[PATCH 09/10] t6423: introduce Windows-specific handling for symlinking to /dev/null

From: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
Date: Nov 29, 2025, 18:28 UTC
Message-ID: <b622ff822c367f20ea2c13fea7f404ea2c01f452.1764440906.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.2009.git.1764440906.gitgitgadget@gmail.com>

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

The device `/dev/null` does not exist on Windows, it's called `NUL` there. Calling `ln -s /dev/null my-symlink` in a symlink-enabled MSYS2 Bash will therefore literally link to a file or directory called `null` that is supposed to be in the current drive's top-level `dev` directory. Which typically does not exist.

The test, however, really wants the created symbolic link to point to the NUL device. Let's instead use the `mklink` utility on Windows to perform that job, and keep using `ln -s /dev/null <target>` on non-Windows platforms.

While at it, add the missing `SYMLINKS` prereq because this test _still_ would not pass on Windows before support for symbolic links is upstreamed from Git for Windows.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 t/t6423-merge-rename-directories.sh | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/t/t6423-merge-rename-directories.sh b/t/t6423-merge-rename-directories.sh
index 533ac85dc8..53535a8ebf 100755
--- a/t/t6423-merge-rename-directories.sh
+++ b/t/t6423-merge-rename-directories.sh
@@ -5158,13 +5158,18 @@ test_setup_12m () {
 		git switch B &&
 		git rm dir/subdir/file &&
 		mkdir dir &&
-		ln -s /dev/null dir/subdir &&
+		if test_have_prereq MINGW
+		then
+			cmd //c 'mklink dir\subdir NUL'
+		else
+			ln -s /dev/null dir/subdir
+		fi &&
 		git add . &&
 		git commit -m "B"
 	)
 }
 
-test_expect_success '12m: Change parent of renamed-dir to symlink on other side' '
+test_expect_success SYMLINKS '12m: Change parent of renamed-dir to symlink on other side' '
 	test_setup_12m &&
 	(
 		cd 12m &&

-- 
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