v3, 5 partsPreparation for non-ff pulls by default

Documentation/config.txt, Documentation/git-pull.txt, branch.c, git-pull.sh, t/t3200-branch.sh, t/t5520-pull.sh, t/t5601-clone.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index ec57a15..9489a59 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -706,7 +706,7 @@ branch.autosetupmerge::
 branch.autosetuprebase::
 	When a new branch is created with 'git branch' or 'git checkout'
 	that tracks another branch, this variable tells Git to set
-	up pull to rebase instead of merge (see "branch.<name>.rebase").
+	up pull to rebase instead of merge (see "branch.<name>.pullmode").
 	When `never`, rebase is never automatically set to true.
 	When `local`, rebase is set to true for tracked branches of
 	other local branches.
@@ -760,11 +760,11 @@ branch.<name>.mergeoptions::
 	option values containing whitespace characters are currently not
 	supported.
 
-branch.<name>.rebase::
-	When true, rebase the branch <name> on top of the fetched branch,
-	instead of merging the default branch from the default remote when
-	"git pull" is run. See "pull.rebase" for doing this in a non
-	branch-specific manner.
+branch.<name>.pullmode::
+	When "git pull" is run, this determines if it would either merge or
+	rebase the fetched branch. The possible values are 'merge' and
+	'rebase'. See "pull.mode" for doing this in a non branch-specific
+	manner.
 +
 *NOTE*: this is a possibly dangerous operation; do *not* use
 it unless you understand the implications (see linkgit:git-rebase[1]
@@ -1820,11 +1820,11 @@ pretty.<name>::
 	Note that an alias with the same name as a built-in format
 	will be silently ignored.
 
-pull.rebase::
-	When true, rebase branches on top of the fetched branch, instead
-	of merging the default branch from the default remote when "git
-	pull" is run. See "branch.<name>.rebase" for setting this on a
-	per-branch basis.
+pull.mode::
+	When "git pull" is run, this determines if it would either merge or
+	rebase the fetched branch. The possible values are 'merge' and
+	'rebase'. See "branch.<name>.pullmode" for doing this in a non
+	branch-specific manner.
 +
 *NOTE*: this is a possibly dangerous operation; do *not* use
 it unless you understand the implications (see linkgit:git-rebase[1]
diff --git a/Documentation/git-pull.txt b/Documentation/git-pull.txt
index 6ef8d59..991352f 100644
--- a/Documentation/git-pull.txt
+++ b/Documentation/git-pull.txt
@@ -109,7 +109,7 @@ include::merge-options.txt[]
 	fetched, the rebase uses that information to avoid rebasing
 	non-local changes.
 +
-See `pull.rebase`, `branch.<name>.rebase` and `branch.autosetuprebase` in
+See `pull.mode`, `branch.<name>.pullmode` and `branch.autosetuprebase` in
 linkgit:git-config[1] if you want to make `git pull` always use
 `--rebase` instead of merging.
 +
diff --git a/branch.c b/branch.c
index c5c6984..c6b70c2 100644
--- a/branch.c
+++ b/branch.c
@@ -71,8 +71,8 @@ void install_branch_config(int flag, const char *local, const char *origin, cons
 
 	if (rebasing) {
 		strbuf_reset(&key);
-		strbuf_addf(&key, "branch.%s.rebase", local);
-		git_config_set(key.buf, "true");
+		strbuf_addf(&key, "branch.%s.pullmode", local);
+		git_config_set(key.buf, "rebase");
 	}
 	strbuf_release(&key);
 
diff --git a/git-pull.sh b/git-pull.sh
index f0df41c..de57c1d 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -43,10 +43,24 @@ log_arg= verbosity= progress= recurse_submodules= verify_signatures=
 merge_args= edit=
 curr_branch=$(git symbolic-ref -q HEAD)
 curr_branch_short="${curr_branch#refs/heads/}"
-rebase=$(git config --bool branch.$curr_branch_short.rebase)
+mode=$(git config branch.${curr_branch_short}.pullmode)
+if test -z "$mode"
+then
+	mode=$(git config pull.mode)
+fi
+test "$mode" == 'rebase' && rebase="true"
 if test -z "$rebase"
 then
-	rebase=$(git config --bool pull.rebase)
+	rebase=$(git config --bool branch.$curr_branch_short.rebase)
+	if test -z "$rebase"
+	then
+		rebase=$(git config --bool pull.rebase)
+	fi
+	if test "$rebase" = 'true'
+	then
+		echo "The configurations pull.rebase and branch.<name>.rebase are deprecated."
+		echo "Please use pull.mode and branch.<name>.pullmode instead."
+	fi
 fi
 dry_run=
 while :
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 44ec6a4..b620798 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -557,7 +557,7 @@ test_expect_success 'autosetuprebase local on a tracked local branch' '
 	git branch --track myr1 mybase &&
 	test "$(git config branch.myr1.remote)" = . &&
 	test "$(git config branch.myr1.merge)" = refs/heads/mybase &&
-	test "$(git config branch.myr1.rebase)" = true
+	test "$(git config branch.myr1.pullmode)" = rebase
 '
 
