refactor: replace Boost.Iterator with Boost.STLInterfaces

[sdebionne]

Description

Contribute to remove dependencies to older c++03 boost libraries.

References

C++11 Modernization

Tasklist

• Add test case(s)
• Ensure all CI builds pass
• Review and approve

[sdebionne]

@mloskot Boost.Iterator provides it's own Concept checking classes in #include <boost/iterator/iterator_concepts.hpp> that matche the (new for the time) Boost.Iterator concepts that never made it to the standard. Since we want to cut the ties with Boost.Iterator, I suppose we need to move to Boost.Concept Iterator concept, what do you think?

Honestly I wonder if it is worth it, and if, for concept checking only, we could require c++20....

[mloskot]

@sdebionne

Honestly I wonder if it is worth it, and if, for concept checking only, we could require c++20...

I don't think it is worth it ...

to move to Boost.Concept Iterator concept,

One of my "next big thing" to do for GIL is to:

1. Freeze current use of Boost.Concept
2. Introduce C++20 concepts (compile-time disabled for older compilation modes)
3. Ensure we CI-test at C++20 level thoroughly (core + extensions) with those concepts enabled.
4. Slowly deprecated use of Boost.Concept, and eventually remove it.

@sdebionne Does the above seem sensible to you?

[mloskot]

This is included in the planning towards C++14/17 discussion here #676

[mloskot]

I guess we may run out of time to squeeze it into Boost 1.80. What do you think @sdebionne ?

[sdebionne]

I guess we may run out of time to squeeze it into Boost 1.80. What do you think @sdebionne ?

Indeed, I underestimate the work and overestimate the time I could spend on the project. Let's move it to 1.81.

[codecov]

Codecov Report

Merging #669 (72d460c) into develop (1df8c24) will increase coverage by 1.03%.
Report is 6 commits behind head on develop.
The diff coverage is 100.00%.

❗ Current head 72d460c differs from pull request most recent head 4470d11. Consider uploading reports for the commit 4470d11 to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #669      +/-   ##
===========================================
+ Coverage    81.10%   82.14%   +1.03%     
===========================================
  Files          117      117              
  Lines         5171     5360     +189     
===========================================
+ Hits          4194     4403     +209     
+ Misses         977      957      -20     

[sdebionne]

@mloskot there is still a bit of cleaning to do but otherwise this PR is ready for review. Beside the switch to Boost.StlInferface, there is a fix for the CI (code coverage), and a fix for std::is_floating_point<> specialization.

I don't known why some of the CI GitHub actions timeout -I have just try to rerun them.

[mloskot]

I don't known why some of the CI GitHub actions timeout -I have just try to rerun them.

It looks like GHA runners availability issue which I'd ignore:

The Ubuntu 18.04 has also been deprecated, so I have just tried to update the GHA:

• ci: ubuntu-18.04 environment is deprecated #738

Let's see if this improves anything.

[mloskot]

Thank you so much for pulling this off @sdebionne

[sdebionne]

I'll rebase on the fixed CI (thank you for that) and cleanup.

[sdebionne]

I wonder if iterator should be removed from .ci/get-boost.sh?

[mloskot]

Yes, I think it should.

It may be required as transitive dependency, but the CI jobs will let us know.