Merged commit includes the following changes:

305054377  by Waymo Research:

    Check fail if required info is missing the submission tool

--
304415340  by Waymo Research:

    Check fail if submission file does not exist.

--

PiperOrigin-RevId: 305054377

Author: Waymo Research

waymo_open_dataset/metrics/tools/create_prediction_file_example.py

@@ -28,7 +28,7 @@ def _create_pd_file_example():
   # The following 3 fields are used to uniquely identify a frame a prediction
   # is predicted at. Make sure you set them to values exactly the same as what
   # we provided in the raw data. Otherwise your prediction is considered as a
-  # false positive.
+  # false negative.
   o.context_name = ('context_name for the prediction. See Frame::context::name '
                     'in  dataset.proto.')
   # The frame timestamp for the prediction. See Frame::timestamp_micros in

waymo_open_dataset/metrics/tools/create_submission.cc

@@ -126,6 +126,7 @@ void ValidateFlags() {
 // Read all content in a file to a string.
 std::string ReadFileToString(const std::string& filename) {
   std::ifstream s(filename.c_str());
+  CHECK(s.is_open()) << filename << " does not exist.";
   const std::string content((std::istreambuf_iterator<char>(s)),
                             std::istreambuf_iterator<char>());
   s.close();
@@ -159,6 +160,10 @@ void Run() {
   Submission submission;
   CHECK(google::protobuf::TextFormat::ParseFromString(submission_content, &submission))
       << "Failed to parse " << submission_content;
+  CHECK(!submission.unique_method_name().empty() &&
+        !submission.account_name().empty())
+      << "unique_method_name and account_name must be set in "
+         "--submission_filename.";
 
   std::vector<Submission> submissions(absl::GetFlag(FLAGS_num_shards),
                                       submission);