 test_expect_success 'autosetuprebase always on a tracked local branch' '
@@ -569,7 +569,7 @@ test_expect_success 'autosetuprebase always on a tracked local branch' '
 	git branch --track myr2 mybase &&
 	test "$(git config branch.myr2.remote)" = . &&
 	test "$(git config branch.myr2.merge)" = refs/heads/mybase &&
-	test "$(git config branch.myr2.rebase)" = true
+	test "$(git config branch.myr2.pullmode)" = rebase
 '
 
 test_expect_success 'autosetuprebase remote on a tracked local branch' '
@@ -581,7 +581,7 @@ test_expect_success 'autosetuprebase remote on a tracked local branch' '
 	git branch --track myr3 mybase2 &&
 	test "$(git config branch.myr3.remote)" = . &&
 	test "$(git config branch.myr3.merge)" = refs/heads/mybase2 &&
-	! test "$(git config branch.myr3.rebase)" = true
+	! test "$(git config branch.myr3.pullmode)" = rebase
 '
 
 test_expect_success 'autosetuprebase never on a tracked local branch' '
@@ -593,7 +593,7 @@ test_expect_success 'autosetuprebase never on a tracked local branch' '
 	git branch --track myr4 mybase2 &&
 	test "$(git config branch.myr4.remote)" = . &&
 	test "$(git config branch.myr4.merge)" = refs/heads/mybase2 &&
-	! test "$(git config branch.myr4.rebase)" = true
+	! test "$(git config branch.myr4.pullmode)" = rebase
 '
 
 test_expect_success 'autosetuprebase local on a tracked remote branch' '
@@ -604,7 +604,7 @@ test_expect_success 'autosetuprebase local on a tracked remote branch' '
 	git branch --track myr5 local/master &&
 	test "$(git config branch.myr5.remote)" = local &&
 	test "$(git config branch.myr5.merge)" = refs/heads/master &&
-	! test "$(git config branch.myr5.rebase)" = true
+	! test "$(git config branch.myr5.pullmode)" = rebase
 '
 
 test_expect_success 'autosetuprebase never on a tracked remote branch' '
@@ -615,7 +615,7 @@ test_expect_success 'autosetuprebase never on a tracked remote branch' '
 	git branch --track myr6 local/master &&
 	test "$(git config branch.myr6.remote)" = local &&
 	test "$(git config branch.myr6.merge)" = refs/heads/master &&
-	! test "$(git config branch.myr6.rebase)" = true
+	! test "$(git config branch.myr6.pullmode)" = rebase
 '
 
 test_expect_success 'autosetuprebase remote on a tracked remote branch' '
@@ -626,7 +626,7 @@ test_expect_success 'autosetuprebase remote on a tracked remote branch' '
 	git branch --track myr7 local/master &&
 	test "$(git config branch.myr7.remote)" = local &&
 	test "$(git config branch.myr7.merge)" = refs/heads/master &&
-	test "$(git config branch.myr7.rebase)" = true
+	test "$(git config branch.myr7.pullmode)" = rebase
 '
 
 test_expect_success 'autosetuprebase always on a tracked remote branch' '
@@ -637,7 +637,7 @@ test_expect_success 'autosetuprebase always on a tracked remote branch' '
 	git branch --track myr8 local/master &&
 	test "$(git config branch.myr8.remote)" = local &&
 	test "$(git config branch.myr8.merge)" = refs/heads/master &&
-	test "$(git config branch.myr8.rebase)" = true
+	test "$(git config branch.myr8.pullmode)" = rebase
 '
 
