jj/lib/src/git.rs
2024-06-23 12:31:43 +10:00

1787 lines
69 KiB
Rust

// 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::borrow::Cow;
use std::collections::{BTreeMap, HashMap, HashSet};
use std::default::Default;
use std::io::Read;
use std::path::PathBuf;
use std::{fmt, iter, str};
use git2::Oid;
use itertools::Itertools;
use tempfile::NamedTempFile;
use thiserror::Error;
use crate::backend::{BackendError, CommitId};
use crate::commit::Commit;
use crate::git_backend::GitBackend;
use crate::index::Index;
use crate::object_id::ObjectId;
use crate::op_store::{RefTarget, RefTargetOptionExt, RemoteRef, RemoteRefState};
use crate::refs::{self, BranchPushUpdate};
use crate::repo::{MutableRepo, Repo};
use crate::revset::RevsetExpression;
use crate::settings::GitSettings;
use crate::store::Store;
use crate::str_util::StringPattern;
use crate::view::View;
/// Reserved remote name for the backing Git repo.
pub const REMOTE_NAME_FOR_LOCAL_GIT_REPO: &str = "git";
/// Ref name used as a placeholder to unset HEAD without a commit.
const UNBORN_ROOT_REF_NAME: &str = "refs/jj/root";
#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Hash, Debug)]
pub enum RefName {
LocalBranch(String),
RemoteBranch { branch: String, remote: String },
Tag(String),
}
impl fmt::Display for RefName {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
RefName::LocalBranch(name) => write!(f, "{name}"),
RefName::RemoteBranch { branch, remote } => write!(f, "{branch}@{remote}"),
RefName::Tag(name) => write!(f, "{name}"),
}
}
}
fn parse_git_ref(ref_name: &str) -> Option<RefName> {
if let Some(branch_name) = ref_name.strip_prefix("refs/heads/") {
// Git CLI says 'HEAD' is not a valid branch name
(branch_name != "HEAD").then(|| RefName::LocalBranch(branch_name.to_string()))
} else if let Some(remote_and_branch) = ref_name.strip_prefix("refs/remotes/") {
remote_and_branch
.split_once('/')
// "refs/remotes/origin/HEAD" isn't a real remote-tracking branch
.filter(|&(_, branch)| branch != "HEAD")
.map(|(remote, branch)| RefName::RemoteBranch {
remote: remote.to_string(),
branch: branch.to_string(),
})
} else {
ref_name
.strip_prefix("refs/tags/")
.map(|tag_name| RefName::Tag(tag_name.to_string()))
}
}
fn to_git_ref_name(parsed_ref: &RefName) -> Option<String> {
match parsed_ref {
RefName::LocalBranch(branch) => {
(!branch.is_empty() && branch != "HEAD").then(|| format!("refs/heads/{branch}"))
}
RefName::RemoteBranch { branch, remote } => (!branch.is_empty() && branch != "HEAD")
.then(|| format!("refs/remotes/{remote}/{branch}")),
RefName::Tag(tag) => Some(format!("refs/tags/{tag}")),
}
}
fn to_remote_branch<'a>(parsed_ref: &'a RefName, remote_name: &str) -> Option<&'a str> {
match parsed_ref {
RefName::RemoteBranch { branch, remote } => (remote == remote_name).then_some(branch),
RefName::LocalBranch(..) | RefName::Tag(..) => None,
}
}
/// Returns true if the `parsed_ref` won't be imported because its remote name
/// is reserved.
///
/// Use this as a negative `git_ref_filter` to be passed in to
/// `import_some_refs()`.
pub fn is_reserved_git_remote_ref(parsed_ref: &RefName) -> bool {
to_remote_branch(parsed_ref, REMOTE_NAME_FOR_LOCAL_GIT_REPO).is_some()
}
fn get_git_backend(store: &Store) -> Option<&GitBackend> {
store.backend_impl().downcast_ref()
}
fn get_git_repo(store: &Store) -> Option<gix::Repository> {
get_git_backend(store).map(|backend| backend.git_repo())
}
/// Checks if `git_ref` points to a Git commit object, and returns its id.
///
/// If the ref points to the previously `known_target` (i.e. unchanged), this
/// should be faster than `git_ref.into_fully_peeled_id()`.
fn resolve_git_ref_to_commit_id(
git_ref: &gix::Reference,
known_target: &RefTarget,
) -> Option<CommitId> {
let mut peeling_ref = Cow::Borrowed(git_ref);
// Try fast path if we have a candidate id which is known to be a commit object.
if let Some(id) = known_target.as_normal() {
let raw_ref = &git_ref.inner;
if matches!(raw_ref.target.try_id(), Some(oid) if oid.as_bytes() == id.as_bytes()) {
return Some(id.clone());
}
if matches!(raw_ref.peeled, Some(oid) if oid.as_bytes() == id.as_bytes()) {
// Perhaps an annotated tag stored in packed-refs file, and pointing to the
// already known target commit.
return Some(id.clone());
}
// A tag (according to ref name.) Try to peel one more level. This is slightly
// faster than recurse into into_fully_peeled_id(). If we recorded a tag oid, we
// could skip this at all.
if raw_ref.peeled.is_none() && git_ref.name().as_bstr().starts_with(b"refs/tags/") {
let maybe_tag = git_ref
.try_id()
.and_then(|id| id.object().ok())
.and_then(|object| object.try_into_tag().ok());
if let Some(oid) = maybe_tag.as_ref().and_then(|tag| tag.target_id().ok()) {
if oid.as_bytes() == id.as_bytes() {
// An annotated tag pointing to the already known target commit.
return Some(id.clone());
}
// Unknown id. Recurse from the current state. A tag may point to
// non-commit object.
peeling_ref.to_mut().inner.target = gix::refs::Target::Peeled(oid.detach());
}
}
}
// Alternatively, we might want to inline the first half of the peeling
// loop. into_fully_peeled_id() looks up the target object to see if it's
// a tag or not, and we need to check if it's a commit object.
let peeled_id = peeling_ref.into_owned().into_fully_peeled_id().ok()?;
let is_commit = peeled_id
.object()
.map_or(false, |object| object.kind.is_commit());
is_commit.then(|| CommitId::from_bytes(peeled_id.as_bytes()))
}
#[derive(Error, Debug)]
pub enum GitImportError {
#[error("Failed to read Git HEAD target commit {id}", id=id.hex())]
MissingHeadTarget {
id: CommitId,
#[source]
err: BackendError,
},
#[error("Ancestor of Git ref {ref_name} is missing")]
MissingRefAncestor {
ref_name: String,
#[source]
err: BackendError,
},
#[error(
"Git remote named '{name}' is reserved for local Git repository",
name = REMOTE_NAME_FOR_LOCAL_GIT_REPO
)]
RemoteReservedForLocalGitRepo,
#[error("Unexpected backend error when importing refs")]
InternalBackend(#[source] BackendError),
#[error("Unexpected git error when importing refs")]
InternalGitError(#[source] Box<dyn std::error::Error + Send + Sync>),
#[error("The repo is not backed by a Git repo")]
UnexpectedBackend,
}
impl GitImportError {
fn from_git(source: impl Into<Box<dyn std::error::Error + Send + Sync>>) -> Self {
GitImportError::InternalGitError(source.into())
}
}
/// Describes changes made by `import_refs()` or `fetch()`.
#[derive(Clone, Debug, Eq, PartialEq, Default)]
pub struct GitImportStats {
/// Commits superseded by newly imported commits.
pub abandoned_commits: Vec<CommitId>,
/// Remote `(ref_name, (old_remote_ref, new_target))`s to be merged in to
/// the local refs.
pub changed_remote_refs: BTreeMap<RefName, (RemoteRef, RefTarget)>,
}
#[derive(Debug)]
struct RefsToImport {
/// Git ref `(full_name, new_target)`s to be copied to the view.
changed_git_refs: Vec<(String, RefTarget)>,
/// Remote `(ref_name, (old_remote_ref, new_target))`s to be merged in to
/// the local refs.
changed_remote_refs: BTreeMap<RefName, (RemoteRef, RefTarget)>,
}
/// Reflect changes made in the underlying Git repo in the Jujutsu repo.
