How to prevent git merge if current branch has uncommitted changes

Question

It's possible to git merge even if current branch has uncommitted changes. Example:

git checkout featureA
ls >> foo
git commit -am "added featureA"
git checkout dev
ls >> bar                    # current branch now has uncommitted changes
git merge featureA

I wonder if it's possible to configure git to always fail as long as current branch has uncommitted changes, just to make the merge safer.

Add them to the index? Otherwise, I'm not sure how this is unsafe. Git will avoid merging if things are unsafe (see also "Pre-merge Checks": https://git-scm.com/docs/git-merge#_pre_merge_checks). — Whymarrh, Feb 22 '16 at 02:03

score 0 · Answer 1 · edited May 23 '17 at 12:31

My first thought was to declare a Git alias to override the merge command and check the state of your working-directory and index prior to performing the operation.

Turns out it's not possible to overwrite an exiting Git command with a Git alias (see this question for more info) but you could define a shell-level alias.

To keep things simple, perhaps it would be better to define an alias called safemerge. You could also define an additional alias to make detecting a clean state easy.

Define these as aliases in your .gitconfig:

isclean = !(git status --porcelain | grep . && exit 1 || exit 0)
safemerge = !git isclean && git-merge

Now, when you go to merge you can run git safemerge and the merge will not happen if you have uncommitted changes.

How to prevent git merge if current branch has uncommitted changes

1 Answers1