installer: drop support for Windows 7 and 8.0

[dennisameling]

As announced in July 2022, Git for Windows is dropping support for these older Windows versions, following MSYS2's lead. Let's make sure that the installer actively blocks the installation process on these versions. The minimal Windows version is now 8.1 (6.3).

Looking ahead: if the minimum version reaches 10.0, GfW could choose to switch to CLANG64 instead of the current MINGW64, which is using the more modern ucrt C library. Our recent work on CLANGARM64 support paves the way for this potential future switch ✨

[dscho]

As announced in July 2022, Git for Windows is dropping support for these older Windows versions, following MSYS2's lead

While that is true, I forgot to repeat that warning in quite a few releases since then. That's why I added the warning again, for the next release yesterday.

So I think that this PR might need a while before it can be merged.

But you got me thinking: maybe we should warn users who install the next Git for Windows version if their Windows version will soon no longer be supported? Something similar to the warning about a downgrade, except instead of checking for the Git for Windows version we would check for the Windows version, similar to what we do when detecting support for symbolic links)?

And once the time actually comes to drop Windows 7/8.0 support, the big change will be to upgrade to MSYS2 runtime v3.5.* (which is not even available yet because Cygwin did not release any v3.5.* version yet). But maybe we should follow Cygwin's lead in prominently declaring one version "the last one to support Windows 7"? Like they do on their home page:

Looking ahead: if the minimum version reaches 10.0, GfW could choose to switch to CLANG64 instead of the current MINGW64, which is using the more modern ucrt C library. Our recent work on CLANGARM64 support paves the way for this potential future switch ✨

Given how finicky even something like the malloc() performance of different CRT versions is (in my mimalloc work, I was able to replicate some poor performance numbers even with recent CRT versions), I am not quite as enthusiastic about that switch. It sounds like quite a risk to me, to be honest, especially in conjunction with switching from GCC to clang (which implies using a low-level virtual machine whose performance characteristics I never thoroughly investigated).

[dscho]

Given that MSYS2 runtime v3.5.0 will drop support for Windows 7/8, but v3.4.0 already dropped i686 support, I realized that the latter is much more pressing. I opened git-for-windows/git#4279 for that.

[dennisameling]

Ok, let's just mark this PR as draft then. Feel free to close this completely if you feel this is premature 👍🏼

[dscho]

Ok, let's just mark this PR as draft then. Feel free to close this completely if you feel this is premature 👍🏼

Oh, let's keep it open. I would not even have minded keeping it in non-draft mode ;-)

[rimrul]

Given that MSYS2 runtime v3.5.0 will drop support for Windows 7/8

git-ecosystem/git-credential-manager#1418

Git Credential Manager is now also working on dropping support for Windows 7/8.

EDIT: Unlike this PR, that also means no more Windows 8.1 support