add missing impl Errors (breaking change)

[rursprung]

use thiserror to do this as it's already used in the crate. this updates it from v1 to v2 and also uses it in no_std environments as that's now supported by thiserror.

this was missing and thus it wasn't possible to use e.g. HostErr in a #[from] with thiserror.

[rursprung]

just spotted in the diff that cargo fmt --all formatted a bit more than just my code... i hope that's ok? probably should add a CI check for proper formatting?

[rursprung]

just spotted in the diff that cargo fmt --all formatted a bit more than just my code... i hope that's ok? probably should add a CI check for proper formatting?

i've undone the re-formatting here and instead did it for all crates in #131 where i also added a CI check for it

[jamesmunns]

This and line 150 makes this a breaking change according to cargo semver-checks:

james@magician ➜  postcard-rpc git:(add-missing-Error-impls) cargo semver-checks
    Building postcard-rpc v0.11.12 (current)
       Built [   9.633s] (current)
     Parsing postcard-rpc v0.11.12 (current)
      Parsed [   0.016s] (current)
    Building postcard-rpc v0.11.12 (baseline)
       Built [   9.127s] (baseline)
     Parsing postcard-rpc v0.11.12 (baseline)
      Parsed [   0.015s] (baseline)
    Checking postcard-rpc v0.11.12 -> v0.11.12 (no change)
     Checked [   0.020s] 153 checks: 152 pass, 1 fail, 0 warn, 11 skip

--- failure trait_added_supertrait: non-sealed trait added new supertraits ---

Description:
A non-sealed trait added one or more supertraits, which breaks downstream implementations of the trait
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#generic-bounds-tighten
       impl: https://github.com/obi1kenobi/cargo-semver-checks/tree/v0.41.0/src/lints/trait_added_supertrait.ron

Failed in:
  trait postcard_rpc::server::AsWireRxErrorKind gained Error in file /Users/james/personal/postcard-rpc/source/postcard-rpc/src/server/mod.rs:150
  trait postcard_rpc::server::AsWireTxErrorKind gained Error in file /Users/james/personal/postcard-rpc/source/postcard-rpc/src/server/mod.rs:97

     Summary semver requires new major version: 1 major and 0 minor checks failed
    Finished [  22.978s] postcard-rpc

[rursprung]

are these traits supposed to be implemented by anyone outside of postcard-rpc? if not then it wouldn't be breaking, right?

[jamesmunns]

They are public, so they can be implemented by anyone: https://docs.rs/postcard-rpc/latest/postcard_rpc/server/index.html#traits

[jamesmunns]

I'm overall fine with this, though this is a breaking change. We might have one soon anyway when the embassy-executor changes are worked through, so maybe we leave this PR open for a bit and we can merge it when getting ready for a v0.12.

[rursprung]

I'm overall fine with this, though this is a breaking change. We might have one soon anyway when the embassy-executor changes are worked through, so maybe we leave this PR open for a bit and we can merge it when getting ready for a v0.12.

otherwise i can split it up and just add the impl Error for HostErr (which is the one i actually care about) in a separate PR to get that in as a non-breaking change?

[jamesmunns]

Feel free to break it up if you'd like! Happy to merge for v0.11.x as long as cargo semver-checks is happy, otherwise happy to merge as part of v0.12 in the nearish future.

[rursprung]

Feel free to break it up if you'd like! Happy to merge for v0.11.x as long as cargo semver-checks is happy, otherwise happy to merge as part of v0.12 in the nearish future.

i've split it to #132 for now

[rursprung]

rebased on top of #132

[jamesmunns]

(updated the title so I don't forget and merge this without thinking about it :) )