31b9af3da3
## Summary
This PR fixes an issue where C# reserved keywords (like `params`,
`class`, `event`, etc.) used as field or parameter names in SpacetimeDB
types would cause compilation errors in the generated code.
## Problem
When a user defines a table or reducer with a field named using a C#
reserved keyword:
```csharp
[SpacetimeDB.Table]
public partial struct MyTable
{
public int @params; // User escapes it in their code
public string @class;
}
```
The codegen would generate invalid C# like:
```csharp
// Generated code (broken)
public int params; // Error: keyword used as identifier
public void Read(BinaryReader reader) {
params = ...; // Error
}
```
## Solution
1. Added an `Identifier` property to `MemberDeclaration` in the codegen
that automatically detects C# reserved keywords using
`SyntaxFacts.GetKeywordKind()` and prefixes them with `@` when needed.
2. Updated all code generation sites to use `Identifier` instead of
`Name` when generating:
- Field declarations
- Property accessors
- Constructor parameters
- BSATN serialization code
- Index accessors
- Reducer/procedure parameters
3. Added a regression test that verifies tables, reducers, and
procedures with keyword field names compile successfully.
## Test Plan
- Added `CSharpKeywordIdentifiersAreEscapedInGeneratedCode` test that
creates a table with `@class` and `@params` fields, plus a reducer and
procedure with keyword parameters
- Existing tests continue to pass (verified locally with
`FormerlyForbiddenFieldNames` fixture which already tests edge cases
like `Read`, `Write`, `GetAlgebraicType`)
Fixes #4529
---------
Co-authored-by: Stable Genius <259448942+stablegenius49@users.noreply.github.com>
Co-authored-by: Ryan <r.ekhoff@clockworklabs.io>
SpacetimeDB.Codegen
This project contains Roslyn incremental source generators that augment types and tables with static methods for self-describing and registration. They look for different attributes to know which types to augment:
-
[SpacetimeDB.Type]- generates aGetSatsTypeInfo()static method that registers this type with the runtime and returns aTypeInfoobject. It supports onlystructs for now to explicitly forbid infinitely recursive types and to make the implementation simpler, as it doesn't need to deal with type references - each table is registered as an entirely self-contained type together with its nested structs if any. This is unlikely to be a problem in common scenarios, but it will be optimised in the future.All the nested fields will be added to the product type. Because it's not possible to implement static extension methods on 3rd-party types (including built-ins) in C#, the codegen is responsible for manually routing different types to their
TypeInfodescriptors. See various staticTypeInfoproperties and helper methods onSpacetimeDB.BSATN.AlgebraicType(Runtime/AlgebraicType.cs) and routing logic inUtils.GetTypeInfo(Codegen/Utils.cs) for more details.Also, for the same reason - absence of static extension methods in C# - the codegen expects that your struct, as well as any of its parents, is
partialso methods can be added from extra source files generated by the codegen. -
[SpacetimeDB.Type]- also supports emulation of tagged enums in C#. For that, the struct needs to inherit a marker interfaceSpacetimeDB.TaggedEnum<Variants>whereVariantsis a named tuple of all possible variants, e.g.:[SpacetimeDB.Type] partial record Option<T> : SpacetimeDB.TaggedEnum<(T Some, Unit None)>;will generate inherited records
Option.Some(T Some_)andOption.None(Unit None_). It allows you to use tagged enums in C# in a similar way to Rust enums by leveraging C# pattern-matching on any instance ofOption<T>. -
[SpacetimeDB.Table]- generates code to register this table in theFFIupon startup so that they can be enumerated by the__describe_module__FFI API. It implies[SpacetimeDB.Type], so you must not specify both attributes on the same struct.The fields can be marked with
[SpacetimeDB.ColumnAttrs]and those will be detected by the codegen and passed on to the runtime as well. Example:[SpacetimeDB.Table] public partial struct Person { [SpacetimeDB.Column(ColumnAttrs.Identity)] public int Id; public string Name; } -
[SpacetimeDB.Reducer]- generates code to register a static function as a SpacetimeDB reducer in theFFIupon startup and creates a wrapper that will parse SATS binary blob into individual arguments and invoke the underlying function for the__call_reducer__FFI API.