Redirect stdin from /dev/null seems to work as a workaround and I will change
my application to call it like that. But it was my understanding that the --
batch flag explicitly means that the program should never expect input on
stdin. Allowing the program to hang waiting for stdin seems to go against the
point of that option.

To reproduce:

The bug I'm reporting is that certain bad-formatted files can cause GPG to hang
in batch mode. It is my understanding that GPG should never hang waiting for
user input when in batch mode. It should process the file and either properly
decrypt or or terminate with an error. Since certain input can make it hang
instead, there is a bug.