From: Matthias Aßhauer <mha1993@live.de>
Date: Fri, 15 Aug 2025 17:12:56 GMT
Subject: Re: [PATCH v2 09/17] Do support Windows again after requiring Rust
Message-ID: <DB9P250MB0692900F30A3E71E4F01DFFFA534A@DB9P250MB0692.EURP250.PROD.OUTLOOK.COM>
In-Reply-To: <96041a10d545e0e431d05b93544771c6bdfc06f1.1755220973.git.gitgitgadget@gmail.com>



On Fri, 15 Aug 2025, Johannes Schindelin via GitGitGadget wrote:

> From: Johannes Schindelin <johannes.schindelin@gmx.de>
>
> By default, Rust wants to build MS Visual C-compatible libraries on
> Windows, because that is _the_ native C compiler.
>
> Git is historically lacking in its MSVC support, and the official Git
> for Windows versions are built using GCC instead. As a consequence, a
> (subset of a) GCC toolchain is installed as part of the `windows-build`
> job of every CI build.
>
> Naturally, this requires adjustments in how Rust is called, most
> importantly it requires installing support for a GCC-compatible build
> target.
>
> Let's make the necessary adjustment both in the CI-specific code that
> installs Rust as well as in the Windows-specific configuration in
> `config.mak.uname`.
>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> [en: Moved lib userenv handling to a later patch]
> Signed-off-by: Ezekiel Newren <ezekielnewren@gmail.com>
> ---
> ci/install-rust.sh | 3 +++
> config.mak.uname   | 7 +++++++
> 2 files changed, 10 insertions(+)
>
> diff --git a/ci/install-rust.sh b/ci/install-rust.sh
> index 141ceddb17cf..c22baa629ceb 100644
> --- a/ci/install-rust.sh
> +++ b/ci/install-rust.sh
> @@ -28,6 +28,9 @@ if [ "$BITNESS" = "32" ]; then
>   $CARGO_HOME/bin/rustup default --force-non-host $RUST_VERSION || exit $?
> else
>   $CARGO_HOME/bin/rustup default $RUST_VERSION || exit $?
> +  if [ "$CI_OS_NAME" = "windows" ]; then
> +    $CARGO_HOME/bin/rustup target add x86_64-pc-windows-gnu || exit $?
> +  fi
> fi
>
> . $CARGO_HOME/env
> diff --git a/config.mak.uname b/config.mak.uname
> index 3e26bb074a4b..a22703284b56 100644
> --- a/config.mak.uname
> +++ b/config.mak.uname
> @@ -727,19 +727,26 @@ ifeq ($(uname_S),MINGW)
> 		prefix = /mingw32
> 		HOST_CPU = i686
> 		BASIC_LDFLAGS += -Wl,--pic-executable,-e,_mainCRTStartup
> +		CARGO_BUILD_TARGET = i686-pc-windows-gnu
>         endif
>         ifeq (MINGW64,$(MSYSTEM))
> 		prefix = /mingw64
> 		HOST_CPU = x86_64
> 		BASIC_LDFLAGS += -Wl,--pic-executable,-e,mainCRTStartup
> +		CARGO_BUILD_TARGET = x86_64-pc-windows-gnu

I've said it when Johannes originally sent this patch[1], but it bears 
repeating: The *-pc-windows-gnu targets will pass CI, but would mean 
raising the required Windows version from 8.1 to 10. We'd want to use
the *-win7-windows-gnu targets[2] to keep Windows 8.1 supported.

[1] 
https://lore.kernel.org/git/pull.1980.git.git.1752784344.gitgitgadget@gmail.com/T/#ma10be2ed0a0e776b0af2fdd0de63d51ba51609e4
[2] 
https://doc.rust-lang.org/nightly/rustc/platform-support/win7-windows-gnu.html

>         else ifeq (CLANGARM64,$(MSYSTEM))
> 		prefix = /clangarm64
> 		HOST_CPU = aarch64
> 		BASIC_LDFLAGS += -Wl,--pic-executable,-e,mainCRTStartup
> +		CARGO_BUILD_TARGET = aarch64-pc-windows-gnu

As I've also mentioned before [1], this target doesn't seem to exist. The 
correct target seems to be aarch64-pc-windows-gnullvm. [3]

[3] https://doc.rust-lang.org/rustc/platform-support/windows-gnullvm.html

>         else
> 		COMPAT_CFLAGS += -D_USE_32BIT_TIME_T
> 		BASIC_LDFLAGS += -Wl,--large-address-aware
>         endif
> +
> +	export CARGO_BUILD_TARGET
> +	RUST_TARGET_DIR = rust/target/$(CARGO_BUILD_TARGET)/$(RUST_BUILD_MODE)
> +
> 	CC = gcc
> 	COMPAT_CFLAGS += -D__USE_MINGW_ANSI_STDIO=0 -DDETECT_MSYS_TTY \
> 		-fstack-protector-strong
> -- 
> gitgitgadget

Best regards

Matthias