[pkg-gnupg-maint] Bug#1143171: libgpgmepp-dev: Should libgpgmepp-dev dependencies match pkg-config requirements?

[Kangjia Huang]

Package: libgpgmepp-dev
Version: 1.24.2-3
Severity: important

Dear Maintainer,

I had a concern about the libgpgmepp-dev package's declared
dependencies. Specifically, I was developing a project where I needed
libgpgmepp, and thus wanted to pull in the necessary development headers
and library by installing libgpgmepp-dev. Critically, however, prior to
this, I had not yet installed packages for libgpgme or libgpg-error.

It seems like the libgpgmepp-dev package currently depends on both
libgpgmepp6t64 and libgpg-error-dev, thus also pulling in development
headers for libgpg-error. However, it would also appear that aside from
libgpg-error, the [pkg-config](https://github.com/gpg/gpgmepp/blob/6a99d7eef09aedd768356792f38aca2cc03659da/src/gpgmepp.pc.in#L8)
file for libgpgmepp has also always explicitly required the pkg-config
file for **libgpgme** to exist, which makes sense as libgpgmepp is a C++
wrapper on top of this library.

I am not sure if the ommittance of libgpgme-dev from libgpgmepp-dev's
dependencies is intentional, but I would have personally assumed that
installing libgpgmepp-dev would pull in all libraries and dependencies
necessary to develop with libgpgmepp, and especially since libgpgmepp's
dependency on libgpgme development files is a foundational aspect of the
library's very purpose, I was wondering if libgpgme-dev should also have
been added as a dependency to libgpgmepp-dev.

Please feel free to let me know what you think about this. It is very
plausible that this is not actually a bug, and that my understanding of
-dev packages in general is slightly flawed, but regardless, I would
certainly greatly appreciate it if you could help point me in the right
direction! :)

Thank you so much for your time and help.

-- System Information:
Debian Release: trixie/sid
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 6.12.12-amd64 (SMP w/16 CPU threads; PREEMPT)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages libgpgmepp-dev depends on:
ii  libgpg-error-dev  1.51-3
ii  libgpgmepp6t64    1.24.2-3

Versions of packages libgpgmepp-dev recommends:
ii  libgpgmepp-doc  1.24.2-3

libgpgmepp-dev suggests no packages.

-- no debconf information

-- debsums errors found:
# [these lines contained some warnings (specifically, missing control
# file Description fields) regarding some packages that I had
# personally made and installed locally on my system. They are entirely
# intentional and isolated from Debian packages,
# and thus are not relevant to this bug report and have been omitted,
# although if you would like to see them regardless, I can provide a
# partial dump on request.]