fix OutputArray release for std::array<Mat>

modules/core/src/matrix_wrap.cpp

@@ -1868,6 +1868,14 @@ void _OutputArray::release() const
         return;
     }
 
+    if( k == STD_ARRAY_MAT )
+    {
+        Mat* v = (Mat*)obj;
+        for( int i = 0; i < sz.height; i++ )
+            v[i].release();
+        return;
+    }
+
     if( k == STD_VECTOR_UMAT )
     {
         ((std::vector<UMat>*)obj)->clear();

modules/core/test/test_mat.cpp

@@ -1195,6 +1195,24 @@ TEST(Core_Array, basic_operations) { Core_ArrayOpTest test; test.safe_run(); }
 TEST(Core_Merge, shape_operations) { Core_MergeTest test; test.safe_run(); }
 TEST(Core_Split, shape_operations) { Core_SplitTest test; test.safe_run(); }
 
+TEST(Core_Split, empty_std_array_output)
+{
+    std::array<Mat, 3> outputs = {
+        Mat::ones(2, 2, CV_8U),
+        Mat::ones(3, 1, CV_32F),
+        Mat::eye(2, 3, CV_64F)
+    };
+
+    for( size_t i = 0; i < outputs.size(); i++ )
+        ASSERT_FALSE(outputs[i].empty());
+
+    EXPECT_NO_THROW(split(Mat(), outputs));
+
+    EXPECT_EQ((size_t)3, outputs.size());
+    for( size_t i = 0; i < outputs.size(); i++ )
+        EXPECT_TRUE(outputs[i].empty());
+}
+
 
 TEST(Core_IOArray, submat_assignment)
 {