System information (version)

• OpenCV => 4.1.2-dev
• Operating System / Platform => win7 32bit
• Compiler => mingw64 8.1

assuming X a valid Mat and Y an empty/invalid one, the expression X / Y does not throw an exception, but calculates 1 / X instead.

because here (e.b.data is invalid in our case):

why does it have e.a and e.alpha in reverse ?
shouldn't it have thrown Sizes of input arguments do not match , like it does in the Y / X case ?

Steps to reproduce

Mat x(3,3,CV_32FC3,Scalar(3,2,1));
Mat y; // invalid
Mat r = x / y;
cout << r << endl;

[0.33333334, 0.5, 1, 0.33333334, 0.5, 1, 0.33333334, 0.5, 1;
0.33333334, 0.5, 1, 0.33333334, 0.5, 1, 0.33333334, 0.5, 1;
0.33333334, 0.5, 1, 0.33333334, 0.5, 1, 0.33333334, 0.5, 1]