Indicate whether file has uncommited changes in mode line

Question

In my mode line I can see if a buffer has unsaved changes (**- or a red x in my case, since I am using smart-mode-line).

Is there a similar way to display whether or not the file visited by the current buffer has uncommitted changes in Git or whatever VCS you are using?

Answer 1

Well, vc does that by default. From its documentation (emphasis mine):

When you visit a file that is under version control, Emacs indicates this on the mode line. For example, ‘Bzr-1223’ says that Bazaar is used for that file, and the current revision ID is 1223.

The character between the back-end name and the revision ID indicates the "version control status" of the work file. In a merge-based version control system, a ‘-’ character indicates that the work file is unmodified, and ‘:’ indicates that it has been modified. ‘!’ indicates that the file contains conflicts as result of a recent merge operation (*note Merging::), or that the file was removed from the version control. Finally, ‘?’ means that the file is under version control, but is missing from the working tree.