Allow extensionless document in a strict site

[ashmaroli]

• This is a 🐛 bug fix.
• I've added tests

Background

Jekyll allows Documents in a custom collection to be without an extension (even if Markdown content in it won't get converted).
But in Jekyll 4.0, such documents output an error:

Error: could not read file source/_foo/bar: undefined method `gsub!' for nil:NilClass

But building proceeds since the error is rescued away.
However, if the site has been configured with strict_front_matter: true, the build aborts on error.

Summary

Ensure a non-nil slug for extensionless document in a custom collection and not abort builds with strict_front_matter: true.
Extensionless document inside _posts continue to remain unread.

[DirtyF]

I don't really remember why we allow extensionless documents in collection :)

[ashmaroli]

why we allow extensionless documents in collection

@DirtyF I tested down until Jekyll 3.6..
It doesn't look like if we ever explicitly supported extensionless documents in a collection.. 🤷‍♂️

[DirtyF]

We should rather aim at removing those discrepancies and align on posts behavior for extensionless documents.

[ashmaroli]

aim at removing those discrepancies and align on posts behavior for extensionless documents

Could you clarify with an example scenario..?

[DirtyF]

I haven't got a specific scenario in mind, where you would need to have extensionless files in a collection, do you?

[DirtyF]

@jekyll: merge +fix