Electron Node.js Upgrade: Phase One

Summary

Run e sync --3 repeatedly, fixing patch conflicts as they arise, until it succeeds. Then export patches and commit changes atomically.

Success Criteria

Phase One is complete when:

• e sync --3 exits with code 0 (no patch failures)
• All changes are committed per the commit guidelines

Do not stop until these criteria are met.

CRITICAL Do not delete or skip patches unless 100% certain the patch is no longer needed. For major version upgrades, patches that shim deprecated V8 APIs or backport upstream changes are often deletable because the new Node.js version already incorporates them — but verify before removing. Complicated conflicts or hard to resolve issues should be presented to the user after you have exhausted all other options. Do not delete the patch just because you can't solve it.

CRITICAL Never use git am --skip and then manually recreate a patch by making a new commit. This destroys the original patch's authorship, commit message, and position in the series. If git am --continue reports "No changes", investigate why — the changes were likely absorbed by a prior conflict resolution's 3-way merge. Present this situation to the user rather than skipping and recreating.

Context

The roller/node/main branch is created by automation to update Electron's Node.js dependency version in DEPS. No work has been done to handle breaking changes between the old and new versions.

There are two types of Node.js version updates:

• Bumps (patch/minor): Automated by electron-roller[bot] with commit title chore: bump node to v{version}. Trivial patch index updates are handled automatically by patchup[bot]. These often land cleanly, but may require manual patch fixes.
• Major upgrades (e.g., v22 → v24): Manual, large PRs with commit title chore: upgrade Node.js to v{X}.{Y}.{Z}. These typically involve deleting obsolete patches, adapting many others, and updating @types/node in package.json.

Key directories:

• Current directory: Electron repo (always run e commands here)
• ../third_party/electron_node: Node.js repo (where patches apply)
• patches/node/: Patch files for Node.js
• docs/development/patches.md: Patch system documentation

Pre-flight Checks

Run these once at the start of each upgrade session:

1. Clear rerere cache (if enabled): git rerere clear in both the electron and ../third_party/electron_node repos. Stale recorded resolutions from a prior attempt can silently apply wrong merges.
2. Ensure pre-commit hooks are installed: Check that .git/hooks/pre-commit exists. If not, run yarn husky to install it. The hook runs lint-staged which handles clang-format for C++ files.

Workflow

1. Run e sync --3 (the --3 flag enables 3-way merge, always required)
2. If succeeds → skip to step 5
3. If patch fails:
   • Identify target repo and patch from error output
   • Analyze failure (see references/patch-analysis.md)
   • Fix conflict in ../third_party/electron_node working directory
   • Run git am --continue in ../third_party/electron_node
   • Repeat until all patches for that repo apply
   • IMPORTANT: Once git am --continue succeeds you MUST run e patches node to export fixes
   • Return to step 1
4. When e sync --3 succeeds, run e patches all
5. Read references/phase-one-commit-guidelines.md NOW, then commit changes following those instructions exactly.

Commands Reference

Patch System Mental Model

patches/node/*.patch  →  [e sync --3]  →  ../third_party/electron_node commits
                      ←  [e patches]   ←

When to Edit Patches

Fix existing patches 99% of the time rather than creating new ones.

Patch Fixing Rules

1. Preserve authorship: Keep original author in TODO comments (from patch From: field)
2. Never change TODO assignees: TODO(name) must retain original name
3. Update descriptions: If upstream changed APIs or macros, update patch commit message to reflect current state
4. Never skip-and-recreate a patch: If git am --continue says "No changes — did you forget to use 'git add'?", do NOT run git am --skip and create a replacement commit. The patch's changes were already absorbed by a prior 3-way merge resolution. This means an earlier conflict resolution pulled in too many changes. Present the situation to the user for guidance — the correct fix may require re-doing an earlier resolution more carefully to keep each patch's changes separate.

Electron Node.js Upgrade: Phase Two

Summary

Run e build -k 999 -- --quiet repeatedly, fixing build issues as they arise, until it succeeds. Then run e start --version to validate Electron launches and commit changes atomically.

Run Phase Two immediately after Phase One is complete.

Success Criteria

Phase Two is complete when:

• e build -k 999 -- --quiet exits with code 0 (no build failures)
• e start --version has been run to check Electron launches
• All changes are committed per the commit guidelines

Do not stop until these criteria are met. Do not delete code or features, never comment out code in order to take short cut. Make all existing code, logic and intention work.

Context

The roller/node/main branch is created by automation to update Electron's Node.js dependency version in DEPS. No work has been done to handle breaking changes between the old and new versions. Node.js APIs (especially internal V8 integration, OpenSSL/BoringSSL compatibility, and build system files) frequently change between versions. In every case the code in Electron must be updated to account for the change in Node.js, strongly avoid making changes to the code in Node.js to fix Electron's build.

