Default version uses master branch in Git. Another branch contains changes which will be merged to master.
Meanwhile, another developer has made changes in the Default version (master branch) which are *not committed* (which is not great, but might not be avoidable).
When I then perform a Git merge into master from another branch, those changes in master are completely removed. This is not normal Git behavior as far as I can tell, those changes in master should be retained as un-committed (but they are not, which seems like a bug to me).
Correct behavior on my box:
username@hostname:~/temp/git_test $ git init
Initialized empty Git repository in /home/username/temp/git_test/.git/
username@hostname:~/temp/git_test $ git status
username@hostname:~/temp/git_test $ echo "testing" > test_file
username@hostname:~/temp/git_test $ git add .
username@hostname:~/temp/git_test $ git commit -m "First commit"
[main (root-commit) 104b85e] First commit
1 file changed, 1 insertion(+)
create mode 100644 test_file
username@hostname:~/temp/git_test (main)$ git branch my_branch
username@hostname:~/temp/git_test (main)$ git checkout my_branch
Switched to branch 'my_branch'
username@hostname:~/temp/git_test (my_branch)$ echo "other file" > other_file
username@hostname:~/temp/git_test (my_branch)$ git add .
username@hostname:~/temp/git_test (my_branch)$ git commit -m "Adding other file in my_branch"
[my_branch 1b45ddb] Adding other file in my_branch
1 file changed, 1 insertion(+)
create mode 100644 other_file
username@hostname:~/temp/git_test (my_branch)$ git checkout main
Switched to branch 'main'
username@hostname:~/temp/git_test (main)$ echo "new file" > new_file
username@hostname:~/temp/git_test (main)$ git status
On branch main
Untracked files:
(use "git add <file>..." to include in what will be committed)
new_file
nothing added to commit but untracked files present (use "git add" to track)
username@hostname:~/temp/git_test (main)$ git merge my_branch
Updating 104b85e..1b45ddb
Fast-forward
other_file | 1 +
1 file changed, 1 insertion(+)
create mode 100644 other_file
username@hostname:~/temp/git_test (main)$ git status
On branch main
Untracked files:
(use "git add <file>..." to include in what will be committed)
new_file
nothing added to commit but untracked files present (use "git add" to track)
username@hostname:~/temp/git_test (main)$ ls
total 24K
drwxr-xr-x 3 username username 4.0K 2022-12-15 10:20 .
drwxr-xr-x 13 username username 4.0K 2022-12-15 10:18 ..
drwxr-xr-x 8 username username 4.0K 2022-12-15 10:20 .git
-rw-r--r-- 1 username username 9 2022-12-15 10:20 new_file
-rw-r--r-- 1 username username 11 2022-12-15 10:20 other_file
-rw-r--r-- 1 username username 8 2022-12-15 10:19 test_file
username@hostname:~/temp/git_test (main)$