diff --git a/lib/build.rs b/lib/build.rs
index a78929024..56e497b67 100644
--- a/lib/build.rs
+++ b/lib/build.rs
@@ -14,9 +14,10 @@
 
 extern crate protobuf_codegen_pure;
 
-use protobuf_codegen_pure::Customize;
 use std::path::Path;
 
+use protobuf_codegen_pure::Customize;
+
 fn main() {
     let out_dir = format!("{}/protos", std::env::var("OUT_DIR").unwrap());
 
diff --git a/lib/src/commit_builder.rs b/lib/src/commit_builder.rs
index 9da6e65e2..6b82ca4f2 100644
--- a/lib/src/commit_builder.rs
+++ b/lib/src/commit_builder.rs
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::sync::Arc;
+
 use uuid::Uuid;
 
 use crate::commit::Commit;
@@ -21,7 +23,6 @@ use crate::store;
 use crate::store::{ChangeId, CommitId, Signature, Timestamp, TreeId};
 use crate::store_wrapper::StoreWrapper;
 use crate::transaction::Transaction;
-use std::sync::Arc;
 
 #[derive(Debug)]
 pub struct CommitBuilder {
diff --git a/lib/src/conflicts.rs b/lib/src/conflicts.rs
index 5c12e5add..46cdcff7c 100644
--- a/lib/src/conflicts.rs
+++ b/lib/src/conflicts.rs
@@ -12,11 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::io::{Cursor, Write};
+
 use crate::files;
 use crate::repo_path::RepoPath;
 use crate::store::{Conflict, TreeValue};
 use crate::store_wrapper::StoreWrapper;
-use std::io::{Cursor, Write};
 
 pub fn materialize_conflict(
     store: &StoreWrapper,
diff --git a/lib/src/dag_walk.rs b/lib/src/dag_walk.rs
index 38f0dcd94..0d9c8dfd1 100644
--- a/lib/src/dag_walk.rs
+++ b/lib/src/dag_walk.rs
@@ -13,11 +13,11 @@
 // limitations under the License.
 
 use std::collections::HashSet;
+use std::hash::Hash;
 use std::iter::Iterator;
 
 use crate::commit::Commit;
 use crate::store::CommitId;
-use std::hash::Hash;
 
 pub struct AncestorsIter {
     bfs_iter: BfsIter<'static, 'static, Commit, CommitId, Vec<Commit>>,
diff --git a/lib/src/files.rs b/lib/src/files.rs
index 8236a7e40..599e81d80 100644
--- a/lib/src/files.rs
+++ b/lib/src/files.rs
@@ -12,10 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use diff::slice as diff_slice;
 use std::fmt::{Debug, Error, Formatter};
 use std::ops::Range;
 
+use diff::slice as diff_slice;
+
 fn is_word_byte(a: u8) -> bool {
     a.is_ascii_alphanumeric() || a == b'_'
 }
diff --git a/lib/src/git.rs b/lib/src/git.rs
index a095bccbe..9c1cf3104 100644
--- a/lib/src/git.rs
+++ b/lib/src/git.rs
@@ -12,10 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use thiserror::Error;
+
 use crate::commit::Commit;
 use crate::store::CommitId;
 use crate::transaction::Transaction;
-use thiserror::Error;
 
 #[derive(Error, Debug, PartialEq)]
 pub enum GitImportError {
diff --git a/lib/src/git_store.rs b/lib/src/git_store.rs
index 5b6fc599f..c166bab22 100644
--- a/lib/src/git_store.rs
+++ b/lib/src/git_store.rs
@@ -15,21 +15,21 @@
 use std::fmt::{Debug, Error, Formatter};
 use std::io::Cursor;
 use std::io::Read;
+use std::ops::Deref;
 use std::path::Path;
 use std::sync::Mutex;
 use std::time::Duration;
 
+use backoff::{ExponentialBackoff, Operation};
 use git2::Oid;
 use protobuf::Message;
+use uuid::Uuid;
 
 use crate::repo_path::{DirRepoPath, FileRepoPath};
 use crate::store::{
     ChangeId, Commit, CommitId, Conflict, ConflictId, ConflictPart, FileId, MillisSinceEpoch,
     Signature, Store, StoreError, StoreResult, SymlinkId, Timestamp, Tree, TreeId, TreeValue,
 };
-use backoff::{ExponentialBackoff, Operation};
-use std::ops::Deref;
-use uuid::Uuid;
 
