Attachments with very long filenames fail to save to the database

[mboynes]

When an attachment is uploaded and the attachment post is inserted into the database, the guid is set to the attachment URL. The guid database column is limited to 255 characters, so a very long domain/filename combination can result in the post failing to save to the database with the vague message "Could not insert post into the database". The uploaded file does not get deleted from the uploads directory, and further attempts to upload the same file without renaming it will result in a different error, "The uploaded file could not be moved to {location}".

The issue occurs in wpdb::strip_invalid_text() and wpdb::process_fields(). wpdb::strip_invalid_text() trims the field contents down to 255 characters, and wpdb::process_fields() fails as a result of this data change.

The root cause is the same as #32315, though I believe this should still be tracked and handled separately. Judging by the trajectory of #32315, the user would be presented with a cryptic database-focused error message, whereas a better solution for this problem would be that the attachment successfully inserts.

To Replicate

1. Create a file and give it a name composed of 240+ characters (the "tipping point" length depends on the site's domain, amongst other factors, so this error can occur with shorter filenames).
2. Upload the file to WordPress anywhere media can be added.
3. The database insert should have failed with the error message, "Could not insert post into the database".
4. Attempt to upload the same file again to observe the error message, "The uploaded file could not be moved to..."

[ianbelanger]

Removing the Version as this was not introduced in 5.2. I am not sure in which version this problem was introduced, so leaving it blank for now.

[brunochartier]

Previous edits deleted (redundant with post description).

[programmin]

Issue persists in 5.7.4.
Just add "LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL..." to the file name accidentally, and it fails to upload with no useful error message.