Fix Partial Signature Signing.

[ziggie1984]

Was fixed after a node-runner reached out with the following stack trace:

Helping someone after a crash :

"I use chantools version v0.12.1 for the recovery of 2 channels with the command:"

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x316d0c]

goroutine 1 [running]:
github.com/btcsuite/btcd/txscript.NewTxSigHashes(0x4000127998, {0x11057a0, 0x4000186188})
github.com/btcsuite/btcd@v0.23.5-0.20230905170901-80f5a0ffdf36/txscript/hashcache.go:243 +0x12c
github.com/lightninglabs/chantools/lnd.(*Signer).AddPartialSignature(0x0?, 0x4000127a18, {{0x2312ba5?, 0x13dea5f?}, 0x400056b680?}, 0x40000486e0, {0x4000586d70, 0x47, 0x47}, 0x0)
github.com/lightninglabs/chantools/lnd/signer.go:154 +0x78
main.(*zombieRecoveryMakeOfferCommand).Execute(0x40001a6c00, 0xa48680?, {0x4000017af0?, 0x4000017ac8?, 0x0?})
github.com/lightninglabs/chantools/cmd/chantools/zombierecovery_makeoffer.go:425 +0x1f3c
github.com/spf13/cobra.(*Command).execute(0x4000215b80, {0x400007e9c0, 0x6, 0x6})
github.com/spf13/cobra@v1.1.3/command.go:852 +0x554
github.com/spf13/cobra.(*Command).ExecuteC(0x19d6f20)
github.com/spf13/cobra@v1.1.3/command.go:960 +0x310
github.com/spf13/cobra.(*Command).Execute(...)
github.com/spf13/cobra@v1.1.3/command.go:897
main.main()
github.com/lightninglabs/chantools/cmd/chantools/root.go:137 +0x370

[guggero]

Thank you for the fix! I guess I just never actually tested the command with multiple channels before.

LGTM 🎉

[wyssblitz]

thank you for the fix. We will try it today or tomorrow and give you a feedback.

[wyssblitz]

the error persists with version v0.12.2. We used the binary, did not compile from source.

we only used the command chantools zombierecovery makeoffer with the previously generated keyfiles.

We will try again doing the following

• regenerate the keyfiles on both nodes, using the original matchfile
• try the makoffer again
• if this does not work we will change the matchfile to a single channel

If there is no other suggestion from you side, we will proceed either today or tomorrow and keep you informed

[guggero]

You need to compile from source from the latest master branch. I didn't create a new release yet.

[wyssblitz]

The fix worked like a charm after I did the compile. A big thanks to all involved!