 /// Ref namespace used only for preventing GC.
 const NO_GC_REF_NAMESPACE: &str = "refs/jj/keep/";
@@ -489,9 +489,8 @@ fn bytes_vec_from_json(value: &serde_json::Value) -> Vec<u8> {
 #[cfg(test)]
 mod tests {
 
-    use crate::store::{FileId, MillisSinceEpoch};
-
     use super::*;
+    use crate::store::{FileId, MillisSinceEpoch};
 
     #[test]
     fn read_plain_git_commit() {
diff --git a/lib/src/index.rs b/lib/src/index.rs
index 8a1708e5c..d609480ae 100644
--- a/lib/src/index.rs
+++ b/lib/src/index.rs
@@ -16,9 +16,11 @@ extern crate byteorder;
 
 use std::cmp::{max, min, Ordering};
 use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashSet};
+use std::fmt::{Debug, Formatter};
 use std::fs::File;
 use std::io;
 use std::io::{Cursor, Read, Write};
+use std::ops::Bound;
 use std::path::PathBuf;
 use std::sync::Arc;
 
@@ -27,12 +29,8 @@ use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use tempfile::NamedTempFile;
 
 use crate::commit::Commit;
-
 use crate::store::{ChangeId, CommitId};
 
-use std::fmt::{Debug, Formatter};
-use std::ops::Bound;
-
 #[derive(Clone)]
 pub enum IndexRef<'a> {
     Readonly(Arc<ReadonlyIndex>),
@@ -1485,9 +1483,9 @@ impl ReadonlyIndex {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
     use test_case::test_case;
 
+    use super::*;
     use crate::commit_builder::new_change_id;
 
     #[test_case(false; "memory")]
diff --git a/lib/src/index_store.rs b/lib/src/index_store.rs
index eed998e7d..56c45761b 100644
--- a/lib/src/index_store.rs
+++ b/lib/src/index_store.rs
@@ -12,6 +12,15 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::collections::{HashMap, HashSet};
+use std::fs::File;
+use std::io;
+use std::io::{Read, Write};
+use std::path::PathBuf;
+use std::sync::Arc;
+
+use tempfile::NamedTempFile;
+
 use crate::commit::Commit;
 use crate::dag_walk;
 use crate::index::{MutableIndex, ReadonlyIndex};
@@ -19,13 +28,6 @@ use crate::op_store::OperationId;
 use crate::operation::Operation;
 use crate::store::CommitId;
 use crate::store_wrapper::StoreWrapper;
-use std::collections::{HashMap, HashSet};
-use std::fs::File;
-use std::io;
-use std::io::{Read, Write};
-use std::path::PathBuf;
-use std::sync::Arc;
-use tempfile::NamedTempFile;
 
 pub struct IndexStore {
     dir: PathBuf,
diff --git a/lib/src/lock.rs b/lib/src/lock.rs
index 7dc527dd7..08dc938ec 100644
--- a/lib/src/lock.rs
+++ b/lib/src/lock.rs
@@ -12,11 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use backoff::{ExponentialBackoff, Operation};
 use std::fs::{File, OpenOptions};
 use std::path::PathBuf;
 use std::time::Duration;
 
+use backoff::{ExponentialBackoff, Operation};
+
 pub struct FileLock {
     path: PathBuf,
     _file: File,
diff --git a/lib/src/op_heads_store.rs b/lib/src/op_heads_store.rs
index 87738b075..22fccf3d0 100644
--- a/lib/src/op_heads_store.rs
+++ b/lib/src/op_heads_store.rs
@@ -12,19 +12,20 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::collections::HashSet;
+use std::path::PathBuf;
+use std::sync::Arc;
+
+use thiserror::Error;
+
 use crate::dag_walk;
 use crate::lock::FileLock;
 use crate::op_store;
 use crate::op_store::{OpStore, OperationId, OperationMetadata};
 use crate::operation::Operation;
-use crate::transaction::UnpublishedOperation;
-use std::path::PathBuf;
-use std::sync::Arc;
-
 use crate::repo::RepoLoader;
 use crate::store::{CommitId, Timestamp};
-use std::collections::HashSet;
-use thiserror::Error;
+use crate::transaction::UnpublishedOperation;
 
