"git pull" broken

Interesting. try echo $GIT_EXEC_PATH, which git. It's unlikely to be related to the snow beast…

Looking in the source of git, there's a comment in git.c:

/*
 * We use PATH to find git commands, but we prepend some higher
 * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 * environment, and the $(gitexecdir) from the Makefile at build
 * time.
 */

If you call git --exec-path, you end up calling const char *git_exec_path(void) in exec_cmd.c. That looks like this:

const char *env;

if (argv_exec_path)
    return argv_exec_path;

env = getenv(EXEC_PATH_ENVIRONMENT);
if (env && *env) {
    return env;
}

return system_path(GIT_EXEC_PATH);

Now, _argv_exec_path_ is set when you say --exec-path=/some/where so can be discounted. You've stated that the environment variable isn't set. GIT_EXEC_PATH is defined during compilation in the Makefile. Going backwards, it seems to be defined as just libexec/git-core. So, we need to look at what system_path() does instead.

I'm not sure whether RUNTIME_PREFIX is defined for you. But while nosing in the Makefile, I did notice that prefix defaults to $(HOME). I suspect that this may be the cause of your problems.

The simple answer is to put this in ~/.bashrc:

export GIT_EXEC_PATH=/opt/local/libexec/git-core

If you want to find out more about what's going on, you'll probably have to recompile git using port -d upgrade -f git-core (or similar) and look closely at the build log to see where prefix is being set. Incidentally, port cat git-core shows heavy usage of ${prefix} so it should (hopefully) be obvious.