///
/// This function detects conflicts (if both Git and JJ modified a branch) and
/// records them in JJ's view.
pub fn import_refs(
mut_repo: &mut MutableRepo,
git_settings: &GitSettings,
) -> Result<GitImportStats, GitImportError> {
import_some_refs(mut_repo, git_settings, |_| true)
}
/// Reflect changes made in the underlying Git repo in the Jujutsu repo.
///
/// Only branches whose git full reference name pass the filter will be
/// considered for addition, update, or deletion.
pub fn import_some_refs(
mut_repo: &mut MutableRepo,
git_settings: &GitSettings,
git_ref_filter: impl Fn(&RefName) -> bool,
) -> Result<GitImportStats, GitImportError> {
let store = mut_repo.store();
let git_backend = get_git_backend(store).ok_or(GitImportError::UnexpectedBackend)?;
let git_repo = git_backend.git_repo();
let RefsToImport {
changed_git_refs,
changed_remote_refs,
} = diff_refs_to_import(mut_repo.view(), &git_repo, git_ref_filter)?;
// Bulk-import all reachable Git commits to the backend to reduce overhead
// of table merging and ref updates.
//
// changed_remote_refs might contain new_targets that are not in
// changed_git_refs, but such targets should have already been imported to
// the backend.
let index = mut_repo.index();
let missing_head_ids = changed_git_refs
.iter()
.flat_map(|(_, new_target)| new_target.added_ids())
.filter(|&id| !index.has_id(id));
let heads_imported = git_backend.import_head_commits(missing_head_ids).is_ok();
// Import new remote heads
let mut head_commits = Vec::new();
let get_commit = |id| {
// If bulk-import failed, try again to find bad head or ref.
if !heads_imported && !index.has_id(id) {
git_backend.import_head_commits([id])?;
}
store.get_commit(id)
};
for (ref_name, (_, new_target)) in &changed_remote_refs {
for id in new_target.added_ids() {
let commit = get_commit(id).map_err(|err| GitImportError::MissingRefAncestor {
ref_name: ref_name.to_string(),
err,
})?;
head_commits.push(commit);
}
}
// It's unlikely the imported commits were missing, but I/O-related error
// can still occur.
mut_repo
.add_heads(&head_commits)
.map_err(GitImportError::InternalBackend)?;
// Apply the change that happened in git since last time we imported refs.
for (full_name, new_target) in changed_git_refs {
mut_repo.set_git_ref_target(&full_name, new_target);
}
for (ref_name, (old_remote_ref, new_target)) in &changed_remote_refs {
let base_target = old_remote_ref.tracking_target();
let new_remote_ref = RemoteRef {
target: new_target.clone(),
state: if old_remote_ref.is_present() {
old_remote_ref.state
} else {
default_remote_ref_state_for(ref_name, git_settings)
},
};
match ref_name {
RefName::LocalBranch(branch) => {
if new_remote_ref.is_tracking() {
mut_repo.merge_local_branch(branch, base_target, &new_remote_ref.target);
}
// Update Git-tracking branch like the other remote branches.
mut_repo.set_remote_branch(branch, REMOTE_NAME_FOR_LOCAL_GIT_REPO, new_remote_ref);
}
RefName::RemoteBranch { branch, remote } => {
if new_remote_ref.is_tracking() {
mut_repo.merge_local_branch(branch, base_target, &new_remote_ref.target);
}
// Remote-tracking branch is the last known state of the branch in the remote.
// It shouldn't diverge even if we had inconsistent view.
mut_repo.set_remote_branch(branch, remote, new_remote_ref);
}
RefName::Tag(name) => {
if new_remote_ref.is_tracking() {
mut_repo.merge_tag(name, base_target, &new_remote_ref.target);
}
// TODO: If we add Git-tracking tag, it will be updated here.
}
}
}
let abandoned_commits = if git_settings.abandon_unreachable_commits {
abandon_unreachable_commits(mut_repo, &changed_remote_refs)
} else {
vec![]
};
let stats = GitImportStats {
abandoned_commits,
changed_remote_refs,
};
Ok(stats)
}
/// Finds commits that used to be reachable in git that no longer are reachable.
/// Those commits will be recorded as abandoned in the `MutableRepo`.
fn abandon_unreachable_commits(
mut_repo: &mut MutableRepo,
changed_remote_refs: &BTreeMap<RefName, (RemoteRef, RefTarget)>,
) -> Vec<CommitId> {
let hidable_git_heads = changed_remote_refs
.values()
.flat_map(|(old_remote_ref, _)| old_remote_ref.target.added_ids())
.cloned()
.collect_vec();
if hidable_git_heads.is_empty() {
return vec![];
}
let pinned_expression = RevsetExpression::union_all(&[
// Local refs are usually visible, no need to filter out hidden
RevsetExpression::commits(pinned_commit_ids(mut_repo.view())),
RevsetExpression::commits(remotely_pinned_commit_ids(mut_repo.view()))
// Hidden remote branches should not contribute to pinning
.intersection(&RevsetExpression::visible_heads().ancestors()),
RevsetExpression::root(),
]);
let abandoned_expression = pinned_expression
.range(&RevsetExpression::commits(hidable_git_heads))
// Don't include already-abandoned commits in GitImportStats
.intersection(&RevsetExpression::visible_heads().ancestors());
let abandoned_commits = abandoned_expression
.evaluate_programmatic(mut_repo)
.unwrap()
.iter()
.collect_vec();
for abandoned_commit in &abandoned_commits {
mut_repo.record_abandoned_commit(abandoned_commit.clone());
}
abandoned_commits
}
/// Calculates diff of git refs to be imported.
fn diff_refs_to_import(
view: &View,
git_repo: &gix::Repository,
git_ref_filter: impl Fn(&RefName) -> bool,
) -> Result<RefsToImport, GitImportError> {
let mut known_git_refs: HashMap<&str, &RefTarget> = view
.git_refs()
.iter()
.filter_map(|(full_name, target)| {
// TODO: or clean up invalid ref in case it was stored due to historical bug?
let ref_name = parse_git_ref(full_name).expect("stored git ref should be parsable");
git_ref_filter(&ref_name).then_some((full_name.as_ref(), target))
})
.collect();
// TODO: migrate tags to the remote view, and don't destructure &RemoteRef
let mut known_remote_refs: HashMap<RefName, (&RefTarget, RemoteRefState)> = itertools::chain(
view.all_remote_branches()
.map(|((branch, remote), remote_ref)| {
// TODO: want to abstract local ref as "git" tracking remote, but
// we'll probably need to refactor the git_ref_filter API first.
let ref_name = if remote == REMOTE_NAME_FOR_LOCAL_GIT_REPO {
RefName::LocalBranch(branch.to_owned())
} else {
RefName::RemoteBranch {
branch: branch.to_owned(),
remote: remote.to_owned(),
}
};
let RemoteRef { target, state } = remote_ref;
(ref_name, (target, *state))
}),
// TODO: compare to tags stored in the "git" remote view. Since tags should never
// be moved locally in jj, we can consider local tags as merge base.
view.tags().iter().map(|(name, target)| {
let ref_name = RefName::Tag(name.to_owned());
(ref_name, (target, RemoteRefState::Tracking))
}),
)
.filter(|(ref_name, _)| git_ref_filter(ref_name))
.collect();
let mut changed_git_refs = Vec::new();
let mut changed_remote_refs = BTreeMap::new();
let git_references = git_repo.references().map_err(GitImportError::from_git)?;
let chain_git_refs_iters = || -> Result<_, gix::reference::iter::init::Error> {
// Exclude uninteresting directories such as refs/jj/keep.
