(node:68141) Warning: Closing file descriptor NNN on garbage collection

[aradzie]

This warning appears when I am trying to read exif data from a large collection of files. It seems like Exifr does not close file handles.

Example code:

await exifr.parse("filename.jpeg", true)

[boxymoron]

I am experiencing the same when parsing a PNG file. The error is 'Error: Unknown file format' followed by 'Warning: Closing file descriptor 35 on garbage collection'

[adhamu]

Is there any update on this?

For reference, I am using the code like so on Node v14.15.5

const getFileModifiedTime = (file: string): Date => {
  const stats = statSync(file)

  return stats.mtime
}

export const getModifiedTime = async (file: string): Promise<Date> => {
  try {
    const output = await exifr.parse(file)

    return output?.DateTimeOriginal ?? getFileModifiedTime(file)
  } catch {
    return getFileModifiedTime(file)
  }
}

Which gives warnings like below:

(node:3306326) Warning: Closing file descriptor 196 on garbage collection
(Use node --trace-warnings ... to show where the warning was created)
(node:3306326) [DEP0137] DeprecationWarning: Closing a FileHandle object on garbage collection is deprecated. Please close FileHandle objects explicitly using FileHandle.prototype.close(). In the future, an error will be thrown if a file descriptor is closed during garbage collection.

This does happen, as @boxymoron says, when a PNG is parsed. Logging out the error in the catch gives the Unknown file format message already mentioned

[MikeKovarik]

Hello. Thanks for reaching out.
I'm sorry for responding late. As always, I can only find a few hours throughout the week to work on my projects and I'm currently occupied by finding a new job and PR #57.

Thanks for providing the info. @adhamu I suppose you call the getModifiedTime() method on a large ammount of files all at once, right?

I'm currently working on the code responsible for opening (and apparently not closing) files in PR #57 . But I can't assure it'll fix the problem.

[adhamu]

Thanks @MikeKovarik.

I have run this code against 100s of JPGs at a time and all works fine. It's only when a PNG (like a screenshot) is parsed, I get the warning.

Hopefully, your PR fixes it 👍

[MikeKovarik]

And exifr version are you using?

I tried running similar code to yours on a folder of about 170 png screenshots and I couldn't replicate it. Neither on windows nor wsl ubuntu. With the latest node 15 and current exifr 6.1.1.

As a matter of fact I remember these warnings occasionally occurring when running tests but it's no longer present there either.

[adhamu]

I'm using "exifr": "^6.1.1",

I'm struggling to reliably reproduce this myself.

[adhamu]

Ok found out why. I think when an unsupported file is attempted to be parsed, I get the warning.

I ran the code against a mix of file types including jpeg, png, gif, html, psd, and logged out the filename in the catch

image.gif [Error: Unknown file format]
image.psd [Error: Unknown file format]
(node:5033) Warning: Closing file descriptor 23 on garbage collection
(Use node --trace-warnings ... to show where the warning was created)
(node:5033) [DEP0137] DeprecationWarning: Closing a FileHandle object on garbage collection is deprecated. Please close FileHandle objects explicitly using FileHandle.prototype.close(). In the future, an error will be thrown if a file descriptor is closed during garbage collection.
(node:5033) Warning: Closing file descriptor 89 on garbage collection
image.html [Error: Unknown file format]
image-2.html [Error: Unknown file format]

[MikeKovarik]

Aaaaah :D so that's what's happening.
It's somewhere between a bug and not-a-bug but I'll fix it. I was about to release new minor version. Gues it'll have to wait a few more minutes :D

[adhamu]

Nice one. Cheers @MikeKovarik 👍

[MikeKovarik]

Closed with the latest commit. Thanks @adhamu for pin this down.