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jj/lib/src/git_backend.rs
Yuya Nishihara f20004fffe git_backend: classify "merge with root" as user error 
Perhaps, there will be more error types that hold BackendError internally, but
this change is good enough to handle a merge error.
2024-03-30 11:14:25 +09:00

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// 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.
#![allow(missing_docs)]
use std::any::Any;
use std::collections::HashSet;
use std::fmt::{Debug, Error, Formatter};
use std::io::{Cursor, Read};
use std::path::{Path, PathBuf};
use std::process::{Command, ExitStatus};
use std::sync::{Arc, Mutex, MutexGuard};
use std::time::SystemTime;
use std::{fs, io, str};
use async_trait::async_trait;
use gix::bstr::BString;
use gix::objs::{CommitRef, CommitRefIter, WriteTo};
use itertools::Itertools;
use prost::Message;
use smallvec::SmallVec;
use thiserror::Error;
use crate::backend::{
make_root_commit, Backend, BackendError, BackendInitError, BackendLoadError, BackendResult,
ChangeId, Commit, CommitId, Conflict, ConflictId, ConflictTerm, FileId, MergedTreeId,
MillisSinceEpoch, SecureSig, Signature, SigningFn, SymlinkId, Timestamp, Tree, TreeId,
TreeValue,
};
use crate::file_util::{IoResultExt as _, PathError};
use crate::index::Index;
use crate::lock::FileLock;
use crate::merge::{Merge, MergeBuilder};
use crate::object_id::ObjectId;
use crate::repo_path::{RepoPath, RepoPathComponentBuf};
use crate::settings::UserSettings;
use crate::stacked_table::{
MutableTable, ReadonlyTable, TableSegment, TableStore, TableStoreError,
};
const HASH_LENGTH: usize = 20;
const CHANGE_ID_LENGTH: usize = 16;
/// Ref namespace used only for preventing GC.
const NO_GC_REF_NAMESPACE: &str = "refs/jj/keep/";
const CONFLICT_SUFFIX: &str = ".jjconflict";
const JJ_TREES_COMMIT_HEADER: &[u8] = b"jj:trees";
#[derive(Debug, Error)]
pub enum GitBackendInitError {
#[error("Failed to initialize git repository")]
InitRepository(#[source] gix::init::Error),
#[error("Failed to open git repository")]
OpenRepository(#[source] gix::open::Error),
#[error(transparent)]
Path(PathError),
}
impl From<Box<GitBackendInitError>> for BackendInitError {
fn from(err: Box<GitBackendInitError>) -> Self {
BackendInitError(err)
}
}
#[derive(Debug, Error)]
pub enum GitBackendLoadError {
#[error("Failed to open git repository")]
OpenRepository(#[source] gix::open::Error),
#[error(transparent)]
Path(PathError),
}
impl From<Box<GitBackendLoadError>> for BackendLoadError {
fn from(err: Box<GitBackendLoadError>) -> Self {
BackendLoadError(err)
}
}
/// `GitBackend`-specific error that may occur after the backend is loaded.
#[derive(Debug, Error)]
pub enum GitBackendError {
#[error("Failed to read non-git metadata")]
ReadMetadata(#[source] TableStoreError),
#[error("Failed to write non-git metadata")]
WriteMetadata(#[source] TableStoreError),
}
impl From<GitBackendError> for BackendError {
fn from(err: GitBackendError) -> Self {
BackendError::Other(err.into())
}
}
#[derive(Debug, Error)]
pub enum GitGcError {
#[error("Failed to run git gc command")]
GcCommand(#[source] std::io::Error),
#[error("git gc command exited with an error: {0}")]
GcCommandErrorStatus(ExitStatus),
}
pub struct GitBackend {
// While gix::Repository can be created from gix::ThreadSafeRepository, it's
// cheaper to cache the thread-local instance behind a mutex than creating
// one for each backend method call. Our GitBackend is most likely to be
// used in a single-threaded context.
base_repo: gix::ThreadSafeRepository,
repo: Mutex<gix::Repository>,
root_commit_id: CommitId,
root_change_id: ChangeId,
empty_tree_id: TreeId,
extra_metadata_store: TableStore,
cached_extra_metadata: Mutex<Option<Arc<ReadonlyTable>>>,
/// Whether tree of imported commit should be promoted to non-legacy format.
imported_commit_uses_tree_conflict_format: bool,
}
impl GitBackend {
pub fn name() -> &'static str {
"git"
}
fn new(
base_repo: gix::ThreadSafeRepository,
extra_metadata_store: TableStore,
imported_commit_uses_tree_conflict_format: bool,
) -> Self {
let repo = Mutex::new(base_repo.to_thread_local());
let root_commit_id = CommitId::from_bytes(&[0; HASH_LENGTH]);
let root_change_id = ChangeId::from_bytes(&[0; CHANGE_ID_LENGTH]);
let empty_tree_id = TreeId::from_hex("4b825dc642cb6eb9a060e54bf8d69288fbee4904");
GitBackend {
base_repo,
repo,
root_commit_id,
root_change_id,
empty_tree_id,
extra_metadata_store,
cached_extra_metadata: Mutex::new(None),
imported_commit_uses_tree_conflict_format,
}
}
pub fn init_internal(
settings: &UserSettings,
store_path: &Path,
) -> Result<Self, Box<GitBackendInitError>> {
let git_repo_path = Path::new("git");
let git_repo = gix::ThreadSafeRepository::init_opts(
store_path.join(git_repo_path),
gix::create::Kind::Bare,
gix::create::Options::default(),
gix_open_opts_from_settings(settings),
)
.map_err(GitBackendInitError::InitRepository)?;
Self::init_with_repo(settings, store_path, git_repo_path, git_repo)
}
/// Initializes backend by creating a new Git repo at the specified
/// workspace path. The workspace directory must exist.
pub fn init_colocated(
settings: &UserSettings,
store_path: &Path,
workspace_root: &Path,
) -> Result<Self, Box<GitBackendInitError>> {
let canonical_workspace_root = {
let path = store_path.join(workspace_root);
path.canonicalize()
.context(&path)
.map_err(GitBackendInitError::Path)?
};
let git_repo = gix::ThreadSafeRepository::init_opts(
canonical_workspace_root,
gix::create::Kind::WithWorktree,
gix::create::Options::default(),
gix_open_opts_from_settings(settings),
)
.map_err(GitBackendInitError::InitRepository)?;
let git_repo_path = workspace_root.join(".git");
Self::init_with_repo(settings, store_path, &git_repo_path, git_repo)
}
/// Initializes backend with an existing Git repo at the specified path.
pub fn init_external(
settings: &UserSettings,
store_path: &Path,
git_repo_path: &Path,
) -> Result<Self, Box<GitBackendInitError>> {
let canonical_git_repo_path = {
let path = store_path.join(git_repo_path);
canonicalize_git_repo_path(&path)
.context(&path)
.map_err(GitBackendInitError::Path)?
};
let git_repo = gix::ThreadSafeRepository::open_opts(
canonical_git_repo_path,
gix_open_opts_from_settings(settings),
)
.map_err(GitBackendInitError::OpenRepository)?;
Self::init_with_repo(settings, store_path, git_repo_path, git_repo)
}
fn init_with_repo(
settings: &UserSettings,
store_path: &Path,
git_repo_path: &Path,
git_repo: gix::ThreadSafeRepository,
) -> Result<Self, Box<GitBackendInitError>> {
let extra_path = store_path.join("extra");
fs::create_dir(&extra_path)
.context(&extra_path)
.map_err(GitBackendInitError::Path)?;
let target_path = store_path.join("git_target");
if cfg!(windows) && git_repo_path.is_relative() {
// When a repository is created in Windows, format the path with *forward
// slashes* and not backwards slashes. This makes it possible to use the same
// repository under Windows Subsystem for Linux.
//
// This only works for relative paths. If the path is absolute, there's not much
// we can do, and it simply won't work inside and outside WSL at the same time.
let git_repo_path_string = git_repo_path
.components()
.map(|component| component.as_os_str().to_str().unwrap().to_owned())
.join("/");
fs::write(&target_path, git_repo_path_string.as_bytes())
.context(&target_path)
.map_err(GitBackendInitError::Path)?;
} else {
fs::write(&target_path, git_repo_path.to_str().unwrap().as_bytes())
.context(&target_path)
.map_err(GitBackendInitError::Path)?;
};
let extra_metadata_store = TableStore::init(extra_path, HASH_LENGTH);
Ok(GitBackend::new(
git_repo,
extra_metadata_store,
settings.use_tree_conflict_format(),
))
}
pub fn load(
settings: &UserSettings,
store_path: &Path,
) -> Result<Self, Box<GitBackendLoadError>> {
let git_repo_path = {
let target_path = store_path.join("git_target");
let git_repo_path_str = fs::read_to_string(&target_path)
.context(&target_path)
.map_err(GitBackendLoadError::Path)?;
let git_repo_path = store_path.join(git_repo_path_str);
canonicalize_git_repo_path(&git_repo_path)
.context(&git_repo_path)
.map_err(GitBackendLoadError::Path)?
