max_file_num_to_ignore conveys the opposite meaning of the variable's use

[Ryan4253]

Within a lot of compaction code, there is a parameter max_file_num_to_ignore. For example this is the declaration of CompactionPicker::CompactRange:

  virtual Compaction* CompactRange(
      const std::string& cf_name, const MutableCFOptions& mutable_cf_options,
      const MutableDBOptions& mutable_db_options, VersionStorageInfo* vstorage,
      int input_level, int output_level,
      const CompactRangeOptions& compact_range_options,
      const InternalKey* begin, const InternalKey* end,
      InternalKey** compaction_end, bool* manual_conflict,
      uint64_t max_file_num_to_ignore, const std::string& trim_ts);

From the variable name, it sounds like every file below max_file_num_to_ignore would be ignored and won't be compacted. In reality, this is what the function does with the variable:

for (size_t i = 0; i < inputs.size(); ++i) {
      if (inputs[i]->fd.GetNumber() < max_file_num_to_ignore) {
        inputs_shrunk.push_back(inputs[i]);
      } else if (!inputs_shrunk.empty()) {
        // inputs[i] was created during the current manual compaction and
        // need to be skipped
        skip_input_index = i;
        break;
      }
    }
    if (inputs_shrunk.empty()) {
      return nullptr;
    }
    if (inputs.size() != inputs_shrunk.size()) {
      inputs.files.swap(inputs_shrunk);
    }

    // set covering_the_whole_range to false if there is any file that need to
    // be compacted in the range of inputs[skip_input_index+1, inputs.size())
    for (size_t i = skip_input_index + 1; i < inputs.size(); ++i) {
      if (inputs[i]->fd.GetNumber() < max_file_num_to_ignore) {
        covering_the_whole_range = false;
      }
    }

It compacts everything that is below max_file_num_to_ignore, which is the opposite of what the variable claims to do. The variable should really be named max_file_num_to_compact or min_file_num_to_ignore (better, since inclusive)