In the package definition the call to the command 'git' is substituted with the full path to the git executable. This change causes the mix formatting tool to complain that the line is too long. This workaround reformats the file after the substitution is made. --- a/Makefile +++ b/Makefile @@ -265,6 +265,7 @@ format: compile $(call FORMAT) test_formatted: compile + $(call FORMAT,lib/mix/lib/mix/scm/git.ex) $(call FORMAT,--check-formatted) test_erlang: compile $(TEST_ERLS)