git error: cannot do a partial commit during a merge.

After a pull command, I ended up with a conflict in a file, which I fixed by manually editing the file (search for the <<< signs). The merge is fine and therefore tried to commit the file again but got this error:

1	fatal: cannot do a partial commit during a merge.

Using :

1	git commit -a my_filename

did not work, instead use

1	git commit -i my_filename

From the git documentation, the -i should be used to conclude a conflicted merge.