Add a way to say "Use this option only if supported" in torrc
It would be nice to have a torrc that sets some option when Tor supports that option, but not otherwise (eg when older versions of Tor read it).
There are two ways to do this I can think of:
- Future-compatible only
We could have a new syntax, something like ?Option Value. Meaning: if the option is prefixed with a question mark, it does not cause an error when unrecognized. (It should cause a warning.)
- Backward-compatible too, kinda ugly
We could have a syntax that old Tor versions interpret as a comment, but which new Tor versions interpret as above. My first thought is to use some magic string like #$%^option value. This could cause problems if anybody is actually writing comments like that.