feat(unenv-preset): add native node:repl module support

[petebacondarwin]

Devin PR requested by @petebacondarwin

Adds support for the native node:repl module from workerd when the enable_nodejs_repl_module and experimental compatibility flags are enabled. This follows the same pattern as other experimental modules (inspector, sqlite, dgram, stream_wrap).

The native code appears in workerd as of https://github.com/cloudflare/workerd/blob/main/src/node/repl.ts. It is currently experimental with no default enable date.

Implementation Comparison

Export	workerd	unenv	node.js	Breaking change?
writer	throws ERR_METHOD_NOT_IMPLEMENTED	throws "not implemented"	full implementation	No (both throw)
start	throws ERR_METHOD_NOT_IMPLEMENTED	throws "not implemented"	full implementation	No (both throw)
Recoverable	class extending SyntaxError	notImplementedClass	full implementation	No (both throw on use)
REPLServer	class, constructor throws	notImplementedClass	full implementation	No (both throw on use)
REPL_MODE_SLOPPY	unique symbol	unique symbol	unique symbol	No (same)
REPL_MODE_STRICT	unique symbol	unique symbol	unique symbol	No (same)
builtinModules	array of module names	array from node:module	array of module names	No (same)
_builtinLibs	alias for builtinModules	alias for builtinModules	alias for builtinModules	No (same)

Breaking change analysis: There are no breaking changes when moving from unenv to workerd. Both implementations throw errors for the main functions (writer, start, REPLServer, Recoverable). The only difference is the error type/message - workerd throws ERR_METHOD_NOT_IMPLEMENTED (Node.js style) while unenv throws a generic "not implemented" error. The workerd implementation is moving closer to Node.js by using proper Node.js error codes.

Updates since last revision

• Refactored test code to use assertTypeOfProperties for symbol assertions (REPL_MODE_SLOPPY, REPL_MODE_STRICT) per review feedback

Human Review Checklist

• Verify the getReplOverrides() function follows the same pattern as other experimental modules
• Confirm the test regex /not implemented|ERR_METHOD_NOT_IMPLEMENTED/ correctly handles both error types

Link to Devin run

---

• Tests
  • Tests included/updated
  • Automated tests not possible - manual testing has been completed as follows:
  • Additional testing not necessary because:
• Public documentation
  • Cloudflare docs PR(s):
  • Documentation not necessary because: internal experimental feature, follows existing patterns
• Wrangler V3 Backport
  • Wrangler PR:
  • Not necessary because: unenv-preset is not backported

---

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[changeset-bot]

🦋 Changeset detected

Latest commit: 9ef23b8

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commit: 9ef23b8

[vicb]

LGTM, one nit

[vicb]

nit: we could factor code

for (const target of [repl, repl.default]) {
  assertTypeOfProperties(target, { ... });
}

we could also do that across the file

[petebacondarwin]

I can do that in a general refactor PR afterwards?

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

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