libdm: report: compact output applicable only if report is buffered

3 files changed, 7 insertions, 1 deletions

diff --git a/conf/example.conf.in b/conf/example.conf.in
index 5ed2b9253..70d3e6b24 100644
--- a/conf/example.conf.in
+++ b/conf/example.conf.in
@@ -1105,7 +1105,8 @@ activation {
 #
 # report {
     # If compact output is enabled, fields which don't have value
-    # set for any of the rows reported are skipped on output.
+    # set for any of the rows reported are skipped on output. Compact
+    # output is applicable only if report is buffered (report/buffered=1).
     # compact_output=0
 
     # Align columns on report output.
diff --git a/libdm/libdevmapper.h b/libdm/libdevmapper.h
index fef035130..f18fba97c 100644
--- a/libdm/libdevmapper.h
+++ b/libdm/libdevmapper.h
@@ -1757,6 +1757,8 @@ int dm_report_object(struct dm_report *rh, void *object);
 /*
  * Compact report output so that if field value is empty for all rows in
  * the report, drop the field from output completely (including headers).
+ * Compact output is applicable only if report is buffered, otherwise
+ * this function has no effect.
  */
 int dm_report_compact_fields(struct dm_report *rh);
 
diff --git a/libdm/libdm-report.c b/libdm/libdm-report.c
index 7dd52d485..f81d964ee 100644
--- a/libdm/libdm-report.c
+++ b/libdm/libdm-report.c
@@ -1696,6 +1696,9 @@ int dm_report_compact_fields(struct dm_report *rh)
 	struct field_properties *fp;
 	struct row *row;
 
+	if (!(rh->flags & DM_REPORT_OUTPUT_BUFFERED))
+		return 1;
+
 	if (!rh || dm_list_empty(&rh->rows)) {
 		log_error("dm_report_enable_compact_output: no report fields to compact");
 		return 0;