'use strict';

/**
 * Tests for config-loader.cjs (ADR-857 phase 2e / #885).
 *
 * Covers:
 *   - loadConfig defaults when no config.json file exists
 *   - loadConfig merges file values over defaults
 *   - legacy-key normalization (branching_strategy → git.branching_strategy)
 *   - workstream overlay (root → workstream inheritance)
 *   - workstream-null fallback when workstream config is absent
 *   - unknown-key warning dedup (_warnedUnknownConfigKeys deduplications)
 *   - malformed JSON handling (falls back to defaults)
 *   - shim identity: core.loadConfig === configLoader.loadConfig
 *   - ADVERSARIAL fixtures: empty JSON, unknown keys, dynamic-prefix keys
 *     like agent_skills.__proto__, scalars-where-objects-expected,
 *     missing config file
 */

const { describe, test, beforeEach, afterEach } = require('node:test');
const assert = require('node:assert/strict');
const fs = require('node:fs');
const path = require('node:path');
const os = require('node:os');
const { cleanup } = require('./helpers.cjs');
const fc = require('fast-check');

// ─── module under test ────────────────────────────────────────────────────────

const configLoader = require('../gsd-core/bin/lib/config-loader.cjs');

const { loadConfig, loadConfigResolved, _resetRuntimeWarningCacheForTests, _deepMergeConfig } = configLoader;

// ─── helpers ──────────────────────────────────────────────────────────────────

function makeTempProject(prefix = 'gsd-cfg-loader-test-') {
  const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), prefix));
  fs.mkdirSync(path.join(tmpDir, '.planning', 'phases'), { recursive: true });
  return tmpDir;
}

function writeConfig(tmpDir, obj) {
  const configPath = path.join(tmpDir, '.planning', 'config.json');
  fs.writeFileSync(configPath, JSON.stringify(obj, null, 2), 'utf-8');
}

function writeWorkstreamConfig(tmpDir, wsName, obj) {
  const wsDir = path.join(tmpDir, '.planning', 'workstreams', wsName);
  fs.mkdirSync(path.join(wsDir, 'phases'), { recursive: true });
  fs.writeFileSync(path.join(wsDir, 'config.json'), JSON.stringify(obj, null, 2), 'utf-8');
}


// ─── defaults when no config.json ────────────────────────────────────────────

describe('loadConfig — defaults when no config.json', () => {
  let tmpDir;

  beforeEach(() => { tmpDir = makeTempProject(); });
  afterEach(() => { if (tmpDir) cleanup(tmpDir); tmpDir = null; });

  test('returns an object with expected default keys when config.json is absent', () => {
    const config = loadConfig(tmpDir);
    // Structural checks — should have canonical keys from CONFIG_DEFAULTS
    assert.ok('model_profile' in config, 'must have model_profile');
    assert.ok('commit_docs' in config, 'must have commit_docs');
    assert.ok('research' in config, 'must have research');
    assert.ok('branching_strategy' in config, 'must have branching_strategy');
    assert.ok('plan_checker' in config, 'must have plan_checker');
    assert.ok('verifier' in config, 'must have verifier');
    assert.ok('parallelization' in config, 'must have parallelization');
    assert.ok('sub_repos' in config, 'must have sub_repos');
    assert.ok('resolve_model_ids' in config, 'must have resolve_model_ids');
  });

  test('model_profile default is "balanced"', () => {
    const config = loadConfig(tmpDir);
    assert.equal(config.model_profile, 'balanced');
  });

  test('config.json present with empty object: agent_skills default is an empty object', () => {
    // agent_skills only appears in the return when a config.json is successfully parsed
    writeConfig(tmpDir, {});
    const config = loadConfig(tmpDir);
    assert.deepEqual(config.agent_skills, {});
  });

  test('config.json present with empty object: model_overrides default is null', () => {
    // model_overrides only appears in the return when a config.json is successfully parsed
    writeConfig(tmpDir, {});
    const config = loadConfig(tmpDir);
    assert.equal(config.model_overrides, null);
  });
});

// ─── file values merge over defaults ─────────────────────────────────────────

describe('loadConfig — file values override defaults', () => {
  let tmpDir;

  beforeEach(() => { tmpDir = makeTempProject(); });
  afterEach(() => { if (tmpDir) cleanup(tmpDir); tmpDir = null; });

  test('model_profile from config.json overrides the default', () => {
    writeConfig(tmpDir, { model_profile: 'quality' });
    const config = loadConfig(tmpDir);
    assert.equal(config.model_profile, 'quality');
  });

  test('workflow.research from nested config is returned', () => {
    writeConfig(tmpDir, { workflow: { research: 'deep' } });
    const config = loadConfig(tmpDir);
    assert.equal(config.research, 'deep');
  });

  test('top-level research is returned', () => {
    writeConfig(tmpDir, { research: 'minimal' });
    const config = loadConfig(tmpDir);
    assert.equal(config.research, 'minimal');
  });

  test('mode from config.json is returned', () => {
    writeConfig(tmpDir, { mode: 'autonomous' });
    const config = loadConfig(tmpDir);
    assert.equal(config.mode, 'autonomous');
  });

  test('model_overrides from config.json is returned', () => {
    writeConfig(tmpDir, { model_overrides: { planner: 'claude-opus-4-5' } });
    const config = loadConfig(tmpDir);
    assert.deepEqual(config.model_overrides, { planner: 'claude-opus-4-5' });
  });
});

// ─── legacy-key normalization ─────────────────────────────────────────────────

describe('loadConfig — legacy-key normalization', () => {
  let tmpDir;

  beforeEach(() => { tmpDir = makeTempProject(); });
  afterEach(() => { if (tmpDir) cleanup(tmpDir); tmpDir = null; });

  test('top-level branching_strategy is migrated to git.branching_strategy', () => {
    writeConfig(tmpDir, { branching_strategy: 'milestone' });
    const config = loadConfig(tmpDir);
    assert.equal(config.branching_strategy, 'milestone');
  });

  test('on-disk file has branching_strategy moved under git.* after migration', () => {
    const configPath = path.join(tmpDir, '.planning', 'config.json');
    fs.writeFileSync(configPath, JSON.stringify({ branching_strategy: 'phase' }, null, 2), 'utf-8');
    loadConfig(tmpDir);
    const onDisk = JSON.parse(fs.readFileSync(configPath, 'utf-8'));
    assert.equal(onDisk.git?.branching_strategy, 'phase');
    assert.equal(onDisk.branching_strategy, undefined);
  });
});

