diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 43430ad40..2dcd6be02 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -42,6 +42,20 @@ jobs:
       env:
         RUST_BACKTRACE: 1
 
+  check-protos:
+    name: Check protos
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@755da8c3cf115ac066823e79a1e1788f8940201b
+      - uses: dtolnay/rust-toolchain@e645b0cf01249a964ec099494d38d2da0f0b349f
+        with:
+          toolchain: stable
+      - run: sudo apt update && sudo apt-get -y install protobuf-compiler
+      - name: Generate Rust code from .proto files
+        run: cargo run -p gen-protos
+      - name: Check for uncommitted changes
+        run: git diff --exit-code
+
   rustfmt:
     name: Check formatting
     runs-on: ubuntu-latest
diff --git a/Cargo.lock b/Cargo.lock
index fcd0c70d2..776eaca94 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -545,6 +545,12 @@ dependencies = [
  "instant",
 ]
 
+[[package]]
+name = "fixedbitset"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
+
 [[package]]
 name = "float-cmp"
 version = "0.9.0"
@@ -564,6 +570,13 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "gen-protos"
+version = "0.1.0"
+dependencies = [
+ "prost-build",
+]
+
 [[package]]
 name = "generic-array"
 version = "0.14.6"
@@ -830,8 +843,7 @@ dependencies = [
  "once_cell",
  "pest",
  "pest_derive",
- "protobuf",
- "protobuf-codegen",
+ "prost",
  "rand",
  "regex",
  "serde_json",
@@ -984,6 +996,12 @@ dependencies = [
  "windows-sys 0.36.1",
 ]
 
+[[package]]
+name = "multimap"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e5ce46fe64a9d73be07dcbe690a38ce1b293be448fd8ce1e6c1b8062c9f72c6a"
+
 [[package]]
 name = "nom"
 version = "7.1.1"
@@ -1180,6 +1198,16 @@ dependencies = [
  "sha1",
 ]
 
+[[package]]
+name = "petgraph"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6d5014253a1331579ce62aa67443b4a658c5e7dd03d4bc6d302b94474888143"
+dependencies = [
+ "fixedbitset",
+ "indexmap",
+]
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.9"
@@ -1256,6 +1284,16 @@ dependencies = [
  "termtree",
 ]
 
+[[package]]
+name = "prettyplease"
+version = "0.1.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2c8992a85d8e93a28bdf76137db888d3874e3b230dee5ed8bebac4c9f7617773"
+dependencies = [
+ "proc-macro2",
+ "syn",
+]
+
 [[package]]
 name = "proc-macro-error"
 version = "1.0.4"
@@ -1290,55 +1328,58 @@ dependencies = [
 ]
 
 [[package]]
-name = "protobuf"
-version = "3.2.0"
+name = "prost"
+version = "0.11.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b55bad9126f378a853655831eb7363b7b01b81d19f8cb1218861086ca4a1a61e"
+checksum = "c01db6702aa05baa3f57dec92b8eeeeb4cb19e894e73996b32a4093289e54592"
 dependencies = [
  "bytes",
- "once_cell",
- "protobuf-support",
- "thiserror",
+ "prost-derive",
 ]
 
 [[package]]
-name = "protobuf-codegen"
-version = "3.2.0"
+name = "prost-build"
+version = "0.11.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0dd418ac3c91caa4032d37cb80ff0d44e2ebe637b2fb243b6234bf89cdac4901"
+checksum = "cb5320c680de74ba083512704acb90fe00f28f79207286a848e730c45dd73ed6"
 dependencies = [
- "anyhow",
- "once_cell",
- "protobuf",
- "protobuf-parse",
- "regex",
- "tempfile",
- "thiserror",
-]
-
-[[package]]
-name = "protobuf-parse"
-version = "3.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9d39b14605eaa1f6a340aec7f320b34064feb26c93aec35d6a9a2272a8ddfa49"
-dependencies = [
- "anyhow",
- "indexmap",
+ "bytes",
+ "heck",
+ "itertools",
+ "lazy_static",
  "log",
- "protobuf",
- "protobuf-support",
+ "multimap",
+ "petgraph",
+ "prettyplease",
+ "prost",
+ "prost-types",
+ "regex",
+ "syn",
  "tempfile",
- "thiserror",
  "which",
 ]
 
 [[package]]
-name = "protobuf-support"
-version = "3.2.0"
+name = "prost-derive"
+version = "0.11.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a5d4d7b8601c814cfb36bcebb79f0e61e45e1e93640cf778837833bbed05c372"
+checksum = "c8842bad1a5419bca14eac663ba798f6bc19c413c2fdceb5f3ba3b0932d96720"
 dependencies = [
- "thiserror",
+ "anyhow",
+ "itertools",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "prost-types"
+version = "0.11.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "017f79637768cde62820bc2d4fe0e45daaa027755c323ad077767c6c5f173091"
+dependencies = [
+ "bytes",
+ "prost",
 ]
 
 [[package]]
diff --git a/Cargo.toml b/Cargo.toml
index 3895a87ce..1bceb9ba2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -31,7 +31,7 @@ name = "diff_bench"
 harness = false
 
 [workspace]
-members = ["lib", "lib/testutils"]
+members = ["lib", "lib/testutils", "lib/gen-protos"]
 
 [dependencies]
 chrono = { version = "0.4.23", default-features = false, features = ["std", "clock"] }
diff --git a/lib/Cargo.toml b/lib/Cargo.toml
index 1419c2b00..6266712d8 100644
--- a/lib/Cargo.toml
+++ b/lib/Cargo.toml
@@ -14,7 +14,6 @@ readme = "../README.md"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [build-dependencies]
-protobuf-codegen = "3.2.0"
 version_check = "0.9.4"
 
 [dependencies]
@@ -32,7 +31,6 @@ maplit = "1.0.2"
 once_cell = "1.16.0"
 pest = "2.5.1"
 pest_derive = "2.5.1"
-protobuf = { version = "3.0.1", features = ["with-bytes"] }
 regex = "1.7.0"
 serde_json = "1.0.91"
 tempfile = "3.3.0"
@@ -42,6 +40,7 @@ uuid = { version = "1.2.2", features = ["v4"] }
 whoami = "1.2.3"
 zstd = "0.12.1"
 tracing = "0.1.37"
+prost = "0.11.5"
 
 [dev-dependencies]
 assert_matches = "1.5.0"
diff --git a/lib/build.rs b/lib/build.rs
index e19aaa80e..c7a3e25e0 100644
--- a/lib/build.rs
+++ b/lib/build.rs
@@ -12,24 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-fn main() {
-    let input = &[
-        "src/protos/op_store.proto",
-        "src/protos/store.proto",
-        "src/protos/working_copy.proto",
-    ];
-    protobuf_codegen::Codegen::new()
-        .pure()
-        .inputs(input)
-        .include("src/protos")
-        .cargo_out_dir("protos")
-        .run_from_script();
+fn main() -> std::io::Result<()> {
     println!("cargo:rerun-if-changed=build.rs");
-    for file in input {
-        println!("cargo:rerun-if-changed={file}");
-    }
 
