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bundler: detect module.exports=require() redirect through a constant-test if/else #35611

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ef2deaf
bundler: detect module.exports=require() redirect through a constant-…
robobun Aug 1, 2026
916f6cb
Merge branch 'main' into farm/af8da350/bundler-cjs-redirect-through-if
Jarred-Sumner Aug 6, 2026
79f05d6
Adapt to SideEffects::to_boolean returning Option<Known>
robobun Aug 6, 2026
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43 changes: 42 additions & 1 deletion src/js_parser/parse/parse_entry.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ use crate::parser::{
Jest, ParseStatementOptions, RuntimeFeatures, RuntimeImports, ScanPassResult, StatementScope,
WrapMode,
};
use crate::scan::scan_side_effects::SideEffects;
use bun_ast as js_ast;
use bun_ast::DeclaredSymbol;
use bun_ast::{B, E, Expr, G, S, Stmt};
Expand Down Expand Up @@ -1252,7 +1253,47 @@ impl<'a> Parser<'a> {
found
};
if let Some(found) = stmt_and_part {
let stmt = found.stmt;
let mut stmt = found.stmt;
// Without --minify-syntax the NODE_ENV if/else above survives
// as `if (<const>) {} else { X }` after DCE empties the dead
// arm; peel to the live arm's single statement. `to_boolean` is
// the same predicate `s_if` used to pick the dead arm.
Comment thread
robobun marked this conversation as resolved.
while let js_ast::StmtData::SIf(s_if) = &stmt.data {
let Some(effects) = SideEffects::to_boolean(p, &s_if.test.data) else {
break;
};
if effects.side_effects != SideEffects::NoSideEffects {
break;
}
let (live, dead) = if effects.value {
(Some(s_if.yes), s_if.no)
} else {
(s_if.no, Some(s_if.yes))
};
let dead_is_empty = match dead {
None => true,
Some(d) => match d.data {
js_ast::StmtData::SEmpty(_) => true,
js_ast::StmtData::SBlock(block) => block.stmts.len() == 0,
_ => false,
},
};
if !dead_is_empty {
break;
}
let Some(live_stmt) = live else { break };
match live_stmt.data {
js_ast::StmtData::SBlock(block) => {
let body = block.stmts.slice();
if body.len() != 1 {
break;
}
stmt = body[0];
}
js_ast::StmtData::SEmpty(_) => break,
_ => stmt = live_stmt,
}
}
let part = &mut parts[found.part_idx];
if p.symbols.as_slice()[p.module_ref.inner_index() as usize].use_count_estimate == 1
{
Expand Down
187 changes: 187 additions & 0 deletions test/bundler/bundler_cjs2esm.test.ts
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Expand Up @@ -200,6 +200,193 @@ describe("bundler", () => {
stdout: "development",
},
});
// https://github.com/oven-sh/bun/issues/12726
itBundled("cjs2esm/ModuleExportsBasedOnNodeEnvProductionNoMinify", {
files: {
"/entry.js": /* js */ `
import { foo } from 'lib';
console.log(foo);
`,
"/node_modules/lib/index.js": /* js */ `
'use strict';
if (process.env.NODE_ENV === 'production') {
module.exports = require('./library.prod.js')
} else {
module.exports = require('./library.dev.js')
}
`,
"/node_modules/lib/library.prod.js": /* js */ `
module.exports.foo = 'production';
`,
"/node_modules/lib/library.dev.js": /* js */ `
module.exports.foo = 'FAILED';
`,
},
cjs2esm: true,
env: {
NODE_ENV: "production",
},
run: {
stdout: "production",
},
});
itBundled("cjs2esm/ModuleExportsBasedOnNodeEnvDevelopmentNoMinify", {
files: {
"/entry.js": /* js */ `
import { foo } from 'lib';
console.log(foo);
`,
"/node_modules/lib/index.js": /* js */ `
'use strict';
if (process.env.NODE_ENV === 'production') {
module.exports = require('./library.prod.js')
} else {
module.exports = require('./library.dev.js')
}
`,
"/node_modules/lib/library.prod.js": /* js */ `
module.exports.foo = 'FAILED';
`,
"/node_modules/lib/library.dev.js": /* js */ `
module.exports.foo = 'development';
`,
},
cjs2esm: true,
env: {
NODE_ENV: "development",
},
run: {
stdout: "development",
},
});
itBundled("cjs2esm/ModuleExportsBasedOnNodeEnvNoBracesNoMinify", {
files: {
"/entry.js": /* js */ `
import { foo } from 'lib';
console.log(foo);
`,
"/node_modules/lib/index.js": /* js */ `
if (process.env.NODE_ENV === 'production')
module.exports = require('./library.prod.js')
else
module.exports = require('./library.dev.js')
`,
"/node_modules/lib/library.prod.js": /* js */ `
module.exports.foo = 'FAILED';
`,
"/node_modules/lib/library.dev.js": /* js */ `
module.exports.foo = 'development';
`,
},
cjs2esm: true,
env: {
NODE_ENV: "development",
},
run: {
stdout: "development",
},
});
itBundled("cjs2esm/ModuleExportsBasedOnDefineNumberNoMinify", {
files: {
"/entry.js": /* js */ `
import { foo } from 'lib';
console.log(foo);
`,
"/node_modules/lib/index.js": /* js */ `
if (__DEV__) {
module.exports = require('./library.dev.js')
} else {
module.exports = require('./library.prod.js')
}
`,
"/node_modules/lib/library.prod.js": /* js */ `
module.exports.foo = 'production';
`,
"/node_modules/lib/library.dev.js": /* js */ `
module.exports.foo = 'FAILED';
`,
},
cjs2esm: true,
define: {
__DEV__: "0",
},
run: {
stdout: "production",
},
});
itBundled("cjs2esm/ModuleExportsBasedOnNodeEnvElseIfChainNoMinify", {
files: {
"/entry.js": /* js */ `
import { foo } from 'lib';
console.log(foo);
`,
"/node_modules/lib/index.js": /* js */ `
if (process.env.NODE_ENV === 'production') {
module.exports = require('./library.prod.js')
} else if (process.env.NODE_ENV === 'test') {
module.exports = require('./library.test.js')
} else {
module.exports = require('./library.dev.js')
}
`,
"/node_modules/lib/library.prod.js": /* js */ `
module.exports.foo = 'FAILED';
`,
"/node_modules/lib/library.test.js": /* js */ `
module.exports.foo = 'FAILED';
`,
"/node_modules/lib/library.dev.js": /* js */ `
module.exports.foo = 'development';
`,
},
cjs2esm: true,
env: {
NODE_ENV: "development",
},
run: {
stdout: "development",
},
});
itBundled("cjs2esm/ReactIndexNodeEnvRedirectNoMinify", {
files: {
"/entry.js": /* js */ `
const react = require("react");
console.log(react.version);
`,
"/node_modules/react/package.json": /* json */ `
{ "name": "react", "version": "18.3.1", "main": "./index.js" }
`,
"/node_modules/react/index.js": /* js */ `
'use strict';