};
let repo = gix::ThreadSafeRepository::open_opts(
git_repo_path,
gix_open_opts_from_settings(settings),
)
.map_err(GitBackendLoadError::OpenRepository)?;
let extra_metadata_store = TableStore::load(store_path.join("extra"), HASH_LENGTH);
Ok(GitBackend::new(
repo,
extra_metadata_store,
settings.use_tree_conflict_format(),
))
}
fn lock_git_repo(&self) -> MutexGuard<'_, gix::Repository> {
self.repo.lock().unwrap()
}
/// Returns new thread-local instance to access to the underlying Git repo.
pub fn git_repo(&self) -> gix::Repository {
self.base_repo.to_thread_local()
}
/// Creates new owned git repository instance.
pub fn open_git_repo(&self) -> Result<git2::Repository, git2::Error> {
git2::Repository::open(self.git_repo_path())
}
/// Path to the `.git` directory or the repository itself if it's bare.
pub fn git_repo_path(&self) -> &Path {
self.base_repo.path()
}
/// Path to the working directory if the repository isn't bare.
pub fn git_workdir(&self) -> Option<&Path> {
self.base_repo.work_dir()
}
fn cached_extra_metadata_table(&self) -> BackendResult<Arc<ReadonlyTable>> {
let mut locked_head = self.cached_extra_metadata.lock().unwrap();
match locked_head.as_ref() {
Some(head) => Ok(head.clone()),
None => {
let table = self
.extra_metadata_store
.get_head()
.map_err(GitBackendError::ReadMetadata)?;
*locked_head = Some(table.clone());
Ok(table)
}
}
}
fn read_extra_metadata_table_locked(&self) -> BackendResult<(Arc<ReadonlyTable>, FileLock)> {
let table = self
.extra_metadata_store
.get_head_locked()
.map_err(GitBackendError::ReadMetadata)?;
Ok(table)
}
fn save_extra_metadata_table(
&self,
mut_table: MutableTable,
_table_lock: &FileLock,
) -> BackendResult<()> {
let table = self
.extra_metadata_store
.save_table(mut_table)
.map_err(GitBackendError::WriteMetadata)?;
// Since the parent table was the head, saved table are likely to be new head.
// If it's not, cache will be reloaded when entry can't be found.
*self.cached_extra_metadata.lock().unwrap() = Some(table);
Ok(())
}
/// Imports the given commits and ancestors from the backing Git repo.
///
/// The `head_ids` may contain commits that have already been imported, but
/// the caller should filter them out to eliminate redundant I/O processing.
#[tracing::instrument(skip(self, head_ids))]
pub fn import_head_commits<'a>(
&self,
head_ids: impl IntoIterator<Item = &'a CommitId>,
) -> BackendResult<()> {
let head_ids: HashSet<&CommitId> = head_ids
.into_iter()
.filter(|&id| *id != self.root_commit_id)
.collect();
if head_ids.is_empty() {
return Ok(());
}
// Create no-gc ref even if known to the extras table. Concurrent GC
// process might have deleted the no-gc ref.
let locked_repo = self.lock_git_repo();
locked_repo
.edit_references(head_ids.iter().copied().map(to_no_gc_ref_update))
.map_err(|err| BackendError::Other(Box::new(err)))?;
// These commits are imported from Git. Make our change ids persist (otherwise
// future write_commit() could reassign new change id.)
tracing::debug!(
heads_count = head_ids.len(),
"import extra metadata entries"
);
let (table, table_lock) = self.read_extra_metadata_table_locked()?;
let mut mut_table = table.start_mutation();
import_extra_metadata_entries_from_heads(
&locked_repo,
&mut mut_table,
&table_lock,
&head_ids,
self.imported_commit_uses_tree_conflict_format,
)?;
self.save_extra_metadata_table(mut_table, &table_lock)
}
fn read_file_sync(&self, id: &FileId) -> BackendResult<Box<dyn Read>> {
let git_blob_id = validate_git_object_id(id)?;
let locked_repo = self.lock_git_repo();
let mut blob = locked_repo
.find_object(git_blob_id)
.map_err(|err| map_not_found_err(err, id))?
.try_into_blob()
.map_err(|err| to_read_object_err(err, id))?;
Ok(Box::new(Cursor::new(blob.take_data())))
}
}
/// Canonicalizes the given `path` except for the last `".git"` component.
///
/// The last path component matters when opening a Git repo without `core.bare`
/// config. This config is usually set, but the "repo" tool will set up such
/// repositories and symlinks. Opening such repo with fully-canonicalized path
/// would turn a colocated Git repo into a bare repo.
pub fn canonicalize_git_repo_path(path: &Path) -> io::Result<PathBuf> {
if path.ends_with(".git") {
let workdir = path.parent().unwrap();
workdir.canonicalize().map(|dir| dir.join(".git"))
} else {
path.canonicalize()
}
}
fn gix_open_opts_from_settings(settings: &UserSettings) -> gix::open::Options {
let user_name = settings.user_name();
let user_email = settings.user_email();
gix::open::Options::default()
.config_overrides([
// Committer has to be configured to record reflog. Author isn't
// needed, but let's copy the same values.
format!("author.name={user_name}"),
format!("author.email={user_email}"),
format!("committer.name={user_name}"),
format!("committer.email={user_email}"),
])
// The git_target path should point the repository, not the working directory.
.open_path_as_is(true)
}
/// Reads the `jj:trees` header from the commit.
fn root_tree_from_header(git_commit: &CommitRef) -> Result<Option<MergedTreeId>, ()> {
for (key, value) in &git_commit.extra_headers {
if *key == JJ_TREES_COMMIT_HEADER {
let mut tree_ids = SmallVec::new();
for hex in str::from_utf8(value.as_ref()).or(Err(()))?.split(' ') {
let tree_id = TreeId::try_from_hex(hex).or(Err(()))?;
if tree_id.as_bytes().len() != HASH_LENGTH {
return Err(());
}
tree_ids.push(tree_id);
}
if tree_ids.len() % 2 == 0 {
return Err(());
}
return Ok(Some(MergedTreeId::Merge(Merge::from_vec(tree_ids))));
}
}
Ok(None)
}
fn commit_from_git_without_root_parent(
id: &CommitId,
git_object: &gix::Object,
uses_tree_conflict_format: bool,
) -> Result<Commit, BackendError> {
let commit = git_object
.try_to_commit_ref()
.map_err(|err| to_read_object_err(err, id))?;
// We reverse the bits of the commit id to create the change id. We don't want
// to use the first bytes unmodified because then it would be ambiguous
// if a given hash prefix refers to the commit id or the change id. It
// would have been enough to pick the last 16 bytes instead of the
// leading 16 bytes to address that. We also reverse the bits to make it less
// likely that users depend on any relationship between the two ids.
let change_id = ChangeId::new(
id.as_bytes()[4..HASH_LENGTH]
.iter()
.rev()
.map(|b| b.reverse_bits())
.collect(),
);
let parents = commit
.parents()
.map(|oid| CommitId::from_bytes(oid.as_bytes()))
.collect_vec();
let tree_id = TreeId::from_bytes(commit.tree().as_bytes());
// If this commit is a conflict, we'll update the root tree later, when we read
// the extra metadata.
let root_tree = root_tree_from_header(&commit)
.map_err(|()| to_read_object_err("Invalid jj:trees header", id))?;
let root_tree = root_tree.unwrap_or_else(|| {
if uses_tree_conflict_format {
MergedTreeId::resolved(tree_id)
} else {
MergedTreeId::Legacy(tree_id)
}
});
// Use lossy conversion as commit message with "mojibake" is still better than
// nothing.
// TODO: what should we do with commit.encoding?
let description = String::from_utf8_lossy(commit.message).into_owned();
let author = signature_from_git(commit.author());
let committer = signature_from_git(commit.committer());
// If the commit is signed, extract both the signature and the signed data
// (which is the commit buffer with the gpgsig header omitted).
// We have to re-parse the raw commit data because gix CommitRef does not give
// us the sogned data, only the signature.
// Ideally, we could use try_to_commit_ref_iter at the beginning of this
// function and extract everything from that. For now, this works
let secure_sig = commit
.extra_headers
.iter()
// gix does not recognize gpgsig-sha256, but prevent future footguns by checking for it too
.any(|(k, _)| *k == "gpgsig" || *k == "gpgsig-sha256")
.then(|| CommitRefIter::signature(&git_object.data))
.transpose()
.map_err(|err| to_read_object_err(err, id))?