 /// Manages the very set of current heads of the operation log. The store is
 /// simply a directory where each operation id is a file with that name (and no
diff --git a/lib/src/op_store.rs b/lib/src/op_store.rs
index 7505ee61e..8d5761f9f 100644
--- a/lib/src/op_store.rs
+++ b/lib/src/op_store.rs
@@ -12,10 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::store::{CommitId, Timestamp};
 use std::collections::{BTreeMap, HashSet};
 use std::fmt::{Debug, Error, Formatter};
 
+use crate::store::{CommitId, Timestamp};
+
 #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
 pub struct ViewId(pub Vec<u8>);
 
diff --git a/lib/src/operation.rs b/lib/src/operation.rs
index 9e0cb7905..b481ae43f 100644
--- a/lib/src/operation.rs
+++ b/lib/src/operation.rs
@@ -12,15 +12,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::op_store;
-use crate::op_store::{OpStore, OperationId, ViewId};
-use crate::store::CommitId;
 use std::cmp::Ordering;
 use std::collections::HashSet;
 use std::fmt::{Debug, Error, Formatter};
 use std::hash::{Hash, Hasher};
 use std::sync::Arc;
 
+use crate::op_store;
+use crate::op_store::{OpStore, OperationId, ViewId};
+use crate::store::CommitId;
+
 #[derive(Clone)]
 pub struct Operation {
     op_store: Arc<dyn OpStore>,
diff --git a/lib/src/repo.rs b/lib/src/repo.rs
index f0a875c19..6bbc62379 100644
--- a/lib/src/repo.rs
+++ b/lib/src/repo.rs
@@ -19,11 +19,11 @@ use std::io::{Read, Write};
 use std::path::{Path, PathBuf};
 use std::sync::{Arc, Mutex, MutexGuard};
 
-use crate::conflicts;
 use thiserror::Error;
 
 use crate::commit::Commit;
 use crate::commit_builder::{new_change_id, signature, CommitBuilder};
+use crate::conflicts;
 use crate::dag_walk::topo_order_reverse;
 use crate::evolution::{EvolutionRef, MutableEvolution, ReadonlyEvolution};
 use crate::git_store::GitStore;
diff --git a/lib/src/store.rs b/lib/src/store.rs
index 788227821..115cae039 100644
--- a/lib/src/store.rs
+++ b/lib/src/store.rs
@@ -12,16 +12,17 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::borrow::Borrow;
 use std::collections::BTreeMap;
 use std::fmt::{Debug, Error, Formatter};
 use std::io::Read;
 use std::result::Result;
 use std::vec::Vec;
 
+use thiserror::Error;
+
 use crate::repo_path::DirRepoPath;
 use crate::repo_path::FileRepoPath;
-use std::borrow::Borrow;
-use thiserror::Error;
 
 #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash)]
 pub struct CommitId(pub Vec<u8>);
diff --git a/lib/src/store_wrapper.rs b/lib/src/store_wrapper.rs
index 2304c74ee..c247c4d6c 100644
--- a/lib/src/store_wrapper.rs
+++ b/lib/src/store_wrapper.rs
@@ -13,6 +13,7 @@
 // limitations under the License.
 
 use std::collections::HashMap;
+use std::io::Read;
 use std::sync::{Arc, RwLock, Weak};
 
 use crate::commit::Commit;
@@ -24,7 +25,6 @@ use crate::store::{
 };
 use crate::tree::Tree;
 use crate::tree_builder::TreeBuilder;
-use std::io::Read;
 
 /// Wraps the low-level store and makes it return more convenient types. Also
 /// adds the root commit and adds caching.
diff --git a/lib/src/transaction.rs b/lib/src/transaction.rs
index e97db961d..6bb0a36c3 100644
--- a/lib/src/transaction.rs
+++ b/lib/src/transaction.rs
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::sync::Arc;
+
 use crate::commit::Commit;
 use crate::evolution::MutableEvolution;
 use crate::index::MutableIndex;
@@ -26,7 +28,6 @@ use crate::store;
 use crate::store::{CommitId, Timestamp};
 use crate::store_wrapper::StoreWrapper;
 use crate::view::MutableView;
-use std::sync::Arc;
 
