Avoid spurious "verification of content failed" message when downloading
content from a ssh or tor remote fails due to the remote no longer having a
copy of the content.
The P2P protocol already handled this case by sending DATA 0, followed by
VALID. But VALID was not really right, because the data is not the
requested data. So, send DATA 0, followed by INVALID. Old versions of
git-annex handle INVALID the same as VALID in this case. Now new versions
avoid displaying an incorrect message.
It would be better for the P2P protocol to have a different way to indicate
this, like perhaps sending INVALID without DATA. But that would be a
breaking change and need a new protocol verison. Since INVALID already is
part of the protocol and already needs to be handled, using it for this
special case too seems ok, and avoids the complication of another protocol
version.
This commit was sponsored by Jochen Bartl on Patreon.
This is an edge case, which happened to be triggered by the P2P protocol
seeing DATA 0. When reading 0 bytes, getting an empty string does
not mean the handle has reached EOF.
I verified there was in fact a bug, where get of an empty file followed
by another file would get the empty file and then fail
with "handle is closed". This fixes it.
This commit was sponsored by Boyd Stephen Smith Jr. on Patreon.
Reversion introduced in version 8.20201007, one release after the 1st
release with the extension.
Surprisingly, hClose can hang if another thread is reading from the
handle. This is because it uses takeMVar.
The use of cancel here does mean that, if receiveMessageAddonProcess
or Remote.External.AsyncExtension.receiveloop allocated some resource in
a non-async-exception safe way, they might not get a chance to clean it up.
They do not appear to, and anyway, this only happens when git-annex is
shutting down, so any recource that did leak would not be a problem.
This commit was sponsored by Boyd Stephen Smith Jr. on Patreon.
