Bug 854123 – app-admin/lnav-0.10.1 fails to compile (lto): lnav_config.cc:376:8: error: type -Werror=odr

• Product: Gentoo Linux
• Status: RESOLVED FIXED

[Description Agostino Sarubbo 2022-06-24 15:17:41 UTC]

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

Issue: app-admin/lnav-0.10.1 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

[Comment 1 Agostino Sarubbo 2022-06-24 15:17:43 UTC]

Created attachment 787406 [details]
build.log

build log and emerge --info

[Comment 2 Agostino Sarubbo 2022-07-26 09:00:07 UTC]

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 3 Larry the Git Cow 2022-09-09 03:46:31 UTC]

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

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=f75f598ccad65de223b8962d0947be1a2b9da0e8

commit f75f598ccad65de223b8962d0947be1a2b9da0e8
Author:     Randy Barlow <[e-mail]>
AuthorDate: 2022-09-03 22:49:40 +0000
Commit:     Sam James <[e-mail]>
CommitDate: 2022-09-09 03:45:58 +0000

    app-admin/lnav: Add 0.11.0
    
    * Remove the unicode USE flag
    
    lnav did not build successfully when this USE flag was disabled. Since
    there are not many use cases for not using unicode today, this commit
    fixes the issue by removing the USE flag and enabling unicode support
    unconditionally.
    
    * Depend on openssh[ssl]
    
    See https://github.com/tstack/lnav/issues/865.
    
    * Conditionally build ssh keys
    
    This commit patches lnav so that it only build ssh keys when tests are
    run. This makes openssh a conditional dependency.
    
    See https://github.com/tstack/lnav/pull/1041.
    
    * Filter LTO flags
    
    Closes: https://github.com/gentoo/gentoo/pull/27130
    Closes: https://bugs.gentoo.org/777981
    Closes: https://bugs.gentoo.org/835636
    Closes: https://bugs.gentoo.org/854123
    Signed-off-by: Randy Barlow <[e-mail]>
    Signed-off-by: Sam James <[e-mail]>

 app-admin/lnav/Manifest                            |  1 +
 .../files/lnav-0.11.0-conditional-ssh-keygen.patch | 34 +++++++++++
 .../lnav/files/lnav-0.11.0-disable-tests.patch     | 67 ++++++++++++++++++++++
 app-admin/lnav/lnav-0.11.0.ebuild                  | 56 ++++++++++++++++++
 app-admin/lnav/metadata.xml                        |  3 +
 5 files changed, 161 insertions(+)