jj-split-file-for-commit

name	jj-split-file-for-commit
description	Split unrelated changes within a single file into separate jj (Jujutsu) commits. Use only when the user explicitly asks — git is the default workflow. Trigger on "split this file into commits with jj", "/jj-split-file-for-commit <file>". Argument: the file to split.
version	0.1.0
allowed-tools	Bash(jj status:*), Bash(jj diff:*), Bash(jj restore:*), Bash(jj commit:*), Bash(jj describe:*), Bash(jj log:*), Read, Edit

jj split file for commit

Context

• Run jj status first.
• The user provides the file to split as the argument.

Your task

Split unrelated changes in one file into separate logical commits.

Workflow

1. Analyze the changes

   • Run jj diff --git <file> to see all changes in the file
   • Identify logical groups (e.g., "refactor" vs "new feature" vs "bugfix")
   • Plan how many commits and what each will contain

2. Save the target state

   • Read and remember the current file content (this is your target end state)

3. For each logical group:

   • jj restore --from @- <file> - reset file to parent version
   • Use Edit tool to apply ONLY changes for this group
   • jj commit -m '<type>: <description>' - commit this group
   • Repeat for next group (restore from new parent @-)

4. Verify final state

   • Read the file content after all commits
   • Compare with saved target state from step 2
   • They MUST match exactly - if not, something went wrong

Example

File has: typo fix + new function + reformatting

# Step 1: See changes
jj diff --git src/utils.ts

# Step 2: Save current content (using Read tool)

# Step 3a: First commit - typo fix
jj restore --from @- src/utils.ts
# Edit: apply only typo fix
jj commit -m 'fix: correct typo in error message'

# Step 3b: Second commit - new function
jj restore --from @- src/utils.ts
# Edit: apply only new function
jj commit -m 'feat: add validateInput helper'

# Step 3c: Third commit - reformatting
jj restore --from @- src/utils.ts
# Edit: apply reformatting
jj commit -m 'refactor: reformat utils module'

# Step 4: Verify final content matches saved target

Important Notes

• Always verify: Final file content must match original before splitting
• If verification fails: Use jj undo to revert and try again
• Commit message conventions: Use conventional commits (feat:, fix:, refactor:, etc.)
• When in doubt: Ask user which changes belong together