 test_expect_success 'autosetuprebase unconfigured on a tracked remote branch' '
@@ -648,7 +648,7 @@ test_expect_success 'autosetuprebase unconfigured on a tracked remote branch' '
 	git branch --track myr9 local/master &&
 	test "$(git config branch.myr9.remote)" = local &&
 	test "$(git config branch.myr9.merge)" = refs/heads/master &&
-	test "z$(git config branch.myr9.rebase)" = z
+	test "z$(git config branch.myr9.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase unconfigured on a tracked local branch' '
@@ -659,7 +659,7 @@ test_expect_success 'autosetuprebase unconfigured on a tracked local branch' '
 	git branch --track myr10 mybase2 &&
 	test "$(git config branch.myr10.remote)" = . &&
 	test "$(git config branch.myr10.merge)" = refs/heads/mybase2 &&
-	test "z$(git config branch.myr10.rebase)" = z
+	test "z$(git config branch.myr10.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase unconfigured on untracked local branch' '
@@ -669,7 +669,7 @@ test_expect_success 'autosetuprebase unconfigured on untracked local branch' '
 	git branch --no-track myr11 mybase2 &&
 	test "z$(git config branch.myr11.remote)" = z &&
 	test "z$(git config branch.myr11.merge)" = z &&
-	test "z$(git config branch.myr11.rebase)" = z
+	test "z$(git config branch.myr11.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase unconfigured on untracked remote branch' '
@@ -679,7 +679,7 @@ test_expect_success 'autosetuprebase unconfigured on untracked remote branch' '
 	git branch --no-track myr12 local/master &&
 	test "z$(git config branch.myr12.remote)" = z &&
 	test "z$(git config branch.myr12.merge)" = z &&
-	test "z$(git config branch.myr12.rebase)" = z
+	test "z$(git config branch.myr12.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase never on an untracked local branch' '
@@ -690,7 +690,7 @@ test_expect_success 'autosetuprebase never on an untracked local branch' '
 	git branch --no-track myr13 mybase2 &&
 	test "z$(git config branch.myr13.remote)" = z &&
 	test "z$(git config branch.myr13.merge)" = z &&
-	test "z$(git config branch.myr13.rebase)" = z
+	test "z$(git config branch.myr13.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase local on an untracked local branch' '
@@ -701,7 +701,7 @@ test_expect_success 'autosetuprebase local on an untracked local branch' '
 	git branch --no-track myr14 mybase2 &&
 	test "z$(git config branch.myr14.remote)" = z &&
 	test "z$(git config branch.myr14.merge)" = z &&
-	test "z$(git config branch.myr14.rebase)" = z
+	test "z$(git config branch.myr14.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase remote on an untracked local branch' '
@@ -712,7 +712,7 @@ test_expect_success 'autosetuprebase remote on an untracked local branch' '
 	git branch --no-track myr15 mybase2 &&
 	test "z$(git config branch.myr15.remote)" = z &&
 	test "z$(git config branch.myr15.merge)" = z &&
-	test "z$(git config branch.myr15.rebase)" = z
+	test "z$(git config branch.myr15.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase always on an untracked local branch' '
@@ -723,7 +723,7 @@ test_expect_success 'autosetuprebase always on an untracked local branch' '
 	git branch --no-track myr16 mybase2 &&
 	test "z$(git config branch.myr16.remote)" = z &&
 	test "z$(git config branch.myr16.merge)" = z &&
-	test "z$(git config branch.myr16.rebase)" = z
+	test "z$(git config branch.myr16.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase never on an untracked remote branch' '
@@ -734,7 +734,7 @@ test_expect_success 'autosetuprebase never on an untracked remote branch' '
 	git branch --no-track myr17 local/master &&
 	test "z$(git config branch.myr17.remote)" = z &&
 	test "z$(git config branch.myr17.merge)" = z &&
-	test "z$(git config branch.myr17.rebase)" = z
+	test "z$(git config branch.myr17.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase local on an untracked remote branch' '
@@ -745,7 +745,7 @@ test_expect_success 'autosetuprebase local on an untracked remote branch' '
 	git branch --no-track myr18 local/master &&
 	test "z$(git config branch.myr18.remote)" = z &&
 	test "z$(git config branch.myr18.merge)" = z &&
-	test "z$(git config branch.myr18.rebase)" = z
+	test "z$(git config branch.myr18.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase remote on an untracked remote branch' '
@@ -756,7 +756,7 @@ test_expect_success 'autosetuprebase remote on an untracked remote branch' '
 	git branch --no-track myr19 local/master &&
 	test "z$(git config branch.myr19.remote)" = z &&
 	test "z$(git config branch.myr19.merge)" = z &&
-	test "z$(git config branch.myr19.rebase)" = z
+	test "z$(git config branch.myr19.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase always on an untracked remote branch' '
@@ -767,7 +767,7 @@ test_expect_success 'autosetuprebase always on an untracked remote branch' '
 	git branch --no-track myr20 local/master &&
 	test "z$(git config branch.myr20.remote)" = z &&
 	test "z$(git config branch.myr20.merge)" = z &&
-	test "z$(git config branch.myr20.rebase)" = z
+	test "z$(git config branch.myr20.pullmode)" = z
 '
 
