Using the configuration file below I obtain a blank entry when listing all the keys in %config.
That's because every config file starts with the "nameless" section. As soon as you name a section, it shifts to that section instead but, even if your first line is a section marker, there will still be an entry for the nameless section (which had no data) in the resulting hash.
Arguably however, that's unintuitive, and the nameless section ought not appear in the resulting hash unless it has actual contents. I'll patch the next release to work that way.
Also, when adding a new section, a blank line separates the section name from the entry of that section
Yes, that's the standard behaviour. And, no, there's currently no way of altering it. I guess read_config
could look at the input file's layout and intuit whether you're separating section markers from config variables. I'll look at adding that behaviour too.