[gallery-dl][error]: error in 'metadata.extension' and 'metadata.extension-format' (KeyError - 'extension')

[rod-giovany]

I was editing options when an error appeared and now no files download, this bug jump;
NT: my english is bad.

C:\Users\Jonathan>gallery-dl --verbose https://www.newgrounds.com/portal/view/740431
[gallery-dl][debug] Version 1.16.4
[gallery-dl][debug] Python 3.9.1 - Windows-10-10.0.19041-SP0
[gallery-dl][debug] requests 2.25.1 - urllib3 1.26.3
[gallery-dl][debug] Starting DownloadJob for 'https://www.newgrounds.com/portal/view/740431'
[newgrounds][debug] Using NewgroundsMediaExtractor for 'https://www.newgrounds.com/portal/view/740431'
[urllib3.connectionpool][debug] Starting new HTTPS connection (1): www.newgrounds.com:443
[urllib3.connectionpool][debug] https://www.newgrounds.com:443 "GET /portal/view/740431/format/flash HTTP/1.1" 200 12831
[urllib3.connectionpool][debug] https://www.newgrounds.com:443 "GET /portal/video/740431 HTTP/1.1" 200 246
[newgrounds][debug] Active postprocessor modules: [MetadataPP, ClassifyPP]
[newgrounds][error] An unexpected error occurred: KeyError - 'extension'. Please run gallery-dl again with the --verbose flag, copy its output and report this issue on https://github.com/mikf/gallery-dl/issues .
[newgrounds][debug]
Traceback (most recent call last):
  File "C:\Users\Jonathan\AppData\Local\Programs\Python\Python39\lib\site-packages\gallery_dl\job.py", line 69, in run
    self.dispatch(msg)
  File "C:\Users\Jonathan\AppData\Local\Programs\Python\Python39\lib\site-packages\gallery_dl\job.py", line 107, in dispatch
    self.handle_directory(msg[1])
  File "C:\Users\Jonathan\AppData\Local\Programs\Python\Python39\lib\site-packages\gallery_dl\job.py", line 276, in handle_directory
    self.initialize(kwdict)
  File "C:\Users\Jonathan\AppData\Local\Programs\Python\Python39\lib\site-packages\gallery_dl\job.py", line 452, in initialize
    callback(pathfmt)
  File "C:\Users\Jonathan\AppData\Local\Programs\Python\Python39\lib\site-packages\gallery_dl\postprocessor\metadata.py", line 69, in run
    path = directory + self._filename(pathfmt)
  File "C:\Users\Jonathan\AppData\Local\Programs\Python\Python39\lib\site-packages\gallery_dl\postprocessor\metadata.py", line 94, in _filename_extfmt
    ext = kwdict["extension"]
KeyError: 'extension'

It seems that the cause of the error is the command: metadata.extension-format and metadata.extension, every time I use it.
I know that the error refers to newgrounds and the code to deviantart, but the error is repeated regardless of which page it is used.
My configuration file would be more or less like this:

{
  "extractor": {
    "deviantart": {
      "username": "mich3218",
      "password": "5514602414",
      "journals": "none",
      "filename": "{filename}.{extension}",
      "base-directory": "~\\gallery-dl\\deviantart",
      "include": [
        "gallery",
        "scraps"
      ],
      "folders": true,
      "extra": true,
      "client-id": "<client-id>",
      "client-secret": "<client-secret>",
      "refresh-token": "cache",
      "cookies": "~\\gallery-dl\\deviantart.com_cookies.txt",
      "cookies-update": true,
      "metadata": true,
      "postprocessors": [
        {
          "name": "metadata",
          "mode": "custom",
                  **"extension-format": "{filename}.json",**
          "event": "init",
          "content-format": [
            "usuario: {username}",
            "url: {url}",
            "fecha: {date}\n",
            "descripcion: {description}"
          ]
        }
      ]
    }
  }
}

[mikf]

Sorry for taking this long to respond ... anyway, this error is mainly caused by using "event": "init". There is no filename extension info available when this event triggers.

To not have gallery-dl throw an exception, use "filename": "{filename}.json" instead of "extension-format": "..." or "extension": "...".

I'd also recommend "event": "post". This triggers for every post, instead of just once before the first one.