diff --git a/lib/src/commit_builder.rs b/lib/src/commit_builder.rs
index da4e2fcaa..a2dea2ef3 100644
--- a/lib/src/commit_builder.rs
+++ b/lib/src/commit_builder.rs
@@ -16,7 +16,7 @@ use std::sync::Arc;
 
 use crate::backend::{self, BackendResult, ChangeId, CommitId, Signature, TreeId};
 use crate::commit::Commit;
-use crate::repo::MutableRepo;
+use crate::repo::{MutableRepo, Repo};
 use crate::settings::{JJRng, UserSettings};
 
 #[must_use]
diff --git a/lib/src/git.rs b/lib/src/git.rs
index 19f400329..5cb79158a 100644
--- a/lib/src/git.rs
+++ b/lib/src/git.rs
@@ -23,9 +23,8 @@ use thiserror::Error;
 use crate::backend::{CommitId, ObjectId};
 use crate::commit::Commit;
 use crate::git_backend::NO_GC_REF_NAMESPACE;
-use crate::index::Index;
 use crate::op_store::RefTarget;
-use crate::repo::MutableRepo;
+use crate::repo::{MutableRepo, Repo};
 use crate::settings::GitSettings;
 use crate::view::RefName;
 
diff --git a/lib/src/repo.rs b/lib/src/repo.rs
index ba45ffcf8..3a7b12bc1 100644
--- a/lib/src/repo.rs
+++ b/lib/src/repo.rs
@@ -49,6 +49,32 @@ use crate::transaction::Transaction;
 use crate::view::{RefName, View};
 use crate::{backend, op_store};
 
+pub trait Repo {
+    fn base_repo(&self) -> &Arc<ReadonlyRepo>;
+
+    fn store(&self) -> &Arc<Store>;
+
+    fn op_store(&self) -> &Arc<dyn OpStore>;
+
+    fn index(&self) -> &dyn Index;
+
+    fn view(&self) -> &View;
+
+    fn resolve_change_id(&self, change_id: &ChangeId) -> Option<Vec<IndexEntry>> {
+        // Replace this if we added more efficient lookup method.
+        let prefix = HexPrefix::from_bytes(change_id.as_bytes());
+        match self.resolve_change_id_prefix(&prefix) {
+            PrefixResolution::NoMatch => None,
+            PrefixResolution::SingleMatch(entries) => Some(entries),
+            PrefixResolution::AmbiguousMatch => panic!("complete change_id should be unambiguous"),
+        }
+    }
+
+    fn resolve_change_id_prefix(&self, prefix: &HexPrefix) -> PrefixResolution<Vec<IndexEntry>>;
+
+    fn shortest_unique_change_id_prefix_len(&self, target_id_bytes: &ChangeId) -> usize;
+}
+
 // TODO: Should we implement From<&ReadonlyRepo> and From<&MutableRepo> for
 // RepoRef?
 #[derive(Clone, Copy)]
@@ -116,7 +142,7 @@ impl<'a> RepoRef<'a> {
     pub fn shortest_unique_change_id_prefix_len(&self, target_id: &ChangeId) -> usize {
         match self {
             RepoRef::Readonly(repo) => repo.shortest_unique_change_id_prefix_len(target_id),
-            RepoRef::Mutable(_) => target_id.as_bytes().len() * 2, // TODO
+            RepoRef::Mutable(repo) => repo.shortest_unique_change_id_prefix_len(target_id),
         }
     }
 }
@@ -272,14 +298,10 @@ impl ReadonlyRepo {
         })
     }
 
-    pub fn index(&self) -> &dyn Index {
-        self.readonly_index().as_ref()
-    }
-
     fn change_id_index(&self) -> &ChangeIdIndex {
         self.change_id_index.get_or_init(|| {
             let heads = self.view().heads().iter().cloned().collect_vec();
-            let walk = self.index().walk_revs(&heads, &[]);
+            let walk = self.readonly_index().walk_revs(&heads, &[]);
             IdIndex::from_vec(
                 walk.map(|entry| (entry.change_id(), entry.position()))
                     .collect(),
@@ -287,27 +309,6 @@ impl ReadonlyRepo {
         })
     }
 
