Exception message in subprocess doesn't say which property in the subprocess was affected

The destination property is added to the exception message in import():

        catch (MigrateException $e) {
          $this->getIdMap()->saveIdMapping($row, [], $e->getStatus());
          $msg = sprintf("%s:%s:%s", $this->migration->getPluginId(), $destination_property_name, $e->getMessage());
          $this->saveMessage($msg, $e->getLevel());
          $save = FALSE;
        }

But SubProcess calls processRow().

I *think* we can fix this by adding the same handling in processRow() -- that is not called by the main import process AFAICT.

Thanks for reporting! Could we get a test case showing the issue or something testing the new exception.

I'm adding tests here: 📌 Add kernel tests for prefixing of migrate process errors Needs review .