Preserve legacy API options in workers

tests/integration/test_api_legacy.py

@@ -13,3 +13,17 @@ def test_legacy_api(tmpdir):
         style_guide = legacy.get_style_guide()
         report = style_guide.check_files([t_py.strpath])
         assert report.total_errors == 1
+
+
+def test_legacy_api_parallel_checks_use_option_overrides(tmpdir):
+    long_line = f"x = \"{'a' * 80}\"\n"
+    assert len(long_line.rstrip()) == 86
+
+    file1 = tmpdir.join("file1.py")
+    file1.write(long_line)
+    file2 = tmpdir.join("file2.py")
+    file2.write(long_line)
+
+    style_guide = legacy.get_style_guide(max_line_length=88)
+    report = style_guide.check_files([file1.strpath, file2.strpath])
+    assert report.total_errors == 0

tests/integration/test_checker.py

@@ -291,7 +291,7 @@ def test_acquire_when_multiprocessing_pool_can_initialize():
     with mock.patch("multiprocessing.Pool") as pool:
         result = checker._try_initialize_processpool(2, [])
 
-    pool.assert_called_once_with(2, checker._mp_init, initargs=([],))
+    pool.assert_called_once_with(2, checker._mp_init, initargs=([], None))
     assert result is pool.return_value
 
 
@@ -310,7 +310,7 @@ def test_acquire_when_multiprocessing_pool_can_not_initialize():
     with mock.patch("multiprocessing.Pool", side_effect=ImportError) as pool:
         result = checker._try_initialize_processpool(2, [])
 
-    pool.assert_called_once_with(2, checker._mp_init, initargs=([],))
+    pool.assert_called_once_with(2, checker._mp_init, initargs=([], None))
     assert result is None
 
 

tests/unit/test_checker_manager.py

@@ -63,6 +63,17 @@ def test_multiprocessing_cpu_count_not_implemented():
     assert manager.jobs == 0
 
 
+def test_mp_init_applies_option_overrides():
+    checker._mp = None
+    try:
+        checker._mp_init([], {"max_line_length": 88})
+        assert checker._mp is not None
+        _, options = checker._mp
+        assert options.max_line_length == 88
+    finally:
+        checker._mp = None
+
+
 def test_jobs_count_limited_to_file_count():
     style_guide = style_guide_mock()
     style_guide.options.jobs = JobsArgument("4")