vercel/ncc

Regression: dynamic runtime `require` works in 0.38.1 but breaks in 0.38.2

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#1,312 opened on Mar 16, 2026

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Description

0.38.1

I have the following source code:

https://github.com/CatChen/eslint-suggestion-action/blob/930479a34a06bfa384291cc877f9d1ce21533ae1/src/getESLint.ts#L16-L19

The dynamic require is compiled into the following code:

https://github.com/CatChen/eslint-suggestion-action/blob/930479a34a06bfa384291cc877f9d1ce21533ae1/bundle/index.js#L37587

0.38.2

The same code is compiled into the following code since 0.38.2:

https://github.com/CatChen/eslint-suggestion-action/blob/bc0de7fa625de9daf56cca84b6084f4d6bcbaca4/bundle/index.js#L37702

Workaround

My current workaround is to use dynamic import inside a new Function() (because dynamic import isn't supported either). I have to change to code into this:

https://github.com/CatChen/eslint-suggestion-action/blob/927208b2e684b1a7c721f4a0e70d4f4e8c11c228/src/getESLint.ts#L15-L26

Contributor guide

Research direction
Compare the bundled output between versions 0.38.1 and 0.38.2 for the dynamic require pattern. Identify what changed in ncc's handling of dynamic requires and locate the relevant code change that caused the regression.
Tech stack
javascript
Domain
build system
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JavaScriptNode.jsncc
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40