     if let Some(true) = version_check::supports_feature("map_first_last") {
         println!("cargo:rustc-cfg=feature=\"map_first_last\"");
     }
+
+    Ok(())
 }
diff --git a/lib/gen-protos/Cargo.toml b/lib/gen-protos/Cargo.toml
new file mode 100644
index 000000000..209d9711a
--- /dev/null
+++ b/lib/gen-protos/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "gen-protos"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dependencies]
+prost-build = "0.11.5"
diff --git a/lib/gen-protos/src/main.rs b/lib/gen-protos/src/main.rs
new file mode 100644
index 000000000..593da9175
--- /dev/null
+++ b/lib/gen-protos/src/main.rs
@@ -0,0 +1,34 @@
+// Copyright 2022 The Jujutsu Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::io::Result;
+use std::path::Path;
+
+fn main() -> Result<()> {
+    let input = ["op_store.proto", "store.proto", "working_copy.proto"];
+
+    let root = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap();
+    let protos_dir = root.join("src").join("protos");
+
+    prost_build::Config::new()
+        .out_dir(&protos_dir)
+        .include_file("mod.rs")
+        .compile_protos(
+            &input
+                .into_iter()
+                .map(|x| protos_dir.join(x))
+                .collect::<Vec<_>>(),
+            &[protos_dir],
+        )
+}
diff --git a/lib/src/git_backend.rs b/lib/src/git_backend.rs
index 2749b0cf0..57c4d4a42 100644
--- a/lib/src/git_backend.rs
+++ b/lib/src/git_backend.rs
@@ -20,7 +20,7 @@ use std::sync::{Arc, Mutex};
 
 use git2::Oid;
 use itertools::Itertools;
-use protobuf::Message;
+use prost::Message;
 use uuid::Uuid;
 
 use crate::backend::{
@@ -126,17 +126,18 @@ fn signature_to_git(signature: &Signature) -> git2::Signature {
 }
 
 fn serialize_extras(commit: &Commit) -> Vec<u8> {
-    let mut proto = crate::protos::store::Commit::new();
-    proto.change_id = commit.change_id.to_bytes();
+    let mut proto = crate::protos::store::Commit {
+        change_id: commit.change_id.to_bytes(),
+        ..Default::default()
+    };
     for predecessor in &commit.predecessors {
         proto.predecessors.push(predecessor.to_bytes());
     }
-    proto.write_to_bytes().unwrap()
+    proto.encode_to_vec()
 }
 
 fn deserialize_extras(commit: &mut Commit, bytes: &[u8]) {
-    let mut cursor = Cursor::new(bytes);
-    let proto: crate::protos::store::Commit = Message::parse_from_reader(&mut cursor).unwrap();
+    let proto = crate::protos::store::Commit::decode(bytes).unwrap();
     commit.change_id = ChangeId::new(proto.change_id);
     for predecessor in &proto.predecessors {
         commit.predecessors.push(CommitId::from_bytes(predecessor));
diff --git a/lib/src/local_backend.rs b/lib/src/local_backend.rs
index 44f350077..9c0cf7dc1 100644
--- a/lib/src/local_backend.rs
+++ b/lib/src/local_backend.rs
@@ -19,7 +19,7 @@ use std::io::{ErrorKind, Read, Write};
 use std::path::{Path, PathBuf};
 
 use blake2::{Blake2b512, Digest};
-use protobuf::{Message, MessageField};
+use prost::Message;
 use tempfile::{NamedTempFile, PersistError};
 
 use crate::backend::{
@@ -43,8 +43,8 @@ impl From<PersistError> for BackendError {
     }
 }
 
-impl From<protobuf::Error> for BackendError {
-    fn from(err: protobuf::Error) -> Self {
+impl From<prost::DecodeError> for BackendError {
+    fn from(err: prost::DecodeError) -> Self {
         BackendError::Other(err.to_string())
     }
 }
@@ -183,17 +183,17 @@ impl Backend for LocalBackend {
 
     fn read_tree(&self, _path: &RepoPath, id: &TreeId) -> BackendResult<Tree> {
         let path = self.tree_path(id);
-        let mut file = File::open(path).map_err(not_found_to_backend_error)?;
+        let buf = fs::read(path).map_err(not_found_to_backend_error)?;
 
-        let proto: crate::protos::store::Tree = Message::parse_from_reader(&mut file)?;
-        Ok(tree_from_proto(&proto))
+        let proto = crate::protos::store::Tree::decode(&*buf)?;
+        Ok(tree_from_proto(proto))
     }
 
     fn write_tree(&self, _path: &RepoPath, tree: &Tree) -> BackendResult<TreeId> {
         let temp_file = NamedTempFile::new_in(&self.path)?;
 
         let proto = tree_to_proto(tree);
-        proto.write_to_writer(&mut temp_file.as_file())?;
+        temp_file.as_file().write_all(&proto.encode_to_vec())?;
 
         let id = TreeId::new(blake2b_hash(tree).to_vec());
 
@@ -203,17 +203,17 @@ impl Backend for LocalBackend {
 
     fn read_conflict(&self, _path: &RepoPath, id: &ConflictId) -> BackendResult<Conflict> {
         let path = self.conflict_path(id);
-        let mut file = File::open(path).map_err(not_found_to_backend_error)?;
+        let buf = fs::read(path).map_err(not_found_to_backend_error)?;
 
-        let proto: crate::protos::store::Conflict = Message::parse_from_reader(&mut file)?;
-        Ok(conflict_from_proto(&proto))
+        let proto = crate::protos::store::Conflict::decode(&*buf)?;
+        Ok(conflict_from_proto(proto))
     }
 
     fn write_conflict(&self, _path: &RepoPath, conflict: &Conflict) -> BackendResult<ConflictId> {
         let temp_file = NamedTempFile::new_in(&self.path)?;
 
         let proto = conflict_to_proto(conflict);
-        proto.write_to_writer(&mut temp_file.as_file())?;
+        temp_file.as_file().write_all(&proto.encode_to_vec())?;
 
         let id = ConflictId::new(blake2b_hash(conflict).to_vec());
 
@@ -227,17 +227,17 @@ impl Backend for LocalBackend {
         }
 
         let path = self.commit_path(id);
-        let mut file = File::open(path).map_err(not_found_to_backend_error)?;
+        let buf = fs::read(path).map_err(not_found_to_backend_error)?;
 
-        let proto: crate::protos::store::Commit = Message::parse_from_reader(&mut file)?;
-        Ok(commit_from_proto(&proto))
+        let proto = crate::protos::store::Commit::decode(&*buf)?;
+        Ok(commit_from_proto(proto))
     }
 
     fn write_commit(&self, commit: &Commit) -> BackendResult<CommitId> {
         let temp_file = NamedTempFile::new_in(&self.path)?;
 
         let proto = commit_to_proto(commit);
-        proto.write_to_writer(&mut temp_file.as_file())?;
+        temp_file.as_file().write_all(&proto.encode_to_vec())?;
 
         let id = CommitId::new(blake2b_hash(commit).to_vec());
 
@@ -247,7 +247,7 @@ impl Backend for LocalBackend {
 }
 
 pub fn commit_to_proto(commit: &Commit) -> crate::protos::store::Commit {
-    let mut proto = crate::protos::store::Commit::new();
+    let mut proto = crate::protos::store::Commit::default();
     for parent in &commit.parents {
         proto.parents.push(parent.to_bytes());
     }
@@ -257,115 +257,116 @@ pub fn commit_to_proto(commit: &Commit) -> crate::protos::store::Commit {
     proto.root_tree = commit.root_tree.to_bytes();
     proto.change_id = commit.change_id.to_bytes();
     proto.description = commit.description.clone();
-    proto.author = MessageField::some(signature_to_proto(&commit.author));
-    proto.committer = MessageField::some(signature_to_proto(&commit.committer));
+    proto.author = Some(signature_to_proto(&commit.author));
+    proto.committer = Some(signature_to_proto(&commit.committer));
     proto
 }
 