// ─── workstream overlay ───────────────────────────────────────────────────────

describe('loadConfig — workstream overlay', () => {
  let tmpDir;

  beforeEach(() => { tmpDir = makeTempProject(); });
  afterEach(() => { if (tmpDir) cleanup(tmpDir); tmpDir = null; });

  test('workstream config overrides root config', () => {
    writeConfig(tmpDir, { model_profile: 'balanced' });
    writeWorkstreamConfig(tmpDir, 'ws-a', { model_profile: 'quality' });
    const config = loadConfig(tmpDir, { workstream: 'ws-a' });
    assert.equal(config.model_profile, 'quality');
  });

  test('root-only keys are inherited by workstream config', () => {
    writeConfig(tmpDir, { model_profile: 'balanced', research: 'deep' });
    writeWorkstreamConfig(tmpDir, 'ws-b', { mode: 'autonomous' });
    const config = loadConfig(tmpDir, { workstream: 'ws-b' });
    // Root's research should still be visible (inherited)
    assert.equal(config.research, 'deep');
    // Workstream's mode should override
    assert.equal(config.mode, 'autonomous');
  });

  test('workstream-null fallback: root config used when workstream has no config.json', () => {
    writeConfig(tmpDir, { model_profile: 'budget' });
    // Create workstream directory but no config.json
    const wsDir = path.join(tmpDir, '.planning', 'workstreams', 'ws-no-config');
    fs.mkdirSync(path.join(wsDir, 'phases'), { recursive: true });
    // loadConfig with missing workstream config.json should fall back to root
    const config = loadConfig(tmpDir, { workstream: 'ws-no-config' });
    assert.equal(config.model_profile, 'budget');
  });
});

// ─── unknown-key warning dedup ────────────────────────────────────────────────

describe('loadConfig — unknown-key warning dedup', () => {
  let tmpDir;
  let originalStderrWrite;
  let stderrLines;

  beforeEach(() => {
    tmpDir = makeTempProject();
    stderrLines = [];
    originalStderrWrite = process.stderr.write.bind(process.stderr);
    process.stderr.write = (chunk) => {
      stderrLines.push(String(chunk));
      return true;
    };
    // Reset the module-level dedup set so each test starts clean
    if (_resetRuntimeWarningCacheForTests) _resetRuntimeWarningCacheForTests();
  });

  afterEach(() => {
    process.stderr.write = originalStderrWrite;
    if (tmpDir) cleanup(tmpDir);
    tmpDir = null;
  });

  test('unknown key produces a warning mentioning the key name', () => {
    writeConfig(tmpDir, { __gsd_unknown_sentinel__: true });
    loadConfig(tmpDir);
    const warnings = stderrLines.filter(l => l.includes('__gsd_unknown_sentinel__'));
    assert.ok(warnings.length >= 1, 'should warn about unknown key');
  });

  test('calling loadConfig twice does not double-emit the same unknown-key warning', () => {
    writeConfig(tmpDir, { __gsd_dedup_test__: true });
    loadConfig(tmpDir);
    loadConfig(tmpDir);
    const warnings = stderrLines.filter(l => l.includes('__gsd_dedup_test__'));
    // Should appear at most once
    assert.ok(warnings.length <= 1, `warning emitted more than once: ${warnings.length} times`);
  });

  // #2674: the two cases above only pass because each picks a key name no other
  // case reuses — so neither can observe whether the documented reset actually
  // runs. _resetRuntimeWarningCacheForTests is documented as resetting
  // "per-process warning state", and this suite's beforeEach calls it expecting
  // exactly that, but it cleared only _warnedConfigKeys and left
  // _warnedUnknownConfigKeys populated. Any later case that reused a key would
  // have its warning silently suppressed by the previous case's leaked state.
  // Asserts on the exported Set rather than stderr prose (CONTRIBUTING.md —
  // Prohibited: Raw Text Matching on Test Outputs).
  test('_resetRuntimeWarningCacheForTests clears the unknown-key dedup set', () => {
    writeConfig(tmpDir, { __gsd_reset_probe__: true });
    loadConfig(tmpDir);
    assert.ok(
      configLoader._warnedUnknownConfigKeys.size > 0,
      'precondition: loading an unknown key must populate the unknown-key dedup set',
    );

    configLoader._resetRuntimeWarningCacheForTests();

    assert.equal(
      configLoader._warnedUnknownConfigKeys.size,
      0,
      'the documented per-process warning-state reset must clear the unknown-key dedup set too',
    );
  });
});

// ─── malformed JSON handling ──────────────────────────────────────────────────

describe('loadConfig — malformed JSON', () => {
  let tmpDir;

  beforeEach(() => { tmpDir = makeTempProject(); });
  afterEach(() => { if (tmpDir) cleanup(tmpDir); tmpDir = null; });

  test('malformed config.json returns defaults without throwing', () => {
    const configPath = path.join(tmpDir, '.planning', 'config.json');
    fs.writeFileSync(configPath, '{ invalid json !!', 'utf-8');
    let config;
    assert.doesNotThrow(() => { config = loadConfig(tmpDir); });
    assert.ok(typeof config === 'object' && config !== null, 'should return an object');
    assert.ok('model_profile' in config, 'should have model_profile key');
  });

  test('empty config.json (empty braces) does not throw and returns defaults', () => {
    writeConfig(tmpDir, {});
    let config;
    assert.doesNotThrow(() => { config = loadConfig(tmpDir); });
    assert.equal(config.model_profile, 'balanced');
  });
});

// ─── ADVERSARIAL fixtures ─────────────────────────────────────────────────────

describe('loadConfig — adversarial fixtures', () => {
  let tmpDir;

  beforeEach(() => { tmpDir = makeTempProject(); });
  afterEach(() => { if (tmpDir) cleanup(tmpDir); tmpDir = null; });

  test('agent_skills.__proto__ key in config does not pollute Object prototype', () => {
    // Write config with a prototype-pollution candidate key
    const configPath = path.join(tmpDir, '.planning', 'config.json');
    // JSON.stringify won't serialize __proto__ as an own property;
    // write the raw string to simulate an adversarial file.
    fs.writeFileSync(
      configPath,
      '{"agent_skills": {"__proto__": {"polluted": true}}}',
      'utf-8'
    );
    const before = ({}).polluted;
    let config;
    assert.doesNotThrow(() => { config = loadConfig(tmpDir); });
    const after = ({}).polluted;
    assert.equal(before, after, 'Object prototype must not be polluted');
    // agent_skills should be the parsed value or an empty object — not throw
    assert.ok(typeof config.agent_skills === 'object', 'agent_skills should be an object');
  });

