Squash Changes Into Ancestors

Move changes from the current working copy into appropriate ancestor commits.

Process

1. •Run jj diff --summary and jj diff --stat for overview
2. •Run jj log -r ::@- --limit 15 to see candidate ancestor commits
3. •Analyze changes:
   • •Small (≤5 files, ≤200 lines): run jj diff directly
   • •Large: use /jj-context for structured summary
4. •Match changes to commits by path and commit descriptions
5. •Execute squashes

Basic Usage

Without options, jj squash moves all changes from @ into its parent:

jj squash  # squash @ into @-

Whole Files

jj squash --into <change-id> path/to/file.py   # -t is short for --into
jj squash --into <change-id> "src/**/*.py"     # glob pattern
jj squash --into @--                            # into grandparent

Sub-File Chunks

For extracting specific hunks (not whole files):

1. •

   Save original @ change ID:

   bash

   jj log -r @ --no-graph -T 'change_id'
   

2. •

   Create intermediate commit:

   bash

   jj new --insert-before @
   

3. •

   Write only the hunks for target commit (use Edit tool)

4. •

   Squash into target:

   bash

   jj squash --into <target-change-id>
   

5. •

   Return to rebased @ and remove duplicated hunks:

   bash

   jj edit <rebased-@-change-id>
   

6. •

   Restore working copy:

   bash

   jj new
   

Notes

• •Always use change IDs (e.g., ksrmwuon) not commit IDs - they're stable across rewrites
• •After squashing, @ remains as working copy (empty if all changes moved)