.flatten()
.map(|(sig, data)| SecureSig {
data: data.to_bstring().into(),
sig: sig.into_owned().into(),
});
Ok(Commit {
parents,
predecessors: vec![],
// If this commit has associated extra metadata, we may reset this later.
root_tree,
change_id,
description,
author,
committer,
secure_sig,
})
}
const EMPTY_STRING_PLACEHOLDER: &str = "JJ_EMPTY_STRING";
fn signature_from_git(signature: gix::actor::SignatureRef) -> Signature {
let name = signature.name;
let name = if name != EMPTY_STRING_PLACEHOLDER {
String::from_utf8_lossy(name).into_owned()
} else {
"".to_string()
};
let email = signature.email;
let email = if email != EMPTY_STRING_PLACEHOLDER {
String::from_utf8_lossy(email).into_owned()
} else {
"".to_string()
};
let timestamp = MillisSinceEpoch(signature.time.seconds * 1000);
let tz_offset = signature.time.offset.div_euclid(60); // in minutes
Signature {
name,
email,
timestamp: Timestamp {
timestamp,
tz_offset,
},
}
}
fn signature_to_git(signature: &Signature) -> gix::actor::SignatureRef<'_> {
// git does not support empty names or emails
let name = if !signature.name.is_empty() {
&signature.name
} else {
EMPTY_STRING_PLACEHOLDER
};
let email = if !signature.email.is_empty() {
&signature.email
} else {
EMPTY_STRING_PLACEHOLDER
};
let time = gix::date::Time::new(
signature.timestamp.timestamp.0.div_euclid(1000),
signature.timestamp.tz_offset * 60, // in seconds
);
gix::actor::SignatureRef {
name: name.into(),
email: email.into(),
time,
}
}
fn serialize_extras(commit: &Commit) -> Vec<u8> {
let mut proto = crate::protos::git_store::Commit {
change_id: commit.change_id.to_bytes(),
..Default::default()
};
if let MergedTreeId::Merge(tree_ids) = &commit.root_tree {
proto.uses_tree_conflict_format = true;
if !tree_ids.is_resolved() {
proto.root_tree = tree_ids.iter().map(|r| r.to_bytes()).collect();
}
}
for predecessor in &commit.predecessors {
proto.predecessors.push(predecessor.to_bytes());
}
proto.encode_to_vec()
}
fn deserialize_extras(commit: &mut Commit, bytes: &[u8]) {
let proto = crate::protos::git_store::Commit::decode(bytes).unwrap();
commit.change_id = ChangeId::new(proto.change_id);
if proto.uses_tree_conflict_format {
if !proto.root_tree.is_empty() {
let merge_builder: MergeBuilder<_> = proto
.root_tree
.iter()
.map(|id_bytes| TreeId::from_bytes(id_bytes))
.collect();
let merge = merge_builder.build();
// Check that the trees from the extras match the one we found in the jj:trees
// header
if let MergedTreeId::Merge(existing_merge) = &commit.root_tree {
assert!(existing_merge.is_resolved() || *existing_merge == merge);
}
commit.root_tree = MergedTreeId::Merge(merge);
} else {
// uses_tree_conflict_format was set but there was no root_tree override in the
// proto, which means we should just promote the tree id from the
// git commit to be a known-conflict-free tree
let MergedTreeId::Legacy(legacy_tree_id) = &commit.root_tree else {
panic!("root tree should have been initialized to a legacy id");
};
commit.root_tree = MergedTreeId::resolved(legacy_tree_id.clone());
}
}
for predecessor in &proto.predecessors {
commit.predecessors.push(CommitId::from_bytes(predecessor));
}
}
/// Returns `RefEdit` that will create a ref in `refs/jj/keep` if not exist.
/// Used for preventing GC of commits we create.
fn to_no_gc_ref_update(id: &CommitId) -> gix::refs::transaction::RefEdit {
let name = format!("{NO_GC_REF_NAMESPACE}{}", id.hex());
let new = gix::refs::Target::Peeled(validate_git_object_id(id).unwrap());
let expected = gix::refs::transaction::PreviousValue::ExistingMustMatch(new.clone());
gix::refs::transaction::RefEdit {
change: gix::refs::transaction::Change::Update {
log: gix::refs::transaction::LogChange {
message: "used by jj".into(),
..Default::default()
},
expected,
new,
},
name: name.try_into().unwrap(),
deref: false,
}
}
fn to_ref_deletion(git_ref: gix::refs::Reference) -> gix::refs::transaction::RefEdit {
let expected = gix::refs::transaction::PreviousValue::ExistingMustMatch(git_ref.target);
gix::refs::transaction::RefEdit {
change: gix::refs::transaction::Change::Delete {
expected,
log: gix::refs::transaction::RefLog::AndReference,
},
name: git_ref.name,
deref: false,
}
}
/// Recreates `refs/jj/keep` refs for the `new_heads`, and removes the other
/// unreachable and non-head refs.
fn recreate_no_gc_refs(
git_repo: &gix::Repository,
new_heads: impl IntoIterator<Item = CommitId>,
keep_newer: SystemTime,
) -> Result<(), BackendError> {
// Calculate diff between existing no-gc refs and new heads.
let new_heads: HashSet<CommitId> = new_heads.into_iter().collect();
let mut no_gc_refs_to_keep_count: usize = 0;
let mut no_gc_refs_to_delete: Vec<gix::refs::Reference> = Vec::new();
let git_references = git_repo
.references()
.map_err(|err| BackendError::Other(err.into()))?;
let no_gc_refs_iter = git_references
.prefixed(NO_GC_REF_NAMESPACE)
.map_err(|err| BackendError::Other(err.into()))?;
for git_ref in no_gc_refs_iter {
let git_ref = git_ref.map_err(BackendError::Other)?.detach();
let oid = git_ref.target.try_id().ok_or_else(|| {
let name = git_ref.name.as_bstr();
BackendError::Other(format!("Symbolic no-gc ref found: {name}").into())
})?;
let id = CommitId::from_bytes(oid.as_bytes());
let name_good = git_ref.name.as_bstr()[NO_GC_REF_NAMESPACE.len()..] == id.hex();
if new_heads.contains(&id) && name_good {
no_gc_refs_to_keep_count += 1;
continue;
}
// Check timestamp of loose ref, but this is still racy on re-import
// because:
// - existing packed ref won't be demoted to loose ref
// - existing loose ref won't be touched
//
// TODO: might be better to switch to a dummy merge, where new no-gc ref
// will always have a unique name. Doing that with the current
// ref-per-head strategy would increase the number of the no-gc refs.
// https://github.com/martinvonz/jj/pull/2659#issuecomment-1837057782
let loose_ref_path = git_repo.path().join(git_ref.name.to_path());
if let Ok(metadata) = loose_ref_path.metadata() {
let mtime = metadata.modified().expect("unsupported platform?");
if mtime > keep_newer {
tracing::trace!(?git_ref, "not deleting new");
no_gc_refs_to_keep_count += 1;
continue;
}
}
// Also deletes no-gc ref of random name created by old jj.
tracing::trace!(?git_ref, ?name_good, "will delete");
no_gc_refs_to_delete.push(git_ref);
}
tracing::info!(
new_heads_count = new_heads.len(),
no_gc_refs_to_keep_count,
no_gc_refs_to_delete_count = no_gc_refs_to_delete.len(),
"collected reachable refs"
);
// It's slow to delete packed refs one by one, so update refs all at once.
let ref_edits = itertools::chain(
no_gc_refs_to_delete.into_iter().map(to_ref_deletion),
new_heads.iter().map(to_no_gc_ref_update),
);
git_repo
.edit_references(ref_edits)
.map_err(|err| BackendError::Other(err.into()))?;
Ok(())
}
fn run_git_gc(git_dir: &Path) -> Result<(), GitGcError> {
let mut git = Command::new("git");
git.arg("--git-dir=."); // turn off discovery
git.arg("gc");
// Don't specify it by GIT_DIR/--git-dir. On Windows, the "\\?\" path might
// not be supported by git.
