Implement and Derive common traits

[kbknapp]

Eagerly derive/implement common traits for all public types. I haven't yet looked at which ones would actually be appropriate to implement. The list below is just a quick list.

I'm not 100% sure, but I think adding these would be a breaking change?

• App
  • Clone
  • Eq
  • PartialEq
  • Ord
  • PartialOrd
  • Hash
  • Debug,
  • Display
  • Default
• Arg
  • Clone
  • Eq
  • PartialEq
  • Ord
  • PartialOrd
  • Hash
  • Debug,
  • Display
  • Default
• ArgMatches
  • Clone
  • Eq
  • PartialEq
  • Ord
  • PartialOrd
  • Hash
  • Debug,
  • Display
  • Default
• Values
  • Copy
  • Clone
  • Eq
  • PartialEq
  • Ord
  • PartialOrd
  • Hash
  • Debug,
  • Display
  • Default
• ValuesOs
  • Copy
  • Clone
  • Eq
  • PartialEq
  • Ord
  • PartialOrd
  • Hash
  • Debug,
  • Display
  • Default

[Vinatorul]

I can work on this. I am not sure about breaking change right now, it depends from associated changes.

[kbknapp]

Yeah I'm concerned with the breaking changes implications. I've got a local 3x branch that I've been working on the past few days. Once I get it to a state where it actually builds I'll push the branch and you can run through the types making sure they're all deriving the traits they should. 👍

I've got one more work trip coming up soon, but I'm hoping to have this branch pushed sometime this coming week.

[Vinatorul]

Nice, is there any issues I can work on while you will be away? Are you still using gitter?

[kbknapp]

@Vinatorul The gitter is still up, and I get pinged on mobile (usually) when new messages are posted. Really any of the current feature requests could get knocked out, but 3.x is being heavily refactored, so it'll probably just be easier to wait until I get it building.

I now have a 3x-dev branch up, but it doesn't compile yet as it's a messy state of partially refactored. I'm hoping to get a large chunk of it complete tomorrow while on an airplane 😄 Once the refactoring is done, adding the new features will be easy, and you can jump on in at that point. I'll publish a list of priorities as well.

Once it's good to go, I'll create a 3x-master branch and start merging feature PRs onto that branch.

[sassman]

Can this issue be tackled now? If that is the case, I'd might have a look at it.

[pksunkara]

Yes, please. Which is why I added it to the rust weekly.

[sassman]

There I saw it and it might be an easy candidate.

[CreepySkeleton]

Regarding certain traits:

• Default is meaningless for Arg, App, ArgGroup.
• Implementing PartialOrd + Ord is probably next to impossible because they aren't implemented for IndexMap. Same with Hash

[kbknapp]

With #1365 we should look at how much this increases the binary size and probably feature gate this (it's ok if it's in the default features) if it negatively effects the size. I think LLVM is pretty good about dead code elimination and removing any trait impls that we impl (or derive) but aren't actually used in the resulting binary...but I'm not 100% certain in all cases. I know there are specific cases where LLVM won't remove dead code, but I believe that is tied to generics and monomorphic trait impls IIRC.

[pickfire]

@sassman are you working on all of it or do you need some help?

[sassman]

@pickfire I started by PartialEq on ArgGroup and App and wrote some little tests for it. But I'm not sure if tests would be necessary for those standard traits.

[pksunkara]

Tests are not needed. Just write derive(PartialEq) and if it compiles, then it's okay. That is why this is a beginner issue 😄

[pksunkara]

Tests are only needed if there is a custom implementation somewhere.

[pickfire]

@pksunkara It would be fun if beginners are able to claim parts of this issue like rust-dc/fish-manpage-completions#2