module: exclude node:ffi from builtinModules when flag is disabled

[ljharb]

Module.builtinModules is supposed to only list modules that are accessible to user code. node:ffi requires --experimental-ffi to be required, so filter it out when the flag is not set, mirroring the existing handling for --experimental-quic.

Refs: #63137 (comment), #62072

[nodejs-github-bot]

Review requested:

• @nodejs/loaders

[github-actions]

Fast-track has been requested by @aduh95. Please 👍 to approve.

[aduh95]

Related failure to address:

=== release test-ffi-module ===
Path: ffi/test-ffi-module
Error: --- stderr ---
(node:87480) ExperimentalWarning: FFI is an experimental feature and might change at any time
(Use `node --trace-warnings ...` to show where the warning was created)
--- stdout ---
Test failure: 'ffi builtin is listed'
Location: test/ffi/test-ffi-module.js:34:1
AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:
'false' !== 'true'
at TestContext.<anonymous> (/home/runner/work/_temp/node-v27.0.0-nightly2026-05-069c7b977313-slim/test/ffi/test-ffi-module.js:42:10)
at Test.runInAsyncScope (node:async_hooks:226:14)
at Test.run (node:internal/test_runner/test:1306:25)
at Test.processPendingSubtests (node:internal/test_runner/test:897:18)
at Test.postRun (node:internal/test_runner/test:1447:19)
at Test.run (node:internal/test_runner/test:1372:12)
at async Test.processPendingSubtests (node:internal/test_runner/test:897:7) {
generatedMessage: true,
code: 'ERR_ASSERTION',
actual: 'false',
expected: 'true',
operator: 'strictEqual',
diff: 'simple'
}
Command: out/Release/node --experimental-ffi --test-reporter=./test/common/test-error-reporter.js --test-reporter-destination=stdout /home/runner/work/_temp/node-v27.0.0-nightly2026-05-069c7b977313-slim/test/ffi/test-ffi-module.js
===
=== 1 tests failed
===

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/73212/

[ljharb]

@aduh95 thanks, fixed!

[mcollina]

lgtm

[ljharb]

the CI failure looks spurious?

[aduh95]

It's a bit annoying that you force-pushed my commit out, it seems unlikely there will be time to include this PR in 26.1.0 now

[ljharb]

@aduh95 sorry; i didn't realize you'd pushed a commit.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/73215/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/73216/

[aduh95]

Landed in 2f5d7e7

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.03%. Comparing base (3c2d2e3) to head (cc2a346).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #63158 +/- ##
==========================================
- Coverage 90.04% 90.03% -0.01% 
==========================================
Files 713 713 Lines 224484 224500 +16 Branches 42430 42421 -9 ==========================================
+ Hits 202134 202136 +2 - Misses 14156 14162 +6 - Partials 8194 8202 +8 

Files with missing lines	Coverage Δ
lib/internal/modules/cjs/loader.js	98.26% <100.00%> (+<0.01%)	⬆️

... and 26 files with indirect coverage changes

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