[pkg-gnupg-maint] Bug#857317: gnupg-agent: console locks up when using gpg-agent with emacs

[Punit Agrawal]

Package: gnupg-agent
Version: 2.1.18-6
Severity: normal

Dear Maintainer,

As a simple test, open a new file "test.gpg" in emacs. Type in some
text and try saving the file. Emacs loads "keys" buffer to query which
key is to be used to encrypt the file. Choose symmetric encryption by
selecting "ok". This brings up the pinentry screen asking for a
passphrase.

The pinentry dialog refuses to accept input no matter what I try. The
only way forward is to wait for the pinentry to timeout returning back
to emacs without having saved the file. The following appears in the
"*Messages*" buffer of emacs - "Opening output file: Encrypt failed,
Exit"

Some detail about my environment that might be relevant in narrowing
down the problem -

I have no windowing system installed and I'm using emacs from the
console. I've tried running emacs in a tmux session as well as over
ssh but there's no noticable difference in behaviour.

While the passphrase dialog was open, I captured the gpg agent command
via ps. Pasting them here as it might help debug the problem.

/usr/bin/gpg --no-tty --status-fd 1 --yes --use-agent --enable-progress-filter --command-fd 0 --output /tmp/epg-output24784KpA --symmetric

I also see "/usr/bin/gpg-agent --supervised" and "pinentry" running in
the same ps output.

My current pinentry symlink points to "/usr/bin/pinentry-curses" but
I've also tried with "pinentry-tty" with no joy.

I've got the following in ~/.gnupg/gpg-agent.conf

allow-emacs-pinentry
enable-ssh-support

One last thing - I'm running debian in a virtualbox VM on a mac.

Please let me know if there's any other relevant information I can
provide to help get to the bottom of the problem.

Thanks,
Punit

-- System Information:
Debian Release: 9.0
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: arm64, i386

Kernel: Linux 4.9.0-2-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages gnupg-agent depends on:
ii  libassuan0                  2.4.3-2
ii  libc6                       2.24-9
ii  libgcrypt20                 1.7.6-1
ii  libgpg-error0               1.26-2
ii  libnpth0                    1.3-1
ii  libreadline7                7.0-2
ii  pinentry-curses [pinentry]  1.0.0-2
ii  pinentry-tty [pinentry]     1.0.0-2

Versions of packages gnupg-agent recommends:
ii  gnupg  2.1.18-6

Versions of packages gnupg-agent suggests:
ii  dbus-user-session  1.10.16-1
ii  libpam-systemd     232-19
pn  pinentry-gnome3    <none>
pn  scdaemon           <none>

-- no debconf information