Fix bug in computation of new tree heads

bwesterb · bwesterb · commit 1709cca3cafb · 2025-04-23T16:44:37.000+02:00
We were dropping "the old head" from the wrong side.
diff --git a/mtc.go b/mtc.go
@@ -798,7 +798,7 @@ func (p *CAParams) NewTreeHeads(prevHeads, root []byte) ([]byte, error) {
 			len(root),
 		)
 	}
-	return append(root, prevHeads[HashLen:]...), nil
+	return append(root, prevHeads[:expected-HashLen]...), nil
 }
 
 func (batch *Batch) Anchor() TrustAnchorIdentifier {

Original file line number	Diff line number	Diff line change
`@@ -798,7 +798,7 @@ func (p *CAParams) NewTreeHeads(prevHeads, root []byte) ([]byte, error) {`
`798`	`798`	`len(root),`
`799`	`799`	`)`
`800`	`800`	`}`
`801`		`- return append(root, prevHeads[HashLen:]...), nil`
	`801`	`+ return append(root, prevHeads[:expected-HashLen]...), nil`
`802`	`802`	`}`
`803`	`803`
`804`	`804`	`func (batch *Batch) Anchor() TrustAnchorIdentifier {`