-fn commit_from_proto(proto: &crate::protos::store::Commit) -> Commit {
-    let commit_id_from_proto = |parent: &Vec<u8>| CommitId::new(parent.clone());
-    let parents = proto.parents.iter().map(commit_id_from_proto).collect();
-    let predecessors = proto
-        .predecessors
-        .iter()
-        .map(commit_id_from_proto)
-        .collect();
-    let root_tree = TreeId::new(proto.root_tree.to_vec());
-    let change_id = ChangeId::new(proto.change_id.to_vec());
+fn commit_from_proto(proto: crate::protos::store::Commit) -> Commit {
+    let parents = proto.parents.into_iter().map(CommitId::new).collect();
+    let predecessors = proto.predecessors.into_iter().map(CommitId::new).collect();
+    let root_tree = TreeId::new(proto.root_tree);
+    let change_id = ChangeId::new(proto.change_id);
     Commit {
         parents,
         predecessors,
         root_tree,
         change_id,
-        description: proto.description.clone(),
-        author: signature_from_proto(&proto.author),
-        committer: signature_from_proto(&proto.committer),
+        description: proto.description,
+        author: signature_from_proto(proto.author.unwrap_or_default()),
+        committer: signature_from_proto(proto.committer.unwrap_or_default()),
     }
 }
 
 fn tree_to_proto(tree: &Tree) -> crate::protos::store::Tree {
-    let mut proto = crate::protos::store::Tree::new();
+    let mut proto = crate::protos::store::Tree::default();
     for entry in tree.entries() {
-        let mut proto_entry = crate::protos::store::tree::Entry::new();
-        proto_entry.name = entry.name().string();
-        proto_entry.value = MessageField::some(tree_value_to_proto(entry.value()));
-        proto.entries.push(proto_entry);
+        proto.entries.push(crate::protos::store::tree::Entry {
+            name: entry.name().string(),
+            value: Some(tree_value_to_proto(entry.value())),
+        });
     }
     proto
 }
 
-fn tree_from_proto(proto: &crate::protos::store::Tree) -> Tree {
+fn tree_from_proto(proto: crate::protos::store::Tree) -> Tree {
     let mut tree = Tree::default();
-    for proto_entry in &proto.entries {
-        let value = tree_value_from_proto(proto_entry.value.as_ref().unwrap());
-        tree.set(RepoPathComponent::from(proto_entry.name.as_str()), value);
+    for proto_entry in proto.entries {
+        let value = tree_value_from_proto(proto_entry.value.unwrap());
+        tree.set(RepoPathComponent::from(proto_entry.name), value);
     }
     tree
 }
 
 fn tree_value_to_proto(value: &TreeValue) -> crate::protos::store::TreeValue {
-    let mut proto = crate::protos::store::TreeValue::new();
+    let mut proto = crate::protos::store::TreeValue::default();
     match value {
         TreeValue::File { id, executable } => {
-            let mut file = crate::protos::store::tree_value::File::new();
-            file.id = id.to_bytes();
-            file.executable = *executable;
-            proto.set_file(file);
+            proto.value = Some(crate::protos::store::tree_value::Value::File(
+                crate::protos::store::tree_value::File {
+                    id: id.to_bytes(),
+                    executable: *executable,
+                },
+            ));
         }
         TreeValue::Symlink(id) => {
-            proto.set_symlink_id(id.to_bytes());
+            proto.value = Some(crate::protos::store::tree_value::Value::SymlinkId(
+                id.to_bytes(),
+            ));
         }
         TreeValue::GitSubmodule(_id) => {
             panic!("cannot store git submodules");
         }
         TreeValue::Tree(id) => {
-            proto.set_tree_id(id.to_bytes());
+            proto.value = Some(crate::protos::store::tree_value::Value::TreeId(
+                id.to_bytes(),
+            ));
         }
         TreeValue::Conflict(id) => {
-            proto.set_conflict_id(id.to_bytes());
+            proto.value = Some(crate::protos::store::tree_value::Value::ConflictId(
+                id.to_bytes(),
+            ));
         }
     }
     proto
 }
 
-fn tree_value_from_proto(proto: &crate::protos::store::TreeValue) -> TreeValue {
-    match proto.value.as_ref().unwrap() {
-        crate::protos::store::tree_value::Value::TreeId(id) => {
-            TreeValue::Tree(TreeId::new(id.clone()))
-        }
+fn tree_value_from_proto(proto: crate::protos::store::TreeValue) -> TreeValue {
+    match proto.value.unwrap() {
+        crate::protos::store::tree_value::Value::TreeId(id) => TreeValue::Tree(TreeId::new(id)),
         crate::protos::store::tree_value::Value::File(crate::protos::store::tree_value::File {
             id,
             executable,
             ..
         }) => TreeValue::File {
-            id: FileId::new(id.clone()),
-            executable: *executable,
+            id: FileId::new(id),
+            executable,
         },
         crate::protos::store::tree_value::Value::SymlinkId(id) => {
-            TreeValue::Symlink(SymlinkId::new(id.clone()))
+            TreeValue::Symlink(SymlinkId::new(id))
         }
         crate::protos::store::tree_value::Value::ConflictId(id) => {
-            TreeValue::Conflict(ConflictId::new(id.clone()))
+            TreeValue::Conflict(ConflictId::new(id))
         }
     }
 }
 
 fn signature_to_proto(signature: &Signature) -> crate::protos::store::commit::Signature {
-    let mut proto = crate::protos::store::commit::Signature::new();
-    proto.name = signature.name.clone();
-    proto.email = signature.email.clone();
-    let mut timestamp_proto = crate::protos::store::commit::Timestamp::new();
-    timestamp_proto.millis_since_epoch = signature.timestamp.timestamp.0;
-    timestamp_proto.tz_offset = signature.timestamp.tz_offset;
-    proto.timestamp = MessageField::some(timestamp_proto);
-    proto
+    crate::protos::store::commit::Signature {
+        name: signature.name.clone(),
+        email: signature.email.clone(),
+        timestamp: Some(crate::protos::store::commit::Timestamp {
+            millis_since_epoch: signature.timestamp.timestamp.0,
+            tz_offset: signature.timestamp.tz_offset,
+        }),
+    }
 }
 
-fn signature_from_proto(proto: &crate::protos::store::commit::Signature) -> Signature {
-    let timestamp = &proto.timestamp;
+fn signature_from_proto(proto: crate::protos::store::commit::Signature) -> Signature {
+    let timestamp = proto.timestamp.unwrap_or_default();
     Signature {
-        name: proto.name.clone(),
-        email: proto.email.clone(),
+        name: proto.name,
+        email: proto.email,
         timestamp: Timestamp {
             timestamp: MillisSinceEpoch(timestamp.millis_since_epoch),
             tz_offset: timestamp.tz_offset,
@@ -374,7 +375,7 @@ fn signature_from_proto(proto: &crate::protos::store::commit::Signature) -> Sign
 }
 
 fn conflict_to_proto(conflict: &Conflict) -> crate::protos::store::Conflict {
-    let mut proto = crate::protos::store::Conflict::new();
+    let mut proto = crate::protos::store::Conflict::default();
     for part in &conflict.adds {
         proto.adds.push(conflict_part_to_proto(part));
     }
@@ -384,25 +385,25 @@ fn conflict_to_proto(conflict: &Conflict) -> crate::protos::store::Conflict {
     proto
 }
 
-fn conflict_from_proto(proto: &crate::protos::store::Conflict) -> Conflict {
+fn conflict_from_proto(proto: crate::protos::store::Conflict) -> Conflict {
     let mut conflict = Conflict::default();
-    for part in &proto.removes {
+    for part in proto.removes {
         conflict.removes.push(conflict_part_from_proto(part))
     }
-    for part in &proto.adds {
+    for part in proto.adds {
         conflict.adds.push(conflict_part_from_proto(part))
     }
     conflict
 }
 