git.current_dir(git_dir);
// TODO: pass output to UI layer instead of printing directly here
let status = git.status().map_err(GitGcError::GcCommand)?;
if !status.success() {
return Err(GitGcError::GcCommandErrorStatus(status));
}
Ok(())
}
fn validate_git_object_id(id: &impl ObjectId) -> Result<gix::ObjectId, BackendError> {
if id.as_bytes().len() != HASH_LENGTH {
return Err(BackendError::InvalidHashLength {
expected: HASH_LENGTH,
actual: id.as_bytes().len(),
object_type: id.object_type(),
hash: id.hex(),
});
}
Ok(id.as_bytes().try_into().unwrap())
}
fn map_not_found_err(err: gix::object::find::existing::Error, id: &impl ObjectId) -> BackendError {
if matches!(err, gix::object::find::existing::Error::NotFound { .. }) {
BackendError::ObjectNotFound {
object_type: id.object_type(),
hash: id.hex(),
source: Box::new(err),
}
} else {
to_read_object_err(err, id)
}
}
fn to_read_object_err(
err: impl Into<Box<dyn std::error::Error + Send + Sync>>,
id: &impl ObjectId,
) -> BackendError {
BackendError::ReadObject {
object_type: id.object_type(),
hash: id.hex(),
source: err.into(),
}
}
fn to_invalid_utf8_err(source: str::Utf8Error, id: &impl ObjectId) -> BackendError {
BackendError::InvalidUtf8 {
object_type: id.object_type(),
hash: id.hex(),
source,
}
}
fn import_extra_metadata_entries_from_heads(
git_repo: &gix::Repository,
mut_table: &mut MutableTable,
_table_lock: &FileLock,
head_ids: &HashSet<&CommitId>,
uses_tree_conflict_format: bool,
) -> BackendResult<()> {
let mut work_ids = head_ids
.iter()
.filter(|&id| mut_table.get_value(id.as_bytes()).is_none())
.map(|&id| id.clone())
.collect_vec();
while let Some(id) = work_ids.pop() {
let git_object = git_repo
.find_object(validate_git_object_id(&id)?)
.map_err(|err| map_not_found_err(err, &id))?;
// TODO(#1624): Should we read the root tree here and check if it has a
// `.jjconflict-...` entries? That could happen if the user used `git` to e.g.
// change the description of a commit with tree-level conflicts.
let commit =
commit_from_git_without_root_parent(&id, &git_object, uses_tree_conflict_format)?;
mut_table.add_entry(id.to_bytes(), serialize_extras(&commit));
work_ids.extend(
commit
.parents
.into_iter()
.filter(|id| mut_table.get_value(id.as_bytes()).is_none()),
);
}
Ok(())
}
impl Debug for GitBackend {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
f.debug_struct("GitBackend")
.field("path", &self.git_repo_path())
.finish()
}
}
#[async_trait]
impl Backend for GitBackend {
fn as_any(&self) -> &dyn Any {
self
}
fn name(&self) -> &str {
Self::name()
}
fn commit_id_length(&self) -> usize {
HASH_LENGTH
}
fn change_id_length(&self) -> usize {
CHANGE_ID_LENGTH
}
fn root_commit_id(&self) -> &CommitId {
&self.root_commit_id
}
fn root_change_id(&self) -> &ChangeId {
&self.root_change_id
}
fn empty_tree_id(&self) -> &TreeId {
&self.empty_tree_id
}
fn concurrency(&self) -> usize {
1
}
async fn read_file(&self, _path: &RepoPath, id: &FileId) -> BackendResult<Box<dyn Read>> {
self.read_file_sync(id)
}
fn write_file(&self, _path: &RepoPath, contents: &mut dyn Read) -> BackendResult<FileId> {
let mut bytes = Vec::new();
contents.read_to_end(&mut bytes).unwrap();
let locked_repo = self.lock_git_repo();
let oid = locked_repo
.write_blob(bytes)
.map_err(|err| BackendError::WriteObject {
object_type: "file",
source: Box::new(err),
})?;
Ok(FileId::new(oid.as_bytes().to_vec()))
}
async fn read_symlink(&self, _path: &RepoPath, id: &SymlinkId) -> Result<String, BackendError> {
let git_blob_id = validate_git_object_id(id)?;
let locked_repo = self.lock_git_repo();
let mut blob = locked_repo
.find_object(git_blob_id)
.map_err(|err| map_not_found_err(err, id))?
.try_into_blob()
.map_err(|err| to_read_object_err(err, id))?;
let target = String::from_utf8(blob.take_data())
.map_err(|err| to_invalid_utf8_err(err.utf8_error(), id))?
.to_owned();
Ok(target)
}
fn write_symlink(&self, _path: &RepoPath, target: &str) -> Result<SymlinkId, BackendError> {
let locked_repo = self.lock_git_repo();
let oid =
locked_repo
.write_blob(target.as_bytes())
.map_err(|err| BackendError::WriteObject {
object_type: "symlink",
source: Box::new(err),
})?;
Ok(SymlinkId::new(oid.as_bytes().to_vec()))
}
async fn read_tree(&self, _path: &RepoPath, id: &TreeId) -> BackendResult<Tree> {
if id == &self.empty_tree_id {
return Ok(Tree::default());
}
let git_tree_id = validate_git_object_id(id)?;
let locked_repo = self.lock_git_repo();
let git_tree = locked_repo
.find_object(git_tree_id)
.map_err(|err| map_not_found_err(err, id))?
.try_into_tree()
.map_err(|err| to_read_object_err(err, id))?;
let mut tree = Tree::default();
for entry in git_tree.iter() {
let entry = entry.map_err(|err| to_read_object_err(err, id))?;
let name =
str::from_utf8(entry.filename()).map_err(|err| to_invalid_utf8_err(err, id))?;
let (name, value) = match entry.mode().kind() {
gix::object::tree::EntryKind::Tree => {
let id = TreeId::from_bytes(entry.oid().as_bytes());
(name, TreeValue::Tree(id))
}
gix::object::tree::EntryKind::Blob => {
let id = FileId::from_bytes(entry.oid().as_bytes());
if let Some(basename) = name.strip_suffix(CONFLICT_SUFFIX) {
(
basename,
TreeValue::Conflict(ConflictId::from_bytes(entry.oid().as_bytes())),
)
} else {
(
name,
TreeValue::File {
id,
executable: false,
},
)
}
}
gix::object::tree::EntryKind::BlobExecutable => {
let id = FileId::from_bytes(entry.oid().as_bytes());
(
name,
TreeValue::File {
id,
executable: true,
},
)
}
gix::object::tree::EntryKind::Link => {
let id = SymlinkId::from_bytes(entry.oid().as_bytes());
(name, TreeValue::Symlink(id))
}
gix::object::tree::EntryKind::Commit => {
let id = CommitId::from_bytes(entry.oid().as_bytes());
(name, TreeValue::GitSubmodule(id))
}
};
tree.set(RepoPathComponentBuf::from(name), value);
}
Ok(tree)
}
fn write_tree(&self, _path: &RepoPath, contents: &Tree) -> BackendResult<TreeId> {
// Tree entries to be written must be sorted by Entry::filename(), which
// is slightly different from the order of our backend::Tree.
let entries = contents
.entries()
.map(|entry| {
let name = entry.name().as_str();
match entry.value() {
TreeValue::File {
id,
executable: false,
} => gix::objs::tree::Entry {
mode: gix::object::tree::EntryKind::Blob.into(),
filename: name.into(),
oid: id.as_bytes().try_into().unwrap(),
},
TreeValue::File {
id,
executable: true,
} => gix::objs::tree::Entry {
mode: gix::object::tree::EntryKind::BlobExecutable.into(),
filename: name.into(),
oid: id.as_bytes().try_into().unwrap(),
},
TreeValue::Symlink(id) => gix::objs::tree::Entry {
mode: gix::object::tree::EntryKind::Link.into(),
filename: name.into(),
oid: id.as_bytes().try_into().unwrap(),
},
TreeValue::Tree(id) => gix::objs::tree::Entry {
mode: gix::object::tree::EntryKind::Tree.into(),
filename: name.into(),
oid: id.as_bytes().try_into().unwrap(),
},
TreeValue::GitSubmodule(id) => gix::objs::tree::Entry {
mode: gix::object::tree::EntryKind::Commit.into(),
filename: name.into(),
oid: id.as_bytes().try_into().unwrap(),
},
TreeValue::Conflict(id) => gix::objs::tree::Entry {
mode: gix::object::tree::EntryKind::Blob.into(),
filename: (name.to_owned() + CONFLICT_SUFFIX).into(),
oid: id.as_bytes().try_into().unwrap(),
},
}
})
.sorted_unstable()
.collect();
let locked_repo = self.lock_git_repo();
let oid = locked_repo
.write_object(gix::objs::Tree { entries })
.map_err(|err| BackendError::WriteObject {
object_type: "tree",
source: Box::new(err),
})?;
Ok(TreeId::from_bytes(oid.as_bytes()))
}
fn read_conflict(&self, _path: &RepoPath, id: &ConflictId) -> BackendResult<Conflict> {
let mut file = self.read_file_sync(&FileId::new(id.to_bytes()))?;
let mut data = String::new();
file.read_to_string(&mut data)
.map_err(|err| BackendError::ReadObject {
object_type: "conflict".to_owned(),
hash: id.hex(),
source: err.into(),
})?;
let json: serde_json::Value = serde_json::from_str(&data).unwrap();
Ok(Conflict {
removes: conflict_term_list_from_json(json.get("removes").unwrap()),
adds: conflict_term_list_from_json(json.get("adds").unwrap()),
})
}
fn write_conflict(&self, _path: &RepoPath, conflict: &Conflict) -> BackendResult<ConflictId> {
let json = serde_json::json!({
"removes": conflict_term_list_to_json(&conflict.removes),
"adds": conflict_term_list_to_json(&conflict.adds),
});
let json_string = json.to_string();
let bytes = json_string.as_bytes();
let locked_repo = self.lock_git_repo();
let oid = locked_repo
.write_blob(bytes)
.map_err(|err| BackendError::WriteObject {
object_type: "conflict",
source: Box::new(err),
})?;
Ok(ConflictId::from_bytes(oid.as_bytes()))
}
#[tracing::instrument(skip(self))]
async fn read_commit(&self, id: &CommitId) -> BackendResult<Commit> {
if *id == self.root_commit_id {
return Ok(make_root_commit(
self.root_change_id().clone(),
self.empty_tree_id.clone(),
));
}
let git_commit_id = validate_git_object_id(id)?;
let mut commit = {
let locked_repo = self.lock_git_repo();
let git_object = locked_repo
.find_object(git_commit_id)
.map_err(|err| map_not_found_err(err, id))?;
commit_from_git_without_root_parent(id, &git_object, false)?
