I saw a command line reference which recommended git pull --rebase --ff-only. I thought git would reject that, but it doesn’t.
What does the combination of --rebase with --ff-only mean?
Edit: I perfectly know what each alone does.
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Robert Siemer
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possible duplicate of [Difference between git pull --rebase and git pull --ff-only](http://stackoverflow.com/questions/25430600/difference-between-git-pull-rebase-and-git-pull-ff-only) – Avalanche Jul 21 '15 at 20:36
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1No, that's not a duplicate. It's the combination of `--rebase` and `--ff-only` passed to `git pull` this is about. – sschuberth Jul 21 '15 at 20:40
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Maybe the recommendation should be either rebase or --ff-only because the default behavior makes merge commits automatically. – Joseph K. Strauss Jul 21 '15 at 20:51
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[Edit, 4 Dec 2016: as of Git version 2.6, git pull is no longer a script, so it is no longer easy to see what it does and the technical details below no longer apply. But --ff-only is still only useful when merging, not when rebasing.]
The git pull script (you can view it yourself, e.g., less $(git --exec-path)/pull) currently separates out --ff-only into a variable named $ff_only that it subsequently ignores entirely if it winds up doing a rebase:
case "$rebase" in
true)
eval="git-rebase $diffstat $strategy_args $merge_args $rebase_args $verbosity"
eval="$eval $gpg_sign_args"
eval="$eval --onto $merge_head ${oldremoteref:-$merge_head}"
;;
*)
eval="git-merge $diffstat $no_commit $verify_signatures $edit $squash $no_ff $ff_only"
eval="$eval $log_arg $strategy_args $merge_args $verbosity $progress"
eval="$eval $gpg_sign_args"
eval="$eval FETCH_HEAD"
;;
esac
eval "exec $eval"
What this means in the end is that your --ff-only option gets ignored.
It's possible that in the future, git might reject these as incompatible, so it's probably wiser to leave out an explicit --ff-only when using an explicit --rebase.
torek
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