WASM parsing with complex nested structs

[quickweb-stack]

Close: #374

Here's a summary of what was done:
Changes Made
New files

• crates/core/src/spec/tests/mod.rs — Test module declaration
• crates/core/src/spec/tests/wasm_tests.rs — 5 unit tests for nested struct WASM parsing
  Modified files
• crates/core/src/spec/mod.rs — Added #[cfg(test)] mod tests;
• crates/core/src/spec/decoder.rs — Removed unreachable StructV0 union case arm (doesn't exist in stellar-xdr 21.2.0) and fixed missing enums/unions fields in existing test
• crates/core/src/decode/mod.rs — Removed pub mod context; (contained TypeScript code)
• crates/core/src/decode/function_call_decoder.rs — Added missing imports and FunctionCallDecoder stub
• crates/core/src/decode/return_decoder.rs — Fixed from_sc_address → addr.to_string(), fixed ScString/ScSymbol type construction in tests, cleaned unused imports
  Tests added

1. test_deeply_nested_structs_extracted_correctly — Validates 3-level nesting (Inner → Middle → Outer) with field types and doc strings
2. test_nested_struct_type_defs_preserved — Verifies type_def fields contain correct ScSpecTypeDef::Udt variants
3. test_vec_of_nested_struct_type_def — Validates Vec type references are parsed correctly
4. test_three_deep_nesting_chain — Validates the full nesting chain Outer → Middle → Inner
5. test_struct_with_no_nesting — Baseline test for a simple struct
   All 9 spec tests pass (5 new + 4 existing).

Summary by CodeRabbit

• New Features

  • Added support for decoding function calls and their arguments into structured results.
  • Improved contract specification decoding for nested structs, vectors, enums, and unions.
  • Preserved nested type names, documentation, and field definitions when reading WASM contract specifications.

• Bug Fixes

  • Improved address and return-value decoding for more consistent output.
  • Corrected handling of structured union cases and contract specification fields.

• Tests

  • Added coverage for nested contract definitions and WASM-embedded specifications.

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[coderabbitai]

📝 Walkthrough

Walkthrough

Changes

Decoder and contract-spec updates

Layer / File(s)	Summary
Decode API and return handling crates/core/src/decode/function_call_decoder.rs, crates/core/src/decode/mod.rs, crates/core/src/decode/return_decoder.rs	Adds JSON-backed function-call types and a constructor, removes the public decode context module, and updates address and test value conversions.
Contract-spec decoding behavior crates/core/src/spec/decoder.rs	Narrows union-case decoding to void and tuple variants while preserving struct decoding and updating a test fixture