-    pub fn resolve_change_id_prefix(
-        &self,
-        prefix: &HexPrefix,
-    ) -> PrefixResolution<Vec<IndexEntry>> {
-        let index = self.index();
-        self.change_id_index()
-            .resolve_prefix_with(prefix, |&pos| index.entry_by_pos(pos))
-    }
-
-    pub fn shortest_unique_change_id_prefix_len(&self, target_id: &ChangeId) -> usize {
-        self.change_id_index().shortest_unique_prefix_len(target_id)
-    }
-
-    pub fn store(&self) -> &Arc<Store> {
-        &self.store
-    }
-
-    pub fn op_store(&self) -> &Arc<dyn OpStore> {
-        &self.op_store
-    }
-
     pub fn op_heads_store(&self) -> &Arc<dyn OpHeadsStore> {
         &self.op_heads_store
     }
@@ -341,6 +342,38 @@ impl ReadonlyRepo {
     }
 }
 
+impl Repo for Arc<ReadonlyRepo> {
+    fn base_repo(&self) -> &Arc<ReadonlyRepo> {
+        self
+    }
+
+    fn store(&self) -> &Arc<Store> {
+        &self.store
+    }
+
+    fn op_store(&self) -> &Arc<dyn OpStore> {
+        &self.op_store
+    }
+
+    fn index(&self) -> &dyn Index {
+        self.readonly_index().as_ref()
+    }
+
+    fn view(&self) -> &View {
+        &self.view
+    }
+
+    fn resolve_change_id_prefix(&self, prefix: &HexPrefix) -> PrefixResolution<Vec<IndexEntry>> {
+        let index = self.index();
+        self.change_id_index()
+            .resolve_prefix_with(prefix, |&pos| index.entry_by_pos(pos))
+    }
+
+    fn shortest_unique_change_id_prefix_len(&self, target_id: &ChangeId) -> usize {
+        self.change_id_index().shortest_unique_prefix_len(target_id)
+    }
+}
+
 type BackendFactory = Box<dyn Fn(&Path) -> Box<dyn Backend>>;
 type OpStoreFactory = Box<dyn Fn(&Path) -> Box<dyn OpStore>>;
 type OpHeadsStoreFactory = Box<dyn Fn(&Path) -> Box<dyn OpHeadsStore>>;
@@ -625,27 +658,6 @@ impl MutableRepo {
         RepoRef::Mutable(self)
     }
 
-    pub fn base_repo(&self) -> &Arc<ReadonlyRepo> {
-        &self.base_repo
-    }
-
-    pub fn store(&self) -> &Arc<Store> {
-        self.base_repo.store()
-    }
-
-    pub fn op_store(&self) -> &Arc<dyn OpStore> {
-        self.base_repo.op_store()
-    }
-
-    pub fn index(&self) -> &MutableIndex {
-        &self.index
-    }
-
-    pub fn view(&self) -> &View {
-        self.view
-            .get_or_ensure_clean(|v| self.enforce_view_invariants(v))
-    }
-
     fn view_mut(&mut self) -> &mut View {
         self.view.get_mut()
     }
@@ -661,31 +673,6 @@ impl MutableRepo {
         (self.index, self.view.into_inner())
     }
 
-    pub fn resolve_change_id_prefix<'a>(
-        &'a self,
-        prefix: &HexPrefix,
-    ) -> PrefixResolution<Vec<IndexEntry<'a>>> {
-        // TODO: Create a persistent lookup from change id to (visible?) commit ids.
-        let mut found_change_id = None;
-        let mut found_entries = vec![];
-        let heads = self.view().heads().iter().cloned().collect_vec();
-        for entry in self.index().walk_revs(&heads, &[]) {
-            let change_id = entry.change_id();
-            if prefix.matches(&change_id) {
-                if let Some(previous_change_id) = found_change_id.replace(change_id.clone()) {
-                    if previous_change_id != change_id {
-                        return PrefixResolution::AmbiguousMatch;
-                    }
-                }
-                found_entries.push(entry);
-            }
-        }
-        if found_change_id.is_none() {
-            return PrefixResolution::NoMatch;
-        }
-        PrefixResolution::SingleMatch(found_entries)
-    }
-
     pub fn new_commit(
         &mut self,
         settings: &UserSettings,
@@ -1157,6 +1144,55 @@ impl MutableRepo {
     }
 }
 