 pub struct Transaction<'r> {
     repo: Option<Arc<MutableRepo<'r>>>,
diff --git a/lib/src/tree.rs b/lib/src/tree.rs
index 78191a510..599fbf448 100644
--- a/lib/src/tree.rs
+++ b/lib/src/tree.rs
@@ -14,6 +14,7 @@
 
 use std::borrow::Borrow;
 use std::fmt::{Debug, Error, Formatter};
+use std::pin::Pin;
 use std::sync::Arc;
 
 use crate::matchers::AlwaysMatcher;
@@ -24,7 +25,6 @@ use crate::store;
 use crate::store::{ConflictId, TreeEntriesNonRecursiveIter, TreeEntry, TreeId, TreeValue};
 use crate::store_wrapper::StoreWrapper;
 use crate::trees::{recursive_tree_diff, TreeValueDiff};
-use std::pin::Pin;
 
 #[derive(Clone)]
 pub struct Tree {
diff --git a/lib/src/tree_builder.rs b/lib/src/tree_builder.rs
index 20953918c..501d08cfb 100644
--- a/lib/src/tree_builder.rs
+++ b/lib/src/tree_builder.rs
@@ -13,13 +13,13 @@
 // limitations under the License.
 
 use std::collections::{BTreeMap, HashSet};
+use std::sync::Arc;
 
 use crate::repo_path::{DirRepoPath, RepoPath, RepoPathJoin};
 use crate::store;
 use crate::store::{TreeId, TreeValue};
 use crate::store_wrapper::StoreWrapper;
 use crate::tree::Tree;
-use std::sync::Arc;
 
 #[derive(Debug)]
 enum Override {
diff --git a/lib/src/trees.rs b/lib/src/trees.rs
index f761047c4..c1fea0c39 100644
--- a/lib/src/trees.rs
+++ b/lib/src/trees.rs
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::cmp::Ordering;
+
 use crate::files;
 use crate::files::MergeResult;
 use crate::matchers::Matcher;
@@ -21,7 +23,6 @@ use crate::repo_path::{
 use crate::store::{Conflict, ConflictPart, StoreError, TreeId, TreeValue};
 use crate::store_wrapper::StoreWrapper;
 use crate::tree::Tree;
-use std::cmp::Ordering;
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum Diff<T> {
diff --git a/lib/src/view.rs b/lib/src/view.rs
index c32ebcbb3..00f3a83be 100644
--- a/lib/src/view.rs
+++ b/lib/src/view.rs
@@ -18,7 +18,6 @@ use std::sync::Arc;
 
 use crate::commit::Commit;
 use crate::op_store;
-
 use crate::store::CommitId;
 use crate::store_wrapper::StoreWrapper;
 
diff --git a/lib/src/working_copy.rs b/lib/src/working_copy.rs
index e896fc8c2..4e77e6cb5 100644
--- a/lib/src/working_copy.rs
+++ b/lib/src/working_copy.rs
@@ -25,8 +25,10 @@ use std::os::unix::fs::PermissionsExt;
 use std::os::windows::fs::symlink_file;
 use std::path::Path;
 use std::path::PathBuf;
+use std::sync::Arc;
 use std::time::UNIX_EPOCH;
 
+use git2::{Repository, RepositoryInitOptions};
 use protobuf::Message;
 use tempfile::NamedTempFile;
 use thiserror::Error;
@@ -42,8 +44,6 @@ use crate::settings::UserSettings;
 use crate::store::{CommitId, FileId, MillisSinceEpoch, StoreError, SymlinkId, TreeId, TreeValue};
 use crate::store_wrapper::StoreWrapper;
 use crate::trees::TreeValueDiff;
-use git2::{Repository, RepositoryInitOptions};
-use std::sync::Arc;
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum FileType {
diff --git a/lib/tests/test_bad_locking.rs b/lib/tests/test_bad_locking.rs
index ca61c9a50..ed377f90a 100644
--- a/lib/tests/test_bad_locking.rs
+++ b/lib/tests/test_bad_locking.rs
@@ -13,12 +13,11 @@
 // limitations under the License.
 
