`fs.readdir`'s new `recursive` option is not fully documented

[chris-sophos]

Affected URL(s)

https://nodejs.org/dist/latest-v20.x/docs/api/fs.html#fspromisesreaddirpath-options and callback/synchronous versions

Description of the problem

From testing, the recursive option does not work with withFileTypes: true.
The behavior of the recursive option is not documented, and only recursive's type and default value are present in the documentation. The callback-async fs.readdir and the synchronous fs.readdirSync yield erraneous results (entries missing or appear with missing fields) when both recursive and withFileTypes are supplied.

This issue tracks missing documentation. Incorrect behavior is tracked at #48858.

[anonrig]

cc @Ethan-Arrowood

[pernelkanic]

can i work on this?

[Ethan-Arrowood]

Can you share the case where it doesn't work with withFileTypes? I added a multitude of tests when I landed the option so I wanna know what I missed

[targos]

Btw it looks more like a bug than a documentation issue.

[chris-sophos]

Btw it looks more like a bug than a documentation issue.

No documentation is provided for recursive regardless, so I think it's still an issue. Maybe I should have filed the lack of documentation and the bug separately.

Can I work on this, it will be my first issue.

[chris-sophos]

@Ethan-Arrowood From further testing, I've found some behavior that varies between the promise, callback, and synchronous versions.

• The promise version appears to not have any issues.

• The callback and synchronous versions can generate a entry Dirent { name: undefined, path: '...', [Symbol(type)]: undefined }, when withFileTypes is supplied, replacing a valid entry.

• The callback and synchronous versions fail to list certain files and directories when both withFileTypes and recursive are provided. I noticed this as several entries under .git missing, I'm unsure what the cause is.

  Note: Since nested directories themselves are not listed, these issues are likely not related to the recursion step as I had previously assumed, however this behavior is only present when recursive is also supplied and is not present in previous versions (Tested on Node v18.16.1.). I will update the original message to reflect this.

A minor inconsistency I found is that when providing the results the promise version appears to act as depth-first, while the callback and synchronous versions act as breath-first in their resulting arrays.

These tests have been on a limited filetree which I've uploaded to fs-readdir-recursive.

[Ethan-Arrowood]

Okay I can confirm there are two issues here.

First, missing documentation for the recursive option for the callback and sync versions.

Second, I am seeing the undefined behavior in the callback and sync versions; I think your latest message @That-Guy977 explains it well. What I'm most intrigued by is how the tests aren't catching this. We definitely need to fix this. I'm going to start investigating this problem now.

Finally, I do not believe the difference in search behavior matters. We make no guarantees in how Node recursively searches a directory. In a long historical thread I commented the possibility of specifying which algorithm could be used, but that is a feature not a bug in this case.

Some users here expressed interest in contributing, @pernelkanic you commented first. Would you like to work on the documentation fix?

[chris-sophos]

First, missing documentation for the recursive option for the callback and sync versions.

I believe the promise version has the same lack of documentation, as it and the other versions are lacking a similar description as opendir or rm, or even an explanation in the method description as is present in mkdir.

[Ethan-Arrowood]

Oh good point 👍 that should be fixed too then