  test('scalars-where-objects-expected: workflow is a string', () => {
    writeConfig(tmpDir, { workflow: 'invalid' });
    let config;
    assert.doesNotThrow(() => { config = loadConfig(tmpDir); });
    assert.ok(typeof config === 'object', 'should return an object');
  });

  test('completely empty JSON file (just whitespace) falls back to defaults', () => {
    const configPath = path.join(tmpDir, '.planning', 'config.json');
    fs.writeFileSync(configPath, '   ', 'utf-8');
    let config;
    assert.doesNotThrow(() => { config = loadConfig(tmpDir); });
    assert.ok('model_profile' in config);
  });

  test('null JSON value (top-level null) falls back to defaults', () => {
    const configPath = path.join(tmpDir, '.planning', 'config.json');
    fs.writeFileSync(configPath, 'null', 'utf-8');
    let config;
    assert.doesNotThrow(() => { config = loadConfig(tmpDir); });
    assert.ok('model_profile' in config);
  });

  test('deeply nested unknown keys do not throw', () => {
    writeConfig(tmpDir, {
      workflow: {
        research: 'minimal',
        __unknown_nested__: { a: 1, b: { c: 2 } },
      },
    });
    let config;
    assert.doesNotThrow(() => { config = loadConfig(tmpDir); });
    assert.equal(config.research, 'minimal');
  });

  test('dynamic-prefix key agent_skills.* with unusual value type does not throw', () => {
    writeConfig(tmpDir, { agent_skills: { 'my-skill': null } });
    let config;
    assert.doesNotThrow(() => { config = loadConfig(tmpDir); });
    assert.ok(typeof config.agent_skills === 'object');
  });

  test('config with only unknown keys returns defaults for known keys', () => {
    writeConfig(tmpDir, { completly_unknown_a: 1, completly_unknown_b: 2 });
    const config = loadConfig(tmpDir);
    assert.equal(config.model_profile, 'balanced');
  });
});

// ─── loadConfigResolved — provenance ──────────────────────────────────────────

describe('loadConfigResolved — provenance', () => {
  let tmpDir;

  beforeEach(() => { tmpDir = makeTempProject(); });
  afterEach(() => { if (tmpDir) cleanup(tmpDir); tmpDir = null; });

  test('source is "root" when config.json exists and no workstream requested', () => {
    writeConfig(tmpDir, { model_profile: 'quality' });
    const result = loadConfigResolved(tmpDir);
    assert.equal(result.source, 'root');
    assert.equal(result.degraded, false);
    assert.ok(typeof result.config === 'object', 'config must be an object');
    assert.equal(result.config.model_profile, 'quality');
  });

  test('source is "workstream", degraded:false when workstream config.json present', () => {
    writeConfig(tmpDir, { model_profile: 'balanced' });
    writeWorkstreamConfig(tmpDir, 'ws-a', { model_profile: 'quality' });
    const result = loadConfigResolved(tmpDir, { workstream: 'ws-a' });
    assert.equal(result.source, 'workstream');
    assert.equal(result.degraded, false);
    assert.equal(result.config.model_profile, 'quality');
  });

  test('source is "root", degraded:true when workstream requested but ws config.json absent', () => {
    writeConfig(tmpDir, { model_profile: 'budget' });
    // Create ws directory without config.json
    const wsDir = path.join(tmpDir, '.planning', 'workstreams', 'ws-no-config');
    fs.mkdirSync(path.join(wsDir, 'phases'), { recursive: true });
    const result = loadConfigResolved(tmpDir, { workstream: 'ws-no-config' });
    assert.equal(result.source, 'root');
    assert.equal(result.degraded, true);
    assert.equal(result.config.model_profile, 'budget');
  });

  test('source is "builtin-defaults" when .planning exists but config.json is absent', () => {
    // tmpDir already has .planning/ but no config.json
    const result = loadConfigResolved(tmpDir);
    assert.equal(result.source, 'builtin-defaults');
    assert.equal(result.degraded, false);
    assert.ok('model_profile' in result.config);
  });

  test('source is "global-defaults" when no .planning exists but ~/.gsd/defaults.json readable', () => {
    const homeTmp = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-home-test-'));
    const origGsdHome = process.env['GSD_HOME'];
    try {
      const gsdDir = path.join(homeTmp, '.gsd');
      fs.mkdirSync(gsdDir, { recursive: true });
      fs.writeFileSync(path.join(gsdDir, 'defaults.json'), JSON.stringify({ model_profile: 'home-defaults' }), 'utf-8');
      process.env['GSD_HOME'] = homeTmp;
      const noPlanning = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-noplanning-'));
      try {
        const result = loadConfigResolved(noPlanning);
        assert.equal(result.source, 'global-defaults');
        assert.equal(result.degraded, false);
        assert.equal(result.config.model_profile, 'home-defaults');
      } finally {
        cleanup(noPlanning);
      }
    } finally {
      if (origGsdHome === undefined) delete process.env['GSD_HOME'];
      else process.env['GSD_HOME'] = origGsdHome;
      cleanup(homeTmp);
    }
  });

  test('source is "builtin-defaults" when no .planning and no global defaults', () => {
    const noPlanning = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-noplanning2-'));
    const homeTmp = fs.mkdtempSync(path.join(os.tmpdir(), 'gsd-nohome-'));
    const origGsdHome = process.env['GSD_HOME'];
    try {
      // Point GSD_HOME to a directory with no .gsd/defaults.json
      process.env['GSD_HOME'] = homeTmp;
      const result = loadConfigResolved(noPlanning);
      assert.equal(result.source, 'builtin-defaults');
      assert.equal(result.degraded, false);
      assert.ok('model_profile' in result.config);
    } finally {
      if (origGsdHome === undefined) delete process.env['GSD_HOME'];
      else process.env['GSD_HOME'] = origGsdHome;
      cleanup(noPlanning);
      cleanup(homeTmp);
    }
  });

  test('back-compat: loadConfig(tmp) deepEquals loadConfigResolved(tmp).config', () => {
    writeConfig(tmpDir, { model_profile: 'quality', research: 'minimal' });
    const fromLoadConfig = loadConfig(tmpDir);
    const { config: fromResolved } = loadConfigResolved(tmpDir);
    assert.deepEqual(fromLoadConfig, fromResolved);
  });

