]:
         if not isabstract(abc):
@@ -78,7 +80,7 @@ def get_pooled_int(value):
     fd_deltas = [0] * repcount
     getallocatedblocks = sys.getallocatedblocks
     gettotalrefcount = sys.gettotalrefcount
-    getunicodeinternedsize = sys.getunicodeinternedsize
+    getunicodeinternedsize: Callable[[], int] = sys.getunicodeinternedsize  # type: ignore[attr-defined]
     fd_count = os_helper.fd_count
     # initialize variables to make pyflakes quiet
     rc_before = alloc_before = fd_before = interned_before = 0
@@ -175,6 +177,7 @@ def dash_R_cleanup(fs, ps, pic, zdc, abcs):
     except ImportError:
         pass # Run unmodified on platforms without zipimport support
     else:
+        assert zdc is not None
         zipimport._zip_directory_cache.clear()
         zipimport._zip_directory_cache.update(zdc)
 

Lib/test/libregrtest/results.py

@@ -1,4 +1,5 @@
 import sys
+import xml.etree.ElementTree as ET
 from test.support import TestStats
 
 from .runtests import RunTests
@@ -31,7 +32,7 @@ def __init__(self):
         self.test_times: list[tuple[float, TestName]] = []
         self.stats = TestStats()
         # used by --junit-xml
-        self.testsuite_xml: list[str] = []
+        self.testsuite_xml: list[ET.Element] = []
 
     def get_executed(self):
         return (set(self.good) | set(self.bad) | set(self.skipped)
@@ -98,6 +99,7 @@ def accumulate_result(self, result: TestResult, runtests: RunTests):
                     raise ValueError(f"invalid test state: {result.state!r}")
 
         if result.has_meaningful_duration() and not rerun:
+            assert result.duration is not None
             self.test_times.append((result.duration, test_name))
         if result.stats is not None:
             self.stats.accumulate(result.stats)
@@ -111,7 +113,7 @@ def accumulate_result(self, result: TestResult, runtests: RunTests):
     def need_rerun(self):
         return bool(self.bad_results)
 
-    def prepare_rerun(self) -> (TestTuple, FilterDict):
+    def prepare_rerun(self) -> tuple[TestTuple, FilterDict]:
         tests: TestList = []
         match_tests_dict = {}
         for result in self.bad_results:
@@ -130,7 +132,6 @@ def prepare_rerun(self) -> (TestTuple, FilterDict):
         return (tuple(tests), match_tests_dict)
 
     def add_junit(self, xml_data: list[str]):
-        import xml.etree.ElementTree as ET
         for e in xml_data:
             try:
                 self.testsuite_xml.append(ET.fromstring(e))
@@ -231,8 +232,7 @@ def display_summary(self, first_runtests: RunTests, filtered: bool):
             report.append(f'failures={stats.failures:,}')
         if stats.skipped:
             report.append(f'skipped={stats.skipped:,}')
-        report = ' '.join(report)
-        print(f"Total tests: {report}")
+        print(f"Total tests: {' '.join(report)}")
 
         # Total test files
         all_tests = [self.good, self.bad, self.rerun,
@@ -256,5 +256,4 @@ def display_summary(self, first_runtests: RunTests, filtered: bool):
         ):
             if tests:
                 report.append(f'{name}={len(tests)}')
-        report = ' '.join(report)
-        print(f"Total test files: {report}")
+        print(f"Total test files: {' '.join(report)}")