 use std::path::Path;
-
-use tempfile::TempDir;
+use std::sync::Arc;
 
 use jujube_lib::repo::ReadonlyRepo;
 use jujube_lib::testutils;
-use std::sync::Arc;
+use tempfile::TempDir;
 use test_case::test_case;
 
 fn copy_directory(src: &Path, dst: &Path) {
diff --git a/lib/tests/test_commit_builder.rs b/lib/tests/test_commit_builder.rs
index 3ae7f7fd7..7694c86dc 100644
--- a/lib/tests/test_commit_builder.rs
+++ b/lib/tests/test_commit_builder.rs
@@ -12,12 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::sync::Arc;
+
 use jujube_lib::commit_builder::CommitBuilder;
 use jujube_lib::repo_path::FileRepoPath;
 use jujube_lib::settings::UserSettings;
 use jujube_lib::testutils;
 use jujube_lib::tree::DiffSummary;
-use std::sync::Arc;
 use test_case::test_case;
 
 #[test_case(false ; "local store")]
diff --git a/lib/tests/test_commit_concurrent.rs b/lib/tests/test_commit_concurrent.rs
index 11fe79b6c..68bec48b9 100644
--- a/lib/tests/test_commit_concurrent.rs
+++ b/lib/tests/test_commit_concurrent.rs
@@ -12,12 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::sync::Arc;
 use std::thread;
 
 use jujube_lib::dag_walk;
 use jujube_lib::repo::ReadonlyRepo;
 use jujube_lib::testutils;
-use std::sync::Arc;
 use test_case::test_case;
 
 fn count_non_merge_operations(repo: &ReadonlyRepo) -> u32 {
diff --git a/lib/tests/test_git.rs b/lib/tests/test_git.rs
index 42f89f5c6..f2a3d3aef 100644
--- a/lib/tests/test_git.rs
+++ b/lib/tests/test_git.rs
@@ -12,6 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::collections::HashSet;
+use std::path::PathBuf;
+use std::sync::Arc;
+
 use git2::Oid;
 use jujube_lib::commit::Commit;
 use jujube_lib::git;
@@ -21,9 +25,6 @@ use jujube_lib::settings::UserSettings;
 use jujube_lib::store::CommitId;
 use jujube_lib::testutils;
 use maplit::hashset;
-use std::collections::HashSet;
-use std::path::PathBuf;
-use std::sync::Arc;
 use tempfile::TempDir;
 
 fn empty_git_commit<'r>(
diff --git a/lib/tests/test_index.rs b/lib/tests/test_index.rs
index 920f80a58..22887ae19 100644
--- a/lib/tests/test_index.rs
+++ b/lib/tests/test_index.rs
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::sync::Arc;
+
 use jujube_lib::commit::Commit;
 use jujube_lib::commit_builder::CommitBuilder;
 use jujube_lib::index::IndexRef;
@@ -20,7 +22,6 @@ use jujube_lib::settings::UserSettings;
 use jujube_lib::store::CommitId;
 use jujube_lib::testutils;
 use jujube_lib::testutils::create_random_commit;
-use std::sync::Arc;
 use test_case::test_case;
 
 #[must_use]
diff --git a/lib/tests/test_load_repo.rs b/lib/tests/test_load_repo.rs
index 339f016af..8c43d16ca 100644
--- a/lib/tests/test_load_repo.rs
+++ b/lib/tests/test_load_repo.rs
@@ -12,9 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::sync::Arc;
+
 use jujube_lib::repo::{ReadonlyRepo, RepoLoadError, RepoLoader};
 use jujube_lib::testutils;
-use std::sync::Arc;
 use test_case::test_case;
 
 #[test]
diff --git a/lib/tests/test_operations.rs b/lib/tests/test_operations.rs
index ff0a3bf45..8034731f0 100644
--- a/lib/tests/test_operations.rs
+++ b/lib/tests/test_operations.rs
@@ -12,12 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::path::Path;
+use std::sync::Arc;
+
 use jujube_lib::commit_builder::CommitBuilder;
 use jujube_lib::repo::RepoRef;
 use jujube_lib::store::CommitId;
 use jujube_lib::testutils;
-use std::path::Path;
-use std::sync::Arc;
 use test_case::test_case;
 
 fn list_dir(dir: &Path) -> Vec<String> {
diff --git a/lib/tests/test_transaction.rs b/lib/tests/test_transaction.rs
index d0f4a0b15..891ffaceb 100644
--- a/lib/tests/test_transaction.rs
+++ b/lib/tests/test_transaction.rs
@@ -12,12 +12,13 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::sync::Arc;
+
 use jujube_lib::commit_builder::CommitBuilder;
 use jujube_lib::repo_path::FileRepoPath;
 use jujube_lib::store::{Conflict, ConflictId, ConflictPart, TreeValue};
 use jujube_lib::store_wrapper::StoreWrapper;
 use jujube_lib::testutils;
-use std::sync::Arc;
 use test_case::test_case;
 