Ok(itertools::chain!(
git_references.local_branches()?,
git_references.remote_branches()?,
git_references.tags()?,
))
};
for git_ref in chain_git_refs_iters().map_err(GitImportError::from_git)? {
let git_ref = git_ref.map_err(GitImportError::from_git)?;
let Ok(full_name) = str::from_utf8(git_ref.name().as_bstr()) else {
// Skip non-utf8 refs.
continue;
};
let Some(ref_name) = parse_git_ref(full_name) else {
// Skip other refs (such as notes) and symbolic refs.
continue;
};
if !git_ref_filter(&ref_name) {
continue;
}
if is_reserved_git_remote_ref(&ref_name) {
return Err(GitImportError::RemoteReservedForLocalGitRepo);
}
let old_git_target = known_git_refs.get(full_name).copied().flatten();
let Some(id) = resolve_git_ref_to_commit_id(&git_ref, old_git_target) else {
// Skip (or remove existing) invalid refs.
continue;
};
let new_target = RefTarget::normal(id);
known_git_refs.remove(full_name);
if new_target != *old_git_target {
changed_git_refs.push((full_name.to_owned(), new_target.clone()));
}
// TODO: Make it configurable which remotes are publishing and update public
// heads here.
let (old_remote_target, old_remote_state) = known_remote_refs
.remove(&ref_name)
.unwrap_or_else(|| (RefTarget::absent_ref(), RemoteRefState::New));
if new_target != *old_remote_target {
let old_remote_ref = RemoteRef {
target: old_remote_target.clone(),
state: old_remote_state,
};
changed_remote_refs.insert(ref_name, (old_remote_ref, new_target));
}
}
for full_name in known_git_refs.into_keys() {
changed_git_refs.push((full_name.to_owned(), RefTarget::absent()));
}
for (ref_name, (old_target, old_state)) in known_remote_refs {
let old_remote_ref = RemoteRef {
target: old_target.clone(),
state: old_state,
};
changed_remote_refs.insert(ref_name, (old_remote_ref, RefTarget::absent()));
}
Ok(RefsToImport {
changed_git_refs,
changed_remote_refs,
})
}
fn default_remote_ref_state_for(ref_name: &RefName, git_settings: &GitSettings) -> RemoteRefState {
match ref_name {
// LocalBranch means Git-tracking branch
RefName::LocalBranch(_) | RefName::Tag(_) => RemoteRefState::Tracking,
RefName::RemoteBranch { .. } => {
if git_settings.auto_local_branch {
RemoteRefState::Tracking
} else {
RemoteRefState::New
}
}
}
}
/// Commits referenced by local branches, tags, or HEAD@git.
///
/// On `import_refs()`, this is similar to collecting commits referenced by
/// `view.git_refs()`. Main difference is that local branches can be moved by
/// tracking remotes, and such mutation isn't applied to `view.git_refs()` yet.
fn pinned_commit_ids(view: &View) -> Vec<CommitId> {
itertools::chain!(
view.local_branches().map(|(_, target)| target),
view.tags().values(),
iter::once(view.git_head()),
)
.flat_map(|target| target.added_ids())
.cloned()
.collect()
}
/// Commits referenced by untracked remote branches including hidden ones.
///
/// Tracked remote branches aren't included because they should have been merged
/// into the local counterparts, and the changes pulled from one remote should
/// propagate to the other remotes on later push. OTOH, untracked remote
/// branches are considered independent refs.
fn remotely_pinned_commit_ids(view: &View) -> Vec<CommitId> {
view.all_remote_branches()
.filter(|(_, remote_ref)| !remote_ref.is_tracking())
.map(|(_, remote_ref)| &remote_ref.target)
.flat_map(|target| target.added_ids())
.cloned()
.collect()
}
/// Imports `HEAD@git` from the underlying Git repo.
///
/// Unlike `import_refs()`, the old HEAD branch is not abandoned because HEAD
/// move doesn't always mean the old HEAD branch has been rewritten.
///
/// Unlike `reset_head()`, this function doesn't move the working-copy commit to
/// the child of the new `HEAD@git` revision.
pub fn import_head(mut_repo: &mut MutableRepo) -> Result<(), GitImportError> {
let store = mut_repo.store();
let git_backend = get_git_backend(store).ok_or(GitImportError::UnexpectedBackend)?;
let git_repo = git_backend.git_repo();
let old_git_head = mut_repo.view().git_head();
let new_git_head_id = if let Ok(oid) = git_repo.head_id() {
Some(CommitId::from_bytes(oid.as_bytes()))
} else {
None
};
if old_git_head.as_resolved() == Some(&new_git_head_id) {
return Ok(());
}
// Import new head
if let Some(head_id) = &new_git_head_id {
let index = mut_repo.index();
if !index.has_id(head_id) {
git_backend.import_head_commits([head_id]).map_err(|err| {
GitImportError::MissingHeadTarget {
id: head_id.clone(),
err,
}
})?;
}
// It's unlikely the imported commits were missing, but I/O-related
// error can still occur.
store
.get_commit(head_id)
.and_then(|commit| mut_repo.add_head(&commit))
.map_err(GitImportError::InternalBackend)?;
}
mut_repo.set_git_head_target(RefTarget::resolved(new_git_head_id));
Ok(())
}
#[derive(Error, Debug)]
pub enum GitExportError {
#[error("Git error")]
InternalGitError(#[source] Box<dyn std::error::Error + Send + Sync>),
#[error("The repo is not backed by a Git repo")]
UnexpectedBackend,
}
impl GitExportError {
fn from_git(source: impl Into<Box<dyn std::error::Error + Send + Sync>>) -> Self {
GitExportError::InternalGitError(source.into())
}
}
/// A ref we failed to export to Git, along with the reason it failed.
#[derive(Debug)]
pub struct FailedRefExport {
pub name: RefName,
pub reason: FailedRefExportReason,
}
/// The reason we failed to export a ref to Git.
#[derive(Debug, Error)]
pub enum FailedRefExportReason {
/// The name is not allowed in Git.
#[error("Name is not allowed in Git")]
InvalidGitName,
/// The ref was in a conflicted state from the last import. A re-import
/// should fix it.
#[error("Ref was in a conflicted state from the last import")]
ConflictedOldState,
/// The branch points to the root commit, which Git doesn't have
#[error("Ref cannot point to the root commit in Git")]
OnRootCommit,
/// We wanted to delete it, but it had been modified in Git.
#[error("Deleted ref had been modified in Git")]
DeletedInJjModifiedInGit,
/// We wanted to add it, but Git had added it with a different target
#[error("Added ref had been added with a different target in Git")]
AddedInJjAddedInGit,
/// We wanted to modify it, but Git had deleted it
#[error("Modified ref had been deleted in Git")]
ModifiedInJjDeletedInGit,
/// Failed to delete the ref from the Git repo
#[error("Failed to delete")]
FailedToDelete(#[source] Box<gix::reference::edit::Error>),
/// Failed to set the ref in the Git repo
#[error("Failed to set")]
FailedToSet(#[source] Box<gix::reference::edit::Error>),
}
#[derive(Debug)]
struct RefsToExport {
branches_to_update: BTreeMap<RefName, (Option<gix::ObjectId>, gix::ObjectId)>,
branches_to_delete: BTreeMap<RefName, gix::ObjectId>,
failed_branches: HashMap<RefName, FailedRefExportReason>,
}
/// Export changes to branches made in the Jujutsu repo compared to our last
/// seen view of the Git repo in `mut_repo.view().git_refs()`. Returns a list of
/// refs that failed to export.
///
/// We ignore changed branches that are conflicted (were also changed in the Git
/// repo compared to our last remembered view of the Git repo). These will be
/// marked conflicted by the next `jj git import`.
