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Implement jj parallelize
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emesterhazy committed Apr 1, 2024
1 parent 9763207 commit d7f398a
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2 changes: 1 addition & 1 deletion cli/src/cli_util.rs
Original file line number Diff line number Diff line change
Expand Up @@ -880,7 +880,7 @@ impl WorkspaceCommandHelper {
self.attach_revset_evaluator(expression)
}

fn attach_revset_evaluator(
pub fn attach_revset_evaluator(
&self,
expression: Rc<RevsetExpression>,
) -> Result<RevsetExpressionEvaluator<'_>, CommandError> {
Expand Down
5 changes: 5 additions & 0 deletions cli/src/commands/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@ mod new;
mod next;
mod obslog;
mod operation;
mod parallelize;
mod prev;
mod rebase;
mod resolve;
Expand Down Expand Up @@ -114,6 +115,7 @@ enum Command {
#[command(subcommand)]
#[command(visible_alias = "op")]
Operation(operation::OperationCommand),
Parallelize(parallelize::ParallelizeArgs),
Prev(prev::PrevArgs),
Rebase(rebase::RebaseArgs),
Resolve(resolve::ResolveArgs),
Expand Down Expand Up @@ -180,6 +182,9 @@ pub fn run_command(ui: &mut Ui, command_helper: &CommandHelper) -> Result<(), Co
Command::Abandon(sub_args) => abandon::cmd_abandon(ui, command_helper, sub_args),
Command::Edit(sub_args) => edit::cmd_edit(ui, command_helper, sub_args),
Command::Next(sub_args) => next::cmd_next(ui, command_helper, sub_args),
Command::Parallelize(sub_args) => {
parallelize::cmd_parallelize(ui, command_helper, sub_args)
}
Command::Prev(sub_args) => prev::cmd_prev(ui, command_helper, sub_args),
Command::New(sub_args) => new::cmd_new(ui, command_helper, sub_args),
Command::Move(sub_args) => r#move::cmd_move(ui, command_helper, sub_args),
Expand Down
163 changes: 163 additions & 0 deletions cli/src/commands/parallelize.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,163 @@
// Copyright 2024 The Jujutsu Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::io::Write;

use indexmap::IndexSet;
use itertools::Itertools;
use jj_lib::backend::CommitId;
use jj_lib::commit::Commit;
use jj_lib::repo::Repo;
use jj_lib::revset::{RevsetExpression, RevsetIteratorExt};
use tracing::instrument;

use crate::cli_util::{short_commit_hash, CommandHelper, RevisionArg};
use crate::command_error::{user_error, CommandError};
use crate::commands::rebase::rebase_descendants;
use crate::ui::Ui;

/// Parallelize revisions by making them siblings
///
/// The set of target commits being parallelized must have a single head and
/// root commit (not to be confused with the repo root), otherwise the command
/// will fail. Each of the target commits is rebased onto the parents of the
/// root commit. The children of the head commit are rebased onto the target
/// commits.
///
/// Example usage:
/// ```text
/// jj log
/// ◉ 3
/// ◉ 2
/// ◉ 1
/// ◉
/// jj parallelize 1::2
/// jj log
/// ◉ 3
/// ├─╮
/// │ ◉ 2
/// ◉ │ 1
/// ├─╯
/// ◉
/// ```
#[derive(clap::Args, Clone, Debug)]
#[command(verbatim_doc_comment)]
pub(crate) struct ParallelizeArgs {
// #[arg(long, short)]
revisions: Vec<RevisionArg>,
}

#[instrument(skip_all)]
pub(crate) fn cmd_parallelize(
ui: &mut Ui,
command: &CommandHelper,
args: &ParallelizeArgs,
) -> Result<(), CommandError> {
let mut workspace_command = command.workspace_helper(ui)?;
// Parse and validate the input revset(s).
// Find the parents of each commit. The parent(s) which are ancestors of
// each revision are the new parents of the input revisions.
// Find the children of each commit. The children which are descendants
// of each revision are the new children of the input revisions.
// If one or both of these sets cannot be found, then parallelize cannot
// proceed.
// let target_commits = workspace_command.parse_union_revsets(&args.revisions)?.
let mut tx = workspace_command.start_transaction();
let target_revset = tx
.base_workspace_helper()
.parse_union_revsets(&args.revisions)?;
let target_commits: Vec<Commit> = target_revset
.evaluate()?
.iter()
// We want parents before children, so we need to reverse the order.
.reversed()
.commits(tx.base_repo().store())
.try_collect::<_, Vec<Commit>, _>()?;
if target_commits.len() < 2 {
return Ok(writeln!(ui.stderr(), "Nothing to do.")?);
}
let target_heads: Vec<CommitId> = tx
.base_workspace_helper()
.attach_revset_evaluator(target_revset.expression().clone().heads())?
.evaluate()?
.iter()
.collect();
if target_heads.len() > 1 {
let heads = target_heads.iter().map(short_commit_hash).join(", ");
return Err(user_error(format!(
"Cannot parallelize a set of revisions with multiple heads. Heads: {heads}"
)));
}
let target_roots: Vec<CommitId> = tx
.base_workspace_helper()
.attach_revset_evaluator(target_revset.expression().clone().roots())?
.evaluate()?
.iter()
.collect();
if target_roots.len() > 1 {
let roots = target_roots.iter().map(short_commit_hash).join(", ");
return Err(user_error(format!(
"Cannot parallelize a set of revisions with multiple roots. Roots: {roots}"
)));
}

