git-pull: Avoid merge-base on detached head

git pull --rebase does some clever tricks to find the base
for $upstream, but it forgets that we may not have any
branch at all.  When this happens, git merge-base reports its
"usage" help in the middle of an otherwise successful
rebase operation, because git-merge is called with one too
few parameters.

Since we do not need the merge-base trick in the case of a
detached HEAD, detect this condition and bypass the clever
trick and the usage noise.

Signed-off-by: Phil Hord <hordp@cisco.com>
Signed-off-by: Jeff King <peff@peff.net>

diff --git a/git-pull.sh b/git-pull.sh
index 2a10047eb710011213024bd0acc57eec87a6f965..266e682f6c518ab72dc710d52ed4f1dbe22881b5 100755 (executable)
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -200,6 +200,7 @@ test true = "$rebase" && {
                require_clean_work_tree "pull with rebase" "Please commit or stash them."
        fi
        oldremoteref= &&
+       test -n "$curr_branch" &&
        . git-parse-remote &&
        remoteref="$(get_remote_merge_branch "$@" 2>/dev/null)" &&
        oldremoteref="$(git rev-parse -q --verify "$remoteref")" &&