///
/// We do not export tags and other refs at the moment, since these aren't
/// supposed to be modified by JJ. For them, the Git state is considered
/// authoritative.
pub fn export_refs(mut_repo: &mut MutableRepo) -> Result<Vec<FailedRefExport>, GitExportError> {
export_some_refs(mut_repo, |_| true)
}
pub fn export_some_refs(
mut_repo: &mut MutableRepo,
git_ref_filter: impl Fn(&RefName) -> bool,
) -> Result<Vec<FailedRefExport>, GitExportError> {
let git_repo = get_git_repo(mut_repo.store()).ok_or(GitExportError::UnexpectedBackend)?;
let RefsToExport {
branches_to_update,
branches_to_delete,
mut failed_branches,
} = diff_refs_to_export(
mut_repo.view(),
mut_repo.store().root_commit_id(),
&git_ref_filter,
);
// TODO: Also check other worktrees' HEAD.
if let Ok(head_ref) = git_repo.find_reference("HEAD") {
if let Some(parsed_ref) = head_ref
.target()
.try_name()
.and_then(|name| str::from_utf8(name.as_bstr()).ok())
.and_then(parse_git_ref)
{
let old_target = head_ref.inner.target.clone();
let current_oid = match head_ref.into_fully_peeled_id() {
Ok(id) => Some(id.detach()),
Err(gix::reference::peel::Error::ToId(gix::refs::peel::to_id::Error::Follow(
gix::refs::file::find::existing::Error::NotFound { .. },
))) => None, // Unborn ref should be considered absent
Err(err) => return Err(GitExportError::from_git(err)),
};
let new_oid = if let Some((_old_oid, new_oid)) = branches_to_update.get(&parsed_ref) {
Some(new_oid)
} else if branches_to_delete.contains_key(&parsed_ref) {
None
} else {
current_oid.as_ref()
};
if new_oid != current_oid.as_ref() {
update_git_head(&git_repo, old_target, current_oid)?;
}
}
}
for (parsed_ref_name, old_oid) in branches_to_delete {
let Some(git_ref_name) = to_git_ref_name(&parsed_ref_name) else {
failed_branches.insert(parsed_ref_name, FailedRefExportReason::InvalidGitName);
continue;
};
if let Err(reason) = delete_git_ref(&git_repo, &git_ref_name, &old_oid) {
failed_branches.insert(parsed_ref_name, reason);
} else {
let new_target = RefTarget::absent();
mut_repo.set_git_ref_target(&git_ref_name, new_target);
}
}
for (parsed_ref_name, (old_oid, new_oid)) in branches_to_update {
let Some(git_ref_name) = to_git_ref_name(&parsed_ref_name) else {
failed_branches.insert(parsed_ref_name, FailedRefExportReason::InvalidGitName);
continue;
};
if let Err(reason) = update_git_ref(&git_repo, &git_ref_name, old_oid, new_oid) {
failed_branches.insert(parsed_ref_name, reason);
} else {
let new_target = RefTarget::normal(CommitId::from_bytes(new_oid.as_bytes()));
mut_repo.set_git_ref_target(&git_ref_name, new_target);
}
}
copy_exportable_local_branches_to_remote_view(
mut_repo,
REMOTE_NAME_FOR_LOCAL_GIT_REPO,
|ref_name| git_ref_filter(ref_name) && !failed_branches.contains_key(ref_name),
);
let failed_branches = failed_branches
.into_iter()
.map(|(name, reason)| FailedRefExport { name, reason })
.sorted_unstable_by(|a, b| a.name.cmp(&b.name))
.collect();
Ok(failed_branches)
}
fn copy_exportable_local_branches_to_remote_view(
mut_repo: &mut MutableRepo,
remote_name: &str,
git_ref_filter: impl Fn(&RefName) -> bool,
) {
let new_local_branches = mut_repo
.view()
.local_remote_branches(remote_name)
.filter_map(|(branch, targets)| {
// TODO: filter out untracked branches (if we add support for untracked @git
// branches)
let old_target = &targets.remote_ref.target;
let new_target = targets.local_target;
(!new_target.has_conflict() && old_target != new_target).then_some((branch, new_target))
})
.filter(|&(branch, _)| git_ref_filter(&RefName::LocalBranch(branch.to_owned())))
.map(|(branch, new_target)| (branch.to_owned(), new_target.clone()))
.collect_vec();
for (branch, new_target) in new_local_branches {
let new_remote_ref = RemoteRef {
target: new_target,
state: RemoteRefState::Tracking,
};
mut_repo.set_remote_branch(&branch, remote_name, new_remote_ref);
}
}
/// Calculates diff of branches to be exported.
fn diff_refs_to_export(
view: &View,
root_commit_id: &CommitId,
git_ref_filter: impl Fn(&RefName) -> bool,
) -> RefsToExport {
// Local targets will be copied to the "git" remote if successfully exported. So
// the local branches are considered to be the new "git" remote branches.
let mut all_branch_targets: HashMap<RefName, (&RefTarget, &RefTarget)> = itertools::chain(
view.local_branches()
.map(|(branch, target)| (RefName::LocalBranch(branch.to_owned()), target)),
view.all_remote_branches()
.filter(|&((_, remote), _)| remote != REMOTE_NAME_FOR_LOCAL_GIT_REPO)
.map(|((branch, remote), remote_ref)| {
let ref_name = RefName::RemoteBranch {
branch: branch.to_owned(),
remote: remote.to_owned(),
};
(ref_name, &remote_ref.target)
}),
)
.map(|(ref_name, new_target)| (ref_name, (RefTarget::absent_ref(), new_target)))
.filter(|(ref_name, _)| git_ref_filter(ref_name))
.collect();
let known_git_refs = view
.git_refs()
.iter()
.map(|(full_name, target)| {
let ref_name = parse_git_ref(full_name).expect("stored git ref should be parsable");
(ref_name, target)
})
.filter(|(ref_name, _)| {
// There are two situations where remote-tracking branches get out of sync:
// 1. `jj branch forget`
// 2. `jj op undo`/`restore` in colocated repo
matches!(
ref_name,
RefName::LocalBranch(..) | RefName::RemoteBranch { .. }
)
})
.filter(|(ref_name, _)| git_ref_filter(ref_name));
for (ref_name, target) in known_git_refs {
all_branch_targets
.entry(ref_name)
.and_modify(|(old_target, _)| *old_target = target)
.or_insert((target, RefTarget::absent_ref()));
}
let mut branches_to_update = BTreeMap::new();
let mut branches_to_delete = BTreeMap::new();
let mut failed_branches = HashMap::new();
let root_commit_target = RefTarget::normal(root_commit_id.clone());
for (ref_name, (old_target, new_target)) in all_branch_targets {
if new_target == old_target {
continue;
}
if *new_target == root_commit_target {
// Git doesn't have a root commit
failed_branches.insert(ref_name, FailedRefExportReason::OnRootCommit);
continue;
}
let old_oid = if let Some(id) = old_target.as_normal() {
Some(gix::ObjectId::try_from(id.as_bytes()).unwrap())
} else if old_target.has_conflict() {
// The old git ref should only be a conflict if there were concurrent import
// operations while the value changed. Don't overwrite these values.
failed_branches.insert(ref_name, FailedRefExportReason::ConflictedOldState);
continue;
} else {
assert!(old_target.is_absent());
None
};
if let Some(id) = new_target.as_normal() {
let new_oid = gix::ObjectId::try_from(id.as_bytes()).unwrap();
branches_to_update.insert(ref_name, (old_oid, new_oid));
} else if new_target.has_conflict() {
// Skip conflicts and leave the old value in git_refs
continue;
} else {
assert!(new_target.is_absent());
branches_to_delete.insert(ref_name, old_oid.unwrap());
}
}
RefsToExport {
branches_to_update,
branches_to_delete,
failed_branches,
}
}
fn delete_git_ref(
git_repo: &gix::Repository,
git_ref_name: &str,
old_oid: &gix::oid,
) -> Result<(), FailedRefExportReason> {
if let Ok(git_ref) = git_repo.find_reference(git_ref_name) {
if git_ref.inner.target.try_id() == Some(old_oid) {
// The branch has not been updated by git, so go ahead and delete it
git_ref
.delete()
.map_err(|err| FailedRefExportReason::FailedToDelete(err.into()))?;
} else {
// The branch was updated by git
return Err(FailedRefExportReason::DeletedInJjModifiedInGit);
}
} else {
// The branch is already deleted
}
Ok(())
}
fn update_git_ref(
git_repo: &gix::Repository,
git_ref_name: &str,
old_oid: Option<gix::ObjectId>,
new_oid: gix::ObjectId,
) -> Result<(), FailedRefExportReason> {
match old_oid {
None => {
if let Ok(git_repo_ref) = git_repo.find_reference(git_ref_name) {
// The branch was added in jj and in git. We're good if and only if git
// pointed it to our desired target.