+impl Repo for MutableRepo {
+    fn base_repo(&self) -> &Arc<ReadonlyRepo> {
+        &self.base_repo
+    }
+
+    fn store(&self) -> &Arc<Store> {
+        self.base_repo.store()
+    }
+
+    fn op_store(&self) -> &Arc<dyn OpStore> {
+        self.base_repo.op_store()
+    }
+
+    fn index(&self) -> &dyn Index {
+        &self.index
+    }
+
+    fn view(&self) -> &View {
+        self.view
+            .get_or_ensure_clean(|v| self.enforce_view_invariants(v))
+    }
+
+    fn resolve_change_id_prefix(&self, prefix: &HexPrefix) -> PrefixResolution<Vec<IndexEntry>> {
+        // TODO: Create a persistent lookup from change id to (visible?) commit ids.
+        let mut found_change_id = None;
+        let mut found_entries = vec![];
+        let heads = self.view().heads().iter().cloned().collect_vec();
+        for entry in self.index().walk_revs(&heads, &[]) {
+            let change_id = entry.change_id();
+            if prefix.matches(&change_id) {
+                if let Some(previous_change_id) = found_change_id.replace(change_id.clone()) {
+                    if previous_change_id != change_id {
+                        return PrefixResolution::AmbiguousMatch;
+                    }
+                }
+                found_entries.push(entry);
+            }
+        }
+        if found_change_id.is_none() {
+            return PrefixResolution::NoMatch;
+        }
+        PrefixResolution::SingleMatch(found_entries)
+    }
+
+    fn shortest_unique_change_id_prefix_len(&self, target_id: &ChangeId) -> usize {
+        target_id.as_bytes().len() * 2 // TODO
+    }
+}
+
 /// Error from attempts to check out the root commit for editing
 #[derive(Debug, Error)]
 #[error("Cannot rewrite the root commit")]
diff --git a/lib/src/rewrite.rs b/lib/src/rewrite.rs
index 19ee5364f..7f645b916 100644
--- a/lib/src/rewrite.rs
+++ b/lib/src/rewrite.rs
@@ -19,9 +19,8 @@ use itertools::{process_results, Itertools};
 use crate::backend::{BackendError, BackendResult, CommitId, ObjectId};
 use crate::commit::Commit;
 use crate::dag_walk;
-use crate::index::Index;
 use crate::op_store::RefTarget;
-use crate::repo::{MutableRepo, RepoRef};
+use crate::repo::{MutableRepo, Repo, RepoRef};
 use crate::repo_path::RepoPath;
 use crate::revset::RevsetExpression;
 use crate::settings::UserSettings;
diff --git a/lib/src/transaction.rs b/lib/src/transaction.rs
index 9e096af4c..7f2002ab9 100644
--- a/lib/src/transaction.rs
+++ b/lib/src/transaction.rs
@@ -20,7 +20,7 @@ use crate::index::ReadonlyIndex;
 use crate::op_store;
 use crate::op_store::OperationMetadata;
 use crate::operation::Operation;
-use crate::repo::{MutableRepo, ReadonlyRepo, RepoLoader};
+use crate::repo::{MutableRepo, ReadonlyRepo, Repo, RepoLoader};
 use crate::settings::UserSettings;
 use crate::view::View;
 
diff --git a/lib/src/workspace.rs b/lib/src/workspace.rs
index a57dc993f..eb2a11f1d 100644
--- a/lib/src/workspace.rs
+++ b/lib/src/workspace.rs
@@ -26,7 +26,7 @@ use crate::op_heads_store::OpHeadsStore;
 use crate::op_store::{self, OpStore, OperationMetadata, WorkspaceId};
 use crate::operation::Operation;
 use crate::repo::{
-    CheckOutCommitError, IoResultExt, PathError, ReadonlyRepo, RepoLoader, StoreFactories,
+    CheckOutCommitError, IoResultExt, PathError, ReadonlyRepo, Repo, RepoLoader, StoreFactories,
 };
 use crate::settings::UserSettings;
 use crate::working_copy::WorkingCopy;
diff --git a/lib/tests/test_bad_locking.rs b/lib/tests/test_bad_locking.rs
index b70c89c38..4a837a973 100644
--- a/lib/tests/test_bad_locking.rs
+++ b/lib/tests/test_bad_locking.rs
@@ -14,7 +14,7 @@
 
 use std::path::Path;
 
