diff --git a/gix-blame/src/file/function.rs b/gix-blame/src/file/function.rs
index c6572e202d1..d9299689c21 100644
--- a/gix-blame/src/file/function.rs
+++ b/gix-blame/src/file/function.rs
@@ -452,12 +452,12 @@ fn tree_diff_at_file_path(
     lhs_tree_buf: &mut Vec<u8>,
     rhs_tree_buf: &mut Vec<u8>,
 ) -> Result<Option<gix_diff::tree::recorder::Change>, Error> {
-    let parent_tree_id = tree_id(find_commit(cache, &odb, &parent_id, commit_buf)?)?;
+    let parent_tree_id = find_commit(cache, &odb, &parent_id, commit_buf)?.tree_id()?;
 
     let parent_tree_iter = odb.find_tree_iter(&parent_tree_id, lhs_tree_buf)?;
     stats.trees_decoded += 1;
 
-    let tree_id = tree_id(find_commit(cache, &odb, &id, commit_buf)?)?;
+    let tree_id = find_commit(cache, &odb, &id, commit_buf)?.tree_id()?;
 
     let tree_iter = odb.find_tree_iter(&tree_id, rhs_tree_buf)?;
     stats.trees_decoded += 1;
@@ -654,7 +654,7 @@ fn find_path_entry_in_commit(
     buf2: &mut Vec<u8>,
     stats: &mut Statistics,
 ) -> Result<Option<ObjectId>, Error> {
-    let tree_id = tree_id(find_commit(cache, odb, commit, buf)?)?;
+    let tree_id = find_commit(cache, odb, commit, buf)?.tree_id()?;
     let tree_iter = odb.find_tree_iter(&tree_id, buf)?;
     stats.trees_decoded += 1;
 
@@ -710,13 +710,6 @@ fn collect_parents(
     Ok(parent_ids)
 }
 
-fn tree_id(commit: gix_traverse::commit::Either<'_, '_>) -> Result<ObjectId, Error> {
-    match commit {
-        gix_traverse::commit::Either::CommitRefIter(mut commit_ref_iter) => Ok(commit_ref_iter.tree_id()?),
-        gix_traverse::commit::Either::CachedCommit(commit) => Ok(commit.root_tree_id().into()),
-    }
-}
-
 /// Return an iterator over tokens for use in diffing. These are usually lines, but it's important
 /// to unify them so the later access shows the right thing.
 pub(crate) fn tokens_for_diffing(data: &[u8]) -> impl TokenSource<Token = &[u8]> {
diff --git a/gix-traverse/src/commit/mod.rs b/gix-traverse/src/commit/mod.rs
index 4db6d4f64fc..1c19a13602a 100644
--- a/gix-traverse/src/commit/mod.rs
+++ b/gix-traverse/src/commit/mod.rs
@@ -77,6 +77,17 @@ pub enum Either<'buf, 'cache> {
     CachedCommit(gix_commitgraph::file::Commit<'cache>),
 }
 
+impl Either<'_, '_> {
+    /// Get a commits `tree_id` by either getting it from a [`gix_commitgraph::Graph`], if
+    /// present, or a [`gix_object::CommitRefIter`] otherwise.
+    pub fn tree_id(self) -> Result<ObjectId, gix_object::decode::Error> {
+        match self {
+            Self::CommitRefIter(mut commit_ref_iter) => commit_ref_iter.tree_id(),
+            Self::CachedCommit(commit) => Ok(commit.root_tree_id().into()),
+        }
+    }
+}
+
 /// Find information about a commit by either getting it from a [`gix_commitgraph::Graph`], if
 /// present, or a [`gix_object::CommitRefIter`] otherwise.
 pub fn find<'cache, 'buf, Find>(