-fn conflict_part_from_proto(proto: &crate::protos::store::conflict::Part) -> ConflictPart {
+fn conflict_part_from_proto(proto: crate::protos::store::conflict::Part) -> ConflictPart {
     ConflictPart {
-        value: tree_value_from_proto(proto.content.as_ref().unwrap()),
+        value: tree_value_from_proto(proto.content.unwrap()),
     }
 }
 
 fn conflict_part_to_proto(part: &ConflictPart) -> crate::protos::store::conflict::Part {
-    let mut proto = crate::protos::store::conflict::Part::new();
-    proto.content = MessageField::some(tree_value_to_proto(&part.value));
-    proto
+    crate::protos::store::conflict::Part {
+        content: Some(tree_value_to_proto(&part.value)),
+    }
 }
diff --git a/lib/src/proto_op_store.rs b/lib/src/proto_op_store.rs
index 6b16a83b1..05bf5b25a 100644
--- a/lib/src/proto_op_store.rs
+++ b/lib/src/proto_op_store.rs
@@ -15,12 +15,11 @@
 use std::collections::BTreeMap;
 use std::fmt::Debug;
 use std::fs;
-use std::fs::File;
-use std::io::ErrorKind;
+use std::io::{ErrorKind, Write};
 use std::path::PathBuf;
 
 use itertools::Itertools;
-use protobuf::{Message, MessageField};
+use prost::Message;
 use tempfile::NamedTempFile;
 
 use crate::backend::{CommitId, MillisSinceEpoch, Timestamp};
@@ -31,8 +30,8 @@ use crate::op_store::{
     RefTarget, View, ViewId, WorkspaceId,
 };
 
-impl From<protobuf::Error> for OpStoreError {
-    fn from(err: protobuf::Error) -> Self {
+impl From<prost::DecodeError> for OpStoreError {
+    fn from(err: prost::DecodeError) -> Self {
         OpStoreError::Other(err.to_string())
     }
 }
@@ -63,17 +62,17 @@ impl ProtoOpStore {
 
     pub fn read_view(&self, id: &ViewId) -> OpStoreResult<View> {
         let path = self.view_path(id);
-        let mut file = File::open(path).map_err(not_found_to_store_error)?;
+        let buf = fs::read(path)?;
 
-        let proto: crate::protos::op_store::View = Message::parse_from_reader(&mut file)?;
-        Ok(view_from_proto(&proto))
+        let proto = crate::protos::op_store::View::decode(&*buf)?;
+        Ok(view_from_proto(proto))
     }
 
     pub fn write_view(&self, view: &View) -> OpStoreResult<ViewId> {
         let temp_file = NamedTempFile::new_in(&self.path)?;
 
         let proto = view_to_proto(view);
-        proto.write_to_writer(&mut temp_file.as_file())?;
+        temp_file.as_file().write_all(&proto.encode_to_vec())?;
 
         let id = ViewId::new(blake2b_hash(view).to_vec());
 
@@ -83,17 +82,17 @@ impl ProtoOpStore {
 
     pub fn read_operation(&self, id: &OperationId) -> OpStoreResult<Operation> {
         let path = self.operation_path(id);
-        let mut file = File::open(path).map_err(not_found_to_store_error)?;
+        let buf = fs::read(path).map_err(not_found_to_store_error)?;
 
-        let proto: crate::protos::op_store::Operation = Message::parse_from_reader(&mut file)?;
-        Ok(operation_from_proto(&proto))
+        let proto = crate::protos::op_store::Operation::decode(&*buf)?;
+        Ok(operation_from_proto(proto))
     }
 
     pub fn write_operation(&self, operation: &Operation) -> OpStoreResult<OperationId> {
         let temp_file = NamedTempFile::new_in(&self.path)?;
 
         let proto = operation_to_proto(operation);
-        proto.write_to_writer(&mut temp_file.as_file())?;
+        temp_file.as_file().write_all(&proto.encode_to_vec())?;
 
         let id = OperationId::new(blake2b_hash(operation).to_vec());
 
@@ -111,13 +110,13 @@ fn not_found_to_store_error(err: std::io::Error) -> OpStoreError {
 }
 
 fn timestamp_to_proto(timestamp: &Timestamp) -> crate::protos::op_store::Timestamp {
-    let mut proto = crate::protos::op_store::Timestamp::new();
-    proto.millis_since_epoch = timestamp.timestamp.0;
-    proto.tz_offset = timestamp.tz_offset;
-    proto
+    crate::protos::op_store::Timestamp {
+        millis_since_epoch: timestamp.timestamp.0,
+        tz_offset: timestamp.tz_offset,
+    }
 }
 
-fn timestamp_from_proto(proto: &crate::protos::op_store::Timestamp) -> Timestamp {
+fn timestamp_from_proto(proto: crate::protos::op_store::Timestamp) -> Timestamp {
     Timestamp {
         timestamp: MillisSinceEpoch(proto.millis_since_epoch),
         tz_offset: proto.tz_offset,
@@ -127,50 +126,47 @@ fn timestamp_from_proto(proto: &crate::protos::op_store::Timestamp) -> Timestamp
 fn operation_metadata_to_proto(
     metadata: &OperationMetadata,
 ) -> crate::protos::op_store::OperationMetadata {
-    let mut proto = crate::protos::op_store::OperationMetadata::new();
-    proto.start_time = MessageField::some(timestamp_to_proto(&metadata.start_time));
-    proto.end_time = MessageField::some(timestamp_to_proto(&metadata.end_time));
-    proto.description = metadata.description.clone();
-    proto.hostname = metadata.hostname.clone();
-    proto.username = metadata.username.clone();
-    proto.tags = metadata.tags.clone();
-    proto
+    crate::protos::op_store::OperationMetadata {
+        start_time: Some(timestamp_to_proto(&metadata.start_time)),
+        end_time: Some(timestamp_to_proto(&metadata.end_time)),
+        description: metadata.description.clone(),
+        hostname: metadata.hostname.clone(),
+        username: metadata.username.clone(),
+        tags: metadata.tags.clone(),
+    }
 }
 
 fn operation_metadata_from_proto(
-    proto: &crate::protos::op_store::OperationMetadata,
+    proto: crate::protos::op_store::OperationMetadata,
 ) -> OperationMetadata {
-    let start_time = timestamp_from_proto(&proto.start_time);
-    let end_time = timestamp_from_proto(&proto.end_time);
-    let description = proto.description.to_owned();
-    let hostname = proto.hostname.to_owned();
-    let username = proto.username.to_owned();
-    let tags = proto.tags.clone();
+    let start_time = timestamp_from_proto(proto.start_time.unwrap_or_default());
+    let end_time = timestamp_from_proto(proto.end_time.unwrap_or_default());
     OperationMetadata {
         start_time,
         end_time,
-        description,
-        hostname,
-        username,
-        tags,
+        description: proto.description,
+        hostname: proto.hostname,
+        username: proto.username,
+        tags: proto.tags,
     }
 }
 
 fn operation_to_proto(operation: &Operation) -> crate::protos::op_store::Operation {
-    let mut proto = crate::protos::op_store::Operation::new();
-    proto.view_id = operation.view_id.as_bytes().to_vec();
+    let mut proto = crate::protos::op_store::Operation {
+        view_id: operation.view_id.as_bytes().to_vec(),
+        metadata: Some(operation_metadata_to_proto(&operation.metadata)),
+        ..Default::default()
+    };
     for parent in &operation.parents {
         proto.parents.push(parent.to_bytes());
     }
-    proto.metadata = MessageField::some(operation_metadata_to_proto(&operation.metadata));
     proto
 }
 
