Hi, Please see the bug report below. Thanks, Tyson Thank you for filling out a Git bug report! Please answer the following questions to help us understand your issue. What did you do before the bug happened? (Steps to reproduce your issue) update ~/.gitconfig with [merge] ff = only add git subtree to repo git subtree add --prefix subtree-path git@xxxxxxxxxx:some-repo.git main --squash push new commit to git@xxxxxxxxxx:some-repo.git try to pull subtree commit $ git subtree pull --prefix subtree-path git@xxxxxxxxxx:some-repo.git main --squash From gitlab.com:some-repo * branch main -> FETCH_HEAD fatal: Not possible to fast-forward, aborting. What did you expect to happen? (Expected behavior) expect git subtree to be able to merge even if default option is ff, or provide git subtree pull with a --no-ff override What happened instead? (Actual behavior) subtree updates do not seem possible to pull with merge ff = only What's different between what you expected and what actually happened? subtree pull doesn't work Anything else you want to add: git subtree works after removing merge ff = only Please review the rest of the bug report below. You can delete any lines you don't wish to share. [System Info] git version: git version 2.35.3 cpu: x86_64 no commit associated with this build sizeof-long: 8 sizeof-size_t: 8 shell-path: /bin/sh uname: Linux 5.16.11-76051611-generic #202202230823~1646248261~21.10~2b22243 SMP PREEMPT Wed Mar 2 20: x86_64 compiler info: gnuc: 11.2 libc info: glibc: 2.34 $SHELL (typically, interactive shell): /bin/bash [Enabled Hooks] pre-commit