auth-yes/forum/poc-g2/git_hooks_poc.ts

/**
 * Automated Git Hooks PoC (Gen 2 - Production Tooling)
 *
 * This script proves that we can hook into Git's native events to automatically
 * generate code intelligence graphs. It creates a temporary Git repository,
 * writes a real bash script to `.git/hooks/pre-commit`, and triggers a commit.
 */

import {
  join,
} from "https://deno.land/std@0.224.0/path/mod.ts";

async function runCommand(cmd: string[], cwd: string): Promise<string> {
  const command = new Deno.Command(cmd[0], {
    args: cmd.slice(1),
    cwd,
    stdout: "piped",
    stderr: "piped",
  });
  const { code, stdout, stderr } = await command.output();
  const decoder = new TextDecoder();

  if (code !== 0) {
    throw new Error(
      `Command ${cmd.join(" ")} failed: ${decoder.decode(stderr)}`,
    );
  }
  return decoder.decode(stdout);
}

async function runGitHooksPoc() {
  console.log("Starting Automated Git Hooks PoC (Gen 2)\n");

  // Setup temporary directory
  const tempDir = await Deno.makeTempDir({
    prefix: "agent-forum-githook-poc-",
  });
  console.log(`[Git] Created temporary workspace: ${tempDir}`);

  try {
    // Init git
    await runCommand(["git", "init"], tempDir);

    // Write a mock pre-commit hook that simulates generating a SCIP index
    const hookPath = join(tempDir, ".git", "hooks", "pre-commit");
    const hookScript = `#!/bin/bash
echo "[Hook] Pre-commit hook triggered by Git natively!"
echo "[Hook] Extracting modified files..."
git diff --cached --name-only
echo "[Hook] Generating 'scip.graph' (Simulated via touch)..."
touch scip.graph
echo "[Hook] Execution complete. Proceeding with commit."
`;

    await Deno.writeTextFile(hookPath, hookScript);

    // Make the hook executable (chmod +x)
    const chmodCmd = new Deno.Command("chmod", { args: ["+x", hookPath] });
    await chmodCmd.output();
    console.log("[Git] pre-commit hook installed and made executable.");

    // Create a dummy file to commit
    const testFile = join(tempDir, "target.js");
    await Deno.writeTextFile(testFile, "console.log('Hello World');");

    console.log("[Git] Staging files...");
    await runCommand(["git", "add", "target.js"], tempDir);

    console.log("[Git] Committing files to trigger hook...\n");

    console.log("[Git] Configuring local git user...");
    await runCommand(["git", "config", "user.name", "Test User"], tempDir);
    await runCommand(["git", "config", "user.email", "test@test.com"], tempDir);

    // We run the commit command and pipe the output so we can see the hook execute
    const commitCmd = new Deno.Command("git", {
      args: ["commit", "-m", "Initial commit"],
      cwd: tempDir,
      stdout: "piped",
      stderr: "piped",
    });

    const { code: _code, stdout, stderr } = await commitCmd.output();
    const decoder = new TextDecoder();

    const output = decoder.decode(stdout);
    console.log(output);

    if (output.includes("Pre-commit hook triggered by Git natively!")) {
      console.log(
        "✅ Git pre-commit hook successfully intercepted commit and executed.",
      );

      // Verify the hook actually created the simulated artifact
      const stat = await Deno.stat(join(tempDir, "scip.graph"));
      if (stat.isFile) {
        console.log(
          "✅ Artifact 'scip.graph' successfully generated by the hook.",
        );
      }
    } else {
      console.error("❌ Hook did not appear to trigger.");
      console.error(decoder.decode(stderr));
      throw new Error("Hook execution failed.");
    }
  } finally {
    // Cleanup
    console.log(`\n[Git] Cleaning up temporary workspace: ${tempDir}`);
    await Deno.remove(tempDir, { recursive: true });
    console.log("Gen 2 Git Hooks execution completed successfully.");
  }
}

if (import.meta.main) {
  runGitHooksPoc().catch(console.error);
}