[pkg-gnupg-maint] Bug#796286: gnupg-agent 2.1.7-2 broke the agent for gpg

[Russ Allbery]

Package: gnupg2
Version: 2.1.7-2
Severity: normal

This may be expected behavior and the right solution is to just switch
to gpg2 because gpg 1.x is no longer supported, but if so, consider this
a request for a NEWS.Debian entry, since that's a rather large change
and a bunch of tools in Debian are still using gpg.

With gnupg-agent 2.1.7-2, there no longer appears to be any way to get
gpg to use the agent.  I have use-agent specified in .gnupg/gpg.conf
and an agent running, but gpg always says:

mithrandir:~/dvl/build-area$ debsign *.changes
 signfile webauth_4.7.0-3.dsc D15D313882004173

You need a passphrase to unlock the secret key for
user: "Russ Allbery <eagle at eyrie.org>"
2048-bit RSA key, ID 7D80315C5736DE75, created 2010-09-17
         (subkey on main key ID D15D313882004173)

gpg: gpg-agent is not available in this session

(for example).  I do have one running:

mithrandir:~$ ps auxwww | grep gpg-agent
eagle      943  0.0  0.0 165284   596 ?        Ss   18:47   0:00 /usr/bin/gpg-agent --daemon

and therefore also can't start a new one.  gpg still wants to have some
sort of GNUPG_AGENT_INFO variable and claims this is documented in the
gpg-agent man page, but there's no longer any information there on what
to set it to.

This is all made worse by the fact that the DEBSIGN_PROGRAM environment
variable is apparently ignored by debsign, so at least for me this
pretty much breaks my signature workflow for packages.  I'll report that
bug separately.

-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (990, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.1.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages gnupg2 depends on:
ii  dpkg           1.18.2
ii  gnupg-agent    2.1.7-2
ii  install-info   6.0.0.dfsg.1-3
ii  libassuan0     2.2.1-1
ii  libbz2-1.0     1.0.6-8
ii  libc6          2.19-19
ii  libgcrypt20    1.6.3-2
ii  libgpg-error0  1.19-2
ii  libksba8       1.3.3-1
ii  libreadline6   6.3-8+b3
ii  zlib1g         1:1.2.8.dfsg-2+b1

Versions of packages gnupg2 recommends:
pn  dirmngr  <none>

Versions of packages gnupg2 suggests:
pn  gnupg-doc   <none>
pn  parcimonie  <none>
pn  xloadimage  <none>

-- no debconf information