gh-158093: Add more test coverage for concurrent set operations

Lib/test/test_free_threading/test_set.py

@@ -148,6 +148,318 @@ def read_set():
         for t in threads:
             t.join()
 
+    def test_pop_concurrent(self):
+        """Test set.pop() from several threads."""
+        NUM_THREADS = 4
+        NUM_ITERS = 20
+
+        for _ in range(NUM_ITERS):
+            items = set(range(self.SET_SIZE))
+            s = set(items)
+            barrier = Barrier(NUM_THREADS, timeout=2)
+            popped = [[] for _ in range(NUM_THREADS)]
+
+            def pop_set(out):
+                barrier.wait()
+                while True:
+                    try:
+                        out.append(s.pop())
+                    except KeyError:
+                        break
+
+            threads = [Thread(target=pop_set, args=(out,)) for out in popped]
+            for t in threads:
+                t.start()
+            for t in threads:
+                t.join()
+
+            all_popped = [item for out in popped for item in out]
+            self.assertEqual(len(all_popped), len(items))
+            self.assertEqual(set(all_popped), items)
+            self.assertEqual(len(s), 0)
+
+    def test_add_concurrent(self):
+        """Test set.add() with disjoint inputs from several threads."""
+        NUM_THREADS = 4
+        NUM_ITERS = 20
+
+        for _ in range(NUM_ITERS):
+            inputs = [
+                range(i * self.SET_SIZE, (i + 1) * self.SET_SIZE)
+                for i in range(NUM_THREADS)
+            ]
+            expected = set().union(*inputs)
+            s = set()
+            barrier = Barrier(NUM_THREADS, timeout=2)
+
+            def add_items(items):
+                barrier.wait()
+                for item in items:
+                    s.add(item)
+
+            threads = [Thread(target=add_items, args=(items,))
+                       for items in inputs]
+            for t in threads:
+                t.start()
+            for t in threads:
+                t.join()
+
+            self.assertEqual(s, expected)
+
+    def test_remove_discard_concurrent(self):
+        """Test set.remove() and set.discard() from several threads."""
+        NUM_THREADS = 4
+        NUM_ITERS = 20
+
+        for method_name in ("remove", "discard"):
+            with self.subTest(method=method_name):
+                for _ in range(NUM_ITERS):
+                    inputs = [
+                        range(i * self.SET_SIZE, (i + 1) * self.SET_SIZE)
+                        for i in range(NUM_THREADS)
+                    ]
+                    untouched = set(range(
+                        NUM_THREADS * self.SET_SIZE,
+                        (NUM_THREADS + 1) * self.SET_SIZE,
+                    ))
+                    s = set().union(untouched, *inputs)
+                    barrier = Barrier(NUM_THREADS, timeout=2)
+
+                    def remove_items(items):
+                        barrier.wait()
+                        method = getattr(s, method_name)
+                        for item in items:
+                            method(item)
+
+                    threads = [Thread(target=remove_items, args=(items,))
+                               for items in inputs]
+                    for t in threads:
+                        t.start()
+                    for t in threads:
+                        t.join()
+
+                    self.assertEqual(s, untouched)
+
+    def test_copy_clear_concurrent(self):
+        """Test set.copy() while another thread clears the set."""
+        NUM_ITERS = 20
+
+        for _ in range(NUM_ITERS):
+            items = set(range(self.SET_SIZE))
+            s = set(items)
+            copies = []
+            barrier = Barrier(2, timeout=2)
+
+            def copy_set():
+                barrier.wait()
+                copies.append(s.copy())
+
+            def clear_set():
+                barrier.wait()
+                s.clear()
+
+            threads = [Thread(target=copy_set), Thread(target=clear_set)]
+            for t in threads:
+                t.start()
+            for t in threads:
+                t.join()
+
+            self.assertIn(copies[0], (items, set()))
+            self.assertEqual(s, set())
+
+    def test_update_concurrent(self):
+        """Test updates of one shared set from disjoint source sets."""
+        NUM_THREADS = 4
+        NUM_ITERS = 20
+
+        sources = [
+            set(range(i * self.SET_SIZE, (i + 1) * self.SET_SIZE))
+            for i in range(NUM_THREADS)
+        ]
+        original_sources = [set(source) for source in sources]
+        initial = set(range(
+            NUM_THREADS * self.SET_SIZE,
+            (NUM_THREADS + 1) * self.SET_SIZE,
+        ))
+        expected = set().union(initial, *sources)
+
+        for _ in range(NUM_ITERS):
+            s = set(initial)
+            barrier = Barrier(NUM_THREADS, timeout=2)
+
+            def update_set(source):
+                barrier.wait()
+                s.update(source)
+
+            threads = [Thread(target=update_set, args=(source,))
+                        for source in sources]
+            for t in threads:
+                t.start()
+            for t in threads:
+                t.join()
+
+            self.assertEqual(s, expected)
+            self.assertEqual(sources, original_sources)
+
+    def test_update_opposing(self):
+        """Test opposing updates of two shared sets."""
