[PATCH v4 11/13] mingw: ensure valid CTYPE

From: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
Date: Sep 10, 2026, 06:05 UTC
Message-ID: <1bbd0dc6aaa362a942d47fc2e4630ca6e7f14cd1.1789020327.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.2195.v4.git.1789020327.gitgitgadget@gmail.com>

From: Johannes Schindelin <johannes.schindelin@gmx.de>

A change between versions 2.4.1 and 2.6.0 of the MSYS2 runtime modified how Cygwin's runtime (and hence Git for Windows' MSYS2 runtime derivative) handles locales: d16a56306d (Consolidate wctomb/mbtowc calls for POSIX-1.2008, 2016-07-20).

An unintended side-effect is that "cold-calling" into the POSIX emulation will start with a locale based on the current code page, something that Git for Windows is very ill-prepared for, as it expects to be able to pass a command-line containing non-ASCII characters to the shell without having those characters munged.

One symptom of this behavior: when `git clone` or `git fetch` shell out to call `git-upload-pack` with a path that contains non-ASCII characters, the shell tried to interpret the entire command-line (including command-line parameters) as executable path, which obviously must fail.

This fixes https://github.com/git-for-windows/git/issues/1036

Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/mingw.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/compat/mingw.c b/compat/mingw.c
index e0fbd2c66d..afdc1ef2db 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -3185,6 +3185,9 @@ static void setup_windows_environment(void)
 		if (!tmp && (tmp = getenv("USERPROFILE")))
 			setenv("HOME", tmp, 1);
 	}
+
+	if (!getenv("LC_ALL") && !getenv("LC_CTYPE") && !getenv("LANG"))
+		setenv("LC_CTYPE", "C.UTF-8", 1);
 }
 
 int mingw_platform_has_symlinks(void)

-- 
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