};
if commit.parents.is_empty() {
commit.parents.push(self.root_commit_id.clone());
};
let table = self.cached_extra_metadata_table()?;
if let Some(extras) = table.get_value(id.as_bytes()) {
deserialize_extras(&mut commit, extras);
} else {
// TODO: Remove this hack and map to ObjectNotFound error if we're sure that
// there are no reachable ancestor commits without extras metadata. Git commits
// imported by jj < 0.8.0 might not have extras (#924).
// https://github.com/martinvonz/jj/issues/2343
tracing::info!("unimported Git commit found");
self.import_head_commits([id])?;
let table = self.cached_extra_metadata_table()?;
let extras = table.get_value(id.as_bytes()).unwrap();
deserialize_extras(&mut commit, extras);
}
Ok(commit)
}
fn write_commit(
&self,
mut contents: Commit,
mut sign_with: Option<&mut SigningFn>,
) -> BackendResult<(CommitId, Commit)> {
assert!(contents.secure_sig.is_none(), "commit.secure_sig was set");
let locked_repo = self.lock_git_repo();
let git_tree_id = match &contents.root_tree {
MergedTreeId::Legacy(tree_id) => validate_git_object_id(tree_id)?,
MergedTreeId::Merge(tree_ids) => match tree_ids.as_resolved() {
Some(tree_id) => validate_git_object_id(tree_id)?,
None => write_tree_conflict(&locked_repo, tree_ids)?,
},
};
let author = signature_to_git(&contents.author);
let mut committer = signature_to_git(&contents.committer);
let message = &contents.description;
if contents.parents.is_empty() {
return Err(BackendError::Other(
"Cannot write a commit with no parents".into(),
));
}
let mut parents = SmallVec::new();
for parent_id in &contents.parents {
if *parent_id == self.root_commit_id {
// Git doesn't have a root commit, so if the parent is the root commit, we don't
// add it to the list of parents to write in the Git commit. We also check that
// there are no other parents since Git cannot represent a merge between a root
// commit and another commit.
if contents.parents.len() > 1 {
return Err(BackendError::Unsupported(
"The Git backend does not support creating merge commits with the root \
commit as one of the parents."
.to_owned(),
));
}
} else {
parents.push(validate_git_object_id(parent_id)?);
}
}
let mut extra_headers = vec![];
if let MergedTreeId::Merge(tree_ids) = &contents.root_tree {
if !tree_ids.is_resolved() {
let value = tree_ids.iter().map(|id| id.hex()).join(" ").into_bytes();
extra_headers.push((
BString::new(JJ_TREES_COMMIT_HEADER.to_vec()),
BString::new(value),
));
}
}
let extras = serialize_extras(&contents);
// If two writers write commits of the same id with different metadata, they
// will both succeed and the metadata entries will be "merged" later. Since
// metadata entry is keyed by the commit id, one of the entries would be lost.
// To prevent such race condition locally, we extend the scope covered by the
// table lock. This is still racy if multiple machines are involved and the
// repository is rsync-ed.
let (table, table_lock) = self.read_extra_metadata_table_locked()?;
let id = loop {
let mut commit = gix::objs::Commit {
message: message.to_owned().into(),
tree: git_tree_id,
author: author.into(),
committer: committer.into(),
encoding: None,
parents: parents.clone(),
extra_headers: extra_headers.clone(),
};
if let Some(sign) = &mut sign_with {
// we don't use gix pool, but at least use their heuristic
let mut data = Vec::with_capacity(512);
commit.write_to(&mut data).unwrap();
let sig = sign(&data).map_err(|err| BackendError::WriteObject {
object_type: "commit",
source: Box::new(err),
})?;
commit
.extra_headers
.push(("gpgsig".into(), sig.clone().into()));
contents.secure_sig = Some(SecureSig { data, sig });
}
let git_id =
locked_repo
.write_object(&commit)
.map_err(|err| BackendError::WriteObject {
object_type: "commit",
source: Box::new(err),
})?;
match table.get_value(git_id.as_bytes()) {
Some(existing_extras) if existing_extras != extras => {
// It's possible a commit already exists with the same commit id but different
// change id. Adjust the timestamp until this is no longer the case.
committer.time.seconds -= 1;
}
_ => break CommitId::from_bytes(git_id.as_bytes()),
}
};
// Everything up to this point had no permanent effect on the repo except
// GC-able objects
locked_repo
.edit_reference(to_no_gc_ref_update(&id))
.map_err(|err| BackendError::Other(Box::new(err)))?;
// Update the signature to match the one that was actually written to the object
// store
contents.committer.timestamp.timestamp = MillisSinceEpoch(committer.time.seconds * 1000);
let mut mut_table = table.start_mutation();
mut_table.add_entry(id.to_bytes(), extras);
self.save_extra_metadata_table(mut_table, &table_lock)?;
Ok((id, contents))
}
#[tracing::instrument(skip(self, index))]
fn gc(&self, index: &dyn Index, keep_newer: SystemTime) -> BackendResult<()> {
let git_repo = self.lock_git_repo();
let new_heads = index
.all_heads_for_gc()
.map_err(|err| BackendError::Other(err.into()))?
.filter(|id| *id != self.root_commit_id);
recreate_no_gc_refs(&git_repo, new_heads, keep_newer)?;
// TODO: remove unreachable entries from extras table if segment file
// mtime <= keep_newer? (it won't be consistent with no-gc refs
// preserved by the keep_newer timestamp though)
// TODO: remove unreachable extras table segments
// TODO: pass in keep_newer to "git gc" command
run_git_gc(self.git_repo_path()).map_err(|err| BackendError::Other(err.into()))
}
}
/// Write a tree conflict as a special tree with `.jjconflict-base-N` and
/// `.jjconflict-base-N` subtrees. This ensure that the parts are not GC'd.
fn write_tree_conflict(
repo: &gix::Repository,
conflict: &Merge<TreeId>,
) -> Result<gix::ObjectId, BackendError> {
// Tree entries to be written must be sorted by Entry::filename().