if git_repo_ref.inner.target.try_id() != Some(&new_oid) {
return Err(FailedRefExportReason::AddedInJjAddedInGit);
}
} else {
// The branch was added in jj but still doesn't exist in git, so add it
git_repo
.reference(
git_ref_name,
new_oid,
gix::refs::transaction::PreviousValue::MustNotExist,
"export from jj",
)
.map_err(|err| FailedRefExportReason::FailedToSet(err.into()))?;
}
}
Some(old_oid) => {
// The branch was modified in jj. We can use gix API for updating under a lock.
if let Err(err) = git_repo.reference(
git_ref_name,
new_oid,
gix::refs::transaction::PreviousValue::MustExistAndMatch(old_oid.into()),
"export from jj",
) {
// The reference was probably updated in git
if let Ok(git_repo_ref) = git_repo.find_reference(git_ref_name) {
// We still consider this a success if it was updated to our desired target
if git_repo_ref.inner.target.try_id() != Some(&new_oid) {
return Err(FailedRefExportReason::FailedToSet(err.into()));
}
} else {
// The reference was deleted in git and moved in jj
return Err(FailedRefExportReason::ModifiedInJjDeletedInGit);
}
} else {
// Successfully updated from old_oid to new_oid (unchanged in
// git)
}
}
}
Ok(())
}
/// Ensures `HEAD@git` is detached and pointing to the `new_oid`. If `new_oid`
/// is `None` (meaning absent), dummy placeholder ref will be set.
fn update_git_head(
git_repo: &gix::Repository,
old_target: gix::refs::Target,
new_oid: Option<gix::ObjectId>,
) -> Result<(), GitExportError> {
let mut ref_edits = Vec::new();
let new_target = if let Some(oid) = new_oid {
gix::refs::Target::Peeled(oid)
} else {
// Can't detach HEAD without a commit. Use placeholder ref to nullify
// the HEAD. The placeholder ref isn't a normal branch ref. Git CLI
// appears to deal with that, and can move the placeholder ref. So we
// need to ensure that the ref doesn't exist.
ref_edits.push(gix::refs::transaction::RefEdit {
change: gix::refs::transaction::Change::Delete {
expected: gix::refs::transaction::PreviousValue::Any,
log: gix::refs::transaction::RefLog::AndReference,
},
name: UNBORN_ROOT_REF_NAME.try_into().unwrap(),
deref: false,
});
gix::refs::Target::Symbolic(UNBORN_ROOT_REF_NAME.try_into().unwrap())
};
ref_edits.push(gix::refs::transaction::RefEdit {
change: gix::refs::transaction::Change::Update {
log: gix::refs::transaction::LogChange {
message: "export from jj".into(),
..Default::default()
},
expected: gix::refs::transaction::PreviousValue::MustExistAndMatch(old_target),
new: new_target,
},
name: "HEAD".try_into().unwrap(),
deref: false,
});
git_repo
.edit_references(ref_edits)
.map_err(GitExportError::from_git)?;
Ok(())
}
/// Sets `HEAD@git` to the parent of the given working-copy commit and resets
/// the Git index.
pub fn reset_head(
mut_repo: &mut MutableRepo,
git_repo: &git2::Repository,
wc_commit: &Commit,
) -> Result<(), git2::Error> {
let first_parent_id = &wc_commit.parent_ids()[0];
let first_parent = if first_parent_id != mut_repo.store().root_commit_id() {
RefTarget::normal(first_parent_id.clone())
} else {
RefTarget::absent()
};
if first_parent.is_present() {
let git_head = mut_repo.view().git_head();
let new_git_commit_id = Oid::from_bytes(first_parent_id.as_bytes()).unwrap();
let new_git_commit = git_repo.find_commit(new_git_commit_id)?;
if git_head != &first_parent {
git_repo.set_head_detached(new_git_commit_id)?;
}
let is_same_tree = if git_head == &first_parent {
true
} else if let Some(git_head_id) = git_head.as_normal() {
let git_head_oid = Oid::from_bytes(git_head_id.as_bytes()).unwrap();
let git_head_commit = git_repo.find_commit(git_head_oid)?;
new_git_commit.tree_id() == git_head_commit.tree_id()
} else {
false
};
let skip_reset = if is_same_tree {
// `HEAD@git` already points to a commit with the correct tree contents,
// so we only need to reset the Git index. We can skip the reset if
// the Git index is empty (i.e. `git add` was never used).
// In large repositories, this is around 2x faster if the Git index is empty
// (~0.89s to check the diff, vs. ~1.72s to reset), and around 8% slower if
// it isn't (~1.86s to check the diff AND reset).
let diff = git_repo.diff_tree_to_index(
Some(&new_git_commit.tree()?),
None,
Some(git2::DiffOptions::new().skip_binary_check(true)),
)?;
diff.deltas().len() == 0
} else {
false
};
if !skip_reset {
git_repo.reset(new_git_commit.as_object(), git2::ResetType::Mixed, None)?;
}
} else {
// Can't detach HEAD without a commit. Use placeholder ref to nullify the HEAD.
// We can't set_head() an arbitrary unborn ref, so use reference_symbolic()
// instead. Git CLI appears to deal with that. It would be nice if Git CLI
// couldn't create a commit without setting a valid branch name.
if mut_repo.git_head().is_present() {
match git_repo.find_reference(UNBORN_ROOT_REF_NAME) {
Ok(mut git_repo_ref) => git_repo_ref.delete()?,
Err(err) if err.code() == git2::ErrorCode::NotFound => {}
Err(err) => return Err(err),
}
git_repo.reference_symbolic("HEAD", UNBORN_ROOT_REF_NAME, true, "unset HEAD by jj")?;
}
// git_reset() of libgit2 requires a commit object. Do that manually.
