Default a compiled executable to production mode by robobun · Pull Request #41506 · oven-sh/bun

robobun · 2026-09-06T07:32:49Z

Problem

A bun build --compile executable serves the development error page by default. Bun.serve() reports development: true, and an uncaught error in a route handler returns a 50 KB text/html page with the message, the stack (/$bunfs/root/app:7:11), and the source line. Same on 1.3.14, 1.4.0, 1.4.2, and canary.
The --compile help text says "Implies --production", but nothing sets production for a compiled executable. ServerConfig::from_js (src/runtime/server/ServerConfig.rs:639-645) only leaves development mode when the runtime NODE_ENV is production or vm.transpiler.options.production is set. The standalone boot sets neither.

Fix

apply_standalone_runtime_flags (src/bun.js.rs) now calls set_production(true) on the transpiler and resolver options unless NODE_ENV or BUN_ENV in the process env is development or test. This runs before configure_defines, so an explicit NODE_ENV still applies through the existing path. development: true in Bun.serve() still wins. Workers in the executable go through the same hook.
Visible effects: Bun.serve() defaults to development: false, and the dotenv loader picks .env.production instead of .env.development. Both match what NODE_ENV=production ./app does today.
set_production on bun_bundler::BundleOptions becomes pub so the runtime crate can call it. ServerConfig.rs is unchanged.
Verified: test/bundler/bundler_compile.test.ts (compile/ServeDefaultsToProduction, compile/ServeExplicitDevelopment) and test/bundler/bundler_compile_autoload.test.ts (compile/AutoloadDotenvProductionSuffix). All three fail on the stock binary and pass with this change. Also ran all of bundler_compile, bundler_compile_autoload, compile-argv, and bun-serve-html (153 pass).

Background

options.production is the transpiler flag that bun run derives from NODE_ENV=production. ServerConfig::from_js reads it to pick the Bun.serve default, and run_env_loader reads it to pick the .env.<suffix> file.
apply_standalone_runtime_flags is the hook that applies the executable's embedded flags (dotenv, tsconfig, package.json autoload) to the transpiler at boot, before configure_defines loads the env.
Not changed: the bundler still inlines process.env.NODE_ENV as the build-time value ("development" when unset), so code that checks process.env.NODE_ENV !== "production" inside the executable still sees development. bun build --compile: read NODE_ENV at runtime, set argv[0] to the executable path #32851 makes that a runtime read. compile: do not inline NODE_ENV into runtime-transpiled files when .env autoload is off #38672 edits the same hook for the autoload-off case and will need a small rebase.

Notes

Repro on 1.4.3-canary:

const srv = Bun.serve({ port: 0, routes: { "/boom": () => { throw new Error("secret-stack-detail"); } }, fetch: () => new Response("nf", { status: 404 }) });
const r = await fetch(`${srv.url}boom`, { headers: { accept: "text/html" } });
console.log({ dev: srv.development, ct: r.headers.get("content-type"), leaks: (await r.text()).includes("secret-stack-detail") });

bun build --compile app.ts --outfile app && ./app printed { dev: true, ct: "text/html;charset=utf-8", leaks: true }. NODE_ENV=production ./app printed { dev: false, ct: "text/plain", leaks: false }.

A first version set the default in ServerConfig::from_js only. Review moved it to the standalone boot hook so it uses the existing production flag, honours BUN_ENV, and does not duplicate the NODE_ENV parsing in configure_defines.

NODE_ENV=test keeps the non-production default so a compiled executable under a test runner behaves like bun run.

Related: #26373 (the help text promise), #32851 (runtime NODE_ENV read), #38672 (same hook, autoload-off inlining).

Self-reviewed: 2 concerns raised. The split-brain with the inlined process.env.NODE_ENV is pre-existing and tracked by #32851, so this change documents it instead of widening scope. The overlap with #38672 is a small merge in one function.

no test proof · iteration 5 · platform-specific test(s) that do not run on this machine, deferring to CI, which covers all platforms: test/bundler/bundler_compile.test.ts

coderabbitai · 2026-09-06T07:32:56Z

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📥 Commits

Reviewing files that changed from the base of the PR and between d316760 and ae117b5.

📒 Files selected for processing (7)

docs/bundler/executables.mdx
packages/bun-types/serve.d.ts
src/bun.js.rs
src/bundler/options.rs
test/bundler/bundler_compile.test.ts
test/bundler/bundler_compile_autoload.test.ts
test/bundler/expectBundled.ts

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robobun · 2026-09-06T07:32:58Z

Status: reproduced on 1.4.3-canary (compiled exe serves the dev error page by default, NODE_ENV=production ./app does not). Fix is in apply_standalone_runtime_flags. Tests: compile/ServeDefaultsToProduction, compile/ServeExplicitDevelopment, compile/AutoloadDotenvProductionSuffix.

