@Assert \文件无效

Question

I've added this annotation to my property;

/**
 * @Assert\File(
 *     mimeTypes = {"text/csv"},
 *     mimeTypesMessage = "Please upload a valid CSV",
 * )
 */

But it doesn't work.

When I try to add a CSV file I still get the "Please upload a valid CSV" message. What is a valid csv file?

I have tried with capital letters extention, and with small letters.

I have tried with comma separations, and with semicolons.

A simple basic demo I've tried that also doesn't work;

test,qwer,asdf,asdf
1,2,3,4
5,6,7,8