let entries = itertools::chain(
conflict
.removes()
.enumerate()
.map(|(i, tree_id)| (format!(".jjconflict-base-{i}"), tree_id)),
conflict
.adds()
.enumerate()
.map(|(i, tree_id)| (format!(".jjconflict-side-{i}"), tree_id)),
)
.map(|(name, tree_id)| gix::objs::tree::Entry {
mode: gix::object::tree::EntryKind::Tree.into(),
filename: name.into(),
oid: tree_id.as_bytes().try_into().unwrap(),
})
.sorted_unstable()
.collect();
let id = repo
.write_object(gix::objs::Tree { entries })
.map_err(|err| BackendError::WriteObject {
object_type: "tree",
source: Box::new(err),
})?;
Ok(id.detach())
}
fn conflict_term_list_to_json(parts: &[ConflictTerm]) -> serde_json::Value {
serde_json::Value::Array(parts.iter().map(conflict_term_to_json).collect())
}
fn conflict_term_list_from_json(json: &serde_json::Value) -> Vec<ConflictTerm> {
json.as_array()
.unwrap()
.iter()
.map(conflict_term_from_json)
.collect()
}
fn conflict_term_to_json(part: &ConflictTerm) -> serde_json::Value {
serde_json::json!({
"value": tree_value_to_json(&part.value),
})
}
fn conflict_term_from_json(json: &serde_json::Value) -> ConflictTerm {
let json_value = json.get("value").unwrap();
ConflictTerm {
value: tree_value_from_json(json_value),
}
}
fn tree_value_to_json(value: &TreeValue) -> serde_json::Value {
match value {
TreeValue::File { id, executable } => serde_json::json!({
"file": {
"id": id.hex(),
"executable": executable,
},
}),
TreeValue::Symlink(id) => serde_json::json!({
"symlink_id": id.hex(),
}),
TreeValue::Tree(id) => serde_json::json!({
"tree_id": id.hex(),
}),
TreeValue::GitSubmodule(id) => serde_json::json!({
"submodule_id": id.hex(),
}),
TreeValue::Conflict(id) => serde_json::json!({
"conflict_id": id.hex(),
}),
}
}
fn tree_value_from_json(json: &serde_json::Value) -> TreeValue {
if let Some(json_file) = json.get("file") {
TreeValue::File {
id: FileId::new(bytes_vec_from_json(json_file.get("id").unwrap())),
executable: json_file.get("executable").unwrap().as_bool().unwrap(),
}
} else if let Some(json_id) = json.get("symlink_id") {
TreeValue::Symlink(SymlinkId::new(bytes_vec_from_json(json_id)))
} else if let Some(json_id) = json.get("tree_id") {
TreeValue::Tree(TreeId::new(bytes_vec_from_json(json_id)))
} else if let Some(json_id) = json.get("submodule_id") {
TreeValue::GitSubmodule(CommitId::new(bytes_vec_from_json(json_id)))
} else if let Some(json_id) = json.get("conflict_id") {
TreeValue::Conflict(ConflictId::new(bytes_vec_from_json(json_id)))
} else {
panic!("unexpected json value in conflict: {json:#?}");
}
}
fn bytes_vec_from_json(value: &serde_json::Value) -> Vec<u8> {
hex::decode(value.as_str().unwrap()).unwrap()
}
#[cfg(test)]
mod tests {
use assert_matches::assert_matches;
use git2::Oid;
use hex::ToHex;
use pollster::FutureExt;
use test_case::test_case;
use super::*;
use crate::content_hash::blake2b_hash;
#[test_case(false; "legacy tree format")]
#[test_case(true; "tree-level conflict format")]
fn read_plain_git_commit(uses_tree_conflict_format: bool) {
let settings = {
let config = config::Config::builder()
.set_override("format.tree-level-conflicts", uses_tree_conflict_format)
.unwrap()
.build()
.unwrap();
UserSettings::from_config(config)
};
let temp_dir = testutils::new_temp_dir();
let store_path = temp_dir.path();
let git_repo_path = temp_dir.path().join("git");
let git_repo = git2::Repository::init(git_repo_path).unwrap();
// Add a commit with some files in
let blob1 = git_repo.blob(b"content1").unwrap();
let blob2 = git_repo.blob(b"normal").unwrap();
let mut dir_tree_builder = git_repo.treebuilder(None).unwrap();
dir_tree_builder.insert("normal", blob1, 0o100644).unwrap();
dir_tree_builder.insert("symlink", blob2, 0o120000).unwrap();
let dir_tree_id = dir_tree_builder.write().unwrap();
let mut root_tree_builder = git_repo.treebuilder(None).unwrap();
root_tree_builder
.insert("dir", dir_tree_id, 0o040000)
.unwrap();
let root_tree_id = root_tree_builder.write().unwrap();
let git_author = git2::Signature::new(
"git author",
"git.author@example.com",
&git2::Time::new(1000, 60),
)
.unwrap();
let git_committer = git2::Signature::new(
"git committer",
"git.committer@example.com",
&git2::Time::new(2000, -480),
)
.unwrap();
let git_tree = git_repo.find_tree(root_tree_id).unwrap();
let git_commit_id = git_repo
.commit(
None,
&git_author,
&git_committer,
"git commit message",
&git_tree,
&[],
)
.unwrap();
let commit_id = CommitId::from_hex("efdcea5ca4b3658149f899ca7feee6876d077263");
// The change id is the leading reverse bits of the commit id
let change_id = ChangeId::from_hex("c64ee0b6e16777fe53991f9281a6cd25");
// Check that the git commit above got the hash we expect
assert_eq!(git_commit_id.as_bytes(), commit_id.as_bytes());
// Add an empty commit on top
let git_commit_id2 = git_repo
.commit(
None,
&git_author,
&git_committer,
"git commit message 2",
&git_tree,
&[&git_repo.find_commit(git_commit_id).unwrap()],
)
.unwrap();
let commit_id2 = CommitId::from_bytes(git_commit_id2.as_bytes());
let backend = GitBackend::init_external(&settings, store_path, git_repo.path()).unwrap();
// Import the head commit and its ancestors
backend.import_head_commits([&commit_id2]).unwrap();
// Ref should be created only for the head commit
let git_refs = backend
.open_git_repo()
.unwrap()
.references_glob("refs/jj/keep/*")
.unwrap()
.map(|git_ref| git_ref.unwrap().target().unwrap())
.collect_vec();
assert_eq!(git_refs, vec![git_commit_id2]);
let commit = backend.read_commit(&commit_id).block_on().unwrap();
assert_eq!(&commit.change_id, &change_id);
assert_eq!(commit.parents, vec![CommitId::from_bytes(&[0; 20])]);
assert_eq!(commit.predecessors, vec![]);
assert_eq!(
commit.root_tree.to_merge(),
Merge::resolved(TreeId::from_bytes(root_tree_id.as_bytes()))
);
if uses_tree_conflict_format {
assert_matches!(commit.root_tree, MergedTreeId::Merge(_));
} else {
assert_matches!(commit.root_tree, MergedTreeId::Legacy(_));
}
assert_eq!(commit.description, "git commit message");
assert_eq!(commit.author.name, "git author");
assert_eq!(commit.author.email, "git.author@example.com");
assert_eq!(
commit.author.timestamp.timestamp,
MillisSinceEpoch(1000 * 1000)
);
assert_eq!(commit.author.timestamp.tz_offset, 60);
assert_eq!(commit.committer.name, "git committer");
assert_eq!(commit.committer.email, "git.committer@example.com");
assert_eq!(
commit.committer.timestamp.timestamp,
MillisSinceEpoch(2000 * 1000)
);
assert_eq!(commit.committer.timestamp.tz_offset, -480);
let root_tree = backend
.read_tree(
RepoPath::root(),
&TreeId::from_bytes(root_tree_id.as_bytes()),
)
.block_on()
.unwrap();
let mut root_entries = root_tree.entries();
let dir = root_entries.next().unwrap();
assert_eq!(root_entries.next(), None);
assert_eq!(dir.name().as_str(), "dir");
assert_eq!(
dir.value(),
&TreeValue::Tree(TreeId::from_bytes(dir_tree_id.as_bytes()))
);
let dir_tree = backend
.read_tree(
RepoPath::from_internal_string("dir"),
&TreeId::from_bytes(dir_tree_id.as_bytes()),
)
.block_on()
.unwrap();
let mut entries = dir_tree.entries();
let file = entries.next().unwrap();
let symlink = entries.next().unwrap();
assert_eq!(entries.next(), None);
assert_eq!(file.name().as_str(), "normal");
assert_eq!(
file.value(),
&TreeValue::File {
id: FileId::from_bytes(blob1.as_bytes()),
executable: false
}
);
assert_eq!(symlink.name().as_str(), "symlink");
assert_eq!(
symlink.value(),
&TreeValue::Symlink(SymlinkId::from_bytes(blob2.as_bytes()))
);
let commit2 = backend.read_commit(&commit_id2).block_on().unwrap();
assert_eq!(commit2.parents, vec![commit_id.clone()]);
assert_eq!(commit.predecessors, vec![]);
assert_eq!(
commit.root_tree.to_merge(),
Merge::resolved(TreeId::from_bytes(root_tree_id.as_bytes()))
);
if uses_tree_conflict_format {
assert_matches!(commit.root_tree, MergedTreeId::Merge(_));
} else {
assert_matches!(commit.root_tree, MergedTreeId::Legacy(_));
}
}
#[test]
fn read_git_commit_without_importing() {
let settings = user_settings();
let temp_dir = testutils::new_temp_dir();
let store_path = temp_dir.path();
let git_repo_path = temp_dir.path().join("git");
let git_repo = git2::Repository::init(git_repo_path).unwrap();
let signature = git2::Signature::now("Someone", "someone@example.com").unwrap();
let empty_tree_id = Oid::from_str("4b825dc642cb6eb9a060e54bf8d69288fbee4904").unwrap();
let empty_tree = git_repo.find_tree(empty_tree_id).unwrap();
let git_commit_id = git_repo
.commit(
Some("refs/heads/main"),
&signature,
&signature,
"git commit message",
&empty_tree,
&[],
)
.unwrap();
let backend = GitBackend::init_external(&settings, store_path, git_repo.path()).unwrap();
// read_commit() without import_head_commits() works as of now. This might be
// changed later.
