sdk-parity-check

name	sdk-parity-check
description	Verify FFI exports have matching wrappers across all 10 language SDKs
user-invocable	true

SDK Parity Check

Scan the FFI layer and verify that every exported function has corresponding wrappers across all 10 language SDKs.

When to Use

Run after adding or modifying FFI functions, after SDK changes, or before releases to verify complete coverage.

SDK Matrix

The engine ships 10 language SDKs under sdks/. Every FFI export MUST have a binding in each:

c, cpp, csharp, go, kotlin, lua, python, rust, swift, typescript

The authoritative coverage gate is codegen/validate_coverage.py, which validates the generated ffi_manifest.json against the resolved FFI contract. The manual audit below is for spot-checking individual functions when coverage fails.

What It Checks

1. FFI → SDK parity: Every #[no_mangle] extern "C" function in goud_engine/src/ffi/ has a matching binding in each of the 10 SDKs
2. C# parity: A matching DllImport declaration in sdks/csharp/generated/
3. Python parity: A matching ctypes declaration in sdks/python/goudengine/generated/_ffi.py
4. Signature matching: Parameter types and return types are compatible across the boundary

Manual Audit Process

Step 1: Collect FFI Exports

Find all public FFI functions:

rg "#\[no_mangle\]" goud_engine/src/ffi/ --type rust -A 2

This produces a list of functions like:

#[no_mangle]
pub extern "C" fn create_context(...) -> *mut Context { ... }

Step 2: Check C# Bindings

For each FFI function, verify a matching DllImport exists:

rg "DllImport.*create_context" sdks/csharp/ --type cs

Also check NativeMethods.g.cs (auto-generated by csbindgen):

rg "create_context" sdks/csharp/generated/NativeMethods.g.cs

Step 3: Check Python Bindings

For each FFI function, verify a matching ctypes declaration exists in generated/_ffi.py:

rg "create_context" sdks/python/goudengine/generated/_ffi.py

Step 4: Check for SDK-Only Functions

Look for SDK functions that don't correspond to any FFI export (potential logic-in-SDK violation):

# C# methods that might contain logic
rg "public .* \w+\(" sdks/csharp/ --type cs -g '!NativeMethods*' -g '!obj/*'

# Python functions
rg "def " sdks/python/goudengine/ --type py -g '!test_*'

Automated Coverage Gate

Run the coverage validator, which checks all 10 SDKs against the resolved FFI contract:

python3 codegen/validate_coverage.py

Regenerate all bindings first if the FFI surface changed:

./codegen.sh

Output Format

# SDK Parity Report

## FFI Functions Found: N

## Coverage (per SDK: c, cpp, csharp, go, kotlin, lua, python, rust, swift, typescript)
| FFI Function | Covered SDKs | Missing SDKs | Status |
|-------------|--------------|--------------|--------|
| create_context | 10/10 | — | OK |
| destroy_context | 9/10 | python | MISSING |
| ... | ... | ... | ... |

## Missing Bindings (X)
- function_name (goud_engine/src/ffi/file.rs:LINE) — missing in: <sdk list>

## SDK-Only Logic (potential violations)
- ClassName.Method (sdks/csharp/File.cs:LINE)

## Summary: X/N functions have full parity

Type Mapping Reference

Rust FFI Type	C# Type	Python ctypes
i32	int	c_int
u32	uint	c_uint
f32	float	c_float
f64	double	c_double
bool	bool	c_bool
*mut T	IntPtr	POINTER(T) or c_void_p
*const c_char	string	c_char_p
() (void)	void	None