Method test_cache_exhaustion

Lib/test/test_external_inspection.py:3445–3514

Test cache works when frame limit (1024) is exceeded. FRAME_CACHE_MAX_FRAMES=1024. With 1100 recursive frames, the cache can't store all of them but should still work.

(self)

        "Test only runs on Linux with process_vm_readv support",
    )
    def test_cache_exhaustion(self):
        """Test cache works when frame limit (1024) is exceeded.

        FRAME_CACHE_MAX_FRAMES=1024. With 1100 recursive frames,
        the cache can't store all of them but should still work.
        """
        # Use 1100 to exceed FRAME_CACHE_MAX_FRAMES=1024
        depth = 1100
        script_body = f"""\
import sys
sys.setrecursionlimit(2000)

def recurse(n):
    if n <= 0:
        sock.sendall(b"ready")
        sock.recv(16)  # wait for ack
        sock.sendall(b"ready2")
        sock.recv(16)  # wait for done
        return
    recurse(n - 1)

recurse({depth})
"""

        with self._target_process(script_body) as (
            p,
            client_socket,
            make_unwinder,
        ):
            unwinder_cache = make_unwinder(cache_frames=True)
            unwinder_no_cache = make_unwinder(cache_frames=False)

            frames_cached = self._sample_frames(
                client_socket,
                unwinder_cache,
                b"ready",
                b"ack",
                {"recurse"},
                expected_frames=1102,
            )
            # Sample again with no cache for comparison
            frames_no_cache = self._sample_frames(
                client_socket,
                unwinder_no_cache,
                b"ready2",
                b"done",
                {"recurse"},
                expected_frames=1102,
            )

        self.assertIsNotNone(frames_cached)
        self.assertIsNotNone(frames_no_cache)

        # Both should have many recurse frames (> 1024 limit)
        cached_count = [f.funcname for f in frames_cached].count("recurse")
        no_cache_count = [f.funcname for f in frames_no_cache].count("recurse")

        self.assertGreater(