msd-core/tests/atomic-write-coverage.test.cjs

// allow-test-rule: structural-regression-guard (#1972)
// Reads milestone.cjs/phase.cjs/frontmatter.cjs source and parses for bare
// fs.writeFileSync call sites — a specific code pattern that must not exist
// to prevent partial-write corruption. Behavioral tests cannot distinguish
// platformWriteSync from a bare fs.writeFileSync; only source inspection can.

/**
 * Structural regression guard for atomic write usage (#1972).
 *
 * Ensures that milestone.cjs, phase.cjs, and frontmatter.cjs do NOT
 * contain bare fs.writeFileSync calls targeting .planning/ files. All
 * such writes must go through platformWriteSync (the shell-projection
 * seam's atomic writer) to prevent partial writes from corrupting planning
 * artifacts on crash. platformWriteSync uses the same tmp-file + rename
 * primitive as the legacy atomicWriteFileSync — migrated in #3467.
 *
 * Allowed exceptions:
 *   - Writes to .gitkeep (empty files, no corruption risk)
 *   - Writes to archive directories (new files, not read-modify-write)
 *
 * This test is structural — it reads the source files and parses for
 * bare writeFileSync patterns. It complements functional tests in
 * atomic-write.test.cjs which verify the helper itself.
 */

'use strict';

const { test, describe } = require('node:test');
const assert = require('node:assert/strict');
const fs = require('node:fs');
const path = require('node:path');

const libDir = path.resolve(__dirname, '..', 'msd-core', 'bin', 'lib');

/**
 * Find all fs.writeFileSync(...) call sites in a file.
 * Returns array of { line: number, text: string }.
 */
function findBareWrites(filePath) {
  const content = fs.readFileSync(filePath, 'utf-8');
  const lines = content.split(/\r?\n/);
  const hits = [];
  for (let i = 0; i < lines.length; i++) {
    if (/\bfs\.writeFileSync\s*\(/.test(lines[i])) {
      hits.push({ line: i + 1, text: lines[i].trim() });
    }
  }
  return hits;
}

/**
 * Classify a bare write as allowed (archive, .gitkeep) or disallowed.
 */
function isAllowedException(lineText) {
  // .gitkeep writes (empty file, no corruption risk)
  if (/\.gitkeep/.test(lineText)) return true;
  // Archive directory writes (new files, not read-modify-write)
  if (/archiveDir/.test(lineText)) return true;
  return false;
}

describe('atomic write coverage (#1972)', () => {
  const targetFiles = ['milestone.cjs', 'phase.cjs', 'frontmatter.cjs'];

  for (const file of targetFiles) {
    test(`${file}: all fs.writeFileSync calls target allowed exceptions`, () => {
      const filePath = path.join(libDir, file);
      assert.ok(fs.existsSync(filePath), `${file} must exist at ${filePath}`);

      const hits = findBareWrites(filePath);
      const violations = hits.filter(h => !isAllowedException(h.text));

      if (violations.length > 0) {
        const report = violations.map(v => `  line ${v.line}: ${v.text}`).join('\n');
        assert.fail(
          `${file} contains ${violations.length} bare fs.writeFileSync call(s) targeting planning files.\n` +
          `These should use platformWriteSync instead:\n${report}`
        );
      }
    });

    test(`${file}: imports platformWriteSync from shell-command-projection.cjs`, () => {
      const filePath = path.join(libDir, file);
      const content = fs.readFileSync(filePath, 'utf-8');
      // Accept both hand-written destructure form and tsc-compiled namespace form:
      //   hand-written: const { platformWriteSync } = require('./shell-command-projection.cjs')
      //   tsc-compiled:  const x = require("./shell-command-projection.cjs"); x.platformWriteSync(...)
      const hasImport =
        // eslint-disable-next-line local/no-unbounded-quantifier -- parses this repo's own bounded lib/*.cjs source file, not adversarial input
        /platformWriteSync[^)]*\}\s*=\s*require\(['"]\.\/shell-command-projection\.cjs['"]\)/s.test(content) ||
        /require\(['"]\.\/shell-command-projection\.cjs['"]\)/.test(content);
      assert.ok(
        hasImport,
        `${file} must import from shell-command-projection.cjs`
      );
    });
  }

  test('all three files use platformWriteSync at least once', () => {
    for (const file of targetFiles) {
      const content = fs.readFileSync(path.join(libDir, file), 'utf-8');
      // Accept both hand-written call form and tsc-compiled IIFE dispatch form:
      //   hand-written: platformWriteSync(path, content)
      //   tsc-compiled:  (0, x.platformWriteSync)(path, content)
      const hasCall = /platformWriteSync[\s)]*\(/.test(content);
      assert.ok(
        hasCall,
        `${file} must contain at least one platformWriteSync call`
      );
    }
  });
});