send_all_to_address with retain_reserves creates 0 amount output #539
Description
In Fedimint, we have a test that first closes all channels, then sends all of the funds onchain, then verifies that the node's balance is 0.
When upgrading to ldk-node v0.5.0, this test fails when retain_reserves is set to true. Setting retain_reserves to false makes the test pass. We have not changed our config or our anchor reserve sats at all.
In LDK node's log, I see the following line:
2025-05-13 15:37:08 ERROR [ldk_node::wallet:370] Failed to create temporary transaction: Output below the dust limit: 0
Is this expected behavior? If I had to guess its trying to create a 0 amount output, because we have 0 channels and the "reserve" calculation dictates it needs to create an output, even though in this case it shouldn't. Let me know if I just have something configured incorrectly.
For now we will be setting retain_reserves to false so that our test passes.