diff --git a/examples/custom-backend/main.rs b/examples/custom-backend/main.rs
index 2210fc06c..af7735ac8 100644
--- a/examples/custom-backend/main.rs
+++ b/examples/custom-backend/main.rs
@@ -92,8 +92,8 @@ impl Backend for JitBackend {
         "jit"
     }
 
-    fn hash_length(&self) -> usize {
-        self.inner.hash_length()
+    fn commit_id_length(&self) -> usize {
+        self.inner.commit_id_length()
     }
 
     fn git_repo(&self) -> Option<Repository> {
diff --git a/lib/src/backend.rs b/lib/src/backend.rs
index b1bbff7b7..ee3300206 100644
--- a/lib/src/backend.rs
+++ b/lib/src/backend.rs
@@ -383,7 +383,8 @@ pub trait Backend: Send + Sync + Debug {
     /// `.jj/repo/store/backend` when the repo is created.
     fn name(&self) -> &str;
 
-    fn hash_length(&self) -> usize;
+    /// The length of commit IDs in bytes.
+    fn commit_id_length(&self) -> usize;
 
     fn git_repo(&self) -> Option<git2::Repository>;
 
diff --git a/lib/src/git_backend.rs b/lib/src/git_backend.rs
index 0af6047fb..011d0cbaf 100644
--- a/lib/src/git_backend.rs
+++ b/lib/src/git_backend.rs
@@ -187,7 +187,7 @@ impl Backend for GitBackend {
         "git"
     }
 
-    fn hash_length(&self) -> usize {
+    fn commit_id_length(&self) -> usize {
         HASH_LENGTH
     }
 
diff --git a/lib/src/index.rs b/lib/src/index.rs
index 52d639538..48b33bfe9 100644
--- a/lib/src/index.rs
+++ b/lib/src/index.rs
@@ -158,14 +158,14 @@ impl<'a> IndexRef<'a> {
 
 struct CommitGraphEntry<'a> {
     data: &'a [u8],
-    hash_length: usize,
+    commit_id_length: usize,
 }
 
 // TODO: Add pointers to ancestors further back, like a skip list. Clear the
 // lowest set bit to determine which generation number the pointers point to.
 impl CommitGraphEntry<'_> {
-    fn size(hash_length: usize) -> usize {
-        36 + hash_length
+    fn size(commit_id_length: usize) -> usize {
+        36 + commit_id_length
     }
 
     fn generation_number(&self) -> u32 {
@@ -195,18 +195,18 @@ impl CommitGraphEntry<'_> {
     }
 
     fn commit_id(&self) -> CommitId {
-        CommitId::from_bytes(&self.data[36..36 + self.hash_length])
+        CommitId::from_bytes(&self.data[36..36 + self.commit_id_length])
     }
 }
 
 struct CommitLookupEntry<'a> {
     data: &'a [u8],
-    hash_length: usize,
+    commit_id_length: usize,
 }
 
 impl CommitLookupEntry<'_> {
-    fn size(hash_length: usize) -> usize {
-        hash_length + 4
+    fn size(commit_id_length: usize) -> usize {
+        commit_id_length + 4
     }
 
     fn commit_id(&self) -> CommitId {
@@ -215,12 +215,12 @@ impl CommitLookupEntry<'_> {
 
     // might be better to add borrowed version of CommitId
     fn commit_id_bytes(&self) -> &[u8] {
-        &self.data[0..self.hash_length]
+        &self.data[0..self.commit_id_length]
     }
 
     fn pos(&self) -> IndexPosition {
         IndexPosition(
-            (&self.data[self.hash_length..self.hash_length + 4])
+            (&self.data[self.commit_id_length..self.commit_id_length + 4])
                 .read_u32::<LittleEndian>()
                 .unwrap(),
         )
@@ -255,7 +255,7 @@ pub struct ReadonlyIndex {
     parent_file: Option<Arc<ReadonlyIndex>>,
     num_parent_commits: u32,
     name: String,
-    hash_length: usize,
+    commit_id_length: usize,
     commit_graph_entry_size: usize,
     commit_lookup_entry_size: usize,
     // Number of commits not counting the parent file
@@ -373,17 +373,17 @@ struct MutableGraphEntry {
 pub struct MutableIndex {
     parent_file: Option<Arc<ReadonlyIndex>>,
     num_parent_commits: u32,
-    hash_length: usize,
+    commit_id_length: usize,
     graph: Vec<MutableGraphEntry>,
     lookup: BTreeMap<CommitId, IndexPosition>,
 }
 
