Why is Git rejecting my pull simply because I have a commit on my local branch?

There is a Git repository on a server that my colleague and I both push to and pull from. It works fine as long as we pull before committing. However, if he has pushed to the master branch, and in the mean time I have made a local commit, when I try to pull I get this: ``` ! [rejected] master -> master (non-fast-forward) ``` But I know that there should be no conflict. The way I get around it is by pulling into a new temporary branch and then merging that into my master like this: ``` % git pull origin master:temp From ssh://example.com/home/my/remote/repo * [new branch] master -> temp Already up-to-date. % git merge temp Already up-to-date. % git push origin master:master ``` Notice that Git acts like I'm not doing anything, but really I have shaken it into submission. Recently I realized that instead of trying to to "convince" Git that it's OK for me to pull. I can just pretend that I haven't committed yet with `git reset --soft HEAD^` and `git stash` and then do the pull and commit on top of that. What might be causing this strangely finicky behavior? I was able to reproduce this problem all on my local machine. Here's what I did: First I made the first "local" repository and added a file. ``` % cd % mkdir local-1 % cd local-1/ % mkdir website % cd website/ % git init Initialized empty Git repository in /Users/jason/local-1/website/.git/ % touch file % git add . % git commit -m 'added file' [master (root-commit) 6d4b322] added file 0 files changed, 0 insertions(+), 0 deletions(-) create mode 100644 file ``` Then I made the "remote" repository. ``` % cd % mkdir remote % cd remote % mkdir website.git % cd website.git/ % git init --bare Initialized empty Git repository in /Users/jason/remote/website.git/ ``` Then I went back to the local, created a ref and pushed to the remote. ``` % cd ~/local-1/website/ % git remote add web ~/remote/website.git % git push web +master:refs/heads/master Counting objects: 3, done. Writing objects: 100% (3/3), 207 bytes, done. Total 3 (delta 0), reused 0 (delta 0) Unpacking objects: 100% (3/3), done. To /Users/jason/remote/website.git * [new branch] master -> master ``` After that I cloned the remote into a second local. ``` % cd % mkdir local-2 % cd local-2 % git clone ~/remote/website.git Cloning into website... done. ``` Then I created a ref to the remote from the second local and pushed (this is where I am creating the problem I think). ``` % cd website/ % git remote add web ~/remote/website.git % git push web +master:refs/heads/master Everything up-to-date ``` Then I made a change to local-2, committed, and pushed. ``` % touch another % git add . % git commit -m 'added another' [master be91180] added another 0 files changed, 0 insertions(+), 0 deletions(-) create mode 100644 another % git push web Counting objects: 3, done. Delta compression using up to 4 threads. Compressing objects: 100% (2/2), done. Writing objects: 100% (2/2), 238 bytes, done. Total 2 (delta 0), reused 0 (delta 0) Unpacking objects: 100% (2/2), done. To /Users/jason/remote/website.git 6d4b322..be91180 master -> master ``` Finally, I made a different change to local-1, committed, and tried to push. ``` % cd ~/local-1/website/ % touch something % git add . % git commit -m 'added something' [master 3984529] added something 0 files changed, 0 insertions(+), 0 deletions(-) create mode 100644 something % git push web To /Users/jason/remote/website.git ! [rejected] master -> master (non-fast-forward) error: failed to push some refs to '/Users/jason/remote/website.git' To prevent you from losing history, non-fast-forward updates were rejected Merge the remote changes (e.g. 'git pull') before pushing again. See the 'Note about fast-forwards' section of 'git push --help' for details. ``` Blast! How about a pull? ``` % git pull web master:master From /Users/jason/remote/website ! [rejected] master -> master (non-fast-forward) ``` OK, so there's the problem. How do I fix it?