Replace error strings with enums

[ariel-miculas]

This is useful in no alloc scenarios and in cases where String is not
available (such as the Linux kernel).

[ariel-miculas]

Relates to #221

[ariel-miculas]

Maybe I should add a conversion from the enum values to the error strings in https://github.com/capnproto/capnproto-rust/blob/6e421db3b13ead5e92cce68cff186a96492b7d1d/capnp-rpc/src/rpc.rs#L368C3-L368C3 since this test is failing

capnproto-rust/capnp-rpc/test/test.rs

Line 339 in 6e421db

.contains("Message contains null capability pointer")

[dwrensha]

Maybe I should add a conversion from the enum values to the error strings in https://github.com/capnproto/capnproto-rust/blob/6e421db3b13ead5e92cce68cff186a96492b7d1d/capnp-rpc/src/rpc.rs#L368C3-L368C3 since this test is failing

capnproto-rust/capnp-rpc/test/test.rs

Line 339 in 6e421db

.contains("Message contains null capability pointer")

I think there should be a conversion from enum values to more verbose messages, and that it should live in an impl Display.

[ariel-miculas]

I think we can remove "except for error message" from the documentation with this PR. Do you have additional technical comments related to the code?

[dwrensha]

I think we can remove "except for error message" from the documentation with this PR.

Yep.

Do you have additional technical comments related to the code?

I think this is in pretty good shape. The main barrier to merging now is that it's a breaking change, so we'll need to bump to version 0.18. To minimize churn, it might be good to try to fit some other pending breaking changes (for example #380) in with that version bump. How time-sensitive is this change for you?

[ariel-miculas]

How time-sensitive is this change for you?

I'm in no rush at all, I just wanted to finish with this PR. I'm still working on getting capnp to compile in the kernel, so I might open other PRs with #[cfg(feature = "alloc")] in places where allocations happen, it's proven to be quite tricky until now.

[dwrensha]

I might open other PRs with #[cfg(feature = "alloc")] in places where allocations happen, it's proven to be quite tricky until now.

Please feel free to add those changes to this PR, if it makes sense to do so.

[ariel-miculas]

I need some help with the remaining cargo clippy warnings:

❯ cargo clippy
warning: unsafe function's docs miss `# Safety` section
  --> capnp/src/private/arena.rs:43:5
   |
43 | /     unsafe fn check_offset(
44 | |         &self,
45 | |         segment_id: u32,
46 | |         start: *const u8,
47 | |         offset_in_words: i32,
48 | |     ) -> Result<*const u8>;
   | |___________________________^
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#missing_safety_doc
   = note: `#[warn(clippy::missing_safety_doc)]` on by default

warning: unsafe function's docs miss `# Safety` section
   --> capnp/src/private/layout.rs:162:5
    |
162 |     pub unsafe fn target(ptr: *const Self) -> *const u8 {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#missing_safety_doc

warning: unsafe function's docs miss `# Safety` section
    --> capnp/src/private/layout.rs:2918:5
     |
2918 |     pub unsafe fn get_root_unchecked<'b>(location: *const u8) -> PointerReader<'b> {
     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#missing_safety_doc

warning: unsafe function's docs miss `# Safety` section
    --> capnp/src/private/layout.rs:3959:5
     |
3959 | /     pub unsafe fn is_canonical(
3960 | |         &self,
3961 | |         read_head: &Cell<*const u8>,
3962 | |         reff: *const WirePointer,
3963 | |     ) -> Result<bool> {
     | |_____________________^
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#missing_safety_doc

warning: `capnp` (lib) generated 4 warnings
    Finished dev [unoptimized + debuginfo] target(s) in 0.01s

[dwrensha]

Do those clippy warnings also get reported on the master branch? If so, then cleaning them up can be considered be out-of-scope for this pull request.

[ariel-miculas]

Do those clippy warnings also get reported on the master branch? If so, then cleaning them up can be considered be out-of-scope for this pull request.

Ok, I will open a subsequent PR for the clippy changes.

[ariel-miculas]

There are some formatting changes with the latest nightly version of rust, I included these changes as a separate commit, let me know if you would like to see them squashed in another commit, I'm not sure what the best practice is in this situation.

[dwrensha]

Rebased and merged in 13ccb48 087a0fe c410b05.

I'm going to aim for releasing v0.18 this week.

[dwrensha]

I enabled more code in 579b4f4, allowing run-time reflection to still work in the no-alloc case. After this change, examples/wasm-hello-world works with capnp in no-alloc mode.

[ariel-miculas]

Kudos for this, I know it was very tedious work

[ariel-miculas]

Btw, here's my perl script I've used to (semi)automate the replacements (in case someone wants to do the same for the other error strings): https://gist.github.com/ariel-miculas/e114394eccda9563434c1ad5af19c797

[dwrensha]

I'm going to aim for releasing v0.18 this week.

I'm now thinking that the release will be at least a few weeks from now.