FEATURES has always said attach-from-Files works "however large", because a
blob the account already holds is attached by reference and nothing is
sent. The code checked every file against maxSizeUpload regardless, so the
two disagreed and the code was the one that was wrong.
maxSizeUpload is what the server will accept for a single upload (RFC
8620). It bears on a file that is about to be uploaded and on nothing
else. Applying it to a by-reference attachment refused a 60 MB message the
server was already storing, on the grounds that it could not have been
uploaded -- which it was not being. Forwarding a large message as an
attachment hit exactly that.
A file from somebody else's account is fetched and re-uploaded into this
one, because a message can only carry blobs from the account sending it.
That upload is real and the limit is real for it, so it still applies
there.
jcoffey-dev
1b4788c0a7