-use jujutsu_lib::repo::{ReadonlyRepo, StoreFactories};
+use jujutsu_lib::repo::{ReadonlyRepo, Repo, StoreFactories};
 use jujutsu_lib::workspace::Workspace;
 use test_case::test_case;
 use testutils::{create_random_commit, TestWorkspace};
diff --git a/lib/tests/test_commit_builder.rs b/lib/tests/test_commit_builder.rs
index 5f2185587..ff44a508e 100644
--- a/lib/tests/test_commit_builder.rs
+++ b/lib/tests/test_commit_builder.rs
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 use jujutsu_lib::matchers::EverythingMatcher;
+use jujutsu_lib::repo::Repo;
 use jujutsu_lib::repo_path::RepoPath;
 use jujutsu_lib::settings::UserSettings;
 use jujutsu_lib::tree::DiffSummary;
diff --git a/lib/tests/test_commit_concurrent.rs b/lib/tests/test_commit_concurrent.rs
index 251e6512b..46123587a 100644
--- a/lib/tests/test_commit_concurrent.rs
+++ b/lib/tests/test_commit_concurrent.rs
@@ -13,14 +13,15 @@
 // limitations under the License.
 
 use std::cmp::max;
+use std::sync::Arc;
 use std::thread;
 
 use jujutsu_lib::dag_walk;
-use jujutsu_lib::repo::{ReadonlyRepo, StoreFactories};
+use jujutsu_lib::repo::{ReadonlyRepo, Repo, StoreFactories};
 use test_case::test_case;
 use testutils::{write_random_commit, TestWorkspace};
 
-fn count_non_merge_operations(repo: &ReadonlyRepo) -> usize {
+fn count_non_merge_operations(repo: &Arc<ReadonlyRepo>) -> usize {
     let op_store = repo.op_store();
     let op_id = repo.op_id().clone();
     let mut num_ops = 0;
diff --git a/lib/tests/test_conflicts.rs b/lib/tests/test_conflicts.rs
index 96759bf3f..47c48860b 100644
--- a/lib/tests/test_conflicts.rs
+++ b/lib/tests/test_conflicts.rs
@@ -15,6 +15,7 @@
 use jujutsu_lib::backend::{Conflict, ConflictPart, TreeValue};
 use jujutsu_lib::conflicts::{materialize_conflict, parse_conflict, update_conflict_from_content};
 use jujutsu_lib::files::{ConflictHunk, MergeHunk};
+use jujutsu_lib::repo::Repo;
 use jujutsu_lib::repo_path::RepoPath;
 use jujutsu_lib::store::Store;
 use testutils::TestRepo;
diff --git a/lib/tests/test_git.rs b/lib/tests/test_git.rs
index 6b11a6cd8..ec26df066 100644
--- a/lib/tests/test_git.rs
+++ b/lib/tests/test_git.rs
@@ -23,7 +23,7 @@ use jujutsu_lib::git;
 use jujutsu_lib::git::{GitFetchError, GitPushError, GitRefUpdate};
 use jujutsu_lib::git_backend::GitBackend;
 use jujutsu_lib::op_store::{BranchTarget, RefTarget};
-use jujutsu_lib::repo::ReadonlyRepo;
+use jujutsu_lib::repo::{ReadonlyRepo, Repo};
 use jujutsu_lib::settings::{GitSettings, UserSettings};
 use maplit::{btreemap, hashset};
 use tempfile::TempDir;
diff --git a/lib/tests/test_index.rs b/lib/tests/test_index.rs
index 34afa9ff8..121b12142 100644
--- a/lib/tests/test_index.rs
+++ b/lib/tests/test_index.rs
@@ -17,8 +17,8 @@ use std::sync::Arc;
 use jujutsu_lib::backend::CommitId;
 use jujutsu_lib::commit::Commit;
 use jujutsu_lib::commit_builder::CommitBuilder;
-use jujutsu_lib::index::{Index};
-use jujutsu_lib::repo::{MutableRepo, ReadonlyRepo, StoreFactories};
+use jujutsu_lib::index::Index;
+use jujutsu_lib::repo::{MutableRepo, ReadonlyRepo, Repo, StoreFactories};
 use jujutsu_lib::settings::UserSettings;
 use test_case::test_case;
 use testutils::{create_random_commit, write_random_commit, CommitGraphBuilder, TestRepo};
@@ -446,7 +446,7 @@ fn create_n_commits(
     tx.commit()
 }
 