assert!(backend
.read_commit(&CommitId::from_bytes(git_commit_id.as_bytes()))
.block_on()
.is_ok());
assert!(
backend
.cached_extra_metadata_table()
.unwrap()
.get_value(git_commit_id.as_bytes())
.is_some(),
"extra metadata should have been be created"
);
}
#[test]
fn read_signed_git_commit() {
let settings = user_settings();
let temp_dir = testutils::new_temp_dir();
let store_path = temp_dir.path();
let git_repo_path = temp_dir.path().join("git");
let git_repo = git2::Repository::init(git_repo_path).unwrap();
let signature = git2::Signature::now("Someone", "someone@example.com").unwrap();
let empty_tree_id = Oid::from_str("4b825dc642cb6eb9a060e54bf8d69288fbee4904").unwrap();
let empty_tree = git_repo.find_tree(empty_tree_id).unwrap();
let commit_buf = git_repo
.commit_create_buffer(
&signature,
&signature,
"git commit message",
&empty_tree,
&[],
)
.unwrap();
// libgit2-rs works with &strs here for some reason
let commit_buf = std::str::from_utf8(&commit_buf).unwrap();
let secure_sig =
"here are some ASCII bytes to be used as a test signature\n\ndefinitely not PGP";
let git_commit_id = git_repo
.commit_signed(commit_buf, secure_sig, None)
.unwrap();
let backend = GitBackend::init_external(&settings, store_path, git_repo.path()).unwrap();
let commit = backend
.read_commit(&CommitId::from_bytes(git_commit_id.as_bytes()))
.block_on()
.unwrap();
let sig = commit.secure_sig.expect("failed to read the signature");
// converting to string for nicer assert diff
assert_eq!(std::str::from_utf8(&sig.sig).unwrap(), secure_sig);
assert_eq!(std::str::from_utf8(&sig.data).unwrap(), commit_buf);
}
#[test]
fn read_empty_string_placeholder() {
let git_signature1 = gix::actor::SignatureRef {
name: EMPTY_STRING_PLACEHOLDER.into(),
email: "git.author@example.com".into(),
time: gix::date::Time::new(1000, 60 * 60),
};
let signature1 = signature_from_git(git_signature1);
assert!(signature1.name.is_empty());
assert_eq!(signature1.email, "git.author@example.com");
let git_signature2 = gix::actor::SignatureRef {
name: "git committer".into(),
email: EMPTY_STRING_PLACEHOLDER.into(),
time: gix::date::Time::new(2000, -480 * 60),
};
let signature2 = signature_from_git(git_signature2);
assert_eq!(signature2.name, "git committer");
assert!(signature2.email.is_empty());
}
#[test]
fn write_empty_string_placeholder() {
let signature1 = Signature {
name: "".to_string(),
email: "someone@example.com".to_string(),
timestamp: Timestamp {
timestamp: MillisSinceEpoch(0),
tz_offset: 0,
},
};
let git_signature1 = signature_to_git(&signature1);
assert_eq!(git_signature1.name, EMPTY_STRING_PLACEHOLDER);
assert_eq!(git_signature1.email, "someone@example.com");
let signature2 = Signature {
name: "Someone".to_string(),
email: "".to_string(),
timestamp: Timestamp {
timestamp: MillisSinceEpoch(0),
tz_offset: 0,
},
};
let git_signature2 = signature_to_git(&signature2);
assert_eq!(git_signature2.name, "Someone");
assert_eq!(git_signature2.email, EMPTY_STRING_PLACEHOLDER);
}
/// Test that parents get written correctly
#[test]
fn git_commit_parents() {
let settings = user_settings();
let temp_dir = testutils::new_temp_dir();
let store_path = temp_dir.path();
let git_repo_path = temp_dir.path().join("git");
let git_repo = git2::Repository::init(git_repo_path).unwrap();
let backend = GitBackend::init_external(&settings, store_path, git_repo.path()).unwrap();
let mut commit = Commit {
parents: vec![],
predecessors: vec![],
root_tree: MergedTreeId::Legacy(backend.empty_tree_id().clone()),
change_id: ChangeId::from_hex("abc123"),
description: "".to_string(),
author: create_signature(),
committer: create_signature(),
secure_sig: None,
};
// No parents
commit.parents = vec![];
assert_matches!(
backend.write_commit(commit.clone(), None),
Err(BackendError::Other(err)) if err.to_string().contains("no parents")
);
// Only root commit as parent
commit.parents = vec![backend.root_commit_id().clone()];
let first_id = backend.write_commit(commit.clone(), None).unwrap().0;
let first_commit = backend.read_commit(&first_id).block_on().unwrap();
assert_eq!(first_commit, commit);
let first_git_commit = git_repo.find_commit(git_id(&first_id)).unwrap();
assert_eq!(first_git_commit.parent_ids().collect_vec(), vec![]);
// Only non-root commit as parent
commit.parents = vec![first_id.clone()];
let second_id = backend.write_commit(commit.clone(), None).unwrap().0;
let second_commit = backend.read_commit(&second_id).block_on().unwrap();
assert_eq!(second_commit, commit);
let second_git_commit = git_repo.find_commit(git_id(&second_id)).unwrap();
assert_eq!(
second_git_commit.parent_ids().collect_vec(),
vec![git_id(&first_id)]
);
// Merge commit
commit.parents = vec![first_id.clone(), second_id.clone()];
let merge_id = backend.write_commit(commit.clone(), None).unwrap().0;
let merge_commit = backend.read_commit(&merge_id).block_on().unwrap();
assert_eq!(merge_commit, commit);
let merge_git_commit = git_repo.find_commit(git_id(&merge_id)).unwrap();
assert_eq!(
merge_git_commit.parent_ids().collect_vec(),
vec![git_id(&first_id), git_id(&second_id)]
);
// Merge commit with root as one parent
commit.parents = vec![first_id, backend.root_commit_id().clone()];
assert_matches!(
backend.write_commit(commit, None),
Err(BackendError::Unsupported(message)) if message.contains("root commit")
);
}
#[test]
fn write_tree_conflicts() {
let settings = user_settings();
let temp_dir = testutils::new_temp_dir();
let store_path = temp_dir.path();
let git_repo_path = temp_dir.path().join("git");
let git_repo = git2::Repository::init(git_repo_path).unwrap();
let backend = GitBackend::init_external(&settings, store_path, git_repo.path()).unwrap();
let create_tree = |i| {
let blob_id = git_repo.blob(b"content {i}").unwrap();
let mut tree_builder = git_repo.treebuilder(None).unwrap();
tree_builder
.insert(format!("file{i}"), blob_id, 0o100644)
.unwrap();
TreeId::from_bytes(tree_builder.write().unwrap().as_bytes())
};
let root_tree = Merge::from_removes_adds(
vec![create_tree(0), create_tree(1)],
vec![create_tree(2), create_tree(3), create_tree(4)],
);
let mut commit = Commit {
parents: vec![backend.root_commit_id().clone()],
predecessors: vec![],
root_tree: MergedTreeId::Merge(root_tree.clone()),
change_id: ChangeId::from_hex("abc123"),
description: "".to_string(),
author: create_signature(),
committer: create_signature(),
secure_sig: None,
};
// When writing a tree-level conflict, the root tree on the git side has the
// individual trees as subtrees.
let read_commit_id = backend.write_commit(commit.clone(), None).unwrap().0;
let read_commit = backend.read_commit(&read_commit_id).block_on().unwrap();
assert_eq!(read_commit, commit);
let git_commit = git_repo
.find_commit(Oid::from_bytes(read_commit_id.as_bytes()).unwrap())
.unwrap();
let git_tree = git_repo.find_tree(git_commit.tree_id()).unwrap();
assert!(git_tree.iter().all(|entry| entry.filemode() == 0o040000));
let mut iter = git_tree.iter();
let entry = iter.next().unwrap();
assert_eq!(entry.name(), Some(".jjconflict-base-0"));
assert_eq!(
entry.id().as_bytes(),
root_tree.get_remove(0).unwrap().as_bytes()
);
let entry = iter.next().unwrap();
assert_eq!(entry.name(), Some(".jjconflict-base-1"));
assert_eq!(
entry.id().as_bytes(),
root_tree.get_remove(1).unwrap().as_bytes()
);
let entry = iter.next().unwrap();
assert_eq!(entry.name(), Some(".jjconflict-side-0"));
assert_eq!(
entry.id().as_bytes(),
root_tree.get_add(0).unwrap().as_bytes()
);
let entry = iter.next().unwrap();
assert_eq!(entry.name(), Some(".jjconflict-side-1"));
assert_eq!(
entry.id().as_bytes(),
root_tree.get_add(1).unwrap().as_bytes()
);
let entry = iter.next().unwrap();
assert_eq!(entry.name(), Some(".jjconflict-side-2"));
assert_eq!(
entry.id().as_bytes(),
root_tree.get_add(2).unwrap().as_bytes()
);
assert!(iter.next().is_none());
// When writing a single tree using the new format, it's represented by a
// regular git tree.
