Bug 878877 – games-action/prismlauncher-5.0 fails to compile (lto): VersionList.h:28:7: error: type struct VersionList violates the C++ One Definition Rule [-Werror=odr]

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Agostino Sarubbo 2022-10-31 11:28:17 UTC]

https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: games-action/prismlauncher-5.0 fails to compile (lto).
Discovered on: amd64 (internal ref: lto_tinderbox)

NOTE:
This machine uses lto with CFLAGS=-flto -Werror=odr -Werror=lto-type-mismatch -Werror=strict-aliasing

Here is a bit of explanation:

-Werror=lto-type-mismatch:
User to find possible runtime issues in packages. It likely means the package is unsafe to build & use with LTO.
For projects using the same identifier but with different types across different files, they must be fixed to be consistent across the codebase.

-Werror=odr:
Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO. C++ code must comply with the One Definition Rule (ODR) - see https://en.cppreference.com/w/cpp/language/definition#One_Definition_Rule.

-Werror=strict-aliasing:
Used to find possible runtime issues in packages. These bugs are a problem anyway but may be even worse when combined with LTO.

Workarounds:
- If upstream is friendly and still active, file a bug upstream. For emulators, codecs, games, or multimedia packages, it may be worth just applying a workaround instead, as upstreams sometimes aren't receptive to these bugs (VALID FOR ALL).
- Use the new 'filter-lto' from flag-o-matic.eclass as it's likely to be unsafe with LTO (VALID FOR lto-type-mismatch - odr).
- Fix it yourself if interested, of course (VALID FOR ALL).
- Append-flags -fno-strict-aliasing (VALID FOR strict-aliasing).
- Use memcpy() but a union is sometimes suitable too (VALID FOR strict-aliasing).
- -fstrict-aliasing is implied by -O2, so this must be addressed in some form (VALID FOR strict-aliasing).

See also: https://marc.info/?l=gentoo-dev&m=165639574126280&w=2

[Comment 1 Agostino Sarubbo 2022-10-31 11:28:19 UTC]

Created attachment 826227 [details]
build.log.xz

build log and emerge --info (compressed because it exceeds attachment limit, use 'xzless' to read it)

[Comment 2 Agostino Sarubbo 2022-10-31 11:28:21 UTC]

Error(s) that match a know pattern in addition to what has been reported in the summary:


FAILED: Index 
FAILED: Library 
FAILED: ResourceFolderModel 
FAILED: ResourcePackParse 
FAILED: Task 
FAILED: TexturePackParse 
FAILED: prismlauncher 
/var/tmp/portage/games-action/prismlauncher-5.0/work/PrismLauncher-5.0_build/launcher/Launcher_logic_autogen/F26Q4VW2FO/../../../../PrismLauncher-5.0/launcher/meta/VersionList.h:28:7: error: type ‘struct VersionList’ violates the C++ One Definition Rule [-Werror=odr]

[Comment 3 Larry the Git Cow 2022-12-12 17:56:04 UTC]

The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=4618b75f3d29a6bee3a9c123da960c04f34f67ba

commit 4618b75f3d29a6bee3a9c123da960c04f34f67ba
Author:     Thiago Donato Ferreira <[e-mail]>
AuthorDate: 2022-12-12 17:35:07 +0000
Commit:     Andrew Ammerlaan <[e-mail]>
CommitDate: 2022-12-12 17:55:50 +0000

    games-action/prismlauncher: drop 5.1
    
    Since 5.2, a fix for LTO compilation was applied upstream.
    
    Closes: https://bugs.gentoo.org/878877
    Signed-off-by: Thiago Donato Ferreira <[e-mail]>
    Closes: https://github.com/gentoo/gentoo/pull/28648
    Signed-off-by: Andrew Ammerlaan <[e-mail]>

 games-action/prismlauncher/Manifest                |   1 -
 .../prismlauncher/prismlauncher-5.1.ebuild         | 147 ---------------------
 2 files changed, 148 deletions(-)