-fn commits_by_level(repo: &ReadonlyRepo) -> Vec<u32> {
+fn commits_by_level(repo: &Arc<ReadonlyRepo>) -> Vec<u32> {
     repo.index()
         .stats()
         .levels
diff --git a/lib/tests/test_init.rs b/lib/tests/test_init.rs
index 38a549534..98bd68656 100644
--- a/lib/tests/test_init.rs
+++ b/lib/tests/test_init.rs
@@ -15,6 +15,7 @@
 use std::path::{Path, PathBuf};
 
 use jujutsu_lib::op_store::WorkspaceId;
+use jujutsu_lib::repo::Repo;
 use jujutsu_lib::settings::UserSettings;
 use jujutsu_lib::workspace::Workspace;
 use test_case::test_case;
diff --git a/lib/tests/test_merge_trees.rs b/lib/tests/test_merge_trees.rs
index 5027be8f0..1fa9d701c 100644
--- a/lib/tests/test_merge_trees.rs
+++ b/lib/tests/test_merge_trees.rs
@@ -15,6 +15,7 @@
 use assert_matches::assert_matches;
 use itertools::Itertools;
 use jujutsu_lib::backend::{ConflictPart, TreeValue};
+use jujutsu_lib::repo::Repo;
 use jujutsu_lib::repo_path::{RepoPath, RepoPathComponent};
 use jujutsu_lib::rewrite::rebase_commit;
 use jujutsu_lib::tree;
diff --git a/lib/tests/test_mut_repo.rs b/lib/tests/test_mut_repo.rs
index c9a0acd60..3fb51bf5d 100644
--- a/lib/tests/test_mut_repo.rs
+++ b/lib/tests/test_mut_repo.rs
@@ -12,8 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use jujutsu_lib::index::Index;
 use jujutsu_lib::op_store::{RefTarget, WorkspaceId};
+use jujutsu_lib::repo::Repo;
 use maplit::hashset;
 use test_case::test_case;
 use testutils::{
diff --git a/lib/tests/test_operations.rs b/lib/tests/test_operations.rs
index 0a18ad7fa..50c5c95e6 100644
--- a/lib/tests/test_operations.rs
+++ b/lib/tests/test_operations.rs
@@ -15,7 +15,7 @@
 use std::path::Path;
 
 use jujutsu_lib::backend::CommitId;
-use jujutsu_lib::repo::RepoRef;
+use jujutsu_lib::repo::{Repo, RepoRef};
 use test_case::test_case;
 use testutils::{create_random_commit, write_random_commit, TestRepo};
 
diff --git a/lib/tests/test_refs.rs b/lib/tests/test_refs.rs
index f4937235a..9cac5f8dd 100644
--- a/lib/tests/test_refs.rs
+++ b/lib/tests/test_refs.rs
@@ -14,6 +14,7 @@
 
 use jujutsu_lib::op_store::RefTarget;
 use jujutsu_lib::refs::merge_ref_targets;
+use jujutsu_lib::repo::Repo;
 use testutils::{CommitGraphBuilder, TestWorkspace};
 
