Bug 880197 – sys-cluster/ceph-18.2.1-r2 one or more CMake variables were not used by the project

• Status: CONFIRMED
• Product: Gentoo Linux

[Description Agostino Sarubbo 2022-11-07 11:17:07 UTC]

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

Issue: sys-cluster/ceph-17.2.5-r1 one or more CMake variables were not used by the project.
Discovered on: amd64 (internal ref: lto_tinderbox)

NOTE:
(LTO-SYSTEM) in the summary means that bug was found on a machine that runs lto but this bug MAY or MAY NOT BE related to lto.

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 2022-11-07 11:17:11 UTC]

Created attachment 828385 [details]
build.log.xz

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

[Comment 2 Agostino Sarubbo 2022-12-30 12:15:35 UTC]

ci has reproduced this issue with version 17.2.5-r2 - Updating summary.

[Comment 3 Agostino Sarubbo 2023-01-13 09:21:01 UTC]

ci has reproduced this issue with version 17.2.5-r3 - Updating summary.

[Comment 4 Agostino Sarubbo 2023-04-12 07:25:14 UTC]

ci has reproduced this issue with version 17.2.6 - Updating summary.

[Comment 5 Patrick McLean 2023-04-12 18:20:08 UTC]

This isn't really fixable. The variable CMAKE_INSTALL_LIBDIR is set by the eclass, but the upstream Ceph build system does not use it for anything, and this warning gets generated.

This warning isn't a problem in practice (it's just there to help catch USE flags that don't do anything any more).

[Comment 6 Agostino Sarubbo 2023-05-10 06:59:16 UTC]

ci has reproduced this issue with version 17.2.6-r2 - Updating summary.

[Comment 7 Agostino Sarubbo 2023-09-12 06:49:13 UTC]

ci has reproduced this issue with version 18.2.0-r1 - Updating summary.

[Comment 8 Agostino Sarubbo 2023-09-14 06:49:29 UTC]

ci has reproduced this issue with version 18.2.0-r2 - Updating summary.

[Comment 9 Agostino Sarubbo 2024-03-06 07:42:40 UTC]

*** Bug 925009 has been marked as a duplicate of this bug. ***

[Comment 10 Agostino Sarubbo 2024-03-06 07:42:59 UTC]

ci has reproduced this issue with version 18.2.1 - Updating summary.

[Comment 11 Agostino Sarubbo 2024-03-27 07:55:51 UTC]

ci has reproduced this issue with version 18.2.1-r1 - Updating summary.

[Comment 12 Agostino Sarubbo 2024-04-02 07:08:22 UTC]

ci has reproduced this issue with version 18.2.1-r2 - Updating summary.