diff --git a/doc/src/sgml/logical-replication.sgml b/doc/src/sgml/logical-replication.sgml
index 57216d6c52..cd92f6a7d5 100644
--- a/doc/src/sgml/logical-replication.sgml
+++ b/doc/src/sgml/logical-replication.sgml
@@ -1595,8 +1595,8 @@ test_sub=# SELECT * FROM t1 ORDER BY id;
        unique constraint. Note that to log the origin and commit
        timestamp details of the conflicting key,
        <link linkend="guc-track-commit-timestamp"><varname>track_commit_timestamp</varname></link>
-       should be enabled. In this case, an error will be raised until the
-       conflict is resolved manually.
+       should be enabled on the subscriber. In this case, an error will be
+       raised until the conflict is resolved manually.
       </para>
      </listitem>
     </varlistentry>
diff --git a/src/backend/executor/execReplication.c b/src/backend/executor/execReplication.c
index 09b51706db..b8a6de5eca 100644
--- a/src/backend/executor/execReplication.c
+++ b/src/backend/executor/execReplication.c
@@ -549,8 +549,9 @@ CheckAndReportConflict(ResultRelInfo *resultRelInfo, EState *estate,
 			TransactionId xmin;
 
 			GetTupleTransactionInfo(conflictslot, &xmin, &origin, &committs);
-			ReportApplyConflict(ERROR, type, resultRelInfo->ri_RelationDesc, uniqueidx,
-								xmin, origin, committs, conflictslot);
+			ReportApplyConflict(ERROR, type, resultRelInfo->ri_RelationDesc,
+								uniqueidx, xmin, origin, committs,
+								conflictslot);
 		}
 	}
 }
@@ -623,8 +624,8 @@ ExecSimpleRelationInsert(ResultRelInfo *resultRelInfo,
 		 *
 		 * XXX OTOH, this could lead to clean-up effort for dead tuples added
 		 * in heap and index in case of conflicts. But as conflicts shouldn't
-		 * be a frequent thing so we preferred to save the performance overhead
-		 * of extra scan before each insertion.
+		 * be a frequent thing so we preferred to save the performance
+		 * overhead of extra scan before each insertion.
 		 */
 		if (conflict)
 			CheckAndReportConflict(resultRelInfo, estate, CT_INSERT_EXISTS,
diff --git a/src/backend/replication/logical/conflict.c b/src/backend/replication/logical/conflict.c
index c69194244c..27e7cb1950 100644
--- a/src/backend/replication/logical/conflict.c
+++ b/src/backend/replication/logical/conflict.c
@@ -20,7 +20,7 @@
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
 
-const char *const ConflictTypeNames[] = {
+static const char *const ConflictTypeNames[] = {
 	[CT_INSERT_EXISTS] = "insert_exists",
 	[CT_UPDATE_DIFFER] = "update_differ",
 	[CT_UPDATE_EXISTS] = "update_exists",
@@ -211,9 +211,15 @@ errdetail_apply_conflict(ConflictType type, Oid conflictidx,
 			}
 		case CT_DELETE_MISSING:
 			return errdetail("Did not find the row to be deleted.");
-	}
 
-	return 0;					/* silence compiler warning */
+		/*
+		 * XXX should we add a default behavior instead of just returning zero?
+		 * This style can detect mistakes of coding.
+		 */
+		default:
+			elog(ERROR, "unexpected conflict type: %d", (int) type);
+			return 0;		/* silence compiler warning */
+	}
 }
 
 /*
diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index b09d780fc5..105af9775c 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -2668,7 +2668,8 @@ apply_handle_update_internal(ApplyExecutionData *edata,
 		TimestampTz localts;
 
 		/*
-		 * Report the conflict if the tuple was modified by a different origin.
+		 * Report the conflict if the tuple was modified by a different
+		 * origin.
 		 */
 		if (GetTupleTransactionInfo(localslot, &localxmin, &localorigin, &localts) &&
 			localorigin != replorigin_session_origin)
@@ -2824,7 +2825,8 @@ apply_handle_delete_internal(ApplyExecutionData *edata,
 		TimestampTz localts;
 
 		/*
-		 * Report the conflict if the tuple was modified by a different origin.
+		 * Report the conflict if the tuple was modified by a different
+		 * origin.
 		 */
 		if (GetTupleTransactionInfo(localslot, &localxmin, &localorigin, &localts) &&
 			localorigin != replorigin_session_origin)
@@ -3036,7 +3038,8 @@ apply_handle_tuple_routing(ApplyExecutionData *edata,
 				}
 
 				/*
-				 * Report the conflict if the tuple was modified by a different origin.
+				 * Report the conflict if the tuple was modified by a
+				 * different origin.
 				 */
 				if (GetTupleTransactionInfo(localslot, &localxmin, &localorigin, &localts) &&
 					localorigin != replorigin_session_origin)
diff --git a/src/include/replication/conflict.h b/src/include/replication/conflict.h
index e9ba6818fc..1d466c3cad 100644
--- a/src/include/replication/conflict.h
+++ b/src/include/replication/conflict.h
@@ -45,12 +45,16 @@ typedef enum
 	 */
 } ConflictType;
 
-extern bool GetTupleTransactionInfo(TupleTableSlot *localslot, TransactionId *xmin,
-									RepOriginId *localorigin, TimestampTz *localts);
+extern bool GetTupleTransactionInfo(TupleTableSlot *localslot,
+									TransactionId *xmin,
+									RepOriginId *localorigin,
+									TimestampTz *localts);
 extern void ReportApplyConflict(int elevel, ConflictType type,
 								Relation localrel, Oid conflictidx,
-								TransactionId localxmin, RepOriginId localorigin,
-								TimestampTz localts, TupleTableSlot *conflictslot);
+								TransactionId localxmin,
+								RepOriginId localorigin,
+								TimestampTz localts,
+								TupleTableSlot *conflictslot);
 extern void InitConflictIndexes(ResultRelInfo *relInfo);
 
 #endif
diff --git a/src/test/subscription/t/013_partition.pl b/src/test/subscription/t/013_partition.pl
index 896985d85b..e26f26acc5 100644
--- a/src/test/subscription/t/013_partition.pl
+++ b/src/test/subscription/t/013_partition.pl
@@ -786,10 +786,12 @@ ok( $logfile =~
 
 # Enable the track_commit_timestamp to detect the conflict when attempting
 # to update a row that was previously modified by a different origin.
-$node_subscriber1->append_conf('postgresql.conf', 'track_commit_timestamp = on');
+$node_subscriber1->append_conf('postgresql.conf',
+	'track_commit_timestamp = on');
 $node_subscriber1->restart;
 
-$node_subscriber1->safe_psql('postgres', "INSERT INTO tab2 VALUES (3, 'yyy')");
+$node_subscriber1->safe_psql('postgres',
+	"INSERT INTO tab2 VALUES (3, 'yyy')");
 $node_publisher->safe_psql('postgres',
 	"UPDATE tab2 SET b = 'quux' WHERE a = 3");
 
@@ -800,7 +802,9 @@ ok( $logfile =~
 	  qr/conflict update_differ detected on relation "public.tab2_1".*\n.*DETAIL:.* Updating a row that was modified locally in transaction [0-9]+ at .*/,
 	'updating a tuple that was modified by a different origin');
 
-$node_subscriber1->append_conf('postgresql.conf', 'track_commit_timestamp = off');
+# The remaining tests no longer test conflict detection.
+$node_subscriber1->append_conf('postgresql.conf',
+	'track_commit_timestamp = off');
 $node_subscriber1->restart;
 
 # Test that replication continues to work correctly after altering the