  test('back-compat: loadConfigResolved(descendant) does NOT walk up — returns defaults, not ancestor config', () => {
    // Fix 1: loadConfigResolved must NOT call findProjectRoot internally.
    // Calling from a descendant that has no .planning/ of its own must return
    // defaults (builtin-defaults source), NOT the ancestor's config value.
    writeConfig(tmpDir, { model_profile: 'ancestor-config-should-not-appear' });
    const deepDir = path.join(tmpDir, 'src', 'deep');
    fs.mkdirSync(deepDir, { recursive: true });
    const result = loadConfigResolved(deepDir);
    // No .planning/ in deepDir → must fall back to defaults, NOT walk up to tmpDir.
    assert.notEqual(result.config.model_profile, 'ancestor-config-should-not-appear',
      'loadConfigResolved must NOT walk up to find ancestor config');
    // The source must be a defaults source (builtin-defaults or global-defaults),
    // NOT "root" (which would imply a config.json was found).
    assert.ok(
      result.source === 'builtin-defaults' || result.source === 'global-defaults',
      `Expected a defaults source, got: ${result.source}`,
    );
  });

  test('Fix 4: loadConfigResolved(tmp, { workstream: "" }) → source:"root"', () => {
    writeConfig(tmpDir, { model_profile: 'quality' });
    // empty-string ws resolves the root path → source must be "root"
    const result = loadConfigResolved(tmpDir, { workstream: '' });
    assert.equal(result.source, 'root', 'empty-string workstream should yield source:"root"');
    assert.equal(result.degraded, false);
  });

  test('Fix 2a: GSD_WORKSTREAM set to nonexistent workstream (dir absent) → source:"root", degraded:true', () => {
    writeConfig(tmpDir, { model_profile: 'root-value' });
    const origWs = process.env['GSD_WORKSTREAM'];
    try {
      process.env['GSD_WORKSTREAM'] = 'nonexistent-ws';
      // Do NOT create the workstream directory
      const result = loadConfigResolved(tmpDir);
      assert.equal(result.source, 'root', 'nonexistent workstream should fall back to source:"root"');
      assert.equal(result.degraded, true, 'should be degraded when workstream dir is absent');
      assert.equal(result.config.model_profile, 'root-value', 'config should equal root config');
    } finally {
      if (origWs === undefined) delete process.env['GSD_WORKSTREAM'];
      else process.env['GSD_WORKSTREAM'] = origWs;
    }
  });

  test('Fix 2b: options.workstream missing dir → source:"root", degraded:true', () => {
    writeConfig(tmpDir, { model_profile: 'root-val' });
    // workstream dir NOT created
    const result = loadConfigResolved(tmpDir, { workstream: 'missing-ws' });
    assert.equal(result.source, 'root');
    assert.equal(result.degraded, true);
    assert.equal(result.config.model_profile, 'root-val');
  });

  test('Fix 2c: workstream dir exists but no config.json → source:"root", degraded:true (existing case still works)', () => {
    writeConfig(tmpDir, { model_profile: 'root-val-c' });
    // Create ws dir but no config.json
    const wsDir = path.join(tmpDir, '.planning', 'workstreams', 'ws-no-cfg');
    fs.mkdirSync(path.join(wsDir, 'phases'), { recursive: true });
    const result = loadConfigResolved(tmpDir, { workstream: 'ws-no-cfg' });
    assert.equal(result.source, 'root');
    assert.equal(result.degraded, true);
    assert.equal(result.config.model_profile, 'root-val-c');
  });
});

// ─── _deepMergeConfig prototype-pollution guard (audit M4) ───────────────────
// The root↔workstream merge once iterated Object.keys(overlay) with no
// __proto__/constructor/prototype guard — while four sibling paths in the same
// file guard them. A config.json with {"__proto__": {...}} could pollute the
// merged object's prototype chain and spoof unset config flags.
describe('_deepMergeConfig — prototype-pollution guard (M4)', () => {
  test('ignores a __proto__ overlay key (no proto pollution, no flag spoofing)', () => {
    // JSON.parse (not an object literal) creates an OWN enumerable "__proto__"
    // key — exactly what a malicious config.json on disk yields.
    const malicious = JSON.parse('{"__proto__": {"injectedFlag": true}}');
    const merged = _deepMergeConfig({ model_profile: 'base' }, malicious);
    assert.equal({}.injectedFlag, undefined, 'global Object.prototype must not be polluted');
    assert.equal(merged.injectedFlag, undefined, 'merged object must not expose the injected flag');
    assert.equal(Object.getPrototypeOf(merged) === Object.prototype, true, 'merged prototype unchanged');
    assert.equal(merged.model_profile, 'base', 'legitimate keys still merge');
  });

  test('ignores constructor/prototype overlay keys too', () => {
    const malicious = JSON.parse('{"constructor": {"x": 1}, "prototype": {"y": 2}}');
    const merged = _deepMergeConfig({ a: 1 }, malicious);
    assert.equal(merged.a, 1);
    // constructor must remain the native Object constructor, not the injected object
    assert.equal(typeof merged.constructor, 'function');
  });
});


// ────────────────────────────────────────────────────────────────────────
// Folded from tests/bug-2638-sub-repos-canonical-location.test.cjs — consolidation epic #1969 (B3 #1972)
// ────────────────────────────────────────────────────────────────────────
{
  const { describe: __foldDescribe } = require('node:test');
  __foldDescribe("folded:bug-2638-sub-repos-canonical-location (consolidation epic #1969 B3 #1972)", () => {
/**
 * Regression test for bug #2638.
 *
 * loadConfig previously migrated/synced sub_repos to the TOP-LEVEL
 * `parsed.sub_repos`, but the KNOWN_TOP_LEVEL allowlist only recognizes
 * `planning.sub_repos` (per #2561 — canonical location). That asymmetry
 * made loadConfig write a key it then warns is unknown on the next read.
 *
 * Fix: writers target `parsed.planning.sub_repos` and strip any stale
 * top-level copy during the same migration pass.
 */

const { test, describe, beforeEach, afterEach } = require('node:test');
const assert = require('node:assert/strict');
const fs = require('fs');
const path = require('path');
const { execFileSync } = require('child_process');
const { createTempProject, cleanup } = require('./helpers.cjs');

const { loadConfig } = require('../gsd-core/bin/lib/config-loader.cjs');

function makeSubRepo(parent, name) {
  const dir = path.join(parent, name);
  fs.mkdirSync(dir, { recursive: true });
  execFileSync('git', ['init'], { cwd: dir, stdio: 'pipe' });
}

function readConfig(tmpDir) {
  return JSON.parse(
    fs.readFileSync(path.join(tmpDir, '.planning', 'config.json'), 'utf-8')
  );
}

function writeConfig(tmpDir, obj) {
  fs.writeFileSync(
    path.join(tmpDir, '.planning', 'config.json'),
    JSON.stringify(obj, null, 2)
  );
}