+        NUM_ITERS = 20
+
+        for _ in range(NUM_ITERS):
+            left = set(range(self.SET_SIZE))
+            right = set(range(self.SET_SIZE, self.SET_SIZE * 2))
+            expected = set(range(self.SET_SIZE * 2))
+            barrier = Barrier(2, timeout=2)
+
+            def update_set(target, source):
+                barrier.wait()
+                target.update(source)
+
+            threads = [
+                Thread(target=update_set, args=(left, right)),
+                Thread(target=update_set, args=(right, left)),
+            ]
+            for t in threads:
+                t.start()
+            for t in threads:
+                t.join()
+
+            self.assertEqual(left, expected)
+            self.assertEqual(right, expected)
+
+    def test_difference_update_concurrent(self):
+        """Test set.difference_update() with disjoint source sets."""
+        NUM_THREADS = 4
+        NUM_ITERS = 20
+
+        sources = [
+            set(range(i * self.SET_SIZE, (i + 1) * self.SET_SIZE))
+            for i in range(NUM_THREADS)
+        ]
+        original_sources = [set(source) for source in sources]
+        untouched = set(range(
+            NUM_THREADS * self.SET_SIZE,
+            (NUM_THREADS + 1) * self.SET_SIZE,
+        ))
+        items = set().union(untouched, *sources)
+
+        for _ in range(NUM_ITERS):
+            s = set(items)
+            barrier = Barrier(NUM_THREADS, timeout=2)
+
+            def difference_update(source):
+                barrier.wait()
+                s.difference_update(source)
+
+            threads = [Thread(target=difference_update, args=(source,))
+                       for source in sources]
+            for t in threads:
+                t.start()
+            for t in threads:
+                t.join()
+
+            self.assertEqual(s, untouched)
+            self.assertEqual(sources, original_sources)
+
+    def test_difference_update_opposing(self):
+        """Test opposing difference updates of two shared sets."""
+        NUM_ITERS = 20
+
+        for _ in range(NUM_ITERS):
+            left = set(range(self.SET_SIZE))
+            right = set(range(1, self.SET_SIZE + 1))
+            original_left = set(left)
+            original_right = set(right)
+            left_only = {0}
+            right_only = {self.SET_SIZE}
+            barrier = Barrier(2, timeout=2)
+
+            def difference_update(target, source):
+                barrier.wait()
+                target.difference_update(source)
+
+            threads = [
+                Thread(target=difference_update, args=(left, right)),
+                Thread(target=difference_update, args=(right, left)),
+            ]
+            for t in threads:
+                t.start()
+            for t in threads:
+                t.join()
+
+            actual = (left, right)
+            expected = [
+                (left_only, original_right),
+                (original_left, right_only),
+            ]
+            self.assertIn(actual, expected)
+
+    def test_symmetric_difference_update_concurrent(self):
+        """Test symmetric difference updates with disjoint source sets."""
+        NUM_THREADS = 4
+        NUM_ITERS = 20
+
+        sources = [
+            set(range(i * self.SET_SIZE, (i + 1) * self.SET_SIZE))
+            for i in range(NUM_THREADS)
+        ]
+        items = set().union(*sources)
+        initial = {item for item in items if item % 2 == 0}
+        expected = {item for item in items if item % 2 == 1}
+
+        for _ in range(NUM_ITERS):
+            s = set(initial)
+            barrier = Barrier(NUM_THREADS, timeout=2)
+
+            def symmetric_difference_update(source):
+                barrier.wait()
+                s.symmetric_difference_update(source)
+
+            threads = [
+                Thread(target=symmetric_difference_update, args=(source,))
+                for source in sources
+            ]
+            for t in threads:
+                t.start()
+            for t in threads:
+                t.join()
+
+            self.assertEqual(s, expected)
+
+    def test_symmetric_difference_update_opposing(self):
+        """Test opposing symmetric difference updates of shared sets."""
+        NUM_ITERS = 20
+
+        for _ in range(NUM_ITERS):
+            left = set(range(self.SET_SIZE))
+            right = set(range(self.SET_SIZE, self.SET_SIZE * 2))
+            original_left = set(left)
+            original_right = set(right)
+            union = set(range(self.SET_SIZE * 2))
+            barrier = Barrier(2, timeout=2)
+
+            def symmetric_update(target, source):
+                barrier.wait()
+                target.symmetric_difference_update(source)
+
+            threads = [
+                Thread(target=symmetric_update, args=(left, right)),
+                Thread(target=symmetric_update, args=(right, left)),
+            ]
+            for t in threads:
+                t.start()
+            for t in threads:
+                t.join()
+
+            actual = (left, right)
+            expected = [
+                (union, original_left),
+                (original_right, union),
+            ]
+            self.assertIn(actual, expected)
+
+    # TODO: test_intersection_update_concurrent
+    # TODO: test_intersection_update_opposing
 
 @threading_helper.requires_working_threading()
 class SmallSetTest(RaceTestBase, unittest.TestCase):