For now I added only the basic build matrix, without coverage
collection and more special builds, like WMAIN.
However, due to GHA being so much faster than AppVeyor, all
these builds are now done against the 'all-tests' prefix, making
the builds more uniform than they were on AppVeyor.
This is needed so that we can use conjunction and other logical
type traits to workaround issue with older GCC versions (8 and
below), when they run into types that have ambiguous constructor
from `0`, see e.g. #2571.
However, using conjunction and friends in the SFINAE constraint
in the template parameter breaks for C++20 and up, due to the new
comparison operator rewriting rules. With C++20, when the compiler
see `a == b`, it also tries `b == a` and collects overload set
for both of these expressions.
In Catch2, this means that e.g. `REQUIRE( 1 == 2 )` would lead
the compiler to check overloads for both `ExprLhs<int> == int`
and `int == ExprLhs<int>`. Since the overload set and SFINAE
constraints assume that `ExprLhs<T>` is always on the left side,
when the compiler tries to resolve the template parameters, all
hell breaks loose and the compilation fails.
By moving the SFINAE constraints to the return type, the compiler
can discard the switched expression without having to resolve
the complex SFINAE constraints, and thus everything works the
way it is supposed to.
Fixes#2571
* Add new `CATCH_CONFIG` option for using `std::getenv`, because PS does not support env vars
* Add PS to platforms that have disabled posix signals.
* Small workaround for PS toolchain bug that prevents it from compiling `std::set` with lambda based comparator.
* Remove from __future__ import print_function, because we
no longer support Python2.
* Clean out unused parts of tools/scripts/scriptCommon.py
* Move appveyorMergeCoverageScript to Python3
* Update user reporting in *release scripts
* Cleanup module imports
This has two effects:
1) This significantly improves the performance of ApprovalTests
run in WSL, because running the massively multi-reporter
test would cause lots of small and parallel writes across the
WSL-Windows FS boundary, completely mudering performance.
2) ApprovalTests can be run from multiple build dirs in parallel,
as long as they do not fail. However, if they do fail,
the multiple runs will still step on each other toes when
writing the unapproved files for user.
This is primarily done to support new `std::*_ordering` types,
but the refactoring also supports any other type with this
property.
The compilation overhead is surprisingly low. Testing it with
clang on a Linux machine, compiling our SelfTest project takes
only 2-3% longer with these changes than it takes otherwise.
Closes#2555
