fix-neovim-shada.ts

#!/usr/bin/env -S deno run --allow-read --allow-write

/**
 * fix-neovim-shada.ts
 *
 * ## What this script does
 *
 * Fixes corrupted Neovim shada files by removing problematic newline characters (0x0a, 0x0d).
 * These newline characters can appear in command history or search history entries,
 * causing plugins like cmdpalette.nvim to crash with errors like:
 * "Error executing Lua callback: 'replacement string' item contains newlines"
 *
 * This script scans the shada file byte-by-byte and removes all newline (0x0a) and
 * carriage return (0x0d) characters, while preserving all other data including
 * command history, search history, marks, registers, and other shada contents.
 *
 * ## Usage
 *
 * 1. Close Neovim completely
 * 2. Run this script:
 *
 *    deno run --allow-read --allow-write ~/.dotfiles/bin/fix-neovim-shada.ts \
 *      ~/.local/state/nvim/shada/main.shada \
 *      ~/.local/state/nvim/shada/main.shada.fixed
 *
 * 3. Replace the original file:
 *
 *    mv ~/.local/state/nvim/shada/main.shada.fixed ~/.local/state/nvim/shada/main.shada
 *
 * 4. Start Neovim again
 *
 * ## Example
 *
 *    # Backup first (recommended)
 *    cp ~/.local/state/nvim/shada/main.shada ~/tmp/main.shada.backup
 *
 *    # Fix the shada file
 *    deno run --allow-read --allow-write ~/.dotfiles/bin/fix-neovim-shada.ts \
 *      ~/.local/state/nvim/shada/main.shada \
 *      ~/.local/state/nvim/shada/main.shada.fixed
 *
 *    # Replace if the fix looks good
 *    mv ~/.local/state/nvim/shada/main.shada.fixed ~/.local/state/nvim/shada/main.shada
 */

async function fixShada(inputPath: string, outputPath: string): Promise<void> {
  console.log(`Reading shada file: ${inputPath}`);

  const data = await Deno.readFile(inputPath);
  console.log(`File size: ${data.length} bytes`);

  // Fix approach: scan and remove problematic newlines byte-by-byte
  const fixedData: number[] = [];
  let fixedCount = 0;

  for (let i = 0; i < data.length; i++) {
    const byte = data[i];

    // Skip newlines (0x0a) and carriage returns (0x0d)
    if (byte === 0x0a || byte === 0x0d) {
      console.log(`  Removing byte 0x${byte.toString(16).padStart(2, '0')} at offset ${i} (${i.toString(16)})`);
      fixedCount++;
      continue;
    }

    fixedData.push(byte);
  }

  if (fixedCount > 0) {
    console.log(`\nRemoved ${fixedCount} problematic bytes`);

    const outputData = new Uint8Array(fixedData);
    await Deno.writeFile(outputPath, outputData);

    console.log(`Fixed shada written to: ${outputPath}`);
    console.log(`New file size: ${outputData.length} bytes (was ${data.length})`);
  } else {
    console.log('\nNo problematic bytes found!');
    await Deno.writeFile(outputPath, data);
  }
}

// Main
if (import.meta.main) {
  const args = Deno.args;

  if (args.length < 2) {
    console.error("Usage: deno run --allow-read --allow-write fix_shada.ts <input_shada> <output_shada>");
    console.error("Example: deno run --allow-read --allow-write fix_shada.ts bad.shada fixed.shada");
    Deno.exit(1);
  }

  const [inputPath, outputPath] = args;

  try {
    await fixShada(inputPath, outputPath);
  } catch (error) {
    console.error("Error:", error);
    Deno.exit(1);
  }
}