let mut index = git_repo.index()?;
index.clear()?; // or read empty tree
index.write()?;
git_repo.cleanup_state()?;
}
mut_repo.set_git_head_target(first_parent);
Ok(())
}
#[derive(Debug, Error)]
pub enum GitRemoteManagementError {
#[error("No git remote named '{0}'")]
NoSuchRemote(String),
#[error("Git remote named '{0}' already exists")]
RemoteAlreadyExists(String),
#[error(
"Git remote named '{name}' is reserved for local Git repository",
name = REMOTE_NAME_FOR_LOCAL_GIT_REPO
)]
RemoteReservedForLocalGitRepo,
#[error(transparent)]
InternalGitError(git2::Error),
}
fn is_remote_not_found_err(err: &git2::Error) -> bool {
matches!(
(err.class(), err.code()),
(
git2::ErrorClass::Config,
git2::ErrorCode::NotFound | git2::ErrorCode::InvalidSpec
)
)
}
fn is_remote_exists_err(err: &git2::Error) -> bool {
matches!(
(err.class(), err.code()),
(git2::ErrorClass::Config, git2::ErrorCode::Exists)
)
}
pub fn add_remote(
git_repo: &git2::Repository,
remote_name: &str,
url: &str,
) -> Result<(), GitRemoteManagementError> {
if remote_name == REMOTE_NAME_FOR_LOCAL_GIT_REPO {
return Err(GitRemoteManagementError::RemoteReservedForLocalGitRepo);
}
git_repo.remote(remote_name, url).map_err(|err| {
if is_remote_exists_err(&err) {
GitRemoteManagementError::RemoteAlreadyExists(remote_name.to_owned())
} else {
GitRemoteManagementError::InternalGitError(err)
}
})?;
Ok(())
}
pub fn remove_remote(
mut_repo: &mut MutableRepo,
git_repo: &git2::Repository,
remote_name: &str,
) -> Result<(), GitRemoteManagementError> {
git_repo.remote_delete(remote_name).map_err(|err| {
if is_remote_not_found_err(&err) {
GitRemoteManagementError::NoSuchRemote(remote_name.to_owned())
} else {
GitRemoteManagementError::InternalGitError(err)
}
})?;
if remote_name != REMOTE_NAME_FOR_LOCAL_GIT_REPO {
remove_remote_refs(mut_repo, remote_name);
}
Ok(())
}
fn remove_remote_refs(mut_repo: &mut MutableRepo, remote_name: &str) {
mut_repo.remove_remote(remote_name);
let prefix = format!("refs/remotes/{remote_name}/");
let git_refs_to_delete = mut_repo
.view()
.git_refs()
.keys()
.filter(|&r| r.starts_with(&prefix))
.cloned()
.collect_vec();
for git_ref in git_refs_to_delete {
mut_repo.set_git_ref_target(&git_ref, RefTarget::absent());
}
}
pub fn rename_remote(
mut_repo: &mut MutableRepo,
git_repo: &git2::Repository,
old_remote_name: &str,
new_remote_name: &str,
) -> Result<(), GitRemoteManagementError> {
if new_remote_name == REMOTE_NAME_FOR_LOCAL_GIT_REPO {
return Err(GitRemoteManagementError::RemoteReservedForLocalGitRepo);
}
git_repo
.remote_rename(old_remote_name, new_remote_name)
.map_err(|err| {
if is_remote_not_found_err(&err) {
GitRemoteManagementError::NoSuchRemote(old_remote_name.to_owned())
} else if is_remote_exists_err(&err) {
GitRemoteManagementError::RemoteAlreadyExists(new_remote_name.to_owned())
} else {
GitRemoteManagementError::InternalGitError(err)
}
})?;
if old_remote_name != REMOTE_NAME_FOR_LOCAL_GIT_REPO {
rename_remote_refs(mut_repo, old_remote_name, new_remote_name);
}
Ok(())
}
pub fn set_remote_url(
git_repo: &git2::Repository,
remote_name: &str,
new_remote_url: &str,
) -> Result<(), GitRemoteManagementError> {
if remote_name == REMOTE_NAME_FOR_LOCAL_GIT_REPO {
return Err(GitRemoteManagementError::RemoteReservedForLocalGitRepo);
}
// Repository::remote_set_url() doesn't ensure the remote exists, it just
// creates it if it's missing.
// Therefore ensure it exists first
git_repo.find_remote(remote_name).map_err(|err| {
if is_remote_not_found_err(&err) {
GitRemoteManagementError::NoSuchRemote(remote_name.to_owned())
} else {
GitRemoteManagementError::InternalGitError(err)
}
})?;
git_repo
.remote_set_url(remote_name, new_remote_url)
.map_err(GitRemoteManagementError::InternalGitError)?;
Ok(())
}
fn rename_remote_refs(mut_repo: &mut MutableRepo, old_remote_name: &str, new_remote_name: &str) {
mut_repo.rename_remote(old_remote_name, new_remote_name);
let prefix = format!("refs/remotes/{old_remote_name}/");
let git_refs = mut_repo
.view()
.git_refs()
.iter()
.filter_map(|(r, target)| {
r.strip_prefix(&prefix).map(|p| {
(
r.clone(),
format!("refs/remotes/{new_remote_name}/{p}"),
target.clone(),
)
})
})
.collect_vec();
for (old, new, target) in git_refs {
mut_repo.set_git_ref_target(&old, RefTarget::absent());
mut_repo.set_git_ref_target(&new, target);
}
}
const INVALID_REFSPEC_CHARS: [char; 5] = [':', '^', '?', '[', ']'];
#[derive(Error, Debug)]
pub enum GitFetchError {
#[error("No git remote named '{0}'")]
NoSuchRemote(String),
#[error(
"Invalid branch pattern provided. Patterns may not contain the characters `{chars}`",
chars = INVALID_REFSPEC_CHARS.iter().join("`, `")
)]
InvalidBranchPattern,
#[error("Failed to import Git refs")]
GitImportError(#[from] GitImportError),
// TODO: I'm sure there are other errors possible, such as transport-level errors.
#[error("Unexpected git error when fetching")]
InternalGitError(#[from] git2::Error),
}
/// Describes successful `fetch()` result.
#[derive(Clone, Debug, Eq, PartialEq, Default)]
pub struct GitFetchStats {
/// Remote's default branch.
pub default_branch: Option<String>,
/// Changes made by the import.
pub import_stats: GitImportStats,
}
#[tracing::instrument(skip(mut_repo, git_repo, callbacks))]
pub fn fetch(
mut_repo: &mut MutableRepo,
git_repo: &git2::Repository,
remote_name: &str,
branch_names: &[StringPattern],
callbacks: RemoteCallbacks<'_>,
git_settings: &GitSettings,
) -> Result<GitFetchStats, GitFetchError> {
// Perform a `git fetch` on the local git repo, updating the remote-tracking
// branches in the git repo.
let mut remote = git_repo.find_remote(remote_name).map_err(|err| {
if is_remote_not_found_err(&err) {
GitFetchError::NoSuchRemote(remote_name.to_string())
} else {
GitFetchError::InternalGitError(err)
}
})?;
let mut fetch_options = git2::FetchOptions::new();
let mut proxy_options = git2::ProxyOptions::new();
proxy_options.auto();
fetch_options.proxy_options(proxy_options);
let callbacks = callbacks.into_git();
fetch_options.remote_callbacks(callbacks);
// At this point, we are only updating Git's remote tracking branches, not the
// local branches.
let refspecs: Vec<_> = branch_names
.iter()
.map(|pattern| {
pattern
.to_glob()
.filter(|glob| !glob.contains(INVALID_REFSPEC_CHARS))
.map(|glob| format!("+refs/heads/{glob}:refs/remotes/{remote_name}/{glob}"))
})
.collect::<Option<_>>()
.ok_or(GitFetchError::InvalidBranchPattern)?;
if refspecs.is_empty() {
// Don't fall back to the base refspecs.
let stats = GitFetchStats::default();
return Ok(stats);
}
tracing::debug!("remote.download");
remote.download(&refspecs, Some(&mut fetch_options))?;
tracing::debug!("remote.prune");
remote.prune(None)?;
tracing::debug!("remote.update_tips");
remote.update_tips(None, false, git2::AutotagOption::Unspecified, None)?;
// TODO: We could make it optional to get the default branch since we only care
// about it on clone.
let mut default_branch = None;
if let Ok(default_ref_buf) = remote.default_branch() {
if let Some(default_ref) = default_ref_buf.as_str() {
// LocalBranch here is the local branch on the remote, so it's really the remote
// branch
if let Some(RefName::LocalBranch(branch_name)) = parse_git_ref(default_ref) {
tracing::debug!(default_branch = branch_name);
default_branch = Some(branch_name);
}
}
}
tracing::debug!("remote.disconnect");
remote.disconnect()?;
// Import the remote-tracking branches into the jj repo and update jj's
// local branches. We also import local tags since remote tags should have
// been merged by Git.
tracing::debug!("import_refs");
let import_stats = import_some_refs(mut_repo, git_settings, |ref_name| {
to_remote_branch(ref_name, remote_name)
.map(|branch| branch_names.iter().any(|pattern| pattern.matches(branch)))
.unwrap_or_else(|| matches!(ref_name, RefName::Tag(_)))
})?;
let stats = GitFetchStats {
default_branch,
import_stats,
};
Ok(stats)
}
#[derive(Error, Debug, PartialEq)]
pub enum GitPushError {
#[error("No git remote named '{0}'")]
NoSuchRemote(String),
#[error(
"Git remote named '{name}' is reserved for local Git repository",
name = REMOTE_NAME_FOR_LOCAL_GIT_REPO
)]
RemoteReservedForLocalGitRepo,
#[error("Refs in unexpected location: {0:?}")]
RefInUnexpectedLocation(Vec<String>),
#[error("Remote rejected the update of some refs (do you have permission to push to {0:?}?)")]