 #[test]
diff --git a/lib/tests/test_revset.rs b/lib/tests/test_revset.rs
index 81bf594c8..c65c99f17 100644
--- a/lib/tests/test_revset.rs
+++ b/lib/tests/test_revset.rs
@@ -19,7 +19,7 @@ use jujutsu_lib::backend::{CommitId, MillisSinceEpoch, ObjectId, Signature, Time
 use jujutsu_lib::git;
 use jujutsu_lib::matchers::{FilesMatcher, Matcher};
 use jujutsu_lib::op_store::{RefTarget, WorkspaceId};
-use jujutsu_lib::repo::RepoRef;
+use jujutsu_lib::repo::{Repo, RepoRef};
 use jujutsu_lib::repo_path::RepoPath;
 use jujutsu_lib::revset::{
     self, optimize, parse, resolve_symbol, RevsetAliasesMap, RevsetError, RevsetExpression,
diff --git a/lib/tests/test_revset_graph_iterator.rs b/lib/tests/test_revset_graph_iterator.rs
index e706cc981..761317564 100644
--- a/lib/tests/test_revset_graph_iterator.rs
+++ b/lib/tests/test_revset_graph_iterator.rs
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 use itertools::Itertools;
+use jujutsu_lib::repo::Repo;
 use jujutsu_lib::revset::revset_for_commits;
 use jujutsu_lib::revset_graph_iterator::RevsetGraphEdge;
 use test_case::test_case;
diff --git a/lib/tests/test_rewrite.rs b/lib/tests/test_rewrite.rs
index 22964f87b..1f56c56b3 100644
--- a/lib/tests/test_rewrite.rs
+++ b/lib/tests/test_rewrite.rs
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 use jujutsu_lib::op_store::{RefTarget, WorkspaceId};
+use jujutsu_lib::repo::Repo;
 use jujutsu_lib::repo_path::RepoPath;
 use jujutsu_lib::rewrite::DescendantRebaser;
 use maplit::{hashmap, hashset};
diff --git a/lib/tests/test_view.rs b/lib/tests/test_view.rs
index b131749c5..4244f9cbd 100644
--- a/lib/tests/test_view.rs
+++ b/lib/tests/test_view.rs
@@ -15,7 +15,7 @@
 use std::sync::Arc;
 
 use jujutsu_lib::op_store::{BranchTarget, RefTarget, WorkspaceId};
-use jujutsu_lib::repo::ReadonlyRepo;
+use jujutsu_lib::repo::{ReadonlyRepo, Repo};
 use jujutsu_lib::settings::UserSettings;
 use jujutsu_lib::transaction::Transaction;
 use maplit::{btreemap, hashset};
diff --git a/lib/tests/test_working_copy.rs b/lib/tests/test_working_copy.rs
index 9f4fbd2a0..07af30825 100644
--- a/lib/tests/test_working_copy.rs
+++ b/lib/tests/test_working_copy.rs
@@ -26,7 +26,7 @@ use jujutsu_lib::gitignore::GitIgnoreFile;
 #[cfg(unix)]
 use jujutsu_lib::op_store::OperationId;
 use jujutsu_lib::op_store::WorkspaceId;
-use jujutsu_lib::repo::ReadonlyRepo;
+use jujutsu_lib::repo::{ReadonlyRepo, Repo};
 use jujutsu_lib::repo_path::{RepoPath, RepoPathComponent, RepoPathJoin};
 use jujutsu_lib::settings::UserSettings;
 use jujutsu_lib::tree_builder::TreeBuilder;
diff --git a/lib/tests/test_working_copy_concurrent.rs b/lib/tests/test_working_copy_concurrent.rs
index 6f1268f39..2b36864a9 100644
--- a/lib/tests/test_working_copy_concurrent.rs
+++ b/lib/tests/test_working_copy_concurrent.rs
@@ -17,7 +17,7 @@ use std::thread;
 