CI: the new tests and every compile lane pass on each run. The remaining red is unrelated to this diff and changes from run to run (test-crypto-dh-leak.js on x64-asan, which also fails on main, and retried flakes on Windows and Alpine lanes). Ready for review.

robobun · 2026-09-06T07:33:08Z

^{Updated 6:27 AM PT - Sep 6th, 2026}

❌ @robobun, your commit ae117b5 has 18 failures in Build #111139 (All Failures):

test/bundler/transpiler/transpiler.test.js - spawn error on 🍎 any x64
test/bundler/transpiler/transpiler-stack-overflow.test.ts - spawn error on 🍎 any x64
test/bundler/bundler_compile_autoload.test.ts - code 1 on 🍎 any x64
test/bundler/transpiler/runtime-transpiler.test.ts - code 1 on 🍎 any x64
test/bundler/transpiler/jsx-production.test.ts - code 1 on 🍎 any x64
test/bundler/resolver/cache-invalidation.test.ts - code 1 on 🍎 any x64
test/bundler/esbuild/importstar_ts.test.ts - code 1 on 🍎 any x64
test/bundler/esbuild/extra.test.ts - code 1 on 🍎 any x64
test/bundler/esbuild/css.test.ts - code 1 on 🍎 any x64
test/bundler/compile-windows-metadata.test.ts - code 1 on 🍎 any x64
test/bundler/bundler_splitting.test.ts - code 1 on 🍎 any x64
test/bundler/bundler_html_server.test.ts - code 1 on 🍎 any x64
test/bundler/bundler_edgecase.test.ts - code 1 on 🍎 any x64
test/bake/dev/stress.test.ts - code 1 on 🍎 any x64
test/bake/dev/ssg-pages-router.test.ts - code 1 on 🍎 any x64
test/bake/dev/hot.test.ts - code 1: [bake-harness] client subprocess failed to connect (attempt 1): Process exited (code=null) before… on 🍎 any x64
test/js/bun/http/bun-serve-static.test.ts - 1 failing in the parallel batch on 🍎 any aarch64
test/js/node/test/parallel/test-crypto-dh-leak.js - code 1 on 🐧 13 x64-asan

🧪 To try this PR locally:

bunx bun-pr 41506

That installs a local version of the PR into your bun-41506 executable, so you can run:

bun-41506 --bun

claude

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

claude

Nothing blocking. The comments below are optional suggestions. There is no need to push a fix for them before merging.

claude

Code review found no issues

No high-confidence issues detected in this change.

A bun build --compile executable never set the production flag on the transpiler, so Bun.serve defaulted to development mode and served the dev error page (message, stack, source) for an uncaught route error, and the dotenv loader picked .env.development. Set production in apply_standalone_runtime_flags unless NODE_ENV or BUN_ENV is development or test. configure_defines still honours an explicit NODE_ENV afterwards, and development: true in Bun.serve still wins.

claude

Code review found no issues

No high-confidence issues detected in this change.

robobun requested a review from alii as a code owner September 6, 2026 07:32

robobun assigned Jarred-Sumner Sep 6, 2026

github-actions Bot added the claude label Sep 6, 2026

claude Bot reviewed Sep 6, 2026

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Comment thread docs/bundler/executables.mdx Outdated

Comment thread test/bundler/bundler_compile.test.ts

github-actions Bot reviewed Sep 6, 2026

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Comment thread src/bun.js.rs Outdated

claude Bot reviewed Sep 6, 2026

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robobun mentioned this pull request Sep 6, 2026

test(bundler): speed up bundler_compile_autoload.test.ts and tighten its assertions #41583

Open

robobun added 5 commits September 6, 2026 10:35

docs: state the compiled executable NODE_ENV default precisely

e9ceedb

Cover NODE_ENV=test and other values in the compiled serve default test

647c843

Shorten the standalone production comment

ceaa4aa

Clear BUN_ENV in the compiled production default tests

ae117b5

robobun force-pushed the robobun/47c1050e/compile-serve-production-default branch from fbf7137 to ae117b5 Compare September 6, 2026 10:43

claude Bot reviewed Sep 6, 2026

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robobun mentioned this pull request Sep 8, 2026

Bun.serve: decide the development default from the live process.env #41926

Open

robobun mentioned this pull request Oct 13, 2026

bun build --production: write NODE_ENV after the process environment loads #45101

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Default a compiled executable to production mode - #41506

Default a compiled executable to production mode#41506
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