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Bug 878139

Summary: sci-libs/arpack-3.8.0 fails tests (lto): dnsimp.f:196:72: error: type of mmread does not match original declaration [-Werror=lto-type-mismatch]
Product: Gentoo Linux Reporter: Agostino Sarubbo <ago>
Component: Current packagesAssignee: Gentoo Science Related Packages <sci>
Status: RESOLVED FIXED    
Severity: normal CC: eschwartz93
Priority: Normal    
Version: unspecified   
Hardware: All   
OS: Linux   
See Also: https://github.com/opencollab/arpack-ng/issues/451
Whiteboard:
Package list:
Runtime testing required: ---
Bug Depends on:    
Bug Blocks: 618550    
Attachments: build.log

Description Agostino Sarubbo gentoo-dev 2022-10-24 06:57:11 UTC
https://blogs.gentoo.org/ago/2020/07/04/gentoo-tinderbox/

Issue: sci-libs/arpack-3.8.0 fails tests (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 gentoo-dev 2022-10-24 06:57:14 UTC
Created attachment 825163 [details]
build.log

build log and emerge --info
Comment 2 Larry the Git Cow gentoo-dev 2024-03-06 05:30:11 UTC
The bug has been closed via the following commit(s):

https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=845cbe2fef97ec5d8f0cb983ff075d2be9d72537

commit 845cbe2fef97ec5d8f0cb983ff075d2be9d72537
Author:     Eli Schwartz <eschwartz93@gmail.com>
AuthorDate: 2024-03-06 03:37:57 +0000
Commit:     Sam James <sam@gentoo.org>
CommitDate: 2024-03-06 05:29:50 +0000

    sci-libs/arpack: mark as LTO-unsafe
    
    It fails in tests, but unfortunately that means we cannot... test...
    compiling with LTO.
    
    Closes: https://bugs.gentoo.org/878139
    Signed-off-by: Eli Schwartz <eschwartz93@gmail.com>
    Signed-off-by: Sam James <sam@gentoo.org>

 sci-libs/arpack/arpack-3.9.1.ebuild | 11 +++++++++--
 sci-libs/arpack/arpack-9999.ebuild  | 11 +++++++++--
 2 files changed, 18 insertions(+), 4 deletions(-)