Key directories:

• Current directory: Electron repo (always run e commands here)
• ../third_party/electron_node: Node.js repo (do not touch this code to fix build issues, just read it to obtain context)

Workflow

1. Run e build -k 999 -- --quiet (the --quiet flag suppresses per-target status lines, showing only errors and the final result)
2. If succeeds → skip to step 6
3. If build fails:
   • Identify underlying file in "electron" from the compilation error message
   • Analyze failure
   • Fix build issue by adapting Electron's code for the change in Node.js
   • Run e build -t {target_that_failed}.o to build just the failed target we were specifically fixing
     • You can identify the target_that_failed from the failure line in the build log. E.g. FAILED: 2e506007-8d5d-4f38-bdd1-b5cd77999a77 "./obj/electron/shell/browser/api/electron_api_utility_process.o" CXX obj/electron/shell/browser/api/electron_api_utility_process.o the target name is obj/electron/shell/browser/api/electron_api_utility_process.o
   • Read references/phase-two-commit-guidelines.md NOW, then commit changes following those instructions exactly.
   • Return to step 1
4. CRITICAL: After ANY commit (especially patch commits), immediately run git status in the electron repo
   • Look for other modified .patch files that only have index/hunk header changes
   • These are dependent patches affected by your fix
   • Commit them immediately with: git commit -am "chore: update patches (trivial only)"
5. Return to step 1
6. When e build succeeds, run e start --version
7. Check if you have any pending changes in the Node.js repo by running git status in ../third_party/electron_node
   • If you have changes follow the instructions below in "A. Patch Fixes" to correctly commit those modifications into the appropriate patch file

Commands Reference

Two Types of Build Fixes

A. Patch Fixes (for files in patched Node.js files)

When the error is in a file that Electron patches (check with grep -l "filename" patches/node/*.patch):

1. Edit the file in the Node.js source tree (../third_party/electron_node/...)
2. Create a fixup commit targeting the original patch commit:

   cd ../third_party/electron_node
   git add <modified-file>
   git commit --fixup=<original-patch-commit-hash>
   GIT_SEQUENCE_EDITOR=: git rebase --autosquash --autostash -i <commit>^
   

3. Export the updated patch: e patches node
4. Commit the updated patch file following references/phase-one-commit-guidelines.md.

To find the original patch commit to fixup: git log --oneline | grep -i "keyword from patch name"

The base commit for rebase is the Node.js commit before patches were applied. Find it by checking the refs/patches/upstream-head ref.

B. Electron Code Fixes (for files in shell/, electron/, etc.)

When the error is in Electron's own source code:

1. Edit files directly in the electron repo
2. Commit directly (no patch export needed)

Electron Node.js Upgrade: Phase Three

Summary

Run the Node.js test suite via script/node-spec-runner.js, fix failing tests, and commit fixes until all tests pass. Certain tests are permanently disabled (listed in script/node-disabled-tests.json) and should not be run.

Run Phase Three immediately after Phase Two is complete.

Success Criteria

Phase Three is complete when:

• node script/node-spec-runner.js --default exits with zero failures
• All changes are committed per the commit guidelines

Do not stop until these criteria are met.

Context

Electron runs a subset of Node.js's upstream test suite using a custom runner (script/node-spec-runner.js). Tests are executed with the built Electron binary via ELECTRON_RUN_AS_NODE=true. Many tests need adaptation because Electron uses BoringSSL (not OpenSSL) and Chromium's V8 (which may differ from Node.js's bundled V8).

Key files:

• script/node-spec-runner.js — Test runner script
• script/node-disabled-tests.json — Permanently disabled tests (do not try to fix these)
• ../third_party/electron_node/test/ — Node.js test files (where patches apply)
• patches/node/fix_crypto_tests_to_run_with_bssl.patch — BoringSSL crypto test adaptations
• patches/node/test_formally_mark_some_tests_as_flaky.patch — Flaky test list

Workflow

1. Run node script/node-spec-runner.js --default from the electron repo
2. If all tests pass → Phase Three is complete
3. If tests fail:
   • Identify the failing test file(s) from the output
   • Analyze each failure (see "Common Failure Patterns" below)
   • Fix the test in ../third_party/electron_node/test/...
   • Re-run the specific failing test to verify: node script/node-spec-runner.js {test-path}
     • The test path is relative to the node test/ directory, e.g. test/parallel/test-crypto-key-objects-raw.js
     • Do NOT use --default when running specific tests — it adds the full suite flags
     • Do NOT run tests directly with ELECTRON_RUN_AS_NODE — the runner handles environment setup (e.g. temporarily switching package.json from ESM to CommonJS)
   • Commit the fix using the fixup workflow and commit guidelines
   • Return to step 1

Commands Reference

Common Failure Patterns

BoringSSL incompatibilities

Electron uses BoringSSL (via Chromium) instead of OpenSSL. Many crypto features are missing or behave differently:

When guarding tests, prefer checking cipher availability (ciphers.includes(algo)) over blanket BoringSSL checks where possible, as it's more precise and self-documenting.

