split-jj-changeset

name	split-jj-changeset
description	jj split, mixed changeset, atomic revision, reviewed history: split a jj changeset into atomic focused changesets without interactive commands. Use in Jujutsu clones whenever one changeset mixes multiple intents.

Split a jj Changeset

Split the changeset $ARGUMENTS into smaller, atomic units.

If $ARGUMENTS is empty, ask the user which revset to split.

Follow commit-guidelines for dirty-worktree decisions, checkpoint strategy, and reviewed-history preservation.

Core safety principle

Never edit the original changeset directly. Duplicate first:

jj duplicate <revset>

Only abandon the original after the split is verified.

Workflow

1. Inspect the changeset.
2. Plan the grouping and validation with the user.
3. Duplicate the original.
4. Split by file path or reconstruct partial files for mixed hunks.
5. Set descriptions.
6. Verify completeness and correctness.
7. Rebase dependents if needed.
8. Clean up the original.

Target outcome

The goal is not only smaller changesets, but atomic changesets that satisfy the revision rules in commit-guidelines.

Inspect the changeset

jj diff -r <revset> --stat
jj diff -r <revset>
jj log -r <revset>

Summarize the logical groups before changing anything.

Apply the grouping rules from commit-guidelines before choosing split boundaries.

Plan with the user

Before proceeding, confirm:

• how to group the changes
• what description each resulting changeset should have
• how to validate each changeset

For mixed hunks within a file, ask the user how those hunks should be assigned.

Split strategies

File-path split

When each file belongs to one group:

jj split -r <rev> <paths...>

Repeat on the remainder until each group is isolated.

Hunk-level split

When one file contains multiple logical groups:

1. Create empty changesets off the parent.
2. Restore whole files from the duplicate where possible.
3. Reconstruct partial files by applying only the intended hunks.
4. Write the resulting file content into the appropriate changeset.

Do not use jj split -i.

Verification

Completeness

jj interdiff --from <original-revset> --to <last-split-revset>

The combined split should match the original.

Correctness

Run the validation plan agreed with the user. It is usually enough to run:

just check

Use narrower crate-level commands when appropriate during iteration.

Cleanup

After verification, ask whether to abandon the original duplicate source:

jj abandon <original-revset>

Rules

• Never use interactive jj commands.
• Never pass --ignore-immutable to a jj command.
• Duplicate first.
• Ask the user before choosing logical groupings.
• Verify both completeness and correctness before cleaning up.