Merge pull request #22 from dunxen/add1924

Add 1924

Author: dunxen

_posts/2023-09-01-#1924.md

@@ -0,0 +1,28 @@
+---
+layout: pr
+date: 2023-09-01
+title: "Handle if funding output is in a coinbase transaction"
+pr: 1924
+authors: [benthecarman]
+components: ["ChannelManager", "Channel"]
+host: dunxen
+status: upcoming
+commit:
+---
+
+## Notes
+
+* Miners are able to open a Lightning channel using the coinbase transaction of a new block. However, according to bitcoin consensus rules,
+  the outputs of coinbase transactions are not spendable until they reach 100 blocks, known as the coinbase maturity delay.
+* As pointed out in [lightning/bolts#1011](https://github.com/lightning/bolts/issues/1011), Lightning implementations need to ensure that
+  sending `channel_ready` is delayed for 100 blocks.
+
+## Questions
+
+1. Did you have a quick glance or review of the PR?
+1. How do we practically enforce the delay of 100 blocks before sending a `channel_open` for channels with coinbase funding transaction in the PR?
+1. Why do we not need to worry about adding any buffer on top of the 100 block maturation delay? Think in terms of re-orgs.
+1. In the Lightning protocol, it's important that the funding transactions (and all others) are non-malleable (their txids are not malleable).
+   Usually we think of transactions solely spending segwit-style UTXOs as being non-malleable. In what sense are coinbase transactions non-malleable?
+1. Before this PR was it possible for LDK users (who are miners) to open channels using coinbase transactions with the checks we had. Why or why not?
+1. How should 0conf coinbase-funded channels be handled? What if we want to close them within the coinbase maturation period?