RefUpdateRejected(Vec<String>),
// TODO: I'm sure there are other errors possible, such as transport-level errors,
// and errors caused by the remote rejecting the push.
#[error("Unexpected git error when pushing")]
InternalGitError(#[from] git2::Error),
}
#[derive(Clone, Debug)]
pub struct GitBranchPushTargets {
pub branch_updates: Vec<(String, BranchPushUpdate)>,
}
pub struct GitRefUpdate {
pub qualified_name: String,
/// Expected position on the remote or None if we expect the ref to not
/// exist on the remote
///
/// This is sourced from the local remote-tracking branch.
pub expected_current_target: Option<CommitId>,
pub new_target: Option<CommitId>,
}
/// Pushes the specified branches and updates the repo view accordingly.
pub fn push_branches(
mut_repo: &mut MutableRepo,
git_repo: &git2::Repository,
remote_name: &str,
targets: &GitBranchPushTargets,
callbacks: RemoteCallbacks<'_>,
) -> Result<(), GitPushError> {
let ref_updates = targets
.branch_updates
.iter()
.map(|(branch_name, update)| GitRefUpdate {
qualified_name: format!("refs/heads/{branch_name}"),
expected_current_target: update.old_target.clone(),
new_target: update.new_target.clone(),
})
.collect_vec();
push_updates(mut_repo, git_repo, remote_name, &ref_updates, callbacks)?;
// TODO: add support for partially pushed refs? we could update the view
// excluding rejected refs, but the transaction would be aborted anyway
// if we returned an Err.
for (branch_name, update) in &targets.branch_updates {
let git_ref_name = format!("refs/remotes/{remote_name}/{branch_name}");
let new_remote_ref = RemoteRef {
target: RefTarget::resolved(update.new_target.clone()),
state: RemoteRefState::Tracking,
};
mut_repo.set_git_ref_target(&git_ref_name, new_remote_ref.target.clone());
mut_repo.set_remote_branch(branch_name, remote_name, new_remote_ref);
}
Ok(())
}
/// Pushes the specified Git refs without updating the repo view.
pub fn push_updates(
repo: &dyn Repo,
git_repo: &git2::Repository,
remote_name: &str,
updates: &[GitRefUpdate],
callbacks: RemoteCallbacks<'_>,
) -> Result<(), GitPushError> {
let mut qualified_remote_refs_expected_locations = HashMap::new();
let mut refspecs = vec![];
for update in updates {
qualified_remote_refs_expected_locations.insert(
update.qualified_name.as_str(),
update.expected_current_target.as_ref(),
);
if let Some(new_target) = &update.new_target {
// We always force-push. We use the push_negotiation callback in
// `push_refs` to check that the refs did not unexpectedly move on
// the remote.
refspecs.push(format!("+{}:{}", new_target.hex(), update.qualified_name));
} else {
// Prefixing this with `+` to force-push or not should make no
// difference. The push negotiation happens regardless, and wouldn't
// allow creating a branch if it's not a fast-forward.
refspecs.push(format!(":{}", update.qualified_name));
}
}
// TODO(ilyagr): `push_refs`, or parts of it, should probably be inlined. This
// requires adjusting some tests.
push_refs(
repo,
git_repo,
remote_name,
&qualified_remote_refs_expected_locations,
&refspecs,
callbacks,
)
}
fn push_refs(
repo: &dyn Repo,
git_repo: &git2::Repository,
remote_name: &str,
qualified_remote_refs_expected_locations: &HashMap<&str, Option<&CommitId>>,
refspecs: &[String],
callbacks: RemoteCallbacks<'_>,
) -> Result<(), GitPushError> {
if remote_name == REMOTE_NAME_FOR_LOCAL_GIT_REPO {
return Err(GitPushError::RemoteReservedForLocalGitRepo);
}
let mut remote = git_repo.find_remote(remote_name).map_err(|err| {
if is_remote_not_found_err(&err) {
GitPushError::NoSuchRemote(remote_name.to_string())
} else {
GitPushError::InternalGitError(err)
}
})?;
let mut remaining_remote_refs: HashSet<_> = qualified_remote_refs_expected_locations
.keys()
.copied()
.collect();
let mut failed_push_negotiations = vec![];
let push_result = {
let mut push_options = git2::PushOptions::new();
let mut proxy_options = git2::ProxyOptions::new();
proxy_options.auto();
push_options.proxy_options(proxy_options);
let mut callbacks = callbacks.into_git();
callbacks.push_negotiation(|updates| {
for update in updates {
let dst_refname = update
.dst_refname()
.expect("Expect reference name to be valid UTF-8");
let expected_remote_location = *qualified_remote_refs_expected_locations
.get(dst_refname)
.expect("Push is trying to move a ref it wasn't asked to move");
let oid_to_maybe_commitid =
|oid: git2::Oid| (!oid.is_zero()).then(|| CommitId::from_bytes(oid.as_bytes()));
let actual_remote_location = oid_to_maybe_commitid(update.src());
let local_location = oid_to_maybe_commitid(update.dst());
match allow_push(
repo.index(),
actual_remote_location.as_ref(),
expected_remote_location,
local_location.as_ref(),
) {
Ok(PushAllowReason::NormalMatch) => {}
Ok(PushAllowReason::UnexpectedNoop) => {
tracing::info!(
"The push of {dst_refname} is unexpectedly a no-op, the remote branch \
is already at {actual_remote_location:?}. We expected it to be at \
{expected_remote_location:?}. We don't consider this an error.",
);
}
Ok(PushAllowReason::ExceptionalFastforward) => {
// TODO(ilyagr): We could consider printing a user-facing message at
// this point.
tracing::info!(
"We allow the push of {dst_refname} to {local_location:?}, even \
though it is unexpectedly at {actual_remote_location:?} on the \
server rather than the expected {expected_remote_location:?}. The \
desired location is a descendant of the actual location, and the \
actual location is a descendant of the expected location.",
);
}
Err(()) => {
// While we show debug info in the message with `--debug`,
// there's probably no need to show the detailed commit
// locations to the user normally. They should do a `jj git
// fetch`, and the resulting branch conflicts should contain
// all the information they need.
tracing::info!(
"Cannot push {dst_refname} to {local_location:?}; it is at \
unexpectedly at {actual_remote_location:?} on the server as opposed \
to the expected {expected_remote_location:?}",
);
failed_push_negotiations.push(dst_refname.to_string());
}
}
}
if failed_push_negotiations.is_empty() {
Ok(())
} else {
Err(git2::Error::from_str("failed push negotiation"))
}
});
callbacks.push_update_reference(|refname, status| {
// The status is Some if the ref update was rejected
if status.is_none() {
remaining_remote_refs.remove(refname);
}
Ok(())
});
push_options.remote_callbacks(callbacks);
remote.push(refspecs, Some(&mut push_options))
};
if !failed_push_negotiations.is_empty() {
// If the push negotiation returned an error, `remote.push` would not
// have pushed anything and would have returned an error, as expected.
// However, the error it returns is not necessarily the error we'd
// expect. It also depends on the exact versions of `libgit2` and
// `git2.rs`. So, we cannot rely on it containing any useful
// information. See https://github.com/rust-lang/git2-rs/issues/1042.
assert!(push_result.is_err());
failed_push_negotiations.sort();
Err(GitPushError::RefInUnexpectedLocation(
failed_push_negotiations,
))
} else {
push_result?;
if remaining_remote_refs.is_empty() {
Ok(())
} else {
Err(GitPushError::RefUpdateRejected(
remaining_remote_refs
.iter()
.sorted()
.map(|name| name.to_string())
.collect(),
))
}
}
}
#[derive(Debug, Clone, PartialEq, Eq)]
enum PushAllowReason {
NormalMatch,
ExceptionalFastforward,
UnexpectedNoop,
}
fn allow_push(
index: &dyn Index,
actual_remote_location: Option<&CommitId>,
expected_remote_location: Option<&CommitId>,
destination_location: Option<&CommitId>,
) -> Result<PushAllowReason, ()> {
if actual_remote_location == expected_remote_location {
return Ok(PushAllowReason::NormalMatch);
}
// If the remote ref is in an unexpected location, we still allow some
// pushes, based on whether `jj git fetch` would result in a conflicted ref.
