From cc584a591785fc5a87e0f242aea8513aa8330c17 Mon Sep 17 00:00:00 2001
From: Dmitry Orlov <orlovdl@gmail.com>
Date: Sun, 27 Sep 2026 00:09:17 +0200
Subject: [PATCH] Cover channel creation during connection restoration

---
 tests/test_reconnect_channel_snapshot.py | 74 ++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 tests/test_reconnect_channel_snapshot.py

diff --git a/tests/test_reconnect_channel_snapshot.py b/tests/test_reconnect_channel_snapshot.py
new file mode 100644
index 00000000..6c04ffa9
--- /dev/null
+++ b/tests/test_reconnect_channel_snapshot.py
@@ -0,0 +1,74 @@
+import asyncio
+import logging
+
+from aio_pika import Message, connect_robust
+
+
+async def test_create_channels_during_reconnect(amqp_url, monkeypatch, caplog):
+    caplog.set_level(logging.ERROR)
+    async with await connect_robust(
+        amqp_url.update_query(reconnect_interval=0.1),
+    ) as connection:
+        existing = await connection.channel()
+        restoring = asyncio.Event()
+        release = asyncio.Event()
+        reconnected = asyncio.Event()
+        connection.reconnect_callbacks.add(lambda *_: reconnected.set())
+        close_reasons = []
+        connection.close_callbacks.add(
+            lambda _, exc: close_reasons.append(str(exc)),
+        )
+        original_restore = existing.restore
+
+        async def delayed_restore(*args, **kwargs):
+            restoring.set()
+            await release.wait()
+            await original_restore(*args, **kwargs)
+
+        monkeypatch.setattr(existing, "restore", delayed_restore)
+        transport = connection.transport
+        assert transport is not None
+        await transport.connection.close(asyncio.CancelledError)
+        try:
+            await asyncio.wait_for(restoring.wait(), 10)
+            # The new transport is connected, but restoration of the original
+            # channels is still suspended. Model concurrent health checks.
+            channels = [await connection.channel() for _ in range(3)]
+            queues = [await ch.declare_queue(exclusive=True) for ch in channels]
+        finally:
+            release.set()
+        await asyncio.wait_for(reconnected.wait(), 10)
+        assert not any(
+            "Set changed size during iteration" in reason
+            for reason in close_reasons
+        ), close_reasons
+        assert not [r for r in caplog.records if r.levelno >= logging.ERROR]
+
+        for channel, queue in zip(channels, queues):
+            await channel.default_exchange.publish(
+                Message(b"healthy"), queue.name
+            )
+            message = await queue.get(timeout=5)
+            assert message is not None and message.body == b"healthy"
+            await message.ack()
+
+        # Newly registered channels must participate in the next restoration.
+        previous = [await ch.get_underlay_channel() for ch in channels]
+        reconnected.clear()
+        transport = connection.transport
+        assert transport is not None
+        await transport.connection.close(asyncio.CancelledError)
+        await asyncio.wait_for(reconnected.wait(), 10)
+        for channel, old, queue in zip(channels, previous, queues):
+            assert await channel.get_underlay_channel() is not old
+            await channel.default_exchange.publish(
+                Message(b"restored"), queue.name
+            )
+            message = await queue.get(timeout=5)
+            assert message is not None and message.body == b"restored"
+            await message.ack()
+        assert not any(
+            "Set changed size during iteration" in reason
+            for reason in close_reasons
+        ), close_reasons
+        assert not [r for r in caplog.records if r.levelno >= logging.ERROR]