multi: bump btcd to taproot aware version

contractcourt/breacharbiter.go

@@ -1441,7 +1441,7 @@ func (b *BreachArbiter) sweepSpendableOutputsTxn(txWeight int64,
 
 	// Create a sighash cache to improve the performance of hashing and
 	// signing SigHashAll inputs.
-	hashCache := txscript.NewTxSigHashes(txn)
+	hashCache := txscript.NewTxSigHashesV0Only(txn)
 
 	// Create a closure that encapsulates the process of initializing a
 	// particular output's witness generation function, computing the

contractcourt/breacharbiter_test.go

@@ -1377,7 +1377,8 @@ func getSpendTransactions(signer input.Signer, chanPoint *wire.OutPoint,
 	// sign and add the witness to the HTLC sweep.
 	retInfo := newRetributionInfo(chanPoint, retribution)
 
-	hashCache := txscript.NewTxSigHashes(htlcSweep)
+	cannedFetcher := txscript.NewCannedPrevOutputFetcher(nil, 0)
+	hashCache := txscript.NewTxSigHashes(htlcSweep, cannedFetcher)
 	for i := range retInfo.breachedOutputs {
 		inp := &retInfo.breachedOutputs[i]
 
@@ -1387,7 +1388,7 @@ func getSpendTransactions(signer input.Signer, chanPoint *wire.OutPoint,
 			fallthrough
 		case input.HtlcOfferedRevoke:
 			inputScript, err := inp.CraftInputScript(
-				signer, htlcSweep, hashCache, 0,
+				signer, htlcSweep, hashCache, cannedFetcher, 0,
 			)
 			if err != nil {
 				return nil, err

go.mod

@@ -112,6 +112,13 @@ replace github.com/gogo/protobuf => github.com/gogo/protobuf v1.3.2
 // version.
 replace github.com/onsi/ginkgo => github.com/onsi/ginkgo v1.14.2
 
+replace (
+	github.com/btcsuite/btcd => github.com/Roasbeef/btcd v0.0.0-20220225020451-4629cbd4eb52
+	github.com/btcsuite/btcd/btcec/v2 => github.com/Roasbeef/btcd/btcec/v2 v2.0.0-20220225020451-4629cbd4eb52
+	github.com/btcsuite/btcwallet => github.com/guggero/btcwallet v0.13.1-0.20220301095026-f656436a1a7a
+	github.com/btcsuite/btcwallet/wallet/txauthor => github.com/guggero/btcwallet/wallet/txauthor v1.1.1-0.20220301095026-f656436a1a7a
+)
+
 // If you change this please also update .github/pull_request_template.md and
 // docs/INSTALL.md.
 go 1.16

