Merge conflicts display error of command not found

[ch1ll0ut1]

When using the merge driver, i get the following error:

> git merge temp   
$(npm bin)/git-json-merge .merge_file_tpeMkq .merge_file_XDZbj1 .merge_file_gwQud5: Unknown: command not found
Auto-merging document.json
CONFLICT (content): Merge conflict in document.json
Automatic merge failed; fix conflicts and then commit the result.

The merge has changes in two different lines, so without this merge driver, there actually is no merge conflict. (the default git resolves it automatically).

I have tried to install the driver globally as well and it didnt make a difference.

File: .gitattributes

*.json merge=json

File: .gitconfig

[core]
    attributesfile = ~/.gitattributes
[merge "json"]
    name = custom merge driver for json files
    driver = git-json-merge %A %O %B