// Rebase the children of the head commit onto the target commits.
let new_children: Vec<Commit> = RevsetExpression::commit(target_heads[0].clone())
.children()
.evaluate_programmatic(tx.base_repo().as_ref())?
.iter()
.commits(tx.base_repo().store())
.try_collect()?;
for child in new_children {
// The ordering here is intentional. We iterate over the target commits first so
// that when `jj log` prints the graph they will be printed in their original
// order. After that, we add any existing parents which aren't being
// parallelized.
let new_parents_for_child: Vec<Commit> = target_commits
.iter()
.map(|c| c.id().clone())
.chain(child.parent_ids().iter().cloned())
.collect::<IndexSet<CommitId>>()
.iter()
.map(|c| tx.mut_repo().store().get_commit(c))
.collect::<Result<Vec<Commit>, _>>()?;
rebase_descendants(
&mut tx,
command.settings(),
&new_parents_for_child,
&[child],
Default::default(),
)?;
}

// Rebase the target commits onto the parents of the root commit.
let new_parents: Vec<Commit> = RevsetExpression::commit(target_roots[0].clone())
.parents()
.evaluate_programmatic(tx.base_repo().as_ref())?
.iter()
.commits(tx.base_repo().store())
.try_collect()?;
rebase_descendants(
&mut tx,
command.settings(),
&new_parents,
&target_commits,
Default::default(),
)?;

tx.finish(
ui,
format!("Parallelized {} commits.", target_commits.len()),
)
}
37 changes: 37 additions & 0 deletions cli/tests/[email protected]
Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,7 @@ This document contains the help content for the `jj` command-line program.
* [`jj operation log`↴](#jj-operation-log)
* [`jj operation undo`↴](#jj-operation-undo)
* [`jj operation restore`↴](#jj-operation-restore)
* [`jj parallelize`↴](#jj-parallelize)
* [`jj prev`↴](#jj-prev)
* [`jj rebase`↴](#jj-rebase)
* [`jj resolve`↴](#jj-resolve)
Expand Down Expand Up @@ -126,6 +127,7 @@ To get started, see the tutorial at https://github.com/martinvonz/jj/blob/main/d
* `next`Move the working-copy commit to the child revision
* `obslog`Show how a change has evolved
* `operation`Commands for working with the operation log
* `parallelize`Parallelize revisions by making them siblings
* `prev`Move the working-copy commit to the parent revision
* `rebase`Move revisions to different parent(s)
* `resolve`Resolve a conflicted file with an external merge tool
Expand Down Expand Up @@ -1345,6 +1347,41 @@ This restores the repo to the state at the specified operation, effectively undo
## `jj parallelize`
Parallelize revisions by making them siblings
The set of target commits being parallelized must have a single head and
root commit (not to be confused with the repo root), otherwise the command
will fail. Each of the target commits is rebased onto the parents of the
root commit. The children of the head commit are rebased onto the target
commits.
Example usage:
```text
jj log
◉ 3
◉ 2
◉ 1
jj parallelize 1::2
jj log
◉ 3
├─╮
│ ◉ 2
◉ │ 1
├─╯
```
**Usage:** `jj parallelize [REVISIONS]...`
###### **Arguments:**
* `<REVISIONS>`
## `jj prev`
Move the working-copy commit to the parent revision
Expand Down
1 change: 1 addition & 0 deletions cli/tests/runner.rs
Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,7 @@ mod test_new_command;
mod test_next_prev_commands;
mod test_obslog_command;
mod test_operations;
mod test_parallelize_command;
mod test_rebase_command;
mod test_repo_change_report;
mod test_resolve_command;
Expand Down
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