go.sum

@@ -43,6 +43,10 @@ github.com/NebulousLabs/fastrand v0.0.0-20181203155948-6fb6489aac4e/go.mod h1:Bd
 github.com/NebulousLabs/go-upnp v0.0.0-20180202185039-29b680b06c82 h1:MG93+PZYs9PyEsj/n5/haQu2gK0h4tUtSy9ejtMwWa0=
 github.com/NebulousLabs/go-upnp v0.0.0-20180202185039-29b680b06c82/go.mod h1:GbuBk21JqF+driLX3XtJYNZjGa45YDoa9IqCTzNSfEc=
 github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
+github.com/Roasbeef/btcd v0.0.0-20220225020451-4629cbd4eb52 h1:wddBOvb9F+PUsJYNJfoenu1GKYAvwZ+0WfwjhC6EaAA=
+github.com/Roasbeef/btcd v0.0.0-20220225020451-4629cbd4eb52/go.mod h1:DV2Y1MUL8kKUq9uRpot9YvKjGuvDZ1OShTmzYPHIsMc=
+github.com/Roasbeef/btcd/btcec/v2 v2.0.0-20220225020451-4629cbd4eb52 h1:P+7ihFY7Lntsg1KAT7wBFYC4elqKB6yYSgI660F9CWI=
+github.com/Roasbeef/btcd/btcec/v2 v2.0.0-20220225020451-4629cbd4eb52/go.mod h1:2VzYrv4Gm4apmbVVsSq5bqf1Ec8v56E48Vt0Y/umPgA=
 github.com/Yawning/aez v0.0.0-20180114000226-4dad034d9db2 h1:2be4ykKKov3M1yISM2E8gnGXZ/N2SsPawfnGiXxaYEU=
 github.com/Yawning/aez v0.0.0-20180114000226-4dad034d9db2/go.mod h1:9pIqrY6SXNL8vjRQE5Hd/OL5GyK/9MrGUWs87z/eFfk=
 github.com/Yawning/bsaes v0.0.0-20180720073208-c0276d75487e h1:n88VxLC80RPVHbFG/kq7ItMizCVRPCyLj63UMqxLkOw=
@@ -74,28 +78,13 @@ github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/bgentry/speakeasy v0.1.0/go.mod h1:+zsyZBPWlz7T6j88CTgSN5bM796AkVf0kBD4zp0CCIs=
 github.com/bketelsen/crypt v0.0.3-0.20200106085610-5cbc8cc4026c/go.mod h1:MKsuJmJgSg28kpZDP6UIiPt0e0Oz0kqKNGyRaWEPv84=
-github.com/btcsuite/btcd v0.0.0-20190824003749-130ea5bddde3/go.mod h1:3J08xEfcugPacsc34/LKRU2yO7YmuT8yt28J8k2+rrI=
-github.com/btcsuite/btcd v0.20.1-beta/go.mod h1:wVuoA8VJLEcwgqHBwHmzLRazpKxTv13Px/pDuV7OomQ=
-github.com/btcsuite/btcd v0.22.0-beta.0.20211005184431-e3449998be39/go.mod h1:3PH+KbvLFfzBTCevQenPiDedjGQGt6aa70dVjJDWGTA=
-github.com/btcsuite/btcd v0.22.0-beta.0.20220111032746-97732e52810c/go.mod h1:tjmYdS6MLJ5/s0Fj4DbLgSbDHbEqLJrtnHecBFkdz5M=
-github.com/btcsuite/btcd v0.22.0-beta.0.20220204213055-eaf0459ff879/go.mod h1:osu7EoKiL36UThEgzYPqdRaxeo0NU8VoXqgcnwpey0g=
-github.com/btcsuite/btcd v0.22.0-beta.0.20220207191057-4dc4ff7963b4 h1:CEGr/598C/0LZQUoioaT6sdGGcJgu4+ck0PDeJ/QkKs=
-github.com/btcsuite/btcd v0.22.0-beta.0.20220207191057-4dc4ff7963b4/go.mod h1:7alexyj/lHlOtr2PJK7L/+HDJZpcGDn/pAU98r7DY08=
-github.com/btcsuite/btcd/btcec/v2 v2.1.0 h1:Whmbo9yShKKG+WrUfYGFfgj77vYBiwhwBSJnM66TMKI=
-github.com/btcsuite/btcd/btcec/v2 v2.1.0/go.mod h1:2VzYrv4Gm4apmbVVsSq5bqf1Ec8v56E48Vt0Y/umPgA=
 github.com/btcsuite/btcd/btcutil v1.0.0/go.mod h1:Uoxwv0pqYWhD//tfTiipkxNfdhG9UrLwaeswfjfdF0A=
 github.com/btcsuite/btcd/btcutil v1.1.0 h1:MO4klnGY+EWJdoWF12Wkuf4AWDBPMpZNeN/jRLrklUU=
 github.com/btcsuite/btcd/btcutil v1.1.0/go.mod h1:5OapHB7A2hBBWLm48mmw4MOHNJCcUBTwmWH/0Jn8VHE=
 github.com/btcsuite/btcd/btcutil/psbt v1.1.0 h1:1LxDjz2ar4L2mrviBdxrzxesMMcAtj4nuBlX4FdqjOA=
 github.com/btcsuite/btcd/btcutil/psbt v1.1.0/go.mod h1:xMuACsIKDzcE3kWMxqK+aLrAWZ8bMdn7YjYEwNs5q8k=
 github.com/btcsuite/btclog v0.0.0-20170628155309-84c8d2346e9f h1:bAs4lUbRJpnnkd9VhRV3jjAVU7DJVjMaK+IsvSeZvFo=
 github.com/btcsuite/btclog v0.0.0-20170628155309-84c8d2346e9f/go.mod h1:TdznJufoqS23FtqVCzL0ZqgP5MqXbb4fg/WgDys70nA=
-github.com/btcsuite/btcutil v0.0.0-20190425235716-9e5f4b9a998d/go.mod h1:+5NJ2+qvTyV9exUAL/rxXi3DcLg2Ts+ymUAY5y4NvMg=
-github.com/btcsuite/btcutil v1.0.3-0.20201208143702-a53e38424cce/go.mod h1:0DVlHczLPewLcPGEIeUEzfOJhqGPQ0mJJRDBtD307+o=
-github.com/btcsuite/btcwallet v0.14.0 h1:+Nwf0GkRUwDjd/F3i9HgrRhDp8RHZFbBZ3kQaZr6zD0=
-github.com/btcsuite/btcwallet v0.14.0/go.mod h1:KFR1x3ZH7c31i4qA34XIvcsnhrEBLK1SHli52lN8E54=
-github.com/btcsuite/btcwallet/wallet/txauthor v1.2.1 h1:oxIaFiF8gmOLJh7wNkXYkyLWT7Pj5igSrn5HthPVDYg=
-github.com/btcsuite/btcwallet/wallet/txauthor v1.2.1/go.mod h1:/74bubxX5Js48d76nf/TsNabpYp/gndUuJw4chzCmhU=
 github.com/btcsuite/btcwallet/wallet/txrules v1.2.0 h1:BtEN5Empw62/RVnZ0VcJaVtVlBijnLlJY+dwjAye2Bg=
 github.com/btcsuite/btcwallet/wallet/txrules v1.2.0/go.mod h1:AtkqiL7ccKWxuLYtZm8Bu8G6q82w4yIZdgq6riy60z0=
 github.com/btcsuite/btcwallet/wallet/txsizes v1.1.0 h1:wZnOolEAeNOHzHTnznw/wQv+j35ftCIokNrnOTOU5o8=
@@ -324,6 +313,10 @@ github.com/grpc-ecosystem/grpc-gateway v1.16.0 h1:gmcG1KaJ57LophUzW0Hy8NmPhnMZb4
 github.com/grpc-ecosystem/grpc-gateway v1.16.0/go.mod h1:BDjrQk3hbvj6Nolgz8mAMFbcEtjT1g+wF4CSlocrBnw=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.5.0 h1:ajue7SzQMywqRjg2fK7dcpc0QhFGpTR2plWfV4EZWR4=
 github.com/grpc-ecosystem/grpc-gateway/v2 v2.5.0/go.mod h1:r1hZAcvfFXuYmcKyCJI9wlyOPIZUJl6FCB8Cpca/NLE=
+github.com/guggero/btcwallet v0.13.1-0.20220301095026-f656436a1a7a h1:cNb7cN0jgpp3k/Sr5rKxcfWRmD8cByXtWvT8R3xpZos=
