* aptly can sign and verify without issues with GnuPG 1.x and 2.x
* aptly auto-detects GnuPG version and adapts accordingly
* aptly automatically finds suitable GnuPG version
Majority of the work was to get unit-tests which can work with GnuPG 1.x & 2.x.
Locally I've verified that aptly supports GnuPG 1.4.x & 2.2.x. Travis CI
environment is based on trusty, so it runs gpg2 tests with GnuPG 2.0.x.
Configuration parameter gpgProvider now supports three values for GnuPG:
* gpg (same as before, default): use GnuPG 1.x if available (checks gpg, gpg1),
otherwise uses GnuPG 2.x; for aptly users who already have GnuPG 1.x
environment (as it was the only supported version) nothing should change; new
users might start with GnuPG 2.x if that's their installed version
* gpg1 looks for GnuPG 1.x only, fails otherwise
* gpg2 looks for GnuPG 2.x only, fails otherwise
These unit-tests cover operations via both PGP providers:
built-in `openpgp` and external `gpg`.
Next step is to run these tests for gpg1 & gpg2
as separate entities.
Init is actually never called and I have no clue why it is there if it is
not called.
Take this opportunity to introduce a New function which only does the
helper lookup and panics iff that fails. Panic may be a bit too aggressive,
but seems the most certain way to get out of not finding a suitable gpg1
binary.
Newer versions of debian and ubuntu come with gpg pointing to gpg2.
We can currently only handle gpg1 CLIs though. Luckily the old gpg is still
available in the package gnupg1 (providing bin/gpg1).
As a bit of a stop-gap, until #657 can be resolved properly, we'll detect
the version of bin/gpg. If it is unsuitable we'll fall back and try
bin/gpg1. If neither is found to be suitable the signer/verifier will
not work.
Same applies to gpgv/gpgv1.
