[git] Git merge error "commit is not possible because you have unmerged files"

Since git 2.23 (August 2019) you now have a shortcut to do that: git restore --staged [filepath]. With this command, you could ignore a conflicted file without needing to add and remove that.

Example:

> git status

  ...
  Unmerged paths:
    (use "git add <file>..." to mark resolution)
      both modified:   file.ex

> git restore --staged file.ex

> git status

  ...
  Changes not staged for commit:
    (use "git add <file>..." to update what will be committed)
    (use "git restore <file>..." to discard changes in working directory)
      modified:   file.ex