+github.com/guggero/btcwallet v0.13.1-0.20220301095026-f656436a1a7a/go.mod h1:D5SJQPQs4bL6s04MrZdUon72222Nc2Sm6bG/r4HCW1E=
+github.com/guggero/btcwallet/wallet/txauthor v1.1.1-0.20220301095026-f656436a1a7a h1:Xdyw76wiY5Ns+tggMSOwgJa0om82Hy61mxdzxpGDCtk=
+github.com/guggero/btcwallet/wallet/txauthor v1.1.1-0.20220301095026-f656436a1a7a/go.mod h1:oGMQA7iI9ZaTpk/glW9DOWDzp1KwLEgdGlbNEwDQ2Gc=
 github.com/hashicorp/consul/api v1.1.0/go.mod h1:VmuI/Lkw1nC05EYQWNKwWGbkg+FbDBtguAZLlVdkD9Q=
 github.com/hashicorp/consul/sdk v0.1.1/go.mod h1:VKf9jXwCTEY1QZP2MOLRhb5i/I/ssyNV1vwHyQBF0x8=
 github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
@@ -344,7 +337,6 @@ github.com/hashicorp/logutils v1.0.0/go.mod h1:QIAnNjmIWmVIIkWDTG1z5v++HQmx9WQRO
 github.com/hashicorp/mdns v1.0.0/go.mod h1:tL+uN++7HEJ6SQLQ2/p+z2pH24WQKWjBPkE0mNTz8vQ=
 github.com/hashicorp/memberlist v0.1.3/go.mod h1:ajVTdAv/9Im8oMAAj5G31PhhMCZJV2pPBoIllUwCN7I=
 github.com/hashicorp/serf v0.8.2/go.mod h1:6hOLApaqBFA1NXqRQAsxw9QxuDEvNxSQRwA/JwenrHc=
-github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
 github.com/jackc/chunkreader v1.0.0 h1:4s39bBR8ByfqH+DKm8rQA3E1LHZWB9XWcrz8fqaZbe0=
@@ -530,7 +522,6 @@ github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn
 github.com/onsi/ginkgo v1.14.2 h1:8mVmC9kjFFmA8H4pKMUhcblgifdkOIXPvbhN1T36q1M=
 github.com/onsi/ginkgo v1.14.2/go.mod h1:iSB4RoI2tjJc9BBv4NKIKWKya62Rps+oPG/Lv9klQyY=
 github.com/onsi/gomega v1.4.1/go.mod h1:C1qb7wdrVGGVU+Z6iS04AVkA3Q65CEZX59MT0QO5uiA=
-github.com/onsi/gomega v1.4.3/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
 github.com/onsi/gomega v1.10.1 h1:o0+MgICZLuZ7xjH7Vx6zS/zcu93/BEp1VwkIW1mEXCE=
 github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
 github.com/opentracing/opentracing-go v1.1.0/go.mod h1:UkNAQd3GIcIGf0SeVgPpRdFStlNbqXla1AfSYxPUl2o=
@@ -727,9 +718,7 @@ golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20190605123033-f99c8df09eb5/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20190820162420-60c769a6c586/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
-golang.org/x/crypto v0.0.0-20200115085410-6d4e4cb37c7d/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20200302210943-78000ba7a073/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/crypto v0.0.0-20200510223506-06a226fb4e37/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20201002170205-7f63de1d35b0/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20201203163018-be400aefbc4c/go.mod h1:jdWPYTVW3xRLrWPugEBEK3UY2ZEsg3UU495nc5E+M+I=
@@ -775,7 +764,6 @@ golang.org/x/mod v0.5.1/go.mod h1:5OXOZSfqPIIbmVBIIKWRFfZjPR0E5r58TLhUjH0a2Ro=
 golang.org/x/net v0.0.0-20180719180050-a680a1efc54d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
-golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181023162649-9b4f9f5ad519/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181106065722-10aee1819953/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181114220301-adae6a3d119a/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
@@ -839,7 +827,6 @@ golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sys v0.0.0-20180823144017-11551d06cbcc/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20181026203630-95b1ffbd15a5/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20181107165924-66b7b1311ac8/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20181116152217-5ac8a444bdc5/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
@@ -881,7 +868,6 @@ golang.org/x/sys v0.0.0-20200523222454-059865788121/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200615200032-f1bc736245b1/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200625212154-ddb9806d33ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200803210538-64077c9b5642/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200814200057-3d37ad5750ed/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200923182605-d9f96fdee20d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -1079,7 +1065,6 @@ gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8
 gopkg.in/errgo.v1 v1.0.1 h1:oQFRXzZ7CkBGdm1XZm/EbQYaYNNEElNBOd09M6cqNso=
 gopkg.in/errgo.v1 v1.0.1/go.mod h1:3NjfXwocQRYAPTq4/fzX+CwUhPRcR/azYRhj8G+LqMo=
 gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
-gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
 gopkg.in/inconshreveable/log15.v2 v2.0.0-20180818164646-67afb5ed74ec/go.mod h1:aPpfJ7XW+gOuirDoZ8gHhLh3kZ1B08FtV2bbmy7Jv3s=
 gopkg.in/ini.v1 v1.51.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
 gopkg.in/macaroon-bakery.v2 v2.0.1 h1:0N1TlEdfLP4HXNCg7MQUMp5XwvOoxk+oe9Owr2cpvsc=

