• Version: master
• Platform: *
• Subsystem: errors

Context

There is an ongoing effort to migrate all JS expectations throws by node core to have a .code property. The error code allows userland to react in different exceptions specific ways.
To that extent a new internal module (internal/errors) was created #11220 and the migration is tracked in #11273 (and to less extent in https://github.com/nodejs/node/projects/4) Some module migrations landed in node@v8.0.0, some have landed in master since, and some have yet to be migrated. Hence it can't be asserted that node core will only throw errors with an error-code, and so we have to assume the existence of userland code that depends on error.message parsing.

Issue

At present there seems to be a difference of opinions as to the semver level of changes in messages of internal/errors.

Action item

A consensus should be reached on this issue as we want to have a clear path forward, and unambiguous guidelines for contributors.

Relevant discussion

1. guides/using-internal-errors.md
   

2. internal/errors: improve ERR_INVALID_ARG_TYPE #13730 (comment)
   

3. internal/errors: improve ERR_INVALID_ARG_TYPE #13730 (comment) (landed as semver-patch but marked don't land on v8.x until discoution is concluded)
   

4. errors: improve invalid arg type #13834 (comment)
   

[EDIT by @Trott: don't land -> don't land on v8.x for clarity.]