Cleanup dead cxx11 guards from /include/boost/pending/container_traits.hpp

[samkelemen]

Before submitting

• This PR targets the develop branch.
• I searched for an existing PR or issue covering the same change.
• My contribution is licensed under the Boost Software License 1.0.

Type of change

• Bug fix
• New feature or API addition
• Refactor (no behavior change)
• Documentation
• Build, CI, or tooling
• Other (specify below)

Does this PR introduce a breaking change?

• Yes (describe migration impact below)
• No

What this PR does

This PR removes the following guards from include/boost/pending/container_traits.hpp:

• #ifndef BOOST_NO_CXX11_HDR_UNORDERED_SET
• #ifndef BOOST_NO_CXX11_HDR_UNORDERED_MAP
• #ifdef BOOST_NO_CXX11_RVALUE_REFERENCES

Motivation

Fixes #587

Checklist

• Existing tests pass (b2 in the test/ directory).
• New behavior is covered by a test, or this is a docs / build / refactor change. -- N/A
• Documentation was updated if user-facing behavior changed. -- N/A
• No new compiler warnings on the platforms I built against.

[github-actions]

Boost dependency footprint vs develop (auto-generated).
PR run 33825610411 vs develop run 33724349044 (9c5a0ca833).

Header-inclusion weights (graph files pulling each direct dependency in):

No header-inclusion-weight changes.

Transitive Boost modules: 65 → 65 (0)

[github-actions]

Compiler-warning counts vs develop (auto-generated).
PR run 33825610381 vs develop run 33724349100 (9c5a0ca833).

Job	Baseline	After	Delta
macos (clang, 14)	438	438	0
macos (clang, 17)	401	401	0
macos (clang, 20)	401	401	0
ubuntu (clang-19, 14)	438	438	0
ubuntu (clang-19, 17)	401	401	0
ubuntu (clang-19, 20)	401	401	0
ubuntu (clang-19, 23)	401	401	0
ubuntu (gcc-14, 14)	371	371	0
ubuntu (gcc-14, 17)	367	367	0
ubuntu (gcc-14, 20)	367	367	0
ubuntu (gcc-14, 23)	367	367	0
windows_msvc_14_3 (msvc-14.3)	961	961	0

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[jeremy-murphy]

Looks great, thank you! Just some minor quibble about unnecessary changes.

[Becheler]

Thank you so much for this first PR !
It revealed a consequent gap in the unit test coverage: I guess because historically the CI was running on old compilers, the modern paths you accidentally deleted were never tested ! So the PR breaks users but CI is green, what a wonderful world ! 😆
The solution is relatively straightforwards (delete the question #ifndef BOOST_NO_CXX11_HDR_UNORDERED_MAP but keep the overload it guards), I indicated it in comment, just let me know if you have questions 🤗

[samkelemen]

Hi @Becheler. I updated the PR, but I just noticed you assigned this PR to yourself. Are you wanting to take this one, perhaps to add test coverage?

[samkelemen]

Also the CI run failed for Linux g++-10 20, but the error looks unrelated to the actual code changes:

Cloning into '/drone/boost-root/tools/build'...
fatal: could not read Username for 'https://github.com': terminal prompts disabled
fatal: the remote end hung up unexpectedly
fatal: clone of 'https://github.com/boostorg/build.git' into submodule path '/drone/boost-root/tools/build' failed
Failed to clone 'tools/build'. Retry scheduled
Cloning into '/drone/boost-root/tools/build'...
fatal: could not read Username for 'https://github.com': terminal prompts disabled
fatal: the remote end hung up unexpectedly
fatal: clone of 'https://github.com/boostorg/build.git' into submodule path '/drone/boost-root/tools/build' failed
Failed to clone 'tools/build' a second time, aborting

[Becheler]

@samkelemen you good, I just use assignment to track what are my tasks in the project's Kanban, I added you too. It's mostly cosmetic and for tracking, it does not signal ownership 😄

Also you will learn not to put too much attention in the drone job, it's runs some complex stuff related to the general boost ecosystem and when it fails it's most of the time not related directly to your changes.
The thing you want to focus is the green CI jobs (ubuntu macos etc).

[Becheler]

@samkelemen congratulations on your first merged Boost PR ! 🥳

We love that you made it as a new contributor ! Your profile should show up in the next review report 🎉

Thank you for your help 🤗