# Description of Changes
Implements the C# equivalent of #3638
This implement uses inheritance, where abstract base classes (like
`ProcedureContextBase` in `ProcedureContext.cs`) store the core of the
implementation, and then generated wrappers (like `ProcedureContext` in
the generated FFI.cs file) inherit from them.
For error handling, we work like Rust's implementation of `Result<T,E>`
but we require `where E : Exception` because of how exceptions work in
C#. Transaction-level failures come back as a `TxOutcome` and user
errors should follow the `Result<T,E>` pattern. In this implementation,
we have `UnwrapOrThrow()` throws exceptions directly because of C#'s
error handling pattern.
Unlike the Rust implementation's direct `Result` propagation, we are
using an `AbortGuard` pattern (in `ProcedureContext.cs`) for exception
handling, which uses `IDisposable` for automatic cleanup.
Most changes should have fairly similar Rust-equivalents beyond that.
For module authors, the changes here allow for the transation logic to
work like:
```csharp
ctx.TryWithTx<ResultType, Exception>(tx => {
// transaction logic
return Result<ResultType, Exception>.Ok(result);
});
```
This change includes a number of tests added to the
`sdks/csharp/examples~/regression-tests/`'s `server` and `client` to
validate the behavior of the changes. `server` changes provide further
usage examples for module authors.
# API and ABI breaking changes
Should not be a breaking change
# Expected complexity level and risk
2
# Testing
- [x] Created Regression Tests that show transitions in procedures
working in various ways, all of which pass.
# Description of Changes
Host-side changes extracted from #3327
I added AUTO_INC_OVERFLOW even though we don't currently ever return it,
in order to future-proof so it's already there when we start emitting
it.
Prepublish was failing because it was expecting a wasm module
unconditionally, so now it takes ?host_type.
I tweaked JS deser to accept null/undefined when the unit type or an
option type is expected.
I switched to bsatn, because the native sats->js translator wasn't
matching what js was expecting.
I renamed the sys module: my thinking is that `spacetime:` as a scheme
will help disambiguate it, and maybe it could also be used for IMC in
the future or something? And I believe we had discussed wanting this to
be versioned, similar to wasm imports.
Trying to get a borrowed str from deserialize_js doesn't work, because
v8 strings don't store utf8.
# Testing
<!-- Describe any testing you've done, and any testing you'd like your
reviewers to do,
so that you're confident that all the changes work as expected! -->
- [x] All this was done in the course of getting an actual typescript
module to successfully publish.
rekhoff