undo-squash

name	undo-squash
description	Restore commits to their pre-squash state. Use when: squash grouping was wrong, need original commit history back, or want to try different grouping.

Undo Squash

Overview

Restores the original commits from before the last squash operation. Works as long as backups exist (preserved until next /start-work or explicit cleanup).

Prerequisites

• Must have backup from recent squash (backup tag or bundle)
• Cannot undo if squashed commits were already pushed (without force push)

Finding Undo Data

Check in order of preference:

1. Check last-squash.json (preferred)

BRANCH=$(git branch --show-current)
SANITIZED_BRANCH=$(echo "$BRANCH" | sed 's#/#%2F#g')   # percent-encode "/" (feat/x ≠ feat-x)
SESSION_DIR=".claude/sessions/${SANITIZED_BRANCH}"

if [ -f "$SESSION_DIR/last-squash.json" ]; then
  BACKUP_TAG=$(jq -r .backupTag "$SESSION_DIR/last-squash.json")
  ORIGINAL_HEAD=$(jq -r .originalHead "$SESSION_DIR/last-squash.json")
  BUNDLE_PATH=$(jq -r .bundlePath "$SESSION_DIR/last-squash.json")
  SQUASH_TIME=$(jq -r .squashedAt "$SESSION_DIR/last-squash.json")

  echo "Found squash from: $SQUASH_TIME"
  echo "Original HEAD: $ORIGINAL_HEAD"
fi

2. Check for backup tag (fallback)

BACKUP_TAG=$(git tag -l "_squash-backup-*" | sort | tail -1)
if [ -n "$BACKUP_TAG" ]; then
  echo "Found backup tag: $BACKUP_TAG"
fi

3. Check for bundle file (last resort)

if [ -f "$SESSION_DIR/pre-squash.bundle" ]; then
  echo "Found backup bundle"
fi

4. Git reflog (emergency)

# If all else fails, check reflog
git reflog | grep -E "reset.*moving to" | head -5
echo "Manual recovery possible via reflog"

Safety Checks

Check if Already Pushed

UPSTREAM=$(git rev-parse --abbrev-ref @{u} 2>/dev/null)
if [ -n "$UPSTREAM" ]; then
  # Check if current HEAD matches remote
  LOCAL_HEAD=$(git rev-parse HEAD)
  REMOTE_HEAD=$(git rev-parse "$UPSTREAM" 2>/dev/null)

  if [ "$LOCAL_HEAD" = "$REMOTE_HEAD" ]; then
    echo "Warning: Squashed commits already pushed."
    echo "Undo would require force push."
    echo "Continue anyway? [y/n]"
    # Only proceed if user explicitly confirms
  fi
fi

Execution

Option A: Restore from Backup Tag (preferred)

if [ -n "$BACKUP_TAG" ] && git rev-parse "$BACKUP_TAG" >/dev/null 2>&1; then
  echo "Restoring from backup tag: $BACKUP_TAG"

  # Get the SHA before reset for confirmation
  RESTORE_SHA=$(git rev-parse "$BACKUP_TAG")
  COMMIT_COUNT=$(git log HEAD.."$BACKUP_TAG" --oneline | wc -l | tr -d " ")

  echo "Will restore $COMMIT_COUNT commits"
  echo "Target: $RESTORE_SHA"

  git reset --hard "$BACKUP_TAG"
  echo "Restored to: $(git log -1 --oneline)"
fi

Option B: Restore from Bundle

if [ -f "$BUNDLE_PATH" ] && [ -n "$ORIGINAL_HEAD" ]; then
  echo "Restoring from bundle..."

  # Unbundle to make commits available
  git bundle unbundle "$BUNDLE_PATH"

  # Reset to original HEAD
  git reset --hard "$ORIGINAL_HEAD"
  echo "Restored to: $(git log -1 --oneline)"
fi

Option C: Restore from Reflog (emergency)

# Show reflog entries for user to choose
git reflog | head -20

echo "Enter the SHA or reflog entry to restore to:"
# User provides SHA like "HEAD@{2}" or "abc123"
# git reset --hard <user-provided-sha>

Cleanup After Undo

# Remove backup tag (used)
if [ -n "$BACKUP_TAG" ]; then
  git tag -d "$BACKUP_TAG" 2>/dev/null
fi

# Remove backup files
rm -f "$SESSION_DIR/pre-squash.bundle"
rm -f "$SESSION_DIR/last-squash.json"
rm -f "$SESSION_DIR/squash-in-progress.json"

echo "Undo complete. Backup artifacts cleaned up."

Confirmation Output

Squash undone successfully!

Restored: 15 original commits
HEAD now at: abc123 "feat: original commit message"
Backup artifacts: cleaned up

You can now:
- Run /squash-commits again with different grouping
- Continue working and make more commits
- Push the original commits as-is

Troubleshooting

"No backup found"

If no backup tag or bundle exists:

1. Check git reflog: git reflog | head -20
2. Look for entries like reset: moving to _session-start-*
3. The entry just before that is your original HEAD
4. Restore manually: git reset --hard <sha>

"Backup tag exists but can't resolve"

The tag might point to a garbage-collected commit:

1. Check if bundle exists: ls -la $SESSION_DIR/*.bundle
2. If bundle exists, unbundle first: git bundle unbundle <bundle>
3. Then reset to the commit

"Already pushed, need force push"

If you really need to undo after pushing:

1. Confirm with team (you'll rewrite shared history)
2. Undo locally: /undo-squash
3. Force push: git push --force-with-lease