commitment: simplify TapscriptRoot

guggero · guggero · commit 1da727b98692 · 2025-07-22T12:30:07.000+02:00
This was always a bit confusing and also unnecessarily complicated.
We'll need to manually re-create the tapscript root given a sibling in
the next commit, where we'll use similar code. This refactor shows that
the root with no sibling can easily be transformed into the root with a
sibling.
diff --git a/commitment/tap.go b/commitment/tap.go
@@ -457,8 +457,7 @@ func IsTaprootAssetCommitmentScript(script []byte) bool {
 func (c *TapCommitment) TapscriptRoot(sibling *chainhash.Hash) chainhash.Hash {
 	commitmentLeaf := c.TapLeaf()
 	if sibling == nil {
-		return txscript.AssembleTaprootScriptTree(commitmentLeaf).
-			RootNode.TapHash()
+		return commitmentLeaf.TapHash()
 	}
 
 	// The ordering of `commitmentLeaf` and `sibling` doesn't matter here as

Original file line number	Diff line number	Diff line change
`@@ -457,8 +457,7 @@ func IsTaprootAssetCommitmentScript(script []byte) bool {`
`457`	`457`	`func (c TapCommitment) TapscriptRoot(sibling chainhash.Hash) chainhash.Hash {`
`458`	`458`	`commitmentLeaf := c.TapLeaf()`
`459`	`459`	`if sibling == nil {`
`460`		`- return txscript.AssembleTaprootScriptTree(commitmentLeaf).`
`461`		`- RootNode.TapHash()`
	`460`	`+ return commitmentLeaf.TapHash()`
`462`	`461`	`}`
`463`	`462`
`464`	`463`	// The ordering of `commitmentLeaf` and `sibling` doesn't matter here as