Support miniserde/nanoserde?

[Supreeeme]

I'd like to use this crate in a custom cargo xtask style thing, however the use of serde adds a notable compile time cost to a simple crate with no other dependencies, which is inconvenient for something that is essentially a script. It would be nice to add support for a lighter-weight deserialization crate, such as miniserde or nanoserde. Alternatively, it would even be useful to just make serde optional, and custom deserialization impls could be tacked on.

[oli-obk]

I don't think we have any notable uses of serde derive features or interesting data structures. I want to avoid writing custom serialization impls, do these others support derives, too?

The main issue is where we use things like Utf8Path, which doesn't support other serialization frameworks

[Supreeeme]

Both miniserde and nanoserde supports derives, although I would personally prefer nanoserde as it has no other dependencies, and miniserde still depends on syn. I think the most useful thing missing though from both is internally tagged enums, which is used for the message types. Those would require a semi-manual implementation, but it's not terribly difficult to implement in the case of nanoserde. Nanoserde also supports remote (called "proxy" there) derives. There's a nice list of supported features on the readme (cargo_metadata obviously only cares about the json column).

[oli-obk]

I think we should put serde under a cargo feature. Internally we can use nanoserde, but others may be using serde on our data structures directly and I want to keep supporting that.

We can even make serde an optional feature to avoid everyone pulling it in unless they need it