New upstream tests that exercise these features will need guards added to the fix_crypto_tests_to_run_with_bssl patch.

Snapshot test mismatches

Some tests compare output against committed .snapshot files using assert.strictEqual — these are NOT wildcard comparisons. When Chromium's V8 produces different output (e.g. different stack traces due to V8 enhancements), the snapshot must be regenerated:

NODE_REGENERATE_SNAPSHOTS=1 node script/node-spec-runner.js test/test-runner/test-foo.mjs

Then inspect the diff to verify the changes are expected, and commit the updated snapshot into the appropriate patch.

V8 behavioral differences

Chromium's V8 may be ahead of Node.js's bundled V8. This can cause:

• Different stack trace formats (e.g. thenable async stack frames)
• Different error messages
• Features available in Chromium V8 that aren't in stock Node.js V8 (or vice versa)

Two Types of Test Fixes

A. Patch Fixes (most common for test failures)

Most test fixes go into existing patches in patches/node/. Use the fixup workflow:

1. Edit the test file in ../third_party/electron_node/test/...
2. Find the relevant patch commit: git log --oneline | grep -i "keyword"
   • Crypto/BoringSSL tests → fix crypto tests to run with bssl
   • Snapshot tests → the specific snapshot patch (e.g. test: accomodate V8 thenable)
   • Flaky tests → test: formally mark some tests as flaky
3. Create a fixup commit:

   cd ../third_party/electron_node
   git add test/path/to/test.js
   git commit --fixup=<patch-commit-hash>
   GIT_SEQUENCE_EDITOR=: git rebase --autosquash --autostash -i <commit>^
   

4. Export: e patches node
5. Read references/phase-three-commit-guidelines.md NOW, then commit the updated patch file.

B. New Patches (rare)

Only create a new patch when the fix doesn't belong in any existing patch. The new patch commit in ../third_party/electron_node must include a description explaining why the patch exists and when it can be removed — the lint check enforces this.

Adding to Disabled Tests

Only add a test to script/node-disabled-tests.json as a last resort — when the test is fundamentally incompatible with Electron's architecture (not just a BoringSSL difference that can be guarded). Tests disabled here are completely skipped and never run.

Critical: Read Before Committing

• Before ANY Phase One commits: Read references/phase-one-commit-guidelines.md
• Before ANY Phase Two commits: Read references/phase-two-commit-guidelines.md
• Before ANY Phase Three commits: Read references/phase-three-commit-guidelines.md

High-Churn Patches

These patches consistently require the most work during Node.js upgrades:

• fix_handle_boringssl_and_openssl_incompatibilities.patch — Electron uses BoringSSL (via Chromium) while Node.js expects OpenSSL. This patch is large and complex, and upstream OpenSSL API changes frequently break it.
• fix_crypto_tests_to_run_with_bssl.patch — Companion to the above; adapts Node.js crypto tests for BoringSSL. Can grow significantly during major upgrades.
• support_v8_sandboxed_pointers.patch — V8 sandbox pointer support requires careful adaptation when V8 APIs change.
• build_add_gn_build_files.patch — The GN build file patch is large and touches many build targets. Upstream build system changes frequently conflict.

Major Version Upgrades

Major Node.js version transitions (e.g., v22 → v24) are significantly more involved than patch bumps:

1. Expect patch deletions. Electron uses Chromium's V8, which is often ahead of the V8 version bundled in Node.js. Many patches exist to bridge this gap — shimming newer V8 APIs that Chromium's V8 has but Node.js' older V8 doesn't. When Node.js bumps to a newer major version, its V8 catches up to Chromium's, and those bridge patches can be deleted. In the v22 → v24 upgrade, 17 patches were deleted for this reason.
2. Update @types/node in package.json to match the new major version.
3. Post-upgrade regressions are expected. Even after the upgrade lands, follow-up fix PRs for edge cases (ESM path handling, certificate loading, platform-specific issues) are normal.

Skill Directory Structure

This skill has additional reference files in references/:

• patch-analysis.md - How to analyze patch failures
• phase-one-commit-guidelines.md - Commit format for Phase One
• phase-two-commit-guidelines.md - Commit format for Phase Two
• phase-three-commit-guidelines.md - Commit format for Phase Three

Read these when referenced in the workflow steps.