Git ignore不能处理以下划线开头的文件

Question

为什么public/_test.php显示为已更改？

[Michael@devserver www]$ cat .gitignore
logs
vendor
src/twig
public/_test.php
.env
[Michael@devserver www]$ git status
# On branch master
# Changed but not updated:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#       modified:   public/_test.php
#       modified:   server.php
#       modified:   src/App.php
#       modified:   src/ServerApp.php
#       modified:   src/classes/Main.php
#
no changes added to commit (use "git add" and/or "git commit -a")
[Michael@devserver www]$