describe('bug #2638 — sub_repos canonical location', () => {
  let tmpDir;
  let originalCwd;
  let stderrCapture;
  let origStderrWrite;

  beforeEach(() => {
    tmpDir = createTempProject();
    originalCwd = process.cwd();
    stderrCapture = '';
    origStderrWrite = process.stderr.write;
    process.stderr.write = (chunk) => { stderrCapture += chunk; return true; };
  });

  afterEach(() => {
    process.stderr.write = origStderrWrite;
    process.chdir(originalCwd);
    cleanup(tmpDir);
  });

  test('does not warn when planning.sub_repos is set (no top-level sub_repos)', () => {
    makeSubRepo(tmpDir, 'backend');
    makeSubRepo(tmpDir, 'frontend');
    writeConfig(tmpDir, {
      planning: { sub_repos: ['backend', 'frontend'] },
    });

    loadConfig(tmpDir);

    assert.ok(
      !stderrCapture.includes('unknown config key'),
      `should not warn for planning.sub_repos, got: ${stderrCapture}`
    );
    assert.ok(
      !stderrCapture.includes('sub_repos'),
      `should not mention sub_repos at all, got: ${stderrCapture}`
    );
  });

  test('migrates legacy multiRepo:true into planning.sub_repos (not top-level)', () => {
    makeSubRepo(tmpDir, 'backend');
    makeSubRepo(tmpDir, 'frontend');
    writeConfig(tmpDir, { multiRepo: true });

    loadConfig(tmpDir);

    const after = readConfig(tmpDir);
    assert.deepStrictEqual(
      after.planning?.sub_repos,
      ['backend', 'frontend'],
      'migration should write to planning.sub_repos'
    );
    assert.strictEqual(
      Object.prototype.hasOwnProperty.call(after, 'sub_repos'),
      false,
      'migration must not leave a top-level sub_repos key'
    );
    assert.strictEqual(after.multiRepo, undefined, 'legacy multiRepo should be removed');

    assert.ok(
      !stderrCapture.includes('unknown config key'),
      `post-migration read should not warn, got: ${stderrCapture}`
    );
  });

  test('filesystem sync writes detected list to planning.sub_repos only', () => {
    makeSubRepo(tmpDir, 'api');
    makeSubRepo(tmpDir, 'web');
    writeConfig(tmpDir, { planning: { sub_repos: ['api'] } });

    loadConfig(tmpDir);

    const after = readConfig(tmpDir);
    assert.deepStrictEqual(after.planning?.sub_repos, ['api', 'web']);
    assert.strictEqual(
      Object.prototype.hasOwnProperty.call(after, 'sub_repos'),
      false,
      'sync must not create a top-level sub_repos key'
    );
    assert.ok(
      !stderrCapture.includes('unknown config key'),
      `sync should not produce unknown-key warning, got: ${stderrCapture}`
    );
  });

  test('stale top-level sub_repos is stripped on load', () => {
    makeSubRepo(tmpDir, 'backend');
    writeConfig(tmpDir, {
      sub_repos: ['backend'],
      planning: { sub_repos: ['backend'] },
    });

    loadConfig(tmpDir);

    const after = readConfig(tmpDir);
    assert.strictEqual(
      Object.prototype.hasOwnProperty.call(after, 'sub_repos'),
      false,
      'stale top-level sub_repos should be removed to self-heal legacy installs'
    );
    assert.deepStrictEqual(after.planning?.sub_repos, ['backend']);
  });
});
  });
}

// ────────────────────────────────────────────────────────────────────────
// Folded from tests/bug-3523-cjs-loadconfig-branching-strategy-warning.test.cjs — consolidation epic #1969 (B6 #1975)
// ────────────────────────────────────────────────────────────────────────
{
  const { describe: __foldDescribe } = require('node:test');
  __foldDescribe("folded:bug-3523-cjs-loadconfig-branching-strategy-warning (consolidation epic #1969 B6 #1975)", () => {
'use strict';

// allow-test-rule: validates runtime CLI stdout/stderr warning behavior, not source grep (see #3523)

/**
 * Regression tests for #3523 — CJS loadConfig must not emit a false
 * "unknown config key(s)" warning for `branching_strategy` when that key
 * is written at the top level of .planning/config.json.
 *
 * Root cause: KNOWN_TOP_LEVEL in core.cjs was built from VALID_CONFIG_KEYS
 * via k.split('.')[0], which turns 'git.branching_strategy' → 'git', not
 * 'branching_strategy'. So a config with the legacy top-level shape tripped
 * the unknown-key warning even though core.cjs:485 actively reads the value.
 *
 * Fix (option 3 — self-healing): mirror the multiRepo → planning.sub_repos
 * precedent: graft branching_strategy into fileData.git.branching_strategy
 * and delete the top-level key, then persist. The KNOWN_TOP_LEVEL list also
 * gains 'branching_strategy' as a deprecated-still-accepted key so the warning
 * never fires even on the first read before the write-back occurs.
 *
 * Double-emission is also reduced: the warning site is guarded by a
 * module-level Set so repeated loadConfig calls during one CLI invocation
 * don't echo the same line twice.
 *
 * CJS↔SDK contract: the SDK mergeDefaults() already handles the legacy
 * top-level key (PR #3116). This file adds a fixture-level parity check
 * that proves both paths produce the same branching_strategy value.
 *
 * Test strategy: we use `resolve-model` as the minimal CJS entry point that
 * calls loadConfig internally, then assert on stderr emptiness (typed-IR
 * "no warning" pattern from #2687).
 */

const { describe, test, afterEach } = require('node:test');
const assert = require('node:assert/strict');
const fs = require('node:fs');
const path = require('node:path');
const { spawnSync } = require('node:child_process');
const { createTempProject, cleanup, TOOLS_PATH } = require('./helpers.cjs');

const TEST_ENV_BASE = {
  GSD_SESSION_KEY: '',
  CODEX_THREAD_ID: '',
  CLAUDE_SESSION_ID: '',
  CLAUDE_CODE_SSE_PORT: '',
  OPENCODE_SESSION_ID: '',
  GEMINI_SESSION_ID: '',
  CURSOR_SESSION_ID: '',
  WINDSURF_SESSION_ID: '',
  TERM_SESSION_ID: '',
  WT_SESSION: '',
  TMUX_PANE: '',
  ZELLIJ_SESSION_NAME: '',
  TTY: '',
  SSH_TTY: '',
};

