--no-commit option does not work.

[BongHo Lee <techcap@live.com>]

Setup
Version : git version 2.12.1.windows.1

OS Version : Microsoft Windows [Version 10.0.14393]

Options 
$ cat /etc/install-options.txt
Path Option: Cmd
SSH Option: OpenSSH
CURL Option: OpenSSL
CRLF Option: CRLFCommitAsIs
Bash Terminal Option: MinTTY
Performance Tweaks FSCache: Enabled
Use Credential Manager: Enabled
Enable Symlinks: Disabled


Git Command : git merge --no-commit origin/workingBranch

. What did you expect to occur after running these commands?
merge but no commit.
. What actually happened instead?
commited

Reference URL : https://github.com/techcap/nf-interpreter

Details
I tried to merge from MergeTest to master.
After checking out master, I run below command.

C:\work\nf-interpreter-techcap>git branch
  MergeTest
  TemplateModification
  UpdateBuildInstruction
* master

C:\work\nf-interpreter-techcap>git merge --no-commit origin/MergeTest
Updating 197ad33..028f9f5
Fast-forward
mergeTest.txt | 1 +
1 file changed, 1 insertion(+)
create mode 100644 mergeTest.txt

C:\work\nf-interpreter-techcap>git status
On branch master
Your branch is ahead of 'origin/master' by 1 commit.
  (use "git push" to publish your local commits)
nothing to commit, working tree clean

If I add --no-ff option, it works properly.
I think --no-commit option should be worked without --no-ff.

https://github.com/git-for-windows/git/issues/1102#issuecomment-289206961