commit.root_tree = MergedTreeId::resolved(create_tree(5));
let read_commit_id = backend.write_commit(commit.clone(), None).unwrap().0;
let read_commit = backend.read_commit(&read_commit_id).block_on().unwrap();
assert_eq!(read_commit, commit);
let git_commit = git_repo
.find_commit(Oid::from_bytes(read_commit_id.as_bytes()).unwrap())
.unwrap();
assert_eq!(
MergedTreeId::resolved(TreeId::from_bytes(git_commit.tree_id().as_bytes())),
commit.root_tree
);
}
#[test]
fn commit_has_ref() {
let settings = user_settings();
let temp_dir = testutils::new_temp_dir();
let backend = GitBackend::init_internal(&settings, temp_dir.path()).unwrap();
let git_repo = backend.open_git_repo().unwrap();
let signature = Signature {
name: "Someone".to_string(),
email: "someone@example.com".to_string(),
timestamp: Timestamp {
timestamp: MillisSinceEpoch(0),
tz_offset: 0,
},
};
let commit = Commit {
parents: vec![backend.root_commit_id().clone()],
predecessors: vec![],
root_tree: MergedTreeId::Legacy(backend.empty_tree_id().clone()),
change_id: ChangeId::new(vec![]),
description: "initial".to_string(),
author: signature.clone(),
committer: signature,
secure_sig: None,
};
let commit_id = backend.write_commit(commit, None).unwrap().0;
let git_refs: Vec<_> = git_repo
.references_glob("refs/jj/keep/*")
.unwrap()
.try_collect()
.unwrap();
assert!(git_refs
.iter()
.any(|git_ref| git_ref.target().unwrap() == git_id(&commit_id)));
// Concurrently-running GC deletes the ref, leaving the extra metadata.
for mut git_ref in git_refs {
git_ref.delete().unwrap();
}
// Re-imported commit should have new ref.
backend.import_head_commits([&commit_id]).unwrap();
let git_refs: Vec<_> = git_repo
.references_glob("refs/jj/keep/*")
.unwrap()
.try_collect()
.unwrap();
assert!(git_refs
.iter()
.any(|git_ref| git_ref.target().unwrap() == git_id(&commit_id)));
}
#[test]
fn import_head_commits_duplicates() {
let settings = user_settings();
let temp_dir = testutils::new_temp_dir();
let backend = GitBackend::init_internal(&settings, temp_dir.path()).unwrap();
let git_repo = backend.open_git_repo().unwrap();
let signature = git2::Signature::now("Someone", "someone@example.com").unwrap();
let empty_tree_id = Oid::from_str("4b825dc642cb6eb9a060e54bf8d69288fbee4904").unwrap();
let empty_tree = git_repo.find_tree(empty_tree_id).unwrap();
let git_commit_id = git_repo
.commit(
Some("refs/heads/main"),
&signature,
&signature,
"git commit message",
&empty_tree,
&[],
)
.unwrap();
let commit_id = CommitId::from_bytes(git_commit_id.as_bytes());
// Ref creation shouldn't fail because of duplicated head ids.
backend
.import_head_commits([&commit_id, &commit_id])
.unwrap();
let git_refs: Vec<_> = git_repo
.references_glob("refs/jj/keep/*")
.unwrap()
.try_collect()
.unwrap();
assert!(git_refs
.iter()
.any(|git_ref| git_ref.target().unwrap() == git_commit_id));
}
#[test]
fn overlapping_git_commit_id() {
let settings = user_settings();
let temp_dir = testutils::new_temp_dir();
let backend = GitBackend::init_internal(&settings, temp_dir.path()).unwrap();
let mut commit1 = Commit {
parents: vec![backend.root_commit_id().clone()],
predecessors: vec![],
root_tree: MergedTreeId::Legacy(backend.empty_tree_id().clone()),
change_id: ChangeId::new(vec![]),
description: "initial".to_string(),
author: create_signature(),
committer: create_signature(),
secure_sig: None,
};
// libgit2 doesn't seem to preserve negative timestamps, so set it to at least 1
// second after the epoch, so the timestamp adjustment can remove 1
// second and it will still be nonnegative
commit1.committer.timestamp.timestamp = MillisSinceEpoch(1000);
let (commit_id1, mut commit2) = backend.write_commit(commit1, None).unwrap();
commit2.predecessors.push(commit_id1.clone());
// `write_commit` should prevent the ids from being the same by changing the
// committer timestamp of the commit it actually writes.
let (commit_id2, mut actual_commit2) = backend.write_commit(commit2.clone(), None).unwrap();
// The returned matches the ID
assert_eq!(
backend.read_commit(&commit_id2).block_on().unwrap(),
actual_commit2
);
assert_ne!(commit_id2, commit_id1);
// The committer timestamp should differ
assert_ne!(
actual_commit2.committer.timestamp.timestamp,
commit2.committer.timestamp.timestamp
);
// The rest of the commit should be the same
actual_commit2.committer.timestamp.timestamp = commit2.committer.timestamp.timestamp;
assert_eq!(actual_commit2, commit2);
}
#[test]
fn write_signed_commit() {
let settings = user_settings();
let temp_dir = testutils::new_temp_dir();
let backend = GitBackend::init_internal(&settings, temp_dir.path()).unwrap();
let commit = Commit {
parents: vec![backend.root_commit_id().clone()],
predecessors: vec![],
root_tree: MergedTreeId::Legacy(backend.empty_tree_id().clone()),
change_id: ChangeId::new(vec![]),
description: "initial".to_string(),
author: create_signature(),
committer: create_signature(),
secure_sig: None,
};
let mut signer = |data: &_| {
let hash: String = blake2b_hash(data).encode_hex();
Ok(format!("test sig\n\n\nhash={hash}").into_bytes())
};
let (id, commit) = backend
.write_commit(commit, Some(&mut signer as &mut SigningFn))
.unwrap();
let git_repo = backend.git_repo();
let obj = git_repo
.find_object(gix::ObjectId::try_from(id.as_bytes()).unwrap())
.unwrap();
insta::assert_snapshot!(std::str::from_utf8(&obj.data).unwrap(), @r###"
tree 4b825dc642cb6eb9a060e54bf8d69288fbee4904
author Someone <someone@example.com> 0 +0000
committer Someone <someone@example.com> 0 +0000
gpgsig test sig
hash=9ad9526c3b2103c41a229f2f3c82d107a0ecd902f476a855f0e1dd5f7bef1430663de12749b73e293a877113895a8a2a0f29da4bbc5a5f9a19c3523fb0e53518
initial
"###);
let returned_sig = commit.secure_sig.expect("failed to return the signature");
let commit = backend.read_commit(&id).block_on().unwrap();
let sig = commit.secure_sig.expect("failed to read the signature");
assert_eq!(&sig, &returned_sig);
insta::assert_snapshot!(std::str::from_utf8(&sig.sig).unwrap(), @r###"
test sig
hash=9ad9526c3b2103c41a229f2f3c82d107a0ecd902f476a855f0e1dd5f7bef1430663de12749b73e293a877113895a8a2a0f29da4bbc5a5f9a19c3523fb0e53518
"###);
insta::assert_snapshot!(std::str::from_utf8(&sig.data).unwrap(), @r###"
tree 4b825dc642cb6eb9a060e54bf8d69288fbee4904
author Someone <someone@example.com> 0 +0000
committer Someone <someone@example.com> 0 +0000
initial
"###);
}
fn git_id(commit_id: &CommitId) -> Oid {
Oid::from_bytes(commit_id.as_bytes()).unwrap()
}
fn create_signature() -> Signature {
Signature {
name: "Someone".to_string(),
email: "someone@example.com".to_string(),
timestamp: Timestamp {
timestamp: MillisSinceEpoch(0),
tz_offset: 0,
},
}
}
// Not using testutils::user_settings() because there is a dependency cycle
// 'jj_lib (1) -> testutils -> jj_lib (2)' which creates another distinct
// UserSettings type. testutils returns jj_lib (2)'s UserSettings, whereas
// our UserSettings type comes from jj_lib (1).
fn user_settings() -> UserSettings {
let config = config::Config::default();
UserSettings::from_config(config)
}
}
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