This took a ridiculously long time for me to figure out. Of course I didn't actually figure it out, I just finally found the right StackOverflow article How to check real git diff before merging from remote branch?.
status you chose to run from git does bupkis in getting the status of the remote origin. Those actions only look at the local cached copy of information, for reasons I do not understand. In order to perform a diff without actually
pulling the changes, you have to
fetch the latest revision first. That gets stored in your local cache, and then your
status commands are worth a damn. I might finally be able to do smart-regenerating of my blog rather than just building the whole thing all the time. Maybe. Regardless, to perform an actual
diff that's worth a sandwich:
git fetch & git diff --name-status HEAD origin/master