/**
 * Run gsd-tools and return { stdout, stderr, status }.
 * Always captures stderr even when exit code is 0.
 */
function runWithStderr(args, cwd, env = {}) {
  const result = spawnSync(process.execPath, [TOOLS_PATH, ...args], {
    cwd,
    encoding: 'utf-8',
    env: { ...process.env, ...TEST_ENV_BASE, ...env },
  });
  return {
    stdout: result.stdout || '',
    stderr: result.stderr || '',
    status: result.status,
  };
}

// ─── Test 1: no warning for legacy top-level branching_strategy ──────────────

describe('bug-3523 — no warning for legacy top-level branching_strategy', () => {
  let tmpDir;

  afterEach(() => {
    if (tmpDir) cleanup(tmpDir);
    tmpDir = null;
  });

  test('loadConfig emits no stderr when config.json has top-level branching_strategy', () => {
    tmpDir = createTempProject('gsd-3523-warn-');
    const configPath = path.join(tmpDir, '.planning', 'config.json');
    fs.writeFileSync(
      configPath,
      JSON.stringify({
        branching_strategy: 'phase',
        git: { base_branch: 'main' },
      }, null, 2),
      'utf-8'
    );

    // resolve-model calls loadConfig internally, triggering KNOWN_TOP_LEVEL check.
    const result = runWithStderr(['resolve-model', 'planner'], tmpDir);

    assert.equal(
      result.stderr.trim(),
      '',
      `loadConfig must not warn about top-level branching_strategy (#3523) — got: ${result.stderr}`
    );
  });

  test('branching_strategy value is still surfaced after loadConfig on legacy shape', () => {
    tmpDir = createTempProject('gsd-3523-value-');
    const configPath = path.join(tmpDir, '.planning', 'config.json');
    fs.writeFileSync(
      configPath,
      JSON.stringify({
        branching_strategy: 'milestone',
        git: { base_branch: 'main' },
      }, null, 2),
      'utf-8'
    );

    // Trigger loadConfig (which runs the migration and writes git.branching_strategy
    // back to disk), then read it with config-get to verify the value is preserved.
    const triggerResult = runWithStderr(['resolve-model', 'planner'], tmpDir);
    assert.equal(
      triggerResult.stderr.trim(),
      '',
      `No warning should fire on legacy shape (#3523) — got: ${triggerResult.stderr}`
    );

    // After migration write-back, config-get should find git.branching_strategy.
    const result = runWithStderr(['config-get', 'git.branching_strategy'], tmpDir);

    assert.equal(
      result.status,
      0,
      `config-get command must succeed — exit status ${result.status}, stderr: ${result.stderr}`
    );
    assert.equal(
      result.stderr.trim(),
      '',
      `No error should fire when reading migrated branching_strategy (#3523) — got: ${result.stderr}`
    );
    assert.ok(
      result.stdout.includes('milestone'),
      `Expected git.branching_strategy to be 'milestone' but got: ${result.stdout}`
    );
  });
});

// ─── Test 2: no duplicated warning (double-emission) ─────────────────────────

describe('bug-3523 — double-emission reduced to single-emission', () => {
  let tmpDir;

  afterEach(() => {
    if (tmpDir) cleanup(tmpDir);
    tmpDir = null;
  });

  test('unknown-key warning appears at most once per process invocation', () => {
    // Use a key that IS genuinely unknown (not branching_strategy, which is now
    // fixed) to verify the deduplication guard works for other keys too.
    // We verify that the count of warning lines for a single unknown key is
    // exactly once — not zero and not two — even if loadConfig is invoked twice internally.
    tmpDir = createTempProject('gsd-3523-dedup-');
    const configPath = path.join(tmpDir, '.planning', 'config.json');
    fs.writeFileSync(
      configPath,
      JSON.stringify({
        // intentionally_unknown_key_for_dedup_test: a key that can never be valid
        __gsd3523_dedup_sentinel__: true,
      }, null, 2),
      'utf-8'
    );

    const result = runWithStderr(['resolve-model', 'planner'], tmpDir);

    // Count how many times the sentinel key appears in warnings
    const warningLines = result.stderr
      .split('\n')
      .filter(l => l.includes('__gsd3523_dedup_sentinel__'));

    assert.equal(
      warningLines.length,
      1,
      `Unknown-key warning must appear exactly once per process invocation — ` +
      `appeared ${warningLines.length} times. stderr:\n${result.stderr}`
    );
  });
});

// ─── Test 3: on-disk migration (option 3 write-back) ─────────────────────────

describe('bug-3523 — option 3 on-disk migration of branching_strategy', () => {
  let tmpDir;

  afterEach(() => {
    if (tmpDir) cleanup(tmpDir);
    tmpDir = null;
  });

  test('after loadConfig, on-disk config.json has branching_strategy under git.*', () => {
    tmpDir = createTempProject('gsd-3523-writeback-');
    const configPath = path.join(tmpDir, '.planning', 'config.json');
    fs.writeFileSync(
      configPath,
      JSON.stringify({
        branching_strategy: 'phase',
        git: { base_branch: 'main' },
      }, null, 2),
      'utf-8'
    );

    // Trigger loadConfig by running a command.
    runWithStderr(['resolve-model', 'planner'], tmpDir);

    // On-disk file should now have git.branching_strategy and no top-level branching_strategy.
    const onDisk = JSON.parse(fs.readFileSync(configPath, 'utf-8'));
    assert.equal(
      onDisk.git?.branching_strategy,
      'phase',
      'Expected on-disk config.json to have git.branching_strategy = "phase" after migration'
    );
    assert.equal(
      onDisk.branching_strategy,
      undefined,
      'Expected on-disk config.json to have no top-level branching_strategy after migration'
    );
  });

  test('migration does not clobber existing git.branching_strategy', () => {
    // If git.branching_strategy is already set, the top-level value should
    // not overwrite it (nested wins, matching SDK mergeDefaults precedence).
    tmpDir = createTempProject('gsd-3523-no-clobber-');
    const configPath = path.join(tmpDir, '.planning', 'config.json');
    fs.writeFileSync(
      configPath,
      JSON.stringify({
        branching_strategy: 'phase',       // legacy top-level
        git: {
          base_branch: 'main',
          branching_strategy: 'milestone', // canonical nested — must win
        },
      }, null, 2),
      'utf-8'
    );

