mergetool: honor tempfile configuration when resolving delete conflicts

Teach resolve_deleted_merge() to honor the mergetool.keepBackup and
mergetool.keepTemporaries configuration knobs.

This ensures that the worktree is kept pristine when resolving deletion
conflicts with the variables both set to false.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-mergetool.sh

diff --git a/git-mergetool.sh b/git-mergetool.sh
index b06ae78..f67bab5 100755
--- a/git-mergetool.sh
+++ b/git-mergetool.sh
@@ -126,7 +126,12 @@
 		case "$ans" in
 		[mMcC]*)
 			git add -- "$MERGED"
-			cleanup_temp_files --save-backup
+			if test "$merge_keep_backup" = "true"
+			then
+				cleanup_temp_files --save-backup
+			else
+				cleanup_temp_files
+			fi
 			return 0
 			;;
 		[dD]*)
@@ -135,6 +140,10 @@
 			return 0
 			;;
 		[aA]*)
+			if test "$merge_keep_temporaries" = "false"
+			then
+				cleanup_temp_files
+			fi
 			return 1
 			;;
 		esac

t/t7610-mergetool.sh

diff --git a/t/t7610-mergetool.sh b/t/t7610-mergetool.sh
index 39469d9..76306cf 100755
--- a/t/t7610-mergetool.sh
+++ b/t/t7610-mergetool.sh
@@ -279,6 +279,31 @@
 	: >expect &&
 	echo d | git mergetool a/a/file.txt 2>actual &&
 	test_cmp expect actual &&
+	! test -d a &&
+	git reset --hard HEAD
+'
+
+test_expect_success 'mergetool honors tempfile config for deleted files' '
+	test_config mergetool.keepTemporaries false &&
+	test_must_fail git merge move-to-b &&
+	echo d | git mergetool a/a/file.txt &&
+	! test -d a &&
+	git reset --hard HEAD
+'
+
+test_expect_success 'mergetool keeps tempfiles when aborting delete/delete' '
+	test_config mergetool.keepTemporaries true &&
+	test_must_fail git merge move-to-b &&
+	! (echo a; echo n) | git mergetool a/a/file.txt &&
+	test -d a/a &&
+	cat >expect <<-\EOF &&
+	file_BASE_.txt
+	file_LOCAL_.txt
+	file_REMOTE_.txt
+	EOF
+	ls -1 a/a | sed -e "s/[0-9]*//g" >actual &&
+	test_cmp expect actual &&
+	git clean -fdx &&
 	git reset --hard HEAD
 '