rebase -i: remember merge options beyond continue actions

If the user explicitly specified a merge strategy or strategy
options, continue to use that strategy/option after
"rebase --continue".  Add a test of the corrected behavior.

If --merge is specified or implied by -s or -X, then "strategy and
"strategy_opts" are set to values from which "strategy_args" can be
derived; otherwise they are set to empty strings.  Either way,
their values are propagated from one step of an interactive rebase
to the next via state files.

"do_merge", on the other hand, is *not* propagated to later steps of
an interactive rebase.  Therefore, making the initialization of
"strategy_args" conditional on "do_merge" being set prevents later
steps of an interactive rebase from setting it correctly.

Luckily, we don't need the "do_merge" guard at all.  If the rebase
was started without --merge, then "strategy" and "strategy_opts"
are both the empty string, which results in "strategy_args" also
being set to the empty string, which is just what we want in that
situation.  So remove the "do_merge" guard and derive
"strategy_args" from "strategy" and "strategy_opts" every time.

Reported-by: Diogo de Campos <[email protected]>
Signed-off-by: Fabian Ruch <[email protected]>
Helped-by: Michael Haggerty <[email protected]>
Signed-off-by: Ralf Thielow <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: bafain

git-rebase--interactive.sh

@@ -81,17 +81,13 @@ rewritten_pending="$state_dir"/rewritten-pending
 # and leaves CR at the end instead.
 cr=$(printf "\015")
 
-strategy_args=
-if test -n "$do_merge"
-then
-	strategy_args=${strategy:+--strategy=$strategy}
-	eval '
-		for strategy_opt in '"$strategy_opts"'
-		do
-			strategy_args="$strategy_args -X$(git rev-parse --sq-quote "${strategy_opt#--}")"
-		done
-	'
-fi
+strategy_args=${strategy:+--strategy=$strategy}
+eval '
+	for strategy_opt in '"$strategy_opts"'
+	do
+		strategy_args="$strategy_args -X$(git rev-parse --sq-quote "${strategy_opt#--}")"
+	done
+'
 
 GIT_CHERRY_PICK_HELP="$resolvemsg"
 export GIT_CHERRY_PICK_HELP

t/t3404-rebase-interactive.sh

@@ -1006,6 +1006,22 @@ test_expect_success 'rebase -i with --strategy and -X' '
 	test $(cat file1) = Z
 '
 
+test_expect_success 'interrupted rebase -i with --strategy and -X' '
+	git checkout -b conflict-merge-use-theirs-interrupted conflict-branch &&
+	git reset --hard HEAD^ &&
+	>breakpoint &&
+	git add breakpoint &&
+	git commit -m "breakpoint for interactive mode" &&
+	echo five >conflict &&
+	echo Z >file1 &&
+	git commit -a -m "one file conflict" &&
+	set_fake_editor &&
+	FAKE_LINES="edit 1 2" git rebase -i --strategy=recursive -Xours conflict-branch &&
+	git rebase --continue &&
+	test $(git show conflict-branch:conflict) = $(cat conflict) &&
+	test $(cat file1) = Z
+'
+
 test_expect_success 'rebase -i error on commits with \ in message' '
 	current_head=$(git rev-parse HEAD) &&
 	test_when_finished "git rebase --abort; git reset --hard $current_head; rm -f error" &&