if (process.env.NODE_ENV === 'production') {
module.exports = require('./cjs/react.production.min.js');
} else {
module.exports = require('./cjs/react.development.js');
}
`,
"/node_modules/react/cjs/react.production.min.js": /* js */ `
exports.version = 'FAILED';
`,
"/node_modules/react/cjs/react.development.js": /* js */ `
exports.version = '18.3.1-dev';
`,
},
target: "bun",
env: {
NODE_ENV: "development",
},
onAfterBundle(api) {
const code = api.readFile("out.js");
expect(code).not.toContain("react/index.js");
expect(code).not.toContain("require_react ");
expect(code).not.toContain("require_react(");
expect(code).not.toContain("react.production.min.js");
},
run: {
stdout: "18.3.1-dev",
},
});
itBundled("cjs2esm/ModuleExportsEqualsRuntimeCondition", {
files: {
"/entry.js": /* js */ `
Expand Down
4 changes: 2 additions & 2 deletions test/bundler/transpiler/jsx-dev/jsx-dev.tsx
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Expand Up @@ -21,13 +21,13 @@ if (!process.env.NO_BUILD) {
let shouldHaveJSX = process.env.CHILD_NODE_ENV === "production";

if (shouldHaveJSXDev) {
if (!code.includes("jsx_dev_runtime.jsxDEV")) {
if (!code.includes("jsx-dev-runtime.development") || !code.includes("jsxDEV(")) {
throw new Error("jsxDEV is not included");
}
}

if (shouldHaveJSX) {
if (!code.includes("jsx_runtime.jsx")) {
if (!code.includes("jsx-runtime.production") || code.includes("jsxDEV(")) {
throw new Error("Jsx is not included");
}
}
Expand Down
4 changes: 2 additions & 2 deletions test/bundler/transpiler/jsx-production.tsx
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Original file line number Diff line number Diff line change
Expand Up @@ -21,13 +21,13 @@ if (!process.env.NO_BUILD) {
let shouldHaveJSX = process.env.CHILD_NODE_ENV === "production";

if (shouldHaveJSXDev) {
if (!code.includes("jsx_dev_runtime.jsxDEV")) {
if (!code.includes("jsx-dev-runtime.development") || !code.includes("jsxDEV(")) {
throw new Error("jsxDEV is not included");
}
}

if (shouldHaveJSX) {
if (!code.includes("jsx_runtime.jsx")) {
if (!code.includes("jsx-runtime.production") || code.includes("jsxDEV(")) {
throw new Error("Jsx is not included");
}
}
Expand Down