fix(opensource-pipeline): keep pre-existing reports out of the first fork commit

Signed-off-by: Wen <jwcastillo@gmail.com>
(cherry picked from commit 35909e548e)

tests/skills/opensource-forker-history.test.js

@@ -0,0 +1,48 @@
+#!/usr/bin/env node
+/**
+ * Runs the documented Step 6 of agents/opensource-forker.md in a throwaway dir that already
+ * holds FORK_REPORT.md / SANITIZATION_REPORT.md (as if the source project shipped them), and
+ * checks they stay out of the first commit.
+ *
+ * Run with: node tests/skills/opensource-forker-history.test.js
+ */
+
+'use strict';
+
+const assert = require('assert');
+const fs = require('fs');
+const os = require('os');
+const path = require('path');
+const { spawnSync } = require('child_process');
+
+const AGENT_MD = path.join(__dirname, '..', '..', 'agents', 'opensource-forker.md');
+
+const step = fs.readFileSync(AGENT_MD, 'utf8').split('### Step 6: Clean Git History')[1];
+assert.ok(step, 'opensource-forker.md is missing "### Step 6: Clean Git History"');
+const block = step.match(/```bash\n([\s\S]*?)```/);
+assert.ok(block, 'no bash block in Step 6');
+
+const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'oss-forker-'));
+try {
+  for (const f of ['README.md', 'FORK_REPORT.md', 'SANITIZATION_REPORT.md']) {
+    fs.writeFileSync(path.join(dir, f), 'x\n');
+  }
+  const r = spawnSync('bash', ['-ec', block[1].replaceAll('TARGET_DIR', dir)], {
+    encoding: 'utf8',
+    env: {
+      ...process.env,
+      GIT_AUTHOR_NAME: 't', GIT_AUTHOR_EMAIL: 't@example.com',
+      GIT_COMMITTER_NAME: 't', GIT_COMMITTER_EMAIL: 't@example.com',
+    },
+  });
+  assert.strictEqual(r.status, 0, r.stderr);
+  const files = spawnSync('git', ['ls-tree', '-r', '--name-only', 'HEAD'], { cwd: dir, encoding: 'utf8' }).stdout.trim();
+  assert.strictEqual(files, 'README.md', `first commit must hold only README.md, got: ${files}`);
+  console.log('  ✓ pre-existing reports stay out of the first fork commit');
+} catch (err) {
+  console.log('  ✗ pre-existing reports stay out of the first fork commit');
+  console.log(`    Error: ${err.message}`);
+  process.exitCode = 1;
+} finally {
+  fs.rmSync(dir, { recursive: true, force: true });
+}