Bug#809991: clang-3.5: should not depend on GCC libobjc

[Niels Grewe]

Package: clang-3.5
Severity: wishlist

Dear LLVM packaging team,

currently the clang packages in Debian depend on the dev package of the Objective-C
runtime library that ships with GCC (libobjc-4.9-dev in jessie). I'd like to suggest
dropping Depends in favour of a Recommends so that it can be removed without
breaking the package. There are a few legitimate reasons to do that. The most basic one
is that you just want to use clang and a C/C++ compiler and don't desire the ability 
to compile Objective-C code. The other one, and the main reason why I am proposing this,
is that to make use of all the Objective-C features that clang provides (non-fragile ABI,
automatic reference counting), you will have to use the GNUstep runtime [0] that is not
currently packaged in Debian. Depending on the GCC runtime makes using the alternative
runtime unnecessary hard because you have to worry about the linker picking the right
runtime library.

I realise that per the policy manual you could be argued that libobjc is 'required [...]
to provide a significant amount of functionality' (namely Objective-C support), but not
installing it does not break clang as a C and C++ compiler at all. Also, C and C++ have
far more widespread use compared to Objective-C, so a fortiori the 'found together [...]
in all but unusual installations' description of Recommends would also apply. In any case,
recommending the Objective-C runtime instead of depending on it would not change anything
for users unless they take explicit action to remove the package.

Please let me know what you think.

Many thanks,

Niels

[0]Âhttps://www.github.com/gnustep/libobjc2 


-- System Information:
Debian Release: 8.2
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.16.0-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
ANSI_X3.4-1968) (ignored: LC_ALL set to de_DE.UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)