input/input.go

@@ -338,7 +338,7 @@ func MakeHtlcSecondLevelTimeoutAnchorInput(signedTx *wire.MsgTx,
 		txinIdx int) (wire.TxWitness, error) {
 
 		desc := signDetails.SignDesc
-		desc.SigHashes = txscript.NewTxSigHashes(txn)
+		desc.SigHashes = txscript.NewTxSigHashesV0Only(txn)
 		desc.InputIndex = txinIdx
 
 		return SenderHtlcSpendTimeout(

input/script_utils.go

@@ -864,7 +864,7 @@ func HtlcSpendSuccess(signer Signer, signDesc *SignDescriptor,
 
 	// As we mutated the transaction, we'll re-calculate the sighashes for
 	// this instance.
-	signDesc.SigHashes = txscript.NewTxSigHashes(sweepTx)
+	signDesc.SigHashes = NewTxSigHashesV0Only(sweepTx)
 
 	// With the proper sequence and version set, we'll now sign the timeout
 	// transaction using the passed signed descriptor. In order to generate
@@ -1558,3 +1558,17 @@ func ComputeCommitmentPoint(commitSecret []byte) *btcec.PublicKey {
 		&commitPointJacobian.X, &commitPointJacobian.Y,
 	)
 }
+
+// NewTxSigHashesV0Only returns a new txscript.TxSigHashes instance that will
+// only calculate the sighash midstate values for segwit v0 inputs and can
+// therefore never be used for transactions that want to spend segwit v1
+// (taproot) inputs.
+func NewTxSigHashesV0Only(tx *wire.MsgTx) *txscript.TxSigHashes {
+	// the canned output fetcher returns a wire.TxOut instance with the
+	// given pk script and amount. We can get away with nil since the first
+	// thing the TxSigHashes constructor checks is the length of the pk
+	// script and whether it matches taproot output script length. If the
+	// length doesn't match it assumes v0 inputs only.
+	nilFetcher := txscript.NewCannedPrevOutputFetcher(nil, 0)
+	return txscript.NewTxSigHashes(tx, nilFetcher)
+}