-fn operation_from_proto(proto: &crate::protos::op_store::Operation) -> Operation {
-    let operation_id_from_proto = |parent: &Vec<u8>| OperationId::new(parent.clone());
-    let parents = proto.parents.iter().map(operation_id_from_proto).collect();
-    let view_id = ViewId::new(proto.view_id.clone());
-    let metadata = operation_metadata_from_proto(&proto.metadata);
+fn operation_from_proto(proto: crate::protos::op_store::Operation) -> Operation {
+    let parents = proto.parents.into_iter().map(OperationId::new).collect();
+    let view_id = ViewId::new(proto.view_id);
+    let metadata = operation_metadata_from_proto(proto.metadata.unwrap_or_default());
     Operation {
         view_id,
         parents,
@@ -179,7 +175,7 @@ fn operation_from_proto(proto: &crate::protos::op_store::Operation) -> Operation
 }
 
 fn view_to_proto(view: &View) -> crate::protos::op_store::View {
-    let mut proto = crate::protos::op_store::View::new();
+    let mut proto = crate::protos::op_store::View::default();
     for (workspace_id, commit_id) in &view.wc_commit_ids {
         proto
             .wc_commit_ids
@@ -193,32 +189,38 @@ fn view_to_proto(view: &View) -> crate::protos::op_store::View {
     }
 
     for (name, target) in &view.branches {
-        let mut branch_proto = crate::protos::op_store::Branch::new();
+        let mut branch_proto = crate::protos::op_store::Branch {
+            name: name.clone(),
+            ..Default::default()
+        };
         branch_proto.name = name.clone();
         if let Some(local_target) = &target.local_target {
-            branch_proto.local_target = MessageField::some(ref_target_to_proto(local_target));
+            branch_proto.local_target = Some(ref_target_to_proto(local_target));
         }
         for (remote_name, target) in &target.remote_targets {
-            let mut remote_branch_proto = crate::protos::op_store::RemoteBranch::new();
-            remote_branch_proto.remote_name = remote_name.clone();
-            remote_branch_proto.target = MessageField::some(ref_target_to_proto(target));
-            branch_proto.remote_branches.push(remote_branch_proto);
+            branch_proto
+                .remote_branches
+                .push(crate::protos::op_store::RemoteBranch {
+                    remote_name: remote_name.clone(),
+                    target: Some(ref_target_to_proto(target)),
+                });
         }
         proto.branches.push(branch_proto);
     }
 
     for (name, target) in &view.tags {
-        let mut tag_proto = crate::protos::op_store::Tag::new();
-        tag_proto.name = name.clone();
-        tag_proto.target = MessageField::some(ref_target_to_proto(target));
-        proto.tags.push(tag_proto);
+        proto.tags.push(crate::protos::op_store::Tag {
+            name: name.clone(),
+            target: Some(ref_target_to_proto(target)),
+        });
     }
 
     for (git_ref_name, target) in &view.git_refs {
-        let mut git_ref_proto = crate::protos::op_store::GitRef::new();
-        git_ref_proto.name = git_ref_name.clone();
-        git_ref_proto.target = MessageField::some(ref_target_to_proto(target));
-        proto.git_refs.push(git_ref_proto);
+        proto.git_refs.push(crate::protos::op_store::GitRef {
+            name: git_ref_name.clone(),
+            target: Some(ref_target_to_proto(target)),
+            ..Default::default()
+        });
     }
 
     if let Some(git_head) = &view.git_head {
@@ -228,41 +230,34 @@ fn view_to_proto(view: &View) -> crate::protos::op_store::View {
     proto
 }
 
-fn view_from_proto(proto: &crate::protos::op_store::View) -> View {
+fn view_from_proto(proto: crate::protos::op_store::View) -> View {
     let mut view = View::default();
     // For compatibility with old repos before we had support for multiple working
     // copies
+    #[allow(deprecated)]
     if !proto.wc_commit_id.is_empty() {
-        view.wc_commit_ids.insert(
-            WorkspaceId::default(),
-            CommitId::new(proto.wc_commit_id.clone()),
-        );
+        view.wc_commit_ids
+            .insert(WorkspaceId::default(), CommitId::new(proto.wc_commit_id));
     }
-    for (workspace_id, commit_id) in &proto.wc_commit_ids {
-        view.wc_commit_ids.insert(
-            WorkspaceId::new(workspace_id.clone()),
-            CommitId::new(commit_id.clone()),
-        );
+    for (workspace_id, commit_id) in proto.wc_commit_ids {
+        view.wc_commit_ids
+            .insert(WorkspaceId::new(workspace_id), CommitId::new(commit_id));
     }
-    for head_id_bytes in &proto.head_ids {
-        view.head_ids.insert(CommitId::from_bytes(head_id_bytes));
+    for head_id_bytes in proto.head_ids {
+        view.head_ids.insert(CommitId::new(head_id_bytes));
     }
-    for head_id_bytes in &proto.public_head_ids {
-        view.public_head_ids
-            .insert(CommitId::from_bytes(head_id_bytes));
+    for head_id_bytes in proto.public_head_ids {
+        view.public_head_ids.insert(CommitId::new(head_id_bytes));
     }
 
-    for branch_proto in &proto.branches {
-        let local_target = branch_proto
-            .local_target
-            .as_ref()
-            .map(ref_target_from_proto);
+    for branch_proto in proto.branches {
+        let local_target = branch_proto.local_target.map(ref_target_from_proto);
 
         let mut remote_targets = BTreeMap::new();
-        for remote_branch in &branch_proto.remote_branches {
+        for remote_branch in branch_proto.remote_branches {
             remote_targets.insert(
-                remote_branch.remote_name.clone(),
-                ref_target_from_proto(&remote_branch.target),
+                remote_branch.remote_name,
+                ref_target_from_proto(remote_branch.target.unwrap_or_default()),
             );
         }
 
@@ -275,69 +270,69 @@ fn view_from_proto(proto: &crate::protos::op_store::View) -> View {
         );
     }
 
-    for tag_proto in &proto.tags {
+    for tag_proto in proto.tags {
         view.tags.insert(
-            tag_proto.name.clone(),
-            ref_target_from_proto(&tag_proto.target),
+            tag_proto.name,
+            ref_target_from_proto(tag_proto.target.unwrap_or_default()),
         );
     }
 
-    for git_ref in &proto.git_refs {
-        if let Some(target) = git_ref.target.as_ref() {
+    for git_ref in proto.git_refs {
+        if let Some(target) = git_ref.target {
             view.git_refs
-                .insert(git_ref.name.clone(), ref_target_from_proto(target));
+                .insert(git_ref.name, ref_target_from_proto(target));
         } else {
             // Legacy format
             view.git_refs.insert(
-                git_ref.name.clone(),
-                RefTarget::Normal(CommitId::new(git_ref.commit_id.clone())),
+                git_ref.name,
+                RefTarget::Normal(CommitId::new(git_ref.commit_id)),
             );
         }
     }
 
     if !proto.git_head.is_empty() {
-        view.git_head = Some(CommitId::new(proto.git_head.clone()));
+        view.git_head = Some(CommitId::new(proto.git_head));
     }
 
     view
 }
 
 fn ref_target_to_proto(value: &RefTarget) -> crate::protos::op_store::RefTarget {
-    let mut proto = crate::protos::op_store::RefTarget::new();
+    let mut proto = crate::protos::op_store::RefTarget::default();
     match value {
         RefTarget::Normal(id) => {
-            proto.set_commit_id(id.to_bytes());
+            proto.value = Some(crate::protos::op_store::ref_target::Value::CommitId(
+                id.to_bytes(),
+            ));
         }
         RefTarget::Conflict { removes, adds } => {
-            let mut ref_conflict_proto = crate::protos::op_store::RefConflict::new();
+            let mut ref_conflict_proto = crate::protos::op_store::RefConflict::default();
             for id in removes {
                 ref_conflict_proto.removes.push(id.to_bytes());
             }
             for id in adds {
                 ref_conflict_proto.adds.push(id.to_bytes());
             }
-            proto.set_conflict(ref_conflict_proto);
+            proto.value = Some(crate::protos::op_store::ref_target::Value::Conflict(
+                ref_conflict_proto,
+            ));
         }
     }
     proto
 }
 
