`git merge --no-overwrite-ignore` overwrites ignored files when merge (i.e. not fast-forward)

[Han Jiang <jhcarl0814@gmail.com>]

Thank you for filling out a Git bug report!
Please answer the following questions to help us understand your issue.

What did you do before the bug happened? (Steps to reproduce your issue)

(`git merge --no-overwrite-ignore` overwrites ignored files when merge
with conflict.)
cd '/'; cd '/'; rm --force --recursive -- './test_git'; mkdir "$_"; cd "$_";
mkdir --parents -- './repo';
git init './repo'
echo '1' >'./repo/file_conflict'; git -C './repo' add
'./file_conflict'; git -C './repo' commit -m "$((++number))"
git -C './repo' branch branch2
git -C './repo' checkout -b branch1; echo 'file' >'./repo/.gitignore';
git -C './repo' add './.gitignore'; echo '2' >'./repo/file_conflict';
git -C './repo' add './file_conflict'; git -C './repo' commit -m
"$((++number))"
git -C './repo' checkout branch2; echo '1' >'./repo/file'; git -C
'./repo' add './file'; echo '3' >'./repo/file_conflict'; git -C
'./repo' add './file_conflict'; git -C './repo' commit -m
"$((++number))"
git -C './repo' checkout branch1
echo '2' >'./repo/file';
git -C './repo' log --graph --all --patch
git -C './repo' status --verbose --verbose
cat './repo/file'
git -C './repo' merge -m "$((++number))" --no-overwrite-ignore branch2
git -C './repo' log --graph --all --patch
git -C './repo' status --verbose --verbose
cat './repo/file'

(`git merge --no-overwrite-ignore` overwrites ignored files when merge
without conflict.)
cd '/'; cd '/'; rm --force --recursive -- './test_git'; mkdir "$_"; cd "$_";
mkdir --parents -- './repo';
git init './repo'
git -C './repo' commit -m "$((++number))" --allow-empty
git -C './repo' branch branch2
git -C './repo' checkout -b branch1; echo 'file' >'./repo/.gitignore';
git -C './repo' add './.gitignore'; git -C './repo' commit -m
"$((++number))"
git -C './repo' checkout branch2; echo '1' >'./repo/file'; git -C
'./repo' add './file'; git -C './repo' commit -m "$((++number))"
git -C './repo' checkout branch1
echo '2' >'./repo/file';
git -C './repo' log --graph --all --patch
git -C './repo' status --verbose --verbose
cat './repo/file'
git -C './repo' merge -m "$((++number))" --no-overwrite-ignore branch2
git -C './repo' log --graph --all --patch
git -C './repo' status --verbose --verbose
cat './repo/file'

What did you expect to happen? (Expected behavior)

`git merge --no-overwrite-ignore` refuses to overwrite ignored files
when merge with conflict.
`git merge --no-overwrite-ignore` refuses to overwrite ignored files
when merge without conflict.

What happened instead? (Actual behavior)

`git merge --no-overwrite-ignore` overwrites ignored files when merge
with conflict.
`git merge --no-overwrite-ignore` overwrites ignored files when merge
without conflict.

What's different between what you expected and what actually happened?

Anything else you want to add:

(`git merge --no-overwrite-ignore` refuses to overwrite ignored files
when fast-forward.)
cd '/'; cd '/'; rm --force --recursive -- './test_git'; mkdir "$_"; cd "$_";
mkdir --parents -- './repo';
git init './repo'
branch_default_path="$(git -C './repo' symbolic-ref HEAD)"
branch_default_name="${branch_default_path#'refs/heads/'}"
echo 'file' >'./repo/.gitignore'; git -C './repo' add './.gitignore';
git -C './repo' commit -m "$((++number))"
git -C './repo' branch branch1
rm './repo/.gitignore'; git -C './repo' add './.gitignore'; echo '1'
>'./repo/file'; git -C './repo' add './file'; git -C './repo' commit
-m "$((++number))"
git -C './repo' checkout branch1
echo '2' >'./repo/file';
git -C './repo' log --graph --all --patch
git -C './repo' status --verbose --verbose
cat './repo/file'
git -C './repo' merge -m "$((++number))" --no-overwrite-ignore
"$branch_default_name"
git -C './repo' log --graph --all --patch
git -C './repo' status --verbose --verbose
cat './repo/file'

Please review the rest of the bug report below.
You can delete any lines you don't wish to share.


[System Info]
git version:
git version 2.46.0.windows.1
cpu: x86_64
built from commit: 2e6a859ffc0471f60f79c1256f766042b0d5d17d
sizeof-long: 4
sizeof-size_t: 8
shell-path: D:/git-sdk-64-build-installers/usr/bin/sh
feature: fsmonitor--daemon
libcurl: 8.9.0
OpenSSL: OpenSSL 3.2.2 4 Jun 2024
zlib: 1.3.1
uname: Windows 10.0 22631
compiler info: gnuc: 14.1
libc info: no libc information available
$SHELL (typically, interactive shell): C:\Program Files\Git\usr\bin\bash.exe


[Enabled Hooks]
not run from a git repository - no hooks to show