The apt-transport-tor package operates via simple symlinks which can
result in 'http' being called as 'tor+https', so it must pick up the
right configuration pieces and trigger https support also in plus names.
To prevent accidents like adding http-sources while using tor+http it
can make sense to allow disabling methods. It might even make sense to
allow "redirections" and adding "symlinked" methods via configuration.
This could e.g. allow using different options for certain sources by
adding and configuring a "virtual" new method which picks up the config
based on the name it was called with like e.g. http does if called as
tor+http.
cURL which backs our https implementation can handle redirects on its
own, but by dealing with them on our own we gain finer control over which
redirections will be performed (we don't like https → http) and by whom
so that redirections to other hosts correctly spawn a new https method
dealing with these instead of letting the current one deal with it.
The worker expects that the methods tell him when they start or finish
downloading a file. Various information pieces are passed along in this
report including the (expected) filesize. https was using a "global"
struct for reporting which made it 'reuse' incorrect values in some
cases like a non-existent InRelease fallbacking to Release{,.gpg}
resulting in a size-mismatch warning. Reducing the scope and redesigning
the setting of the values we can fix this and related issues.
Closes: 777565, 781509
Thanks: Robert Edmonds and Anders Kaseorg for initial patchs
David Kalnischkies