-fn ref_target_from_proto(proto: &crate::protos::op_store::RefTarget) -> RefTarget {
-    match proto.value.as_ref().unwrap() {
+fn ref_target_from_proto(proto: crate::protos::op_store::RefTarget) -> RefTarget {
+    match proto.value.unwrap() {
         crate::protos::op_store::ref_target::Value::CommitId(id) => {
-            RefTarget::Normal(CommitId::from_bytes(id))
+            RefTarget::Normal(CommitId::new(id))
         }
         crate::protos::op_store::ref_target::Value::Conflict(conflict) => {
             let removes = conflict
                 .removes
-                .iter()
-                .map(|id_bytes| CommitId::from_bytes(id_bytes))
-                .collect_vec();
-            let adds = conflict
-                .adds
-                .iter()
-                .map(|id_bytes| CommitId::from_bytes(id_bytes))
+                .into_iter()
+                .map(CommitId::new)
                 .collect_vec();
+            let adds = conflict.adds.into_iter().map(CommitId::new).collect_vec();
             RefTarget::Conflict { removes, adds }
         }
     }
diff --git a/lib/src/protos/mod.rs b/lib/src/protos/mod.rs
index 2a73c7b6d..53aeaae31 100644
--- a/lib/src/protos/mod.rs
+++ b/lib/src/protos/mod.rs
@@ -1,15 +1,9 @@
-// Copyright 2020 The Jujutsu Authors
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-include!(concat!(env!("OUT_DIR"), "/protos/mod.rs"));
+pub mod op_store {
+    include!("op_store.rs");
+}
+pub mod store {
+    include!("store.rs");
+}
+pub mod working_copy {
+    include!("working_copy.rs");
+}
diff --git a/lib/src/protos/op_store.rs b/lib/src/protos/op_store.rs
new file mode 100644
index 000000000..3ed9b1ae6
--- /dev/null
+++ b/lib/src/protos/op_store.rs
@@ -0,0 +1,132 @@
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct RefConflict {
+    #[prost(bytes = "vec", repeated, tag = "1")]
+    pub removes: ::prost::alloc::vec::Vec<::prost::alloc::vec::Vec<u8>>,
+    #[prost(bytes = "vec", repeated, tag = "2")]
+    pub adds: ::prost::alloc::vec::Vec<::prost::alloc::vec::Vec<u8>>,
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct RefTarget {
+    #[prost(oneof = "ref_target::Value", tags = "1, 2")]
+    pub value: ::core::option::Option<ref_target::Value>,
+}
+/// Nested message and enum types in `RefTarget`.
+pub mod ref_target {
+    #[allow(clippy::derive_partial_eq_without_eq)]
+    #[derive(Clone, PartialEq, ::prost::Oneof)]
+    pub enum Value {
+        #[prost(bytes, tag = "1")]
+        CommitId(::prost::alloc::vec::Vec<u8>),
+        #[prost(message, tag = "2")]
+        Conflict(super::RefConflict),
+    }
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct RemoteBranch {
+    #[prost(string, tag = "1")]
+    pub remote_name: ::prost::alloc::string::String,
+    #[prost(message, optional, tag = "2")]
+    pub target: ::core::option::Option<RefTarget>,
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Branch {
+    #[prost(string, tag = "1")]
+    pub name: ::prost::alloc::string::String,
+    /// Unset if the branch has been deleted locally.
+    #[prost(message, optional, tag = "2")]
+    pub local_target: ::core::option::Option<RefTarget>,
+    /// TODO: How would we support renaming remotes while having undo work? If
+    /// the remote name is stored in config, it's going to become a mess if the
+    /// remote is renamed but the configs are left unchanged. Should each remote
+    /// be identified (here and in configs) by a UUID?
+    #[prost(message, repeated, tag = "3")]
+    pub remote_branches: ::prost::alloc::vec::Vec<RemoteBranch>,
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct GitRef {
+    #[prost(string, tag = "1")]
+    pub name: ::prost::alloc::string::String,
+    /// This field is just for historical reasons (before we had the RefTarget
+    /// type). New GitRefs have (only) the target field.
+    /// TODO: Delete support for the old format.
+    #[prost(bytes = "vec", tag = "2")]
+    pub commit_id: ::prost::alloc::vec::Vec<u8>,
+    #[prost(message, optional, tag = "3")]
+    pub target: ::core::option::Option<RefTarget>,
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Tag {
+    #[prost(string, tag = "1")]
+    pub name: ::prost::alloc::string::String,
+    #[prost(message, optional, tag = "2")]
+    pub target: ::core::option::Option<RefTarget>,
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct View {
+    #[prost(bytes = "vec", repeated, tag = "1")]
+    pub head_ids: ::prost::alloc::vec::Vec<::prost::alloc::vec::Vec<u8>>,
+    #[prost(bytes = "vec", repeated, tag = "4")]
+    pub public_head_ids: ::prost::alloc::vec::Vec<::prost::alloc::vec::Vec<u8>>,
+    #[deprecated]
+    #[prost(bytes = "vec", tag = "2")]
+    pub wc_commit_id: ::prost::alloc::vec::Vec<u8>,
+    #[prost(map = "string, bytes", tag = "8")]
+    pub wc_commit_ids: ::std::collections::HashMap<
+        ::prost::alloc::string::String,
+        ::prost::alloc::vec::Vec<u8>,
+    >,
+    #[prost(message, repeated, tag = "5")]
+    pub branches: ::prost::alloc::vec::Vec<Branch>,
+    #[prost(message, repeated, tag = "6")]
+    pub tags: ::prost::alloc::vec::Vec<Tag>,
+    /// Only a subset of the refs. For example, does not include refs/notes/.
+    #[prost(message, repeated, tag = "3")]
+    pub git_refs: ::prost::alloc::vec::Vec<GitRef>,
+    #[prost(bytes = "vec", tag = "7")]
+    pub git_head: ::prost::alloc::vec::Vec<u8>,
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Operation {
+    #[prost(bytes = "vec", tag = "1")]
+    pub view_id: ::prost::alloc::vec::Vec<u8>,
+    #[prost(bytes = "vec", repeated, tag = "2")]
+    pub parents: ::prost::alloc::vec::Vec<::prost::alloc::vec::Vec<u8>>,
+    #[prost(message, optional, tag = "3")]
+    pub metadata: ::core::option::Option<OperationMetadata>,
+}
+/// TODO: Share with store.proto? Do we even need the timezone here?
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Timestamp {
+    #[prost(int64, tag = "1")]
+    pub millis_since_epoch: i64,
+    #[prost(int32, tag = "2")]
+    pub tz_offset: i32,
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct OperationMetadata {
+    #[prost(message, optional, tag = "1")]
+    pub start_time: ::core::option::Option<Timestamp>,
+    #[prost(message, optional, tag = "2")]
+    pub end_time: ::core::option::Option<Timestamp>,
+    #[prost(string, tag = "3")]
+    pub description: ::prost::alloc::string::String,
+    #[prost(string, tag = "4")]
+    pub hostname: ::prost::alloc::string::String,
+    #[prost(string, tag = "5")]
+    pub username: ::prost::alloc::string::String,
+    #[prost(map = "string, string", tag = "6")]
+    pub tags: ::std::collections::HashMap<
+        ::prost::alloc::string::String,
+        ::prost::alloc::string::String,
+    >,
+}
diff --git a/lib/src/protos/store.rs b/lib/src/protos/store.rs
new file mode 100644
index 000000000..04898b86e
--- /dev/null
+++ b/lib/src/protos/store.rs
@@ -0,0 +1,108 @@
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct TreeValue {
+    #[prost(oneof = "tree_value::Value", tags = "2, 3, 4, 5")]
+    pub value: ::core::option::Option<tree_value::Value>,
+}
+/// Nested message and enum types in `TreeValue`.
