Refactor/issue 89 error discriminants

[Chrisbankz0]

#closes
#647

Pull Request: [Contract] Implement Custom Error Enums with Explicit Numerical Discriminants

🎯 Overview

This PR addresses **Issue by annotating all contract error enums with explicit #[repr(u32)] numerical discriminants (e.g. AlreadyInitialized = 1) and exporting a standardized JSON schema specification.

Previously, implicit error discriminant mappings caused cross-language mapping between Rust contracts, the SoroScope web dashboard (Next.js/TypeScript), and external clients to be fragile and prone to decoding mismatches when enums were extended. Explicit numerical discriminants guarantee a stable on-chain ABI and deterministic cross-language error decoding.

✨ Features Implemented

• Explicit #[repr(u32)] Discriminants:
  • Annotated ContractError in contracts/error_codes/src/lib.rs with explicit numerical discriminants (1 to 17).
  • Added conversion utility methods as_u32(&self) and from_u32(code: u32) -> Option<Self>.
• Exported JSON Schema Specification:
  • Defined ERROR_SCHEMA_JSON constant in contracts/error_codes.
  • Created contracts/error_codes/schema.json mapping variant names, integer codes, and descriptions.
• Contract Error Enums Cleanup & Audit:
  • Cleaned up duplicate variant declarations in contracts/liquidity_pool/src/lib.rs.
  • Updated CrossChainError in contracts/cross_chain_payload/src/errors.rs with #[contracterror], #[repr(u32)], and explicit variant discriminants matching as_u32().
• Dual-Directory Alignment:
  • Synchronized changes across both root contracts/ and nested soroscope/contracts/ structures.

🔧 Technical Implementation

• ContractError enum definition:

  #[contracterror]
  #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
  #[repr(u32)]
  pub enum ContractError {
      AlreadyInitialized = 1,
      NotInitialized = 2,
      Unauthorized = 3,
      InsufficientBalance = 4,
      InsufficientLiquidity = 5,
      InsufficientShares = 6,
      InsufficientAllowance = 7,
      SlippageExceeded = 8,
      InvalidFee = 9,
      NoPendingFeeUpdate = 10,
      TimelockNotElapsed = 11,
      OracleNotConfigured = 12,
      InvalidOraclePrice = 13,
      Paused = 14,
      Overflow = 15,
      DivisionByZero = 16,
      InvalidInput = 17,
  }

• Exported JSON Schema layout (contracts/error_codes/schema.json):

  {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "title": "ContractError",
    "type": "object",
    "description": "Explicit numerical discriminant mappings for SoroScope smart contract error codes.",
    "error_codes": [
      { "name": "AlreadyInitialized", "code": 1, "description": "Contract has already been initialized." },
      ...
    ]
  }

🧪 Step-by-Step Testing & Verification Process

Follow these steps to verify that the assignment was successfully completed:

1. Verify Contract Error Code Discriminant Tests:
   Run cargo test on the error codes crate:

   cargo test -p soroscope-error-codes

   (If testing on Windows without MSVC linker installed, use the GNU toolchain):

   cargo +stable-x86_64-pc-windows-gnu test -p soroscope-error-codes

   Expected Result: All 3 tests (test_explicit_numerical_discriminants, test_from_u32_conversion, test_schema_json_contains_all_variants) pass cleanly.

2. Verify JSON Schema Specification:
   Inspect the generated schema file:

   cat contracts/error_codes/schema.json

   Expected Result: Valid JSON structure mapping error variants (AlreadyInitialized through InvalidInput) to their corresponding integer codes (1 through 17).

3. Verify Contract Workspace Checks:
   Check contract compilation across the workspace:

   cargo +stable-x86_64-pc-windows-gnu check

4. Verify Web Frontend Diagnostics:
   Ensure web application lints pass:

   cd web
   npm run lint

📁 Files Changed

• contracts/error_codes/src/lib.rs - Added explicit numerical discriminants, conversion helpers, JSON schema export, and tests.
• contracts/error_codes/schema.json - Added exported JSON schema specification.
• contracts/liquidity_pool/src/lib.rs - Removed duplicate enum variants.
• contracts/cross_chain_payload/src/errors.rs - Added #[contracterror], #[repr(u32)], and explicit discriminants.
• soroscope/contracts/error_codes/src/lib.rs - Synchronized nested crate file.
• soroscope/contracts/error_codes/schema.json - Synchronized nested schema file.
• soroscope/contracts/cross_chain_payload/src/errors.rs - Synchronized nested cross-chain errors.
• docs/PR_DESCRIPTION_ISSUE_647.md - Added PR documentation.

✅ Acceptance Criteria Checklist

• Implementation completed according to specification.
• Code passes all linting and formatting checks.
• Unit and Integration tests added and passing.

🔗 Related Issues

Closes #647

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[EDOHWARES]

Nice implementation, LGTM!