fix: clean up ESM registry when require() of ESM module fails

[robobun]

Summary

• When require() loads an ESM module (.mjs) that throws during evaluation, the module was removed from requireMap but left in the ESM registry (Loader.registry) in a partially-initialized state
• A subsequent import() of the same module would find this corrupt entry and throw ReferenceError: Cannot access 'foo' before initialization instead of re-throwing the original evaluation error
• Fix by also deleting the module from Loader.registry in both overridableRequire and requireESMFromHijackedExtension when ESM evaluation fails, allowing import() to re-evaluate from scratch

Closes #27287

Test plan

• Added regression test in test/regression/issue/27287.test.ts
• Verified test fails with system bun (USE_SYSTEM_BUN=1)
• Verified test passes with bun bd test
• Manual verification: require() correctly throws original error, import() now re-throws the same error instead of ReferenceError

🤖 Generated with Claude Code

[robobun]

^{Updated 10:43 AM PT - Feb 20th, 2026}

❌ @alii, your commit c17ded7 has 5 failures in Build #37738 (All Failures):

• test/integration/next-pages/test/dev-server.test.ts - 1 failing on 🍎 13 aarch64
• test/integration/next-pages/test/dev-server.test.ts - 1 failing on 🍎 14 aarch64
• test/regression/issue/12910/12910.test.ts - 1 failing on 🐧 13 x64-asan
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🪟 11 aarch64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🪟 2019 x64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🪟 2019 x64-baseline
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 25.04 aarch64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 13 aarch64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 3.23 x64-baseline
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 25.04 x64-baseline
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🍎 14 x64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 13 x64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 25.04 x64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 13 x64-asan
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 13 x64-baseline
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 3.23 x64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🍎 13 x64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🐧 3.23 aarch64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🍎 14 aarch64
• test/js/third_party/mongodb/mongodb.test.ts - 1 failing on 🍎 13 aarch64
• test/regression/issue/11297/11297.test.ts - 1 failing on 🪟 2019 x64
• test/regression/issue/11297/11297.test.ts - 1 failing on 🪟 11 aarch64
• test/regression/issue/24364.test.ts - 1 failing on 🪟 11 aarch64

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🧪   To try this PR locally:

bunx bun-pr 27288

That installs a local version of the PR into your bun-27288 executable, so you can run:

bun-27288 --bun

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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Walkthrough

The changes fix a bug where requiring a failing ESM module via CommonJS would leave it in a partially-initialized state in the ESM registry. The fix ensures failed modules are fully cleared from both the require map and ESM registry on error, allowing subsequent imports to re-evaluate the module from scratch.

Changes

Cohort / File(s)	Summary
ESM/CJS Error Handling Fix src/js/builtins/CommonJS.ts	Added cleanup of the ESM registry (Loader.registry.$delete(id)) alongside the existing $requireMap deletion when errors occur during require() calls in both the overridableRequire and requireESMFromHijackedExtension code paths.
Regression Test for Issue #27287 test/regression/issue/27287.test.ts	Added comprehensive regression test verifying that requiring a failing ESM module via CJS does not corrupt state for subsequent dynamic imports. Tests error propagation, exit codes, and absence of ReferenceErrors in output.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: fixing ESM registry cleanup when require() of an ESM module fails.
Description check	✅ Passed	The description covers both required sections: 'What does this PR do?' (detailed summary of the problem and fix) and 'How did you verify your code works?' (test plan with verification steps).
Linked Issues check	✅ Passed	The PR implementation directly addresses issue #27287 by fixing the core problem: deleting modules from Loader.registry when ESM evaluation fails, allowing subsequent imports to re-evaluate from scratch instead of hitting uninitialized state.
Out of Scope Changes check	✅ Passed	All changes are in scope: modifications to CommonJS.ts fix the registry cleanup issue, and the regression test in 27287.test.ts directly validates the fix for the linked issue.

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[claude]

Newest first

✅ c17de — Looks good!

Reviewed 2 files across src/js/builtins/ and test/regression/issue/: Fixes a bug where CJS require() of a failing ESM module left a corrupted entry in the ESM registry, causing subsequent import() calls to fail with a ReferenceError; the fix ensures cleanup of both the require map and ESM registry on failure.

Previous reviews

✅ 68641 — Looks good!

Reviewed 2 files across src/js/builtins/ and test/regression/issue/: Adds cleanup of the ESM registry when require() of an ESM module fails, ensuring subsequent import() calls can re-evaluate the module properly.