 impl MutableIndex {
-    pub(crate) fn full(hash_length: usize) -> Self {
+    pub(crate) fn full(commit_id_length: usize) -> Self {
         Self {
             parent_file: None,
             num_parent_commits: 0,
-            hash_length,
+            commit_id_length,
             graph: vec![],
             lookup: BTreeMap::new(),
         }
@@ -391,11 +391,11 @@ impl MutableIndex {
 
     pub fn incremental(parent_file: Arc<ReadonlyIndex>) -> Self {
         let num_parent_commits = parent_file.num_parent_commits + parent_file.num_local_commits;
-        let hash_length = parent_file.hash_length;
+        let commit_id_length = parent_file.commit_id_length;
         Self {
             parent_file: Some(parent_file),
             num_parent_commits,
-            hash_length,
+            commit_id_length,
             graph: vec![],
             lookup: BTreeMap::new(),
         }
@@ -534,7 +534,7 @@ impl MutableIndex {
             assert_eq!(entry.change_id.as_bytes().len(), 16);
             buf.write_all(entry.change_id.as_bytes()).unwrap();
 
-            assert_eq!(entry.commit_id.as_bytes().len(), self.hash_length);
+            assert_eq!(entry.commit_id.as_bytes().len(), self.commit_id_length);
             buf.write_all(entry.commit_id.as_bytes()).unwrap();
         }
 
@@ -576,7 +576,7 @@ impl MutableIndex {
                     maybe_parent_file = parent_file.parent_file.clone();
                 }
                 None => {
-                    squashed = MutableIndex::full(self.hash_length);
+                    squashed = MutableIndex::full(self.commit_id_length);
                     break;
                 }
             }
@@ -598,7 +598,7 @@ impl MutableIndex {
             return Ok(self.parent_file.unwrap());
         }
 
-        let hash_length = self.hash_length;
+        let commit_id_length = self.commit_id_length;
 
         let buf = self.maybe_squash_with_ancestors().serialize();
         let mut hasher = Blake2b512::new();
@@ -612,14 +612,14 @@ impl MutableIndex {
         persist_content_addressed_temp_file(temp_file, index_file_path)?;
 
         let mut cursor = Cursor::new(&buf);
-        ReadonlyIndex::load_from(&mut cursor, dir, index_file_id_hex, hash_length).map_err(|err| {
-            match err {
+        ReadonlyIndex::load_from(&mut cursor, dir, index_file_id_hex, commit_id_length).map_err(
+            |err| match err {
                 IndexLoadError::IndexCorrupt(err) => {
                     panic!("Just-created index file is corrupt: {err}")
                 }
                 IndexLoadError::IoError(err) => err,
-            }
-        })
+            },
+        )
     }
 
     pub fn num_commits(&self) -> u32 {
@@ -1543,7 +1543,7 @@ impl ReadonlyIndex {
         file: &mut dyn Read,
         dir: PathBuf,
         name: String,
-        hash_length: usize,
+        commit_id_length: usize,
     ) -> Result<Arc<ReadonlyIndex>, IndexLoadError> {
         let parent_filename_len = file.read_u32::<LittleEndian>()?;
         let num_parent_commits;
@@ -1555,7 +1555,7 @@ impl ReadonlyIndex {
             let parent_file_path = dir.join(&parent_filename);
             let mut index_file = File::open(parent_file_path).unwrap();
             let parent_file =
-                ReadonlyIndex::load_from(&mut index_file, dir, parent_filename, hash_length)?;
+                ReadonlyIndex::load_from(&mut index_file, dir, parent_filename, commit_id_length)?;
             num_parent_commits = parent_file.num_parent_commits + parent_file.num_local_commits;
             maybe_parent_file = Some(parent_file);
         } else {
@@ -1566,9 +1566,9 @@ impl ReadonlyIndex {
         let num_parent_overflow_entries = file.read_u32::<LittleEndian>()?;
         let mut data = vec![];
         file.read_to_end(&mut data)?;
-        let commit_graph_entry_size = CommitGraphEntry::size(hash_length);
+        let commit_graph_entry_size = CommitGraphEntry::size(commit_id_length);
         let graph_size = (num_commits as usize) * commit_graph_entry_size;
-        let commit_lookup_entry_size = CommitLookupEntry::size(hash_length);
+        let commit_lookup_entry_size = CommitLookupEntry::size(commit_id_length);
         let lookup_size = (num_commits as usize) * commit_lookup_entry_size;
         let parent_overflow_size = (num_parent_overflow_entries as usize) * 4;
         let expected_size = graph_size + lookup_size + parent_overflow_size;
@@ -1582,7 +1582,7 @@ impl ReadonlyIndex {
             parent_file: maybe_parent_file,
             num_parent_commits,
             name,
-            hash_length,
+            commit_id_length,
             commit_graph_entry_size,
             commit_lookup_entry_size,
             num_local_commits: num_commits,
@@ -1662,7 +1662,7 @@ impl ReadonlyIndex {
         let offset = (local_pos as usize) * self.commit_graph_entry_size;
         CommitGraphEntry {
             data: &self.graph[offset..offset + self.commit_graph_entry_size],
-            hash_length: self.hash_length,
+            commit_id_length: self.commit_id_length,
         }
     }
 