 test_expect_success 'autosetuprebase always on detached HEAD' '
diff --git a/t/t5520-pull.sh b/t/t5520-pull.sh
index ed4d9c8..978a3c1 100755
--- a/t/t5520-pull.sh
+++ b/t/t5520-pull.sh
@@ -284,4 +284,30 @@ test_expect_success 'git pull --rebase against local branch' '
 	test file = "$(cat file2)"
 '
 
+test_expect_success 'pull.mode' '
+	git checkout to-rebase &&
+	git reset --hard before-rebase &&
+	test_config pull.mode rebase &&
+	git pull . copy &&
+	test $(git rev-parse HEAD^) = $(git rev-parse copy) &&
+	test new = $(git show HEAD:file2)
+'
+
+test_expect_success 'branch.to-rebase.pullmode' '
+	git reset --hard before-rebase &&
+	test_config branch.to-rebase.pullmode rebase &&
+	git pull . copy &&
+	test $(git rev-parse HEAD^) = $(git rev-parse copy) &&
+	test new = $(git show HEAD:file2)
+'
+
+test_expect_success 'branch.to-rebase.pullmode should override pull.mode' '
+	git reset --hard before-rebase &&
+	test_config pull.mode rebase &&
+	test_config branch.to-rebase.pullmode merge &&
+	git pull . copy &&
+	test $(git rev-parse HEAD^) != $(git rev-parse copy) &&
+	test new = $(git show HEAD:file2)
+'
+
 test_done
diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index 0629149..6c888ae 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -191,8 +191,8 @@ test_expect_success 'clone respects global branch.autosetuprebase' '
 		rm -fr dst &&
 		git clone src dst &&
 		cd dst &&
-		actual="z$(git config branch.master.rebase)" &&
-		test ztrue = $actual
+		actual="$(git config branch.master.pullmode)" &&
+		test "$actual" = rebase
 	)
 '
 

diff --git a/git-pull.sh b/git-pull.sh
index a9cf7ac..9c4091c 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -58,8 +58,8 @@ then
 	if test "$rebase" = 'true'
 	then
 		mode="rebase"
-		echo "The configurations pull.rebase and branch.<name>.rebase are deprecated."
-		echo "Please use pull.mode and branch.<name>.pullmode instead."
+		echo >&2 "warning: The configurations pull.rebase and branch.<name>.rebase are deprecated."
+		echo >&2 "Please use pull.mode and branch.<name>.pullmode instead."
 	fi
 fi
 test -z "$mode" && mode=merge

diff --git a/git-pull.sh b/git-pull.sh
index de57c1d..f53d193 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -48,8 +48,7 @@ if test -z "$mode"
 then
 	mode=$(git config pull.mode)
 fi
-test "$mode" == 'rebase' && rebase="true"
-if test -z "$rebase"
+if test -z "$mode"
 then
 	rebase=$(git config --bool branch.$curr_branch_short.rebase)
 	if test -z "$rebase"
@@ -58,6 +57,7 @@ then
 	fi
 	if test "$rebase" = 'true'
 	then
+		mode="rebase"
 		echo "The configurations pull.rebase and branch.<name>.rebase are deprecated."
 		echo "Please use pull.mode and branch.<name>.pullmode instead."
 	fi
@@ -125,10 +125,10 @@ do
 		merge_args="$merge_args$xx "
 		;;
 	-r|--r|--re|--reb|--reba|--rebas|--rebase)
-		rebase=true
+		mode=rebase
 		;;
 	--no-r|--no-re|--no-reb|--no-reba|--no-rebas|--no-rebase)
-		rebase=false
+		mode=
 		;;
 	--recurse-submodules)
 		recurse_submodules=--recurse-submodules
@@ -171,7 +171,7 @@ error_on_no_merge_candidates () {
 		esac
 	done
 
