diff --git a/diff.c b/diff.c
index fb8243261c..9dbbed75ba 100644
--- a/diff.c
+++ b/diff.c
@@ -1741,6 +1741,7 @@ int diff_setup_done(struct diff_options *options)
 	 */
 	if (options->output_format & (DIFF_FORMAT_PATCH |
 				      DIFF_FORMAT_DIFFSTAT |
+				      DIFF_FORMAT_SUMMARY |
 				      DIFF_FORMAT_CHECKDIFF))
 		options->recursive = 1;
 	/*
diff --git a/t/t4013/diff.diff-tree_--pretty_--root_--summary_initial b/t/t4013/diff.diff-tree_--pretty_--root_--summary_initial
index ea48205537..58e5f74aea 100644
--- a/t/t4013/diff.diff-tree_--pretty_--root_--summary_initial
+++ b/t/t4013/diff.diff-tree_--pretty_--root_--summary_initial
@@ -5,7 +5,7 @@ Date:   Mon Jun 26 00:00:00 2006 +0000
 
     Initial
 
- create mode 040000 dir
+ create mode 100644 dir/sub
  create mode 100644 file0
  create mode 100644 file2
 $