Well, small issue. ScalarFunctionArgs is in datafusion-expr which can't use SessionConfig directly since it's in datafusion-execution which depends on datafusion-expr which would cause a circular dependency. We can use ConfigOptions there which would give us access to all config except the opaque extensions in SessionConfig which I think is acceptable.

Great work!

Started delving into this trying to find a good way to impl. Trying to add config_options: ConfigOptions to ScalarFunctionExpr Having lots of fun with eq and hash with SessionConfig and f64 atm.

I wonder if we can use this trait: https://docs.rs/datafusion/latest/datafusion/catalog/trait.Session.html

We could but it wouldn't solve the issue. The issue is PhysicalExpr requires implementations to impl Eq and Hash or to have implementations for DynEq and DynHash. That is fine until something like SessionConfig which doesn't is introduced. I am looking at updating the either the 'config_namespace' macro or add explicit implementations for 'ScalarFunctionExpr' to try and impl either of the above and use f64.to_bits() and f64::from_bits(..) to handle the problematic f64's in the config. I think it's possible

It makes sense to me to move SessionConfig to common or common-runtime crate

take

It makes sense to me to move SessionConfig to common or common-runtime crate

I agree

I mistyped above - I meant we couldn't use SessionContext, not SessionConfig. Sorry about the confusion. ... or not. I need more caffeine today. PR uses ConfigOptions.