 use assert_matches::assert_matches;
 use jujutsu_lib::gitignore::GitIgnoreFile;
-use jujutsu_lib::repo::StoreFactories;
+use jujutsu_lib::repo::{Repo, StoreFactories};
 use jujutsu_lib::repo_path::RepoPath;
 use jujutsu_lib::working_copy::CheckoutError;
 use jujutsu_lib::workspace::Workspace;
diff --git a/lib/tests/test_working_copy_sparse.rs b/lib/tests/test_working_copy_sparse.rs
index 06b7728a7..43eb3a85f 100644
--- a/lib/tests/test_working_copy_sparse.rs
+++ b/lib/tests/test_working_copy_sparse.rs
@@ -15,6 +15,7 @@
 use itertools::Itertools;
 use jujutsu_lib::gitignore::GitIgnoreFile;
 use jujutsu_lib::matchers::EverythingMatcher;
+use jujutsu_lib::repo::Repo;
 use jujutsu_lib::repo_path::RepoPath;
 use jujutsu_lib::working_copy::{CheckoutStats, WorkingCopy};
 use testutils::TestWorkspace;
diff --git a/lib/tests/test_workspace.rs b/lib/tests/test_workspace.rs
index 38422bdbd..13537ea97 100644
--- a/lib/tests/test_workspace.rs
+++ b/lib/tests/test_workspace.rs
@@ -14,7 +14,7 @@
 
 use assert_matches::assert_matches;
 use jujutsu_lib::op_store::WorkspaceId;
-use jujutsu_lib::repo::StoreFactories;
+use jujutsu_lib::repo::{Repo, StoreFactories};
 use jujutsu_lib::workspace::{Workspace, WorkspaceLoadError};
 use test_case::test_case;
 use testutils::TestWorkspace;
diff --git a/lib/testutils/src/lib.rs b/lib/testutils/src/lib.rs
index 1880f240b..2e2c7a058 100644
--- a/lib/testutils/src/lib.rs
+++ b/lib/testutils/src/lib.rs
@@ -24,7 +24,7 @@ use jujutsu_lib::commit::Commit;
 use jujutsu_lib::commit_builder::CommitBuilder;
 use jujutsu_lib::git_backend::GitBackend;
 use jujutsu_lib::local_backend::LocalBackend;
-use jujutsu_lib::repo::{MutableRepo, ReadonlyRepo};
+use jujutsu_lib::repo::{MutableRepo, ReadonlyRepo, Repo};
 use jujutsu_lib::repo_path::RepoPath;
 use jujutsu_lib::rewrite::RebasedDescendant;
 use jujutsu_lib::settings::UserSettings;
@@ -189,7 +189,7 @@ pub fn write_symlink(tree_builder: &mut TreeBuilder, path: &RepoPath, target: &s
     tree_builder.set(path.clone(), TreeValue::Symlink(id));
 }
 
-pub fn create_tree(repo: &ReadonlyRepo, path_contents: &[(&RepoPath, &str)]) -> Tree {
+pub fn create_tree(repo: &Arc<ReadonlyRepo>, path_contents: &[(&RepoPath, &str)]) -> Tree {
     let store = repo.store();
     let mut tree_builder = store.tree_builder(store.empty_tree_id().clone());
     for (path, contents) in path_contents {
@@ -200,7 +200,7 @@ pub fn create_tree(repo: &ReadonlyRepo, path_contents: &[(&RepoPath, &str)]) ->
 }
 
 #[must_use]
-pub fn create_random_tree(repo: &ReadonlyRepo) -> TreeId {
+pub fn create_random_tree(repo: &Arc<ReadonlyRepo>) -> TreeId {
     let mut tree_builder = repo
         .store()
         .tree_builder(repo.store().empty_tree_id().clone());
diff --git a/src/cli_util.rs b/src/cli_util.rs
index 6969331ee..9e10b506a 100644
--- a/src/cli_util.rs
+++ b/src/cli_util.rs
@@ -33,13 +33,12 @@ use jujutsu_lib::commit::Commit;
 use jujutsu_lib::git::{GitExportError, GitImportError};
 use jujutsu_lib::gitignore::GitIgnoreFile;
 use jujutsu_lib::hex_util::to_reverse_hex;
-use jujutsu_lib::index::Index;
 use jujutsu_lib::matchers::{EverythingMatcher, Matcher, PrefixMatcher, Visit};
 use jujutsu_lib::op_heads_store::{self, OpHeadResolutionError, OpHeadsStore};
 use jujutsu_lib::op_store::{OpStore, OpStoreError, OperationId, RefTarget, WorkspaceId};
 use jujutsu_lib::operation::Operation;
 use jujutsu_lib::repo::{
-    CheckOutCommitError, EditCommitError, MutableRepo, ReadonlyRepo, RepoLoader, RepoRef,
+    CheckOutCommitError, EditCommitError, MutableRepo, ReadonlyRepo, Repo, RepoLoader, RepoRef,
     RewriteRootCommit, StoreFactories,
 };
 use jujutsu_lib::repo_path::{FsPathParseError, RepoPath};
diff --git a/src/commands/branch.rs b/src/commands/branch.rs
index af456085e..d6bb03376 100644
--- a/src/commands/branch.rs
+++ b/src/commands/branch.rs
@@ -4,7 +4,7 @@ use clap::builder::NonEmptyStringValueParser;
 use itertools::Itertools;
 use jujutsu_lib::backend::{CommitId, ObjectId};
 use jujutsu_lib::op_store::RefTarget;
-use jujutsu_lib::repo::RepoRef;
+use jujutsu_lib::repo::{Repo, RepoRef};
 use jujutsu_lib::view::View;
 
