I was looking to add my (simple) mod to the database. I got to the stage of adding the patch file, and while using the Scratchpad to upload the file, I got the error I mentioned in the title.
Invalid File Extension 'ips' in '<my patch>.ips'. Allowable extensions are gif, png, jpg, jpeg, doc, zip, rar, 7z, 7zp, txt, html, htm, exe, pdf, bz2, dmg, tgz, gz, tar, rtf, msi, txt.
... why? IPS seems like the most common patch type on here, so why not allow uploading the patch file directly? I see the archive formats in the list of allowed extensions, so I assume you're expecting me to compress the patch before uploading. However, That isn't always optimal. Patch files are binary files, meaning they aren't always going to be able to benefit from compression very much. It's also terrible for small patch files. My IPS file is only 17 bytes, but trying to make it a ZIP file increases to 205 bytes, which is an increase of over 12 times.
Since it looks like the submission URL can be any URL, I'm just going to upload the patch to my personal website and use that instead of the Scratchpad. It just seems like an annoying barrier to uploading.
EDIT: Used my own site to upload the file, and got that the Hack Submission page only accepts "ZIP, RAR, 7ZP, TXT, HTML, TAR.GZ, DOC, DMG, and EXE." Again, why? EXE seems more dangerous to allow direct uploads for than just IPS files.