XPost: linux.debian.bugs.dist
From: [email protected]

Package: libdpkg-perl
Version: 1.21.22ubuntu1
Severity: minor
X-Debbugs-Cc: [email protected]

Dear Maintainer,

*** Reporter, please consider answering these questions, where appropriate ***

* What led up to the situation?
- building deb package with dpkg-buildpackage and clang
- hardcoded -ffat-lto-objects cc flag in scripts/Dpkg/Vendor/Debian.pm
https://git.dpkg.org/git/dpkg/dpkg.git/tree/scripts/Dpkg/Vendor/Debian.pm#n451

* What exactly did you do (or not do) that was effective (or ineffective)?
CC=clang dpkg-buildpackage ...

* What was the outcome of this action?
clang: warning: optimization flag '-ffat-lto-objects' is not supported [-Wignored-optimization-argument]

* What outcome did you expect instead?
not sorting out rare flags specific to one compiler
(a possible workaround was manually set DEB_CFLAGS_STRIP=-ffat-lto-objects in environment)

*** End of the template - remove these template lines ***


-- Package-specific info:
This system uses merged-usr-via-aliased-dirs, going behind dpkg's
back, breaking its core assumptions. This can cause silent file
overwrites and disappearances, and its general tools misbehavior.
See <https://wiki.debian.org/Teams/Dpkg/FAQ#broken-usrmerge>.

-- System Information:
Debian Release: bookworm/sid
APT prefers lunar-updates
APT policy: (990, 'lunar-updates'), (990, 'lunar-security'), (990, 'lunar-backports'), (990, 'lunar'), (500, 'mantic')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 6.2.0-23-generic (SMP w/4 CPU threads; PREEMPT)
Kernel taint flags: TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=uk_UA.UTF-8, LC_CTYPE=uk_UA.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 libdpkg-perl depends on:
ii dpkg 1.21.22ubuntu1
ii perl 5.36.0-7ubuntu0.23.04.1

Versions of packages libdpkg-perl recommends:
ii bzip2 1.0.8-5build1
ii libfile-fcntllock-perl 0.22-4build1
ii liblocale-gettext-perl 1.07-5
ii xz-utils 5.4.1-0.2

Versions of packages libdpkg-perl suggests:
ii binutils 2.40-2ubuntu4.1
pn bzr <none>
ii clang-15 [c-compiler] 1:15.0.7-3
ii clang-16 [c-compiler] 1:16.0.0-1~exp5ubuntu3
pn debian-keyring <none>
ii gcc [c-compiler] 4:12.2.0-3ubuntu1
ii gcc-12 [c-compiler] 12.2.0-17ubuntu1
ii gcc-13 [c-compiler] 13-20230320-1ubuntu1
ii git 1:2.39.2-1ubuntu1.1
ii gnupg 2.2.40-1.1ubuntu1
ii gpgv 2.2.40-1.1ubuntu1
ii patch 2.7.6-7build2
ii sensible-utils 0.0.17+nmu1

-- no debconf information

--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)

XPost: linux.debian.bugs.dist
From: [email protected]

Hi!

On Thu, 2023-06-22 at 19:46:11 +0300, VSYakovetsky wrote:

Package: libdpkg-perl
Version: 1.21.22ubuntu1
Severity: minor
X-Debbugs-Cc: [email protected]

* What led up to the situation?
- building deb package with dpkg-buildpackage and clang
- hardcoded -ffat-lto-objects cc flag in scripts/Dpkg/Vendor/Debian.pm
https://git.dpkg.org/git/dpkg/dpkg.git/tree/scripts/Dpkg/Vendor/Debian.pm#n451

This has come up in the past, and while it would be nice to be able to
support multiple compilers in general for a specific vendor the build
flags default and are adapted just to the default compiler for that distribution.

Here's mail covering what autodetection would involve if this was to
be supported:

https://lists.debian.org/debian-dpkg/2014/06/msg00050.html

* What exactly did you do (or not do) that was effective (or ineffective)?
CC=clang dpkg-buildpackage ...

* What was the outcome of this action?
clang: warning: optimization flag '-ffat-lto-objects' is not supported [-Wignored-optimization-argument]

* What outcome did you expect instead?
not sorting out rare flags specific to one compiler
(a possible workaround was manually set DEB_CFLAGS_STRIP=-ffat-lto-objects in environment)

Yes, in this case if you change the compiler, then you need to adapt
any such build flags that might not play well with it.

So, I'm afraid there's not much that can be done here. Perhaps this
could be documented somewhere more prominently, but I'm not sure
where, perhaps the dpkg-buildpackage or dpkg-buildflags man pages or
similar, not sure if that would have helped in your case?

Otherwise, I'm inclined to probably be closing this in a bit.

Thanks,
Guillem

--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)

XPost: linux.debian.bugs.dist
From: [email protected]

Hi!

On Wed, 2023-06-28 at 01:02:30 +0200, Guillem Jover wrote:

On Thu, 2023-06-22 at 19:46:11 +0300, VSYakovetsky wrote:

Package: libdpkg-perl
Version: 1.21.22ubuntu1
Severity: minor
X-Debbugs-Cc: [email protected]

* What exactly did you do (or not do) that was effective (or ineffective)?
CC=clang dpkg-buildpackage ...

* What was the outcome of this action?
clang: warning: optimization flag '-ffat-lto-objects' is not supported [-Wignored-optimization-argument]

* What outcome did you expect instead?
not sorting out rare flags specific to one compiler
(a possible workaround was manually set DEB_CFLAGS_STRIP=-ffat-lto-objects in environment)

Yes, in this case if you change the compiler, then you need to adapt
any such build flags that might not play well with it.

So, I'm afraid there's not much that can be done here. Perhaps this
could be documented somewhere more prominently, but I'm not sure
where, perhaps the dpkg-buildpackage or dpkg-buildflags man pages or
similar, not sure if that would have helped in your case?

I got a reply off-BTS where VSYakovetsky mentioned it would be fine to
close. I still think this could do with some documentation somewhere
so I'll ponder about this, and otherwise either will improve some docs…

Otherwise, I'm inclined to probably be closing this in a bit.

…or if I don't come up with anything will be closing it.

Thanks,
Guillem

--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)