    // Trigger loadConfig.
    runWithStderr(['resolve-model', 'planner'], tmpDir);

    const onDisk = JSON.parse(fs.readFileSync(configPath, 'utf-8'));
    assert.equal(
      onDisk.git?.branching_strategy,
      'milestone',
      'canonical git.branching_strategy must not be overwritten by legacy top-level key'
    );
    // top-level key should be removed since it was redundant
    assert.equal(
      onDisk.branching_strategy,
      undefined,
      'top-level branching_strategy should be removed even when git.branching_strategy already set'
    );
  });

  test('workstream load also self-heals legacy root branching_strategy', () => {
    tmpDir = createTempProject('gsd-3523-workstream-root-');
    const rootConfigPath = path.join(tmpDir, '.planning', 'config.json');
    const workstreamDir = path.join(tmpDir, '.planning', 'workstreams', 'alpha');
    fs.mkdirSync(workstreamDir, { recursive: true });
    fs.writeFileSync(
      rootConfigPath,
      JSON.stringify({
        branching_strategy: 'phase',
        git: { base_branch: 'main' },
      }, null, 2),
      'utf-8'
    );
    fs.writeFileSync(
      path.join(workstreamDir, 'config.json'),
      JSON.stringify({ workflow: { tdd: true } }, null, 2),
      'utf-8'
    );

    const triggerResult = runWithStderr(['resolve-model', 'planner'], tmpDir, {
      GSD_WORKSTREAM: 'alpha',
    });

    assert.equal(
      triggerResult.status,
      0,
      `workstream load command must succeed — exit status ${triggerResult.status}, stderr: ${triggerResult.stderr}`
    );
    assert.equal(
      triggerResult.stderr.trim(),
      '',
      `No warning should fire while migrating root config for a workstream — got: ${triggerResult.stderr}`
    );

    const onDisk = JSON.parse(fs.readFileSync(rootConfigPath, 'utf-8'));
    assert.equal(
      onDisk.git?.branching_strategy,
      'phase',
      'Expected root config.json to persist git.branching_strategy after workstream load'
    );
    assert.equal(
      onDisk.branching_strategy,
      undefined,
      'Expected root config.json to remove top-level branching_strategy after workstream load'
    );

    const rootResult = runWithStderr(['config-get', 'git.branching_strategy'], tmpDir);
    assert.equal(
      rootResult.status,
      0,
      `root config-get command must succeed after workstream migration — exit status ${rootResult.status}, stderr: ${rootResult.stderr}`
    );
    assert.ok(
      rootResult.stdout.includes('phase'),
      `Expected migrated root git.branching_strategy to be 'phase' but got: ${rootResult.stdout}`
    );
  });
});

// ─── Test 4: CJS↔SDK contract parity ────────────────────────────────────────

describe('bug-3523 — CJS↔SDK contract: both agree on legacy branching_strategy fixture', () => {
  /**
   * This is a light-touch contract test: we invoke the CJS path via CLI and
   * compare the branching_strategy value it returns against what the SDK's
   * mergeDefaults would compute for the same fixture.
   *
   * We can't import SDK TypeScript here, so we assert on the CJS output and
   * use a snapshot of expected SDK behavior derived from the mergeDefaults
   * source (sdk/src/config.ts:192-218):
   *   mergeDefaults({ branching_strategy: 'phase', git: { base_branch: 'main' } })
   *   → git.branching_strategy = 'phase'
   */
  let tmpDir;

  afterEach(() => {
    if (tmpDir) cleanup(tmpDir);
    tmpDir = null;
  });

  test('CJS loadConfig surfaces branching_strategy matching SDK mergeDefaults behavior', () => {
    tmpDir = createTempProject('gsd-3523-parity-');
    const configPath = path.join(tmpDir, '.planning', 'config.json');
    // The fixture that the SDK's mergeDefaults handles correctly (PR #3116).
    fs.writeFileSync(
      configPath,
      JSON.stringify({
        branching_strategy: 'phase',
        git: { base_branch: 'main' },
      }, null, 2),
      'utf-8'
    );

    // SDK mergeDefaults produces: git.branching_strategy = 'phase'
    // CJS loadConfig must produce the same. Trigger loadConfig first (migration
    // writes git.branching_strategy to disk), then verify with config-get.
    const triggerResult = runWithStderr(['resolve-model', 'planner'], tmpDir);
    assert.equal(
      triggerResult.stderr.trim(),
      '',
      `No warning must fire on a standard legacy fixture — got: ${triggerResult.stderr}`
    );

    // After the migration write-back, config-get must find git.branching_strategy = 'phase',
    // matching what the SDK's mergeDefaults would compute.
    const result = runWithStderr(['config-get', 'git.branching_strategy'], tmpDir);

    assert.equal(
      result.status,
      0,
      `config-get command must succeed — exit status ${result.status}, stderr: ${result.stderr}`
    );
    assert.equal(
      result.stderr.trim(),
      '',
      `No error when reading post-migration git.branching_strategy — got: ${result.stderr}`
    );
    assert.ok(
      result.stdout.includes('phase'),
      `CJS must agree with SDK: git.branching_strategy = 'phase' for legacy fixture. ` +
      `Got: ${result.stdout}`
    );
  });
});
  });
}

// ─── #1880: corrupt is not absent (ADR-1411 amendment) ────────────────────────

describe("loadConfigResolved — corrupt config is distinguishable from absent", () => {
  let tmpDir;
  let stderrLines;
  let originalStderrWrite;

  beforeEach(() => {
    tmpDir = makeTempProject();
    stderrLines = [];
    originalStderrWrite = process.stderr.write.bind(process.stderr);
    process.stderr.write = (chunk) => { stderrLines.push(String(chunk)); return true; };
    configLoader._resetRuntimeWarningCacheForTests();
  });

  afterEach(() => {
    process.stderr.write = originalStderrWrite;
    if (tmpDir) cleanup(tmpDir);
    tmpDir = null;
  });

  const configPath = (d) => path.join(d, ".planning", "config.json");
  const R = configLoader.CONFIG_REASON;