//
// For `merge_ref_targets` to work correctly, `actual_remote_location` must
// be a commit that we locally know about.
//
// This does not lose any generality since for `merge_ref_targets` to
// resolve to `local_target` below, it is conceptually necessary (but not
// sufficient) for the destination_location to be either a descendant of
// actual_remote_location or equal to it. Either way, we would know about that
// commit locally.
if !actual_remote_location.map_or(true, |id| index.has_id(id)) {
return Err(());
}
let remote_target = RefTarget::resolved(actual_remote_location.cloned());
let base_target = RefTarget::resolved(expected_remote_location.cloned());
// The push destination is the local position of the ref
let local_target = RefTarget::resolved(destination_location.cloned());
if refs::merge_ref_targets(index, &remote_target, &base_target, &local_target) == local_target {
// Fetch would not change the local branch, so the push is OK in spite of
// the discrepancy with the expected location. We return some debug info and
// verify some invariants before OKing the push.
Ok(if actual_remote_location == destination_location {
// This is the situation of what we call "A - B + A = A"
// conflicts, see also test_refs.rs and
// https://github.com/martinvonz/jj/blob/c9b44f382824301e6c0fdd6f4cbc52bb00c50995/lib/src/merge.rs#L92.
PushAllowReason::UnexpectedNoop
} else {
// Due to our ref merge rules, this case should happen if an only
// if:
//
// 1. This is a fast-forward.
// 2. The expected location is an ancestor of both the actual location and the
// destination (local position).
PushAllowReason::ExceptionalFastforward
})
} else {
Err(())
}
}
#[non_exhaustive]
#[derive(Default)]
#[allow(clippy::type_complexity)]
pub struct RemoteCallbacks<'a> {
pub progress: Option<&'a mut dyn FnMut(&Progress)>,
pub sideband_progress: Option<&'a mut dyn FnMut(&[u8])>,
pub get_ssh_keys: Option<&'a mut dyn FnMut(&str) -> Vec<PathBuf>>,
pub get_password: Option<&'a mut dyn FnMut(&str, &str) -> Option<String>>,
pub get_username_password: Option<&'a mut dyn FnMut(&str) -> Option<(String, String)>>,
}
impl<'a> RemoteCallbacks<'a> {
fn into_git(mut self) -> git2::RemoteCallbacks<'a> {
let mut callbacks = git2::RemoteCallbacks::new();
if let Some(progress_cb) = self.progress {
callbacks.transfer_progress(move |progress| {
progress_cb(&Progress {
bytes_downloaded: (progress.received_objects() < progress.total_objects())
.then(|| progress.received_bytes() as u64),
overall: (progress.indexed_objects() + progress.indexed_deltas()) as f32
/ (progress.total_objects() + progress.total_deltas()) as f32,
});
true
});
}
if let Some(sideband_progress_cb) = self.sideband_progress {
callbacks.sideband_progress(move |data| {
sideband_progress_cb(data);
true
});
}
// TODO: We should expose the callbacks to the caller instead -- the library
// crate shouldn't read environment variables.
let mut tried_ssh_agent = false;
let mut ssh_key_paths_to_try: Option<Vec<PathBuf>> = None;
callbacks.credentials(move |url, username_from_url, allowed_types| {
let span = tracing::debug_span!("RemoteCallbacks.credentials");
let _ = span.enter();
let git_config = git2::Config::open_default();
let credential_helper = git_config
.and_then(|conf| git2::Cred::credential_helper(&conf, url, username_from_url));
if let Ok(creds) = credential_helper {
tracing::info!("using credential_helper");
return Ok(creds);
} else if let Some(username) = username_from_url {
if allowed_types.contains(git2::CredentialType::SSH_KEY) {
// Try to get the SSH key from the agent once. We don't even check if
// $SSH_AUTH_SOCK is set because Windows uses another mechanism.
if !tried_ssh_agent {
tracing::info!(username, "trying ssh_key_from_agent");
tried_ssh_agent = true;
return git2::Cred::ssh_key_from_agent(username).map_err(|err| {
tracing::error!(err = %err);
err
});
}
let paths = ssh_key_paths_to_try.get_or_insert_with(|| {
if let Some(ref mut cb) = self.get_ssh_keys {
let mut paths = cb(username);
paths.reverse();
paths
} else {
vec![]
}
});
if let Some(path) = paths.pop() {
tracing::info!(username, path = ?path, "trying ssh_key");
return git2::Cred::ssh_key(username, None, &path, None).map_err(|err| {
tracing::error!(err = %err);
err
});
}
}
if allowed_types.contains(git2::CredentialType::USER_PASS_PLAINTEXT) {
if let Some(ref mut cb) = self.get_password {
if let Some(pw) = cb(url, username) {
tracing::info!(
username,
"using userpass_plaintext with username from url"
);
return git2::Cred::userpass_plaintext(username, &pw).map_err(|err| {
tracing::error!(err = %err);
err
});
}
}
}
} else if allowed_types.contains(git2::CredentialType::USER_PASS_PLAINTEXT) {
if let Some(ref mut cb) = self.get_username_password {
if let Some((username, pw)) = cb(url) {
tracing::info!(username, "using userpass_plaintext");
return git2::Cred::userpass_plaintext(&username, &pw).map_err(|err| {
tracing::error!(err = %err);
err
});
}
}
}
tracing::info!("using default");
git2::Cred::default()
});
callbacks
}
}
pub struct Progress {
/// `Some` iff data transfer is currently in progress
pub bytes_downloaded: Option<u64>,
pub overall: f32,
}
#[derive(Default)]
struct PartialSubmoduleConfig {
path: Option<String>,
url: Option<String>,
}
/// Represents configuration from a submodule, e.g. in .gitmodules
/// This doesn't include all possible fields, only the ones we care about
#[derive(Debug, PartialEq, Eq)]
pub struct SubmoduleConfig {
pub name: String,
pub path: String,
pub url: String,
}
#[derive(Error, Debug)]
pub enum GitConfigParseError {
#[error("Unexpected io error when parsing config")]
IoError(#[from] std::io::Error),
#[error("Unexpected git error when parsing config")]
InternalGitError(#[from] git2::Error),
}
pub fn parse_gitmodules(
config: &mut dyn Read,
) -> Result<BTreeMap<String, SubmoduleConfig>, GitConfigParseError> {
// git2 can only read from a path, so set one up
let mut temp_file = NamedTempFile::new()?;
std::io::copy(config, &mut temp_file)?;
let path = temp_file.into_temp_path();
let git_config = git2::Config::open(&path)?;
// Partial config value for each submodule name
let mut partial_configs: BTreeMap<String, PartialSubmoduleConfig> = BTreeMap::new();
let entries = git_config.entries(Some(r"submodule\..+\."))?;
entries.for_each(|entry| {
let (config_name, config_value) = match (entry.name(), entry.value()) {
// Reject non-utf8 entries
(Some(name), Some(value)) => (name, value),
_ => return,
};
// config_name is of the form submodule.<name>.<variable>
let (submod_name, submod_var) = config_name
.strip_prefix("submodule.")
.unwrap()
.split_once('.')
.unwrap();
let map_entry = partial_configs.entry(submod_name.to_string()).or_default();
match (submod_var.to_ascii_lowercase().as_str(), &map_entry) {
// TODO Git warns when a duplicate config entry is found, we should
// consider doing the same.
("path", PartialSubmoduleConfig { path: None, .. }) => {
map_entry.path = Some(config_value.to_string())
}
("url", PartialSubmoduleConfig { url: None, .. }) => {
map_entry.url = Some(config_value.to_string())
}
_ => (),
};
})?;
let ret = partial_configs
.into_iter()
.filter_map(|(name, val)| {
Some((
name.clone(),
SubmoduleConfig {
name,
path: val.path?,
url: val.url?,
},
))
})
.collect();
Ok(ret)
}