replace-git-history

#!/usr/bin/env bash

# Script to replace git history with original repo history using rebase

set -e  # Exit on error

readonly MAIN_BRANCH='main'
# Using commit hash instead of tag v2.2.5 to avoid clobbering local tags with remote tags
readonly LEGACY_COMMIT='b92ac00feff206cbb7d3e9e4b48c494d6fedb3bf'  # corresponds to v2.2.5 tag

# Step 1: Ensure we have the original repo as remote
echo ""
echo "Step 1: Checking for original repo remote..."
if ! git remote | grep -q "jellyfin-legacy"; then
    echo "Adding jellyfin-legacy remote..."
    git remote add jellyfin-legacy https://github.com/jellyfin-archive/jellyfin-roku-legacy.git
    git fetch jellyfin-legacy "$LEGACY_COMMIT"
    echo "✓ Remote added and fetched"
else
    echo "✓ Remote already exists"
fi

# Step 2: Get the initial commit hash from main branch
echo ""
echo "Step 2: Identifying initial commit to replace..."
git checkout "$MAIN_BRANCH"
INITIAL_COMMIT=$(git rev-list --max-parents=0 HEAD)
echo "Initial commit to replace: $INITIAL_COMMIT"

# Step 3: Create new branch from legacy commit
echo ""
echo "Step 3: Creating new branch from legacy commit (v2.2.5)..."
# Delete new-history branch if it exists
if git branch | grep -q "new-history"; then
    git branch -D new-history
fi
git checkout -b new-history "$LEGACY_COMMIT"
echo "✓ New branch created from legacy commit"

# Step 4: Rebase all commits after initial commit onto legacy commit
echo ""
echo "Step 4: Rebasing your commits onto legacy commit (v2.2.5)..."
echo "This will replay all commits from $MAIN_BRANCH (excluding the initial commit)"
echo ""

# Use rebase --onto to rebase everything after INITIAL_COMMIT from MAIN_BRANCH onto current HEAD (legacy commit)
git rebase --onto HEAD "$INITIAL_COMMIT" "$MAIN_BRANCH"
echo "✓ Rebase completed successfully"

# Step 5: Replace main branch
echo ""
echo "Step 5: Replacing $MAIN_BRANCH branch with new history..."
git checkout -B "$MAIN_BRANCH"
echo "✓ $MAIN_BRANCH branch updated with new history"

# Step 6: Cleanup
echo ""
echo "Step 6: Cleaning up..."
git branch -D new-history
git remote remove jellyfin-legacy
echo "✓ Cleanup complete"

echo ""
echo "=== Success! ==="
echo "Your git history has been successfully replaced."
echo "The legacy commit (v2.2.5) is now at the base of your repository."
echo ""
echo "Current branch: $(git branch --show-current)"
echo ""
echo "Next steps:"
echo "1. Verify the history looks correct: git log --oneline"
echo "2. If everything looks good, force push to remote: git push --force-with-lease origin $MAIN_BRANCH"
echo ""
echo "WARNING: This has rewritten history. Anyone who has cloned your repo"
echo "will need to re-clone or reset their local copy."