@@ -1670,7 +1670,7 @@ impl ReadonlyIndex {
         let offset = (lookup_pos as usize) * self.commit_lookup_entry_size;
         CommitLookupEntry {
             data: &self.lookup[offset..offset + self.commit_lookup_entry_size],
-            hash_length: self.hash_length,
+            commit_id_length: self.commit_id_length,
         }
     }
 
diff --git a/lib/src/index_store.rs b/lib/src/index_store.rs
index 147824374..925bbef77 100644
--- a/lib/src/index_store.rs
+++ b/lib/src/index_store.rs
@@ -54,7 +54,7 @@ impl IndexStore {
         let op_id_hex = op.id().hex();
         let op_id_file = self.dir.join("operations").join(op_id_hex);
         if op_id_file.exists() {
-            match self.load_index_at_operation(store.hash_length(), op.id()) {
+            match self.load_index_at_operation(store.commit_id_length(), op.id()) {
                 Err(IndexLoadError::IndexCorrupt(_)) => {
                     // If the index was corrupt (maybe it was written in a different format),
                     // we just reindex.
@@ -77,7 +77,7 @@ impl IndexStore {
 
     fn load_index_at_operation(
         &self,
-        hash_length: usize,
+        commit_id_length: usize,
         op_id: &OperationId,
     ) -> Result<Arc<ReadonlyIndex>, IndexLoadError> {
         let op_id_file = self.dir.join("operations").join(op_id.hex());
@@ -93,7 +93,7 @@ impl IndexStore {
             &mut index_file,
             self.dir.clone(),
             index_file_id_hex,
-            hash_length,
+            commit_id_length,
         )
     }
 
@@ -104,7 +104,7 @@ impl IndexStore {
     ) -> io::Result<Arc<ReadonlyIndex>> {
         let view = operation.view();
         let operations_dir = self.dir.join("operations");
-        let hash_length = store.hash_length();
+        let commit_id_length = store.commit_id_length();
         let mut new_heads = view.heads().clone();
         let mut parent_op_id: Option<OperationId> = None;
         for op in dag_walk::bfs(
@@ -127,11 +127,11 @@ impl IndexStore {
         match parent_op_id {
             None => {
                 maybe_parent_file = None;
-                data = MutableIndex::full(hash_length);
+                data = MutableIndex::full(commit_id_length);
             }
             Some(parent_op_id) => {
                 let parent_file = self
-                    .load_index_at_operation(hash_length, &parent_op_id)
+                    .load_index_at_operation(commit_id_length, &parent_op_id)
                     .unwrap();
                 maybe_parent_file = Some(parent_file.clone());
                 data = MutableIndex::incremental(parent_file)
diff --git a/lib/src/local_backend.rs b/lib/src/local_backend.rs
index bed9b74a1..b8e33d5b3 100644
--- a/lib/src/local_backend.rs
+++ b/lib/src/local_backend.rs
@@ -123,7 +123,7 @@ impl Backend for LocalBackend {
         "local"
     }
 
-    fn hash_length(&self) -> usize {
+    fn commit_id_length(&self) -> usize {
         64
     }
 
diff --git a/lib/src/revset.rs b/lib/src/revset.rs
index ed223c7cd..3b6181ed5 100644
--- a/lib/src/revset.rs
+++ b/lib/src/revset.rs
@@ -86,7 +86,7 @@ fn resolve_full_commit_id(
     symbol: &str,
 ) -> Result<Option<Vec<CommitId>>, RevsetError> {
     if let Ok(binary_commit_id) = hex::decode(symbol) {
-        if repo.store().hash_length() != binary_commit_id.len() {
+        if repo.store().commit_id_length() != binary_commit_id.len() {
             return Ok(None);
         }
         let commit_id = CommitId::new(binary_commit_id);
diff --git a/lib/src/store.rs b/lib/src/store.rs
index 9ad71b8ba..6892fda06 100644
--- a/lib/src/store.rs
+++ b/lib/src/store.rs
@@ -43,8 +43,8 @@ impl Store {
         })
     }
 
-    pub fn hash_length(&self) -> usize {
-        self.backend.hash_length()
+    pub fn commit_id_length(&self) -> usize {
+        self.backend.commit_id_length()
     }
 
     pub fn git_repo(&self) -> Option<git2::Repository> {