 // TODO Many of the tests here are not run with Git because they end up creating
diff --git a/lib/tests/test_working_copy.rs b/lib/tests/test_working_copy.rs
index bf5f154d3..7aec37290 100644
--- a/lib/tests/test_working_copy.rs
+++ b/lib/tests/test_working_copy.rs
@@ -12,8 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::fs::OpenOptions;
+use std::io::Write;
 #[cfg(unix)]
 use std::os::unix::fs::PermissionsExt;
+use std::sync::Arc;
 
 use jujube_lib::commit_builder::CommitBuilder;
 use jujube_lib::repo::ReadonlyRepo;
@@ -22,9 +25,6 @@ use jujube_lib::settings::UserSettings;
 use jujube_lib::store::TreeValue;
 use jujube_lib::testutils;
 use jujube_lib::tree_builder::TreeBuilder;
-use std::fs::OpenOptions;
-use std::io::Write;
-use std::sync::Arc;
 use test_case::test_case;
 
 #[test_case(false ; "local store")]
diff --git a/lib/tests/test_working_copy_concurrent.rs b/lib/tests/test_working_copy_concurrent.rs
index d2d622400..55ff47adf 100644
--- a/lib/tests/test_working_copy_concurrent.rs
+++ b/lib/tests/test_working_copy_concurrent.rs
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::collections::HashSet;
+use std::sync::Arc;
 use std::thread;
 
 use jujube_lib::commit_builder::CommitBuilder;
@@ -20,8 +22,6 @@ use jujube_lib::repo_path::FileRepoPath;
 use jujube_lib::store::CommitId;
 use jujube_lib::testutils;
 use jujube_lib::working_copy::CheckoutError;
-use std::collections::HashSet;
-use std::sync::Arc;
 use test_case::test_case;
 
 #[test_case(false ; "local store")]
diff --git a/rustfmt.toml b/rustfmt.toml
index 8b287f1a7..b8d5849ba 100644
--- a/rustfmt.toml
+++ b/rustfmt.toml
@@ -1,3 +1,4 @@
 max_width = 100
 wrap_comments = true
 error_on_line_overflow = true
+group_imports = "StdExternalCrate"
diff --git a/src/commands.rs b/src/commands.rs
index c2edcadb1..90bc1477e 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -18,19 +18,17 @@ extern crate config;
 
 use std::collections::{HashSet, VecDeque};
 use std::ffi::OsString;
+use std::fmt::Debug;
 use std::fs;
 use std::fs::OpenOptions;
 use std::io;
 use std::io::{Read, Write};
 use std::process::Command;
 use std::sync::Arc;
+use std::time::Instant;
 
 use clap::{crate_version, App, Arg, ArgMatches, SubCommand};
-
 use criterion::Criterion;
-
-use pest::Parser;
-
 use jujube_lib::commit::Commit;
 use jujube_lib::commit_builder::CommitBuilder;
 use jujube_lib::conflicts;
@@ -40,16 +38,23 @@ use jujube_lib::evolution::EvolveListener;
 use jujube_lib::files;
 use jujube_lib::files::DiffLine;
 use jujube_lib::git;
+use jujube_lib::git::GitFetchError;
+use jujube_lib::index::{HexPrefix, PrefixResolution};
 use jujube_lib::op_store::{OpStore, OpStoreError, OperationId};
+use jujube_lib::operation::Operation;
 use jujube_lib::repo::{ReadonlyRepo, RepoLoadError, RepoLoader};
 use jujube_lib::repo_path::RepoPath;
 use jujube_lib::rewrite::{back_out_commit, merge_commit_trees, rebase_commit};
 use jujube_lib::settings::UserSettings;
 use jujube_lib::store::{CommitId, Timestamp};
 use jujube_lib::store::{StoreError, TreeValue};
+use jujube_lib::store_wrapper::StoreWrapper;
+use jujube_lib::transaction::Transaction;
 use jujube_lib::tree::Tree;
 use jujube_lib::trees::TreeValueDiff;
+use jujube_lib::view::merge_views;
 use jujube_lib::working_copy::{CheckoutStats, WorkingCopy};
+use pest::Parser;
 