 use crate::cli_util::{user_error, user_error_with_hint, CommandError, CommandHelper, RevisionArg};
diff --git a/src/commands/git.rs b/src/commands/git.rs
index 1c33a1dad..0b65f09be 100644
--- a/src/commands/git.rs
+++ b/src/commands/git.rs
@@ -12,7 +12,7 @@ use jujutsu_lib::backend::ObjectId;
 use jujutsu_lib::git::{self, GitFetchError, GitRefUpdate};
 use jujutsu_lib::op_store::{BranchTarget, RefTarget};
 use jujutsu_lib::refs::{classify_branch_push_action, BranchPushAction, BranchPushUpdate};
-use jujutsu_lib::repo::RepoRef;
+use jujutsu_lib::repo::{Repo, RepoRef};
 use jujutsu_lib::settings::UserSettings;
 use jujutsu_lib::store::Store;
 use jujutsu_lib::view::View;
diff --git a/src/commands/mod.rs b/src/commands/mod.rs
index bc7897a30..b7dd85cd2 100644
--- a/src/commands/mod.rs
+++ b/src/commands/mod.rs
@@ -20,6 +20,7 @@ use std::collections::{BTreeMap, HashSet};
 use std::fmt::Debug;
 use std::io::{Read, Seek, SeekFrom, Write};
 use std::path::PathBuf;
+use std::sync::Arc;
 use std::{fs, io};
 
 use clap::builder::NonEmptyStringValueParser;
@@ -32,7 +33,7 @@ use jujutsu_lib::dag_walk::topo_order_reverse;
 use jujutsu_lib::index::{Index, IndexEntry};
 use jujutsu_lib::matchers::EverythingMatcher;
 use jujutsu_lib::op_store::{RefTarget, WorkspaceId};
-use jujutsu_lib::repo::ReadonlyRepo;
+use jujutsu_lib::repo::{ReadonlyRepo, Repo};
 use jujutsu_lib::repo_path::RepoPath;
 use jujutsu_lib::revset::{RevsetAliasesMap, RevsetExpression};
 use jujutsu_lib::revset_graph_iterator::{RevsetGraphEdge, RevsetGraphEdgeType};
@@ -2917,7 +2918,7 @@ fn rebase_revision(
 }
 
 fn check_rebase_destinations(
-    repo: &ReadonlyRepo,
+    repo: &Arc<ReadonlyRepo>,
     new_parents: &[Commit],
     commit: &Commit,
 ) -> Result<(), CommandError> {
diff --git a/src/diff_util.rs b/src/diff_util.rs
index e752b1188..ee8167886 100644
--- a/src/diff_util.rs
+++ b/src/diff_util.rs
@@ -23,7 +23,7 @@ use jujutsu_lib::commit::Commit;
 use jujutsu_lib::diff::{Diff, DiffHunk};
 use jujutsu_lib::files::DiffLine;
 use jujutsu_lib::matchers::Matcher;
-use jujutsu_lib::repo::ReadonlyRepo;
+use jujutsu_lib::repo::{ReadonlyRepo, Repo};
 use jujutsu_lib::repo_path::RepoPath;
 use jujutsu_lib::settings::UserSettings;
 use jujutsu_lib::tree::{Tree, TreeDiffIterator};