feat: add custom error handler

[etnoy]

What is the purpose of this pull request?

Add the option to suppress EACCES, permission denied errors.

This is an error we're seeing in Immich when fast-glob is crawling a directory that contains items that we lack read permission for. We don't want to error out and stop crawling, and we don't want to suppress all errors. This is a reasonable middle road that adds an option, suppressEaccess

Ref: immich-app/immich#12713

In the above bug, a user has a few files in their NAS that wan't accessible. This throws out the whole crawl process even though only a few items are missing

What changes did you make? (Give an overview)

Add option suppressEacces
Add more conditions in isNonFatalError and _isFatalError
Added documentation in README

[benmccann]

I wonder if an error handling function might be a better solution to this problem. Then you could choose which types of errors to ignore vs error on, etc. Otherwise you might end up with a new option for each type of error that could be encountered

[etnoy]

I wonder if an error handling function might be a better solution to this problem. Then you could choose which types of errors to ignore vs error on, etc. Otherwise you might end up with a new option for each type of error that could be encountered

That could work, but I'm trying to figure out what further errors a user might want to filter out beyond the permission error. I can only think of EMFILE and EINVAL, both of which are pretty fatal to any further globbing.

Maybe we can look at a refactor of this as a follow-up?

Also, maybe we should add a log warning to any file that was skipped due to EACCES?

[benmccann]

I'm trying to figure out what further errors a user might want to filter out beyond the permission error.

Perhaps ENOENT if a file/directory is deleted during globbing. I'm not sure if it's possible to trigger it not

Maybe we can look at a refactor of this as a follow-up?

I don't think you'd want to change the option in that manner in a follow up as it'd be a breaking change. Better to do it up front

Also, maybe we should add a log warning to any file that was skipped due to EACCES?

That's the beauty of making it a function. Some users can silently proceed while others can log an error with their logging framework of choice

[etnoy]

Thanks for your feedback. I've pushed some changes that allows the user to supply an error handler function.

In Immich, we'll use it something like this:

From my testing it seems to work very well, and also allows us to log warnings if we get ENOENT or EACCES.

Let me know if this seems to be the correct approach and I'll make sure everything is cleaned up and nice

[etnoy]

Hello @mrmlnc , what is your opinion of this PR so far? Thanks