+pub mod tree_value {
+    #[allow(clippy::derive_partial_eq_without_eq)]
+    #[derive(Clone, PartialEq, ::prost::Message)]
+    pub struct File {
+        #[prost(bytes = "vec", tag = "1")]
+        pub id: ::prost::alloc::vec::Vec<u8>,
+        #[prost(bool, tag = "2")]
+        pub executable: bool,
+    }
+    #[allow(clippy::derive_partial_eq_without_eq)]
+    #[derive(Clone, PartialEq, ::prost::Oneof)]
+    pub enum Value {
+        #[prost(message, tag = "2")]
+        File(File),
+        #[prost(bytes, tag = "3")]
+        SymlinkId(::prost::alloc::vec::Vec<u8>),
+        #[prost(bytes, tag = "4")]
+        TreeId(::prost::alloc::vec::Vec<u8>),
+        #[prost(bytes, tag = "5")]
+        ConflictId(::prost::alloc::vec::Vec<u8>),
+    }
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Tree {
+    #[prost(message, repeated, tag = "1")]
+    pub entries: ::prost::alloc::vec::Vec<tree::Entry>,
+}
+/// Nested message and enum types in `Tree`.
+pub mod tree {
+    #[allow(clippy::derive_partial_eq_without_eq)]
+    #[derive(Clone, PartialEq, ::prost::Message)]
+    pub struct Entry {
+        #[prost(string, tag = "1")]
+        pub name: ::prost::alloc::string::String,
+        #[prost(message, optional, tag = "2")]
+        pub value: ::core::option::Option<super::TreeValue>,
+    }
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Commit {
+    #[prost(bytes = "vec", repeated, tag = "1")]
+    pub parents: ::prost::alloc::vec::Vec<::prost::alloc::vec::Vec<u8>>,
+    #[prost(bytes = "vec", repeated, tag = "2")]
+    pub predecessors: ::prost::alloc::vec::Vec<::prost::alloc::vec::Vec<u8>>,
+    #[prost(bytes = "vec", tag = "3")]
+    pub root_tree: ::prost::alloc::vec::Vec<u8>,
+    #[prost(bytes = "vec", tag = "4")]
+    pub change_id: ::prost::alloc::vec::Vec<u8>,
+    #[prost(string, tag = "5")]
+    pub description: ::prost::alloc::string::String,
+    #[prost(message, optional, tag = "6")]
+    pub author: ::core::option::Option<commit::Signature>,
+    #[prost(message, optional, tag = "7")]
+    pub committer: ::core::option::Option<commit::Signature>,
+    #[deprecated]
+    #[prost(bool, tag = "8")]
+    pub is_open: bool,
+    #[deprecated]
+    #[prost(bool, tag = "9")]
+    pub is_pruned: bool,
+}
+/// Nested message and enum types in `Commit`.
+pub mod commit {
+    #[allow(clippy::derive_partial_eq_without_eq)]
+    #[derive(Clone, PartialEq, ::prost::Message)]
+    pub struct Timestamp {
+        #[prost(int64, tag = "1")]
+        pub millis_since_epoch: i64,
+        #[prost(int32, tag = "2")]
+        pub tz_offset: i32,
+    }
+    #[allow(clippy::derive_partial_eq_without_eq)]
+    #[derive(Clone, PartialEq, ::prost::Message)]
+    pub struct Signature {
+        #[prost(string, tag = "1")]
+        pub name: ::prost::alloc::string::String,
+        #[prost(string, tag = "2")]
+        pub email: ::prost::alloc::string::String,
+        #[prost(message, optional, tag = "3")]
+        pub timestamp: ::core::option::Option<Timestamp>,
+    }
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Conflict {
+    #[prost(message, repeated, tag = "1")]
+    pub removes: ::prost::alloc::vec::Vec<conflict::Part>,
+    #[prost(message, repeated, tag = "2")]
+    pub adds: ::prost::alloc::vec::Vec<conflict::Part>,
+}
+/// Nested message and enum types in `Conflict`.
+pub mod conflict {
+    #[allow(clippy::derive_partial_eq_without_eq)]
+    #[derive(Clone, PartialEq, ::prost::Message)]
+    pub struct Part {
+        #[prost(message, optional, tag = "1")]
+        pub content: ::core::option::Option<super::TreeValue>,
+    }
+}
diff --git a/lib/src/protos/working_copy.rs b/lib/src/protos/working_copy.rs
new file mode 100644
index 000000000..b0d5535c5
--- /dev/null
+++ b/lib/src/protos/working_copy.rs
@@ -0,0 +1,85 @@
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct FileState {
+    #[prost(int64, tag = "1")]
+    pub mtime_millis_since_epoch: i64,
+    #[prost(uint64, tag = "2")]
+    pub size: u64,
+    #[prost(enumeration = "FileType", tag = "3")]
+    pub file_type: i32,
+    /// Set only if file_type is Conflict
+    #[prost(bytes = "vec", tag = "4")]
+    pub conflict_id: ::prost::alloc::vec::Vec<u8>,
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct SparsePatterns {
+    #[prost(string, repeated, tag = "1")]
+    pub prefixes: ::prost::alloc::vec::Vec<::prost::alloc::string::String>,
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct TreeState {
+    #[prost(bytes = "vec", tag = "1")]
+    pub tree_id: ::prost::alloc::vec::Vec<u8>,
+    #[prost(map = "string, message", tag = "2")]
+    pub file_states: ::std::collections::HashMap<
+        ::prost::alloc::string::String,
+        FileState,
+    >,
+    #[prost(message, optional, tag = "3")]
+    pub sparse_patterns: ::core::option::Option<SparsePatterns>,
+}
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Checkout {
+    /// The operation at which the working copy was updated.
+    #[prost(bytes = "vec", tag = "2")]
+    pub operation_id: ::prost::alloc::vec::Vec<u8>,
+    /// An identifier for this workspace. It is used for looking up the current
+    /// checkout in the repo view. Currently a human-readable name.
+    /// TODO: Is it better to make this a UUID and a have map that to a name in
+    /// config? That way users can rename a workspace.
+    #[prost(string, tag = "3")]
+    pub workspace_id: ::prost::alloc::string::String,
+    /// The checked-out commit, which can be viewed as a cache of the working-copy
+    /// commit ID recorded in `operation_id`'s operation. No longer used.
+    /// TODO: Delete this mid 2022 or so
+    #[prost(bytes = "vec", tag = "1")]
+    pub commit_id: ::prost::alloc::vec::Vec<u8>,
+}
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, ::prost::Enumeration)]
+#[repr(i32)]
+pub enum FileType {
+    Normal = 0,
+    Symlink = 1,
+    Executable = 2,
+    Conflict = 3,
+    GitSubmodule = 4,
+}
+impl FileType {
+    /// String value of the enum field names used in the ProtoBuf definition.
+    ///
+    /// The values are not transformed in any way and thus are considered stable
+    /// (if the ProtoBuf definition does not change) and safe for programmatic use.
+    pub fn as_str_name(&self) -> &'static str {
+        match self {
+            FileType::Normal => "Normal",
+            FileType::Symlink => "Symlink",
+            FileType::Executable => "Executable",
+            FileType::Conflict => "Conflict",
+            FileType::GitSubmodule => "GitSubmodule",
+        }
+    }
+    /// Creates an enum from field names used in the ProtoBuf definition.
+    pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+        match value {
+            "Normal" => Some(Self::Normal),
+            "Symlink" => Some(Self::Symlink),
+            "Executable" => Some(Self::Executable),
+            "Conflict" => Some(Self::Conflict),
+            "GitSubmodule" => Some(Self::GitSubmodule),
+            _ => None,
+        }
+    }
+}
diff --git a/lib/src/repo_path.rs b/lib/src/repo_path.rs
index d32bd822e..1b92a63a6 100644
--- a/lib/src/repo_path.rs
+++ b/lib/src/repo_path.rs
@@ -39,10 +39,14 @@ impl RepoPathComponent {
 
