in owners-common/src/main/java/com/googlesource/gerrit/owners/common/OwnersMap.java [96:108]
public void addFileReviewers(String file, Set<Id> reviewers) {
if (reviewers.isEmpty()) {
return;
}
Set<Id> set = fileReviewers.get(file);
if (set != null) {
// add new owners removing duplicates
set.addAll(reviewers);
} else {
fileReviewers.put(file, Sets.newHashSet(reviewers));
}
}