removehistoryfromgit.js

// Usage: node removehistoryfromgit.js <path/to/your/file_to_remove.txt>
// Example: node removehistoryfromgit.js assets/images/large_confidential_file.jpg
//          node removehistoryfromgit.js src/old_module.js
//
// This script completely removes a file from the Git repository's history.
// WARNING: This operation REWRITES HISTORY and is DANGEROUS.
// ALWAYS BACK UP YOUR REPOSITORY BEFORE RUNNING THIS SCRIPT.
// If the repository is shared, this will cause severe issues for collaborators
// who will need to re-clone or perform complex rebasing.

const { exec } = require('child_process');
const path = require('path');
const readline = require('readline');

const filePathArg = process.argv[2];

if (!filePathArg) {
  console.error('\n❌ Error: You must specify the path of the file to remove.');
  console.log('Usage: node removehistoryfromgit.js <path/relative/to/repo/root/file.ext>');
  console.log('Example: node removehistoryfromgit.js src/confidential_data.txt\n');
  process.exit(1);
}

const normalizedFilePath = path.normalize(filePathArg).replace(/\\/g, '/').replace(/^\/+/, '');

const command = `git filter-branch --force --index-filter 'git rm --cached --ignore-unmatch "${normalizedFilePath}"' --prune-empty --tag-name-filter cat -- --all`;

console.log(`\n--- ⚠️ CRITICAL WARNING ⚠️ ---`);
console.log(`You are about to attempt to COMPLETELY remove the file "${normalizedFilePath}" from this Git repository's history.`);
console.log(`This operation REWRITES THE REPOSITORY'S HISTORY.`);
console.log(`\n🛑 BEFORE YOU PROCEED:`);
console.log(`   1. ENSURE YOU HAVE A COMPLETE BACKUP OF THE REPOSITORY.`);
console.log(`   2. IF THIS REPOSITORY IS SHARED, NOTIFY ALL COLLABORATORS. They will need to handle the rewritten history (usually by re-cloning or performing complex rebases).`);
console.log(`   3. Understand that this operation is IRREVERSIBLE on your local repository once completed (aside from restoring from your backup).`);

console.log(`\nThe Git command that will be executed is:`);
console.log(`   ${command}`);

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

rl.question('\nAre you absolutely sure you want to proceed? (yes/no): ', (answer) => {
  rl.close();
  if (answer.toLowerCase() !== 'yes' && answer.toLowerCase() !== 'y') {
    console.log('\nOperation cancelled by the user. No changes have been made.');
    process.exit(0);
  }

  console.log('\n🚀 Executing command... This process can take a long time for large repositories.');
  console.log('Please wait for the completion or error message.\n');

  const gitProcess = exec(command, (error, stdout, stderr) => {
    if (error) {
      console.error(`\n❌ Error during git filter-branch execution:`);
      console.error(error.message);
      if (stderr) {
        console.error('\nError output (stderr):');
        console.error(stderr);
      }
      if (stdout) {
        console.log('\nStandard output (stdout):');
        console.log(stdout);
      }
      console.log('\n‼️ Operation failed. The repository history has not been modified or might be in an inconsistent state.');
      console.log('Check the error messages to understand the cause.');
      return;
    }

    console.log('\n✅ --- OPERATION COMPLETED SUCCESSFULLY (locally) ---');
    
    if (stderr) {
        console.log('\nInformational output from git filter-branch (stderr):');
        console.log(stderr);
    }
    if (stdout && stdout.trim() !== "") {
        console.log('\nStandard output from git filter-branch (stdout):');
        console.log(stdout);
    }    

    console.log(`\n\n--- 🔥 IMPORTANT POST-REWRITE ACTIONS (TO BE PERFORMED MANUALLY) 🔥 ---`);
    console.log(`The LOCAL history of your repository has been rewritten.`);
    console.log(`The file "${normalizedFilePath}" should have been removed from the entire history.`);

    console.log(`\n   1. CAREFULLY INSPECT THE REPOSITORY:`);
    console.log(`      - Verify that the file has actually been removed from past commits (e.g., using 'git log --all --full-history -- "${normalizedFilePath}"' which should no longer show the file, or 'git log --name-status HEAD~5' to check recent commits).`);
    console.log(`      - Ensure no other files have been inadvertently altered or lost.`);

    console.log(`\n   2. LOCAL REPOSITORY CLEANUP (Recommended):`);
    console.log(`      git reflog expire --expire=now --all`);
    console.log(`      git gc --prune=now --aggressive`);
    console.log(`      (Note: 'git filter-branch' moves the original refs to 'refs/original/'. You can remove them manually if you are certain about the outcome, e.g., 'git for-each-ref --format="delete %(refname)" refs/original | git update-ref --stdin' or by deleting specific refs like 'git update-ref -d refs/original/refs/heads/main' etc.)`);

    console.log(`\n   3. UPDATING THE REMOTE REPOSITORY (IF IT EXISTS):`);
    console.log(`      WARNING: This will overwrite history on the remote server. This is a destructive action for anyone else using the repository.`);
    console.log(`      git push origin --force --all`);
    console.log(`      git push origin --force --tags`);
    console.log(`      (Replace 'origin' with the name of your remote, if different).`);

    console.log(`\n   4. COMMUNICATE WITH COLLABORATORS:`);
    console.log(`      - All collaborators will need to re-clone the repository or perform complex procedures to synchronize their local copies (e.g., fetch and forcibly rebase their branches).`);
    console.log(`      - It is crucial to notify them BEFORE force-pushing and coordinate the update.`);

    console.log(`\nIf something went wrong and you have a backup, restore it now.`);
    console.log(`If you are unsure about these steps, seek help from someone experienced with Git before proceeding with the force push.`);
  });
});