Require feature option_shutdown_anysegwit

[jkczyz]

Fixes #1006.

TODO: Fix full_stack fuzz test failure likely caused by:

Invalid funding_created signature from peer

[TheBlueMatt]

Needs rebase on keysend.

[codecov]

Codecov Report

Merging #1018 (8d84e15) into main (f3b63e4) will decrease coverage by 0.07%.
The diff coverage is 84.21%.

❗ Current head 8d84e15 differs from pull request most recent head 1e27816. Consider uploading reports for the commit 1e27816 to get more accurate results

@@            Coverage Diff             @@
##             main    #1018      +/-   ##
==========================================
- Coverage   90.79%   90.72%   -0.08%     
==========================================
  Files          60       60              
  Lines       31434    31745     +311     
==========================================
+ Hits        28542    28802     +260     
- Misses       2892     2943      +51     

Impacted Files	Coverage Δ
lightning/src/ln/peer_handler.rs	49.69% <50.00%> (+3.70%)	⬆️
lightning/src/ln/functional_tests.rs	97.31% <92.30%> (+0.01%)	⬆️
lightning/src/ln/features.rs	99.60% <100.00%> (+0.16%)	⬆️

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[TheBlueMatt]

Grrrrrr, I'm more than a little bit pissed about this, but it looks like maybe lnd doesn't support shutdown_anysegwit? At least my immediate peers don't seem to support it. I've asked on their slack but its a bit disappointing that a 2-year-old spec change isn't supported. It's quite annoying, but I guess we could simply document this and then check if the peer supports anysegwit when we open the channel?

[jkczyz]

Grrrrrr, I'm more than a little bit pissed about this, but it looks like maybe lnd doesn't support shutdown_anysegwit? At least my immediate peers don't seem to support it. I've asked on their slack but its a bit disappointing that a 2-year-old spec change isn't supported. It's quite annoying, but I guess we could simply document this and then check if the peer supports anysegwit when we open the channel?

Hmmm... looks like it was only merged into the spec back on May 24 of this year. Could check at channel open and would also need to check at close after #1019.

[jkczyz]

Though it would make our interfaces more complicated if the validity of the user's shutdown script provided by KeysInterface depended on the counterparty's features.

[TheBlueMatt]

Hmmm... looks like it was only merged into the spec back on May 24 of this year

It's been around for much longer, though. At least it's super trivial to implement, too.

Though it would make our interfaces more complicated if the validity of the user's shutdown script provided by KeysInterface depended on the counterparty's features.

I think we should just force-close in that case and document it. Hopefully eventually lnd will implement it and until then warning users is fine I think.

[TheBlueMatt]

#1019 is going ahead without requiring anysegwit. I don't think there's a reason to require it any time soon.