Merge branch 'rs/pull-signed-tag'

When "git merge-recursive" works on history with many criss-cross
merges in "verbose" mode, the names the command assigns to the
virtual merge bases could have overwritten each other by unintended
reuse of the same piece of memory.

* rs/pull-signed-tag:
  commit: use FLEX_ARRAY in struct merge_remote_desc
  merge-recursive: fix verbose output for multiple base trees
  commit: factor out set_merge_remote_desc()
  commit: use xstrdup() in get_merge_parent()

t/t3030-merge-recursive.sh

@@ -660,4 +660,22 @@ test_expect_success 'merging with triple rename across D/F conflict' '
 	git merge other
 '
 
+test_expect_success 'merge-recursive remembers the names of all base trees' '
+	git reset --hard HEAD &&
+
+	# more trees than static slots used by oid_to_hex()
+	for commit in $c0 $c2 $c4 $c5 $c6 $c7
+	do
+		git rev-parse "$commit^{tree}"
+	done >trees &&
+
+	# ignore the return code -- it only fails because the input is weird
+	test_must_fail git -c merge.verbosity=5 merge-recursive $(cat trees) -- $c1 $c3 >out &&
+
+	# merge-recursive prints in reverse order, but we do not care
+	sort <trees >expect &&
+	sed -n "s/^virtual //p" out | sort >actual &&
+	test_cmp expect actual
+'
+
 test_done