-	if test true = "$rebase"
+	if test "$mode" = rebase
 	then
 		op_type=rebase
 		op_prep=against
@@ -185,7 +185,7 @@ error_on_no_merge_candidates () {
 	remote=$(git config "branch.$curr_branch.remote")
 
 	if [ $# -gt 1 ]; then
-		if [ "$rebase" = true ]; then
+		if [ "$mode" = rebase ]; then
 			printf "There is no candidate for rebasing against "
 		else
 			printf "There are no candidates for merging "
@@ -208,7 +208,7 @@ error_on_no_merge_candidates () {
 	exit 1
 }
 
-test true = "$rebase" && {
+test "$mode" = rebase && {
 	if ! git rev-parse -q --verify HEAD >/dev/null
 	then
 		# On an unborn branch
@@ -273,7 +273,7 @@ case "$merge_head" in
 	then
 		die "$(gettext "Cannot merge multiple branches into empty head")"
 	fi
-	if test true = "$rebase"
+	if test "$mode" = rebase
 	then
 		die "$(gettext "Cannot rebase onto multiple branches")"
 	fi
@@ -294,7 +294,7 @@ then
 	exit
 fi
 
-if test true = "$rebase"
+if test "$mode" = rebase
 then
 	o=$(git show-branch --merge-base $curr_branch $merge_head $oldremoteref)
 	if test "$oldremoteref" = "$o"
@@ -304,8 +304,8 @@ then
 fi
 
 merge_name=$(git fmt-merge-msg $log_arg <"$GIT_DIR/FETCH_HEAD") || exit
-case "$rebase" in
-true)
+case "$mode" in
+rebase)
 	eval="git-rebase $diffstat $strategy_args $merge_args $verbosity"
 	eval="$eval --onto $merge_head ${oldremoteref:-$merge_head}"
 	;;

Documentation/git-pull.txt, git-pull.sh

diff --git a/Documentation/git-pull.txt b/Documentation/git-pull.txt
index 991352f..e09f004 100644
--- a/Documentation/git-pull.txt
+++ b/Documentation/git-pull.txt
@@ -119,8 +119,12 @@ It rewrites history, which does not bode well when you
 published that history already.  Do *not* use this option
 unless you have read linkgit:git-rebase[1] carefully.
 
---no-rebase::
-	Override earlier --rebase.
+-m::
+--merge::
+	Force a merge.
++
+See `pull.mode`, `branch.<name>.pullmode` in linkgit:git-config[1] if you want
+to make `git pull` always use `--merge`.
 
 Options related to fetching
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/git-pull.sh b/git-pull.sh
index f53d193..fbb8a9b 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -127,8 +127,12 @@ do
 	-r|--r|--re|--reb|--reba|--rebas|--rebase)
 		mode=rebase
 		;;
+	-m|--m|--me|--mer|--merg|--merge)
+		mode=merge
+		;;
 	--no-r|--no-re|--no-reb|--no-reba|--no-rebas|--no-rebase)
-		mode=
+		mode=merge
+		echo "--no-rebase is deprecated, please use --merge instead"
 		;;
 	--recurse-submodules)
 		recurse_submodules=--recurse-submodules

Documentation/config.txt, git-pull.sh, t/t5520-pull.sh

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 9489a59..13635e0 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1822,9 +1822,11 @@ pretty.<name>::
 
 pull.mode::
 	When "git pull" is run, this determines if it would either merge or
-	rebase the fetched branch. The possible values are 'merge' and
-	'rebase'. See "branch.<name>.pullmode" for doing this in a non
-	branch-specific manner.
+	rebase the fetched branch. The possible values are 'merge',
+	'rebase', and 'merge-ff-only'. If 'merge-ff-only' is specified, the
+	merge will only succeed if it's fast-forward. See
+	"branch.<name>.pullmode" for doing this in a non branch-specific
+	manner.
 +
 *NOTE*: this is a possibly dangerous operation; do *not* use
 it unless you understand the implications (see linkgit:git-rebase[1]
diff --git a/git-pull.sh b/git-pull.sh
index fbb8a9b..580d633 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -62,6 +62,7 @@ then
 		echo "Please use pull.mode and branch.<name>.pullmode instead."
 	fi
 fi
+test -z "$mode" && mode=merge
 dry_run=
 while :
 do
@@ -282,6 +283,17 @@ case "$merge_head" in
 		die "$(gettext "Cannot rebase onto multiple branches")"
 	fi
 	;;
+*)
+	# check if a non-fast-foward merge would be needed
+	merge_head=${merge_head% }
+	if test "$mode" = merge-ff-only -a -z "$no_ff$ff_only${squash#--no-squash}" &&
+		test -n "$orig_head" &&
+		! git merge-base --is-ancestor "$orig_head" "$merge_head" &&
+		! git merge-base --is-ancestor "$merge_head" "$orig_head"
+	then
+		die "The pull was not fast-forward, please either merge or rebase."
+	fi
+	;;
 esac
 