  // The repro from the issue: absent and malformed were byte-identical.
  test("absent config resolves not_configured and is NOT degraded", () => {
    const res = configLoader.loadConfigResolved(tmpDir);
    assert.equal(res.degraded, false, "a missing config is legitimate absence");
    assert.equal(res.reason, R.NOT_CONFIGURED);
    assert.equal(res.reason, "not_configured", "enum value is the wire contract");
  });

  test("malformed config is degraded with reason config_unparseable", () => {
    fs.writeFileSync(configPath(tmpDir), '{"model_profile":"budget",}', "utf-8");
    const res = configLoader.loadConfigResolved(tmpDir);
    assert.equal(res.reason, R.CONFIG_UNPARSEABLE,
      "a trailing comma must not read as \"no config here\"");
    assert.equal(res.degraded, true, "corruption is a degraded resolution");
  });

  test("absent and malformed no longer produce the same resolution", () => {
    const absent = configLoader.loadConfigResolved(tmpDir);
    configLoader._resetRuntimeWarningCacheForTests();
    fs.writeFileSync(configPath(tmpDir), '{"model_profile":"budget",}', "utf-8");
    const corrupt = configLoader.loadConfigResolved(tmpDir);
    assert.notEqual(absent.reason, corrupt.reason,
      "the whole defect: these two were indistinguishable");
    assert.notEqual(absent.degraded, corrupt.degraded);
  });

  test("unreadable config is degraded with reason config_unreadable", (t) => {
    fs.writeFileSync(configPath(tmpDir), '{"model_profile":"budget"}', "utf-8");
    // Deterministic IO fault via fs monkeypatch, restored in t.after() — never
    // chmod 0o000, which root bypasses (CLAUDE.md cross-platform IO rule).
    const realRead = fs.readFileSync;
    t.after(() => { fs.readFileSync = realRead; });
    fs.readFileSync = (f, ...rest) => {
      if (String(f).endsWith("config.json")) {
        const e = new Error("EACCES: permission denied"); e.code = "EACCES"; throw e;
      }
      return realRead(f, ...rest);
    };
    const res = configLoader.loadConfigResolved(tmpDir);
    assert.equal(res.reason, R.CONFIG_UNREADABLE);
    assert.equal(res.degraded, true);
  });

  // The wiring clause: loadConfig returns .config alone to ~51 call sites, so
  // without a diagnostic the reason field is unreachable to nearly every consumer.
  test("the plain loadConfig path still surfaces the cause on stderr", () => {
    fs.writeFileSync(configPath(tmpDir), '{"model_profile":"budget",}', "utf-8");
    configLoader.loadConfig(tmpDir);
    assert.equal(configLoader._warnedUnusableConfig.size, 1,
      "a loadConfig caller must still get a signal it can act on");
  });

  test("the diagnostic is deduplicated across repeat loads", () => {
    fs.writeFileSync(configPath(tmpDir), '{"model_profile":"budget",}', "utf-8");
    configLoader.loadConfig(tmpDir);
    configLoader.loadConfig(tmpDir);
    configLoader.loadConfig(tmpDir);
    assert.equal(configLoader._warnedUnusableConfig.size, 1, "keyed on path+errno, warned once");
  });

  // Regression: found by isolated review of the first cut of this fix. The
  // success path returned early WITHOUT consulting configFault, so a corrupt
  // ROOT config whose workstream override happened to parse reported
  // degraded:false / resolved — the same silent-discard defect this issue
  // exists to close, reappearing for any project that uses workstreams.
  test("a corrupt ROOT config still degrades when the workstream config parses", () => {
    const wsDir = path.join(tmpDir, ".planning", "workstreams", "ws-a");
    fs.mkdirSync(wsDir, { recursive: true });
    fs.writeFileSync(configPath(tmpDir), '{"model_profile":"budget",}', "utf-8");
    fs.writeFileSync(path.join(wsDir, "config.json"), '{"mode":"autonomous"}', "utf-8");
    const res = configLoader.loadConfigResolved(tmpDir, { workstream: "ws-a" });
    assert.equal(res.reason, R.CONFIG_UNPARSEABLE,
      "the root config was discarded — that must not report as a clean resolve");
    assert.equal(res.degraded, true);
  });

  // Regression: reason was computed from the root+workstream MERGE, so an empty
  // workstream file inheriting a non-empty root reported "resolved" despite
  // carrying no settings of its own.
  test("an empty workstream file inheriting a non-empty root is configured_empty", () => {
    const wsDir = path.join(tmpDir, ".planning", "workstreams", "ws-b");
    fs.mkdirSync(wsDir, { recursive: true });
    fs.writeFileSync(configPath(tmpDir), '{"model_profile":"quality"}', "utf-8");
    fs.writeFileSync(path.join(wsDir, "config.json"), "{}", "utf-8");
    const res = configLoader.loadConfigResolved(tmpDir, { workstream: "ws-b" });
    assert.equal(res.reason, R.CONFIGURED_EMPTY,
      "emptiness is a property of the file read, not of the merged result");
    assert.equal(res.degraded, false, "an empty file is not corruption");
  });

  // Found by the property test below: valid JSON that is not an OBJECT parsed
  // "ok", then threw downstream, and the outer catch reported not_configured —
  // a present file indistinguishable from an absent one, the exact defect this
  // issue closes. Shape is now validated at the read seam (ADR-227).
  for (const body of ["0", '"a string"', "[]", "null", "true"]) {
    test(`valid JSON that is not an object is unusable, not absent: ${body}`, () => {
      fs.writeFileSync(configPath(tmpDir), body, "utf-8");
      const res = configLoader.loadConfigResolved(tmpDir);
      assert.equal(res.reason, R.CONFIG_UNPARSEABLE,
        "a present-but-unusable file must never report as not_configured");
      assert.equal(res.degraded, true);
    });
  }

  // Property test (CONTRIBUTING.md: parsers require >=1 fast-check property).
  // The classification is total and mutually exclusive: any byte string is
  // exactly one of resolved/configured_empty (parses) or config_unparseable.
  test("classification is total and never reports a corrupt file as absent", () => {
    fc.assert(
      fc.property(fc.string(), (body) => {
        configLoader._resetRuntimeWarningCacheForTests();
        fs.writeFileSync(configPath(tmpDir), body, "utf-8");
        const res = configLoader.loadConfigResolved(tmpDir);
        let parses = true;
        try { const v = JSON.parse(body); parses = v !== null && typeof v === "object" && !Array.isArray(v); }
        catch { parses = false; }
        // The invariant that matters: a file that is PRESENT is never reported
        // as not_configured, whatever its bytes.
        assert.notEqual(res.reason, R.NOT_CONFIGURED);
        if (!parses) assert.equal(res.reason, R.CONFIG_UNPARSEABLE);
        return true;
      }),
      { numRuns: 200, seed: 1880 },
    );
  });

  // Contract markers required by scripts/lint-resolution-provenance.cjs:
  // configured_empty and not_configured must stay distinguishable.
  test("an empty config object is configured_empty, not not_configured", () => {
    fs.writeFileSync(configPath(tmpDir), "{}", "utf-8");
    const res = configLoader.loadConfigResolved(tmpDir);
    assert.equal(res.reason, R.CONFIGURED_EMPTY,
      "configured_empty and not_configured must be distinguishable (ADR-1411 rule 3)");
    assert.equal(res.reason, "configured_empty", "enum value is the wire contract");
    assert.equal(res.degraded, false, "an empty file is not corruption");
  });
});