 use self::chrono::{FixedOffset, TimeZone, Utc};
 use crate::commands::CommandError::UserError;
@@ -59,14 +64,6 @@ use crate::styler::{ColorStyler, Styler};
 use crate::template_parser::TemplateParser;
 use crate::templater::Template;
 use crate::ui::Ui;
-use jujube_lib::git::GitFetchError;
-use jujube_lib::index::{HexPrefix, PrefixResolution};
-use jujube_lib::operation::Operation;
-use jujube_lib::store_wrapper::StoreWrapper;
-use jujube_lib::transaction::Transaction;
-use jujube_lib::view::merge_views;
-use std::fmt::Debug;
-use std::time::Instant;
 
 enum CommandError {
     UserError(String),
diff --git a/src/diff_edit.rs b/src/diff_edit.rs
index 2a284e6d0..8b136c8d1 100644
--- a/src/diff_edit.rs
+++ b/src/diff_edit.rs
@@ -12,6 +12,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::path::{Path, PathBuf};
+use std::process::Command;
+use std::sync::Arc;
+
 use jujube_lib::repo_path::{DirRepoPath, RepoPath};
 use jujube_lib::store::{StoreError, TreeId, TreeValue};
 use jujube_lib::store_wrapper::StoreWrapper;
@@ -19,9 +23,6 @@ use jujube_lib::tree::Tree;
 use jujube_lib::tree_builder::TreeBuilder;
 use jujube_lib::trees::merge_trees;
 use jujube_lib::working_copy::{CheckoutError, TreeState};
-use std::path::{Path, PathBuf};
-use std::process::Command;
-use std::sync::Arc;
 use tempfile::tempdir;
 use thiserror::Error;
 
diff --git a/src/graphlog.rs b/src/graphlog.rs
index f27ffdbfe..c179724c3 100644
--- a/src/graphlog.rs
+++ b/src/graphlog.rs
@@ -285,9 +285,10 @@ where
 
 #[cfg(test)]
 mod tests {
-    use super::*;
     use indoc::indoc;
 
+    use super::*;
+
     #[test]
     fn single_node() {
         let mut buffer = vec![];
diff --git a/src/template_parser.rs b/src/template_parser.rs
index 58a5f0efe..dcbc9dbce 100644
--- a/src/template_parser.rs
+++ b/src/template_parser.rs
@@ -14,13 +14,13 @@
 
 extern crate pest;
 
+use jujube_lib::commit::Commit;
+use jujube_lib::repo::RepoRef;
+use jujube_lib::store::{CommitId, Signature};
 use pest::iterators::Pair;
 use pest::iterators::Pairs;
 use pest::Parser;
 
-use jujube_lib::commit::Commit;
-use jujube_lib::store::{CommitId, Signature};
-
 use crate::styler::PlainTextStyler;
 use crate::templater::{
     AuthorProperty, ChangeIdProperty, CommitIdKeyword, CommitterProperty, ConditionalTemplate,
@@ -29,7 +29,6 @@ use crate::templater::{
     LiteralTemplate, ObsoleteProperty, OpenProperty, OrphanProperty, PrunedProperty,
     StringPropertyTemplate, Template, TemplateFunction, TemplateProperty,
 };
-use jujube_lib::repo::RepoRef;
 
 #[derive(Parser)]
 #[grammar = "template.pest"]
diff --git a/src/ui.rs b/src/ui.rs
index a85c0a4e6..2f63463d8 100644
--- a/src/ui.rs
+++ b/src/ui.rs
@@ -19,11 +19,11 @@ use std::path::{Path, PathBuf};
 use std::sync::{Mutex, MutexGuard};
 
 use jujube_lib::commit::Commit;
+use jujube_lib::repo::RepoRef;
 use jujube_lib::settings::UserSettings;
 
 use crate::styler::{ColorStyler, PlainTextStyler, Styler};
 use crate::templater::TemplateFormatter;
-use jujube_lib::repo::RepoRef;
 
 pub struct Ui<'a> {
     cwd: PathBuf,