 # Pulling into unborn branch: a shorthand for branching off
diff --git a/t/t5520-pull.sh b/t/t5520-pull.sh
index 978a3c1..798ae2f 100755
--- a/t/t5520-pull.sh
+++ b/t/t5520-pull.sh
@@ -310,4 +310,40 @@ test_expect_success 'branch.to-rebase.pullmode should override pull.mode' '
 	test new = $(git show HEAD:file2)
 '
 
+test_expect_success 'git pull fast-forward' '
+	test_when_finished "git checkout master && git branch -D other test" &&
+	test_config pull.mode merge-ff-only &&
+	git checkout -b other master &&
+	>new &&
+	git add new &&
+	git commit -m new &&
+	git checkout -b test -t other &&
+	git reset --hard master &&
+	git pull
+'
+
+test_expect_success 'git pull non-fast-forward' '
+	test_when_finished "git checkout master && git branch -D other test" &&
+	test_config pull.mode merge-ff-only &&
+	git checkout -b other master^ &&
+	>new &&
+	git add new &&
+	git commit -m new &&
+	git checkout -b test -t other &&
+	git reset --hard master &&
+	test_must_fail git pull
+'
+
+test_expect_success 'git pull non-fast-forward (merge)' '
+	test_when_finished "git checkout master && git branch -D other test" &&
+	test_config pull.mode merge-ff-only &&
+	git checkout -b other master^ &&
+	>new &&
+	git add new &&
+	git commit -m new &&
+	git checkout -b test -t other &&
+	git reset --hard master &&
+	git pull --merge
+'
+
 test_done

diff --git a/git-pull.sh b/git-pull.sh
index 580d633..1f777de 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -62,7 +62,7 @@ then
 		echo "Please use pull.mode and branch.<name>.pullmode instead."
 	fi
 fi
-test -z "$mode" && mode=merge
+test -z "$mode" && mode=default
 dry_run=
 while :
 do
@@ -286,12 +286,21 @@ case "$merge_head" in
 *)
 	# check if a non-fast-foward merge would be needed
 	merge_head=${merge_head% }
-	if test "$mode" = merge-ff-only -a -z "$no_ff$ff_only${squash#--no-squash}" &&
+	if test -z "$no_ff$ff_only${squash#--no-squash}" &&
 		test -n "$orig_head" &&
 		! git merge-base --is-ancestor "$orig_head" "$merge_head" &&
 		! git merge-base --is-ancestor "$merge_head" "$orig_head"
 	then
-		die "The pull was not fast-forward, please either merge or rebase."
+		case "$mode" in
+		merge-ff-only)
+			die "The pull was not fast-forward, please either merge or rebase."
+			;;
+		default)
+			say "The pull was not fast-forward, in the future you would have to choose
+a merge or a rebase, falling back to old style for now (git pull --merge).
+Read 'git pull --help' for more information."
+			;;
+		esac
 	fi
 	;;
 esac

diff --git a/Documentation/git-pull.txt b/Documentation/git-pull.txt
index 6d55737..d503924 100644
--- a/Documentation/git-pull.txt
+++ b/Documentation/git-pull.txt
@@ -23,6 +23,7 @@ More precisely, 'git pull' runs 'git fetch' with the given
 parameters and calls 'git merge' to merge the retrieved branch
 heads into the current branch.
 With `--rebase`, it runs 'git rebase' instead of 'git merge'.
+With `--merge`, it forces the merge, even if it's non-fast forward.

 <repository> should be the name of a remote repository as
 passed to linkgit:git-fetch[1].  <refspec> can name an
@@ -41,9 +42,26 @@ Assume the following history exists and the current branch is
 ------------
          A---B---C origin/master
         /
+    D---E master
+------------
+
+Then `git pull` will merge in a fast-foward way up to the new master.
+
+------------
+    D---E---A---B---C master, origin/master
+------------
+
+However, a non-fast-foward case looks very different.
+
+------------
+         A---B---C origin/master
+        /
     D---E---F---G master
 ------------

+In the future, `git pull` will fail on these situations, however, most likely
+you would want to force a merge, which you can do with `git pull --merge`.
+
 Then "`git pull`" will fetch and replay the changes from the remote
 `master` branch since it diverged from the local `master` (i.e., `E`)
 until its current commit (`C`) on top of `master` and record the