 impl From<&str> for RepoPathComponent {
     fn from(value: &str) -> Self {
+        RepoPathComponent::from(value.to_owned())
+    }
+}
+
+impl From<String> for RepoPathComponent {
+    fn from(value: String) -> Self {
         assert!(!value.contains('/'));
-        RepoPathComponent {
-            value: value.to_owned(),
-        }
+        RepoPathComponent { value }
     }
 }
 
diff --git a/lib/src/working_copy.rs b/lib/src/working_copy.rs
index 4e57e2462..5d273e424 100644
--- a/lib/src/working_copy.rs
+++ b/lib/src/working_copy.rs
@@ -27,7 +27,7 @@ use std::sync::Arc;
 use std::time::UNIX_EPOCH;
 
 use once_cell::unsync::OnceCell;
-use protobuf::{EnumOrUnknown, Message, MessageField};
+use prost::Message;
 use tempfile::NamedTempFile;
 use thiserror::Error;
 
@@ -125,13 +125,13 @@ pub struct TreeState {
     own_mtime: MillisSinceEpoch,
 }
 
-fn file_state_from_proto(proto: &crate::protos::working_copy::FileState) -> FileState {
-    let file_type = match proto.file_type.enum_value_or_default() {
+fn file_state_from_proto(proto: crate::protos::working_copy::FileState) -> FileState {
+    let file_type = match proto.file_type() {
         crate::protos::working_copy::FileType::Normal => FileType::Normal { executable: false },
         crate::protos::working_copy::FileType::Executable => FileType::Normal { executable: true },
         crate::protos::working_copy::FileType::Symlink => FileType::Symlink,
         crate::protos::working_copy::FileType::Conflict => {
-            let id = ConflictId::new(proto.conflict_id.to_vec());
+            let id = ConflictId::new(proto.conflict_id);
             FileType::Conflict { id }
         }
         crate::protos::working_copy::FileType::GitSubmodule => FileType::GitSubmodule,
@@ -144,7 +144,7 @@ fn file_state_from_proto(proto: &crate::protos::working_copy::FileState) -> File
 }
 
 fn file_state_to_proto(file_state: &FileState) -> crate::protos::working_copy::FileState {
-    let mut proto = crate::protos::working_copy::FileState::new();
+    let mut proto = crate::protos::working_copy::FileState::default();
     let file_type = match &file_state.file_type {
         FileType::Normal { executable: false } => crate::protos::working_copy::FileType::Normal,
         FileType::Normal { executable: true } => crate::protos::working_copy::FileType::Executable,
@@ -155,7 +155,7 @@ fn file_state_to_proto(file_state: &FileState) -> crate::protos::working_copy::F
         }
         FileType::GitSubmodule => crate::protos::working_copy::FileType::GitSubmodule,
     };
-    proto.file_type = EnumOrUnknown::new(file_type);
+    proto.file_type = file_type as i32;
     proto.mtime_millis_since_epoch = file_state.mtime.0;
     proto.size = file_state.size;
     proto
@@ -167,7 +167,7 @@ fn file_states_from_proto(
     let mut file_states = BTreeMap::new();
     for (path_str, proto_file_state) in &proto.file_states {
         let path = RepoPath::from_internal_string(path_str.as_str());
-        file_states.insert(path, file_state_from_proto(proto_file_state));
+        file_states.insert(path, file_state_from_proto(proto_file_state.clone()));
     }
     file_states
 }
@@ -401,32 +401,38 @@ impl TreeState {
 
     fn read(&mut self, mut file: File) {
         self.update_own_mtime();
-        let proto: crate::protos::working_copy::TreeState =
-            Message::parse_from_reader(&mut file).unwrap();
+        let mut buf = Vec::new();
+        file.read_to_end(&mut buf).unwrap();
+        let proto = crate::protos::working_copy::TreeState::decode(&*buf).unwrap();
         self.tree_id = TreeId::new(proto.tree_id.clone());
         self.file_states = file_states_from_proto(&proto);
         self.sparse_patterns = sparse_patterns_from_proto(&proto);
     }
 
     fn save(&mut self) {
-        let mut proto = crate::protos::working_copy::TreeState::new();
-        proto.tree_id = self.tree_id.to_bytes();
+        let mut proto = crate::protos::working_copy::TreeState {
+            tree_id: self.tree_id.to_bytes(),
+            ..Default::default()
+        };
         for (file, file_state) in &self.file_states {
             proto.file_states.insert(
                 file.to_internal_file_string(),
                 file_state_to_proto(file_state),
             );
         }
-        let mut sparse_patterns = crate::protos::working_copy::SparsePatterns::new();
+        let mut sparse_patterns = crate::protos::working_copy::SparsePatterns::default();
         for path in &self.sparse_patterns {
             sparse_patterns
                 .prefixes
                 .push(path.to_internal_file_string());
         }
-        proto.sparse_patterns = MessageField::some(sparse_patterns);
+        proto.sparse_patterns = Some(sparse_patterns);
 
         let mut temp_file = NamedTempFile::new_in(&self.state_path).unwrap();
-        proto.write_to_writer(temp_file.as_file_mut()).unwrap();
+        temp_file
+            .as_file_mut()
+            .write_all(&proto.encode_to_vec())
+            .unwrap();
         // update own write time while we before we rename it, so we know
         // there is no unknown data in it
         self.update_own_mtime();
@@ -1012,15 +1018,17 @@ impl WorkingCopy {
         operation_id: OperationId,
         workspace_id: WorkspaceId,
     ) -> WorkingCopy {
-        let mut proto = crate::protos::working_copy::Checkout::new();
-        proto.operation_id = operation_id.to_bytes();
-        proto.workspace_id = workspace_id.as_str().to_string();
+        let proto = crate::protos::working_copy::Checkout {
+            operation_id: operation_id.to_bytes(),
+            workspace_id: workspace_id.as_str().to_string(),
+            ..Default::default()
+        };
         let mut file = OpenOptions::new()
             .create_new(true)
             .write(true)
             .open(state_path.join("checkout"))
             .unwrap();
-        proto.write_to_writer(&mut file).unwrap();
+        file.write_all(&proto.encode_to_vec()).unwrap();
         WorkingCopy {
             store,
             working_copy_path,
@@ -1050,7 +1058,10 @@ impl WorkingCopy {
 
     fn write_proto(&self, proto: crate::protos::working_copy::Checkout) {
         let mut temp_file = NamedTempFile::new_in(&self.state_path).unwrap();
-        proto.write_to_writer(temp_file.as_file_mut()).unwrap();
+        temp_file
+            .as_file_mut()
+            .write_all(&proto.encode_to_vec())
+            .unwrap();
         // TODO: Retry if persisting fails (it will on Windows if the file happened to
         // be open for read).
         temp_file.persist(self.state_path.join("checkout")).unwrap();
@@ -1058,9 +1069,8 @@ impl WorkingCopy {
 
     fn checkout_state(&self) -> &CheckoutState {
         self.checkout_state.get_or_init(|| {
-            let mut file = File::open(self.state_path.join("checkout")).unwrap();
-            let proto: crate::protos::working_copy::Checkout =
-                Message::parse_from_reader(&mut file).unwrap();
+            let buf = fs::read(self.state_path.join("checkout")).unwrap();
+            let proto = crate::protos::working_copy::Checkout::decode(&*buf).unwrap();
             CheckoutState {
                 operation_id: OperationId::new(proto.operation_id),
                 workspace_id: if proto.workspace_id.is_empty() {
@@ -1115,10 +1125,11 @@ impl WorkingCopy {
     }
 
     fn save(&mut self) {
-        let mut proto = crate::protos::working_copy::Checkout::new();
-        proto.operation_id = self.operation_id().to_bytes();
-        proto.workspace_id = self.workspace_id().as_str().to_string();
-        self.write_proto(proto);
+        self.write_proto(crate::protos::working_copy::Checkout {
+            operation_id: self.operation_id().to_bytes(),
+            workspace_id: self.workspace_id().as_str().to_string(),
+            ..Default::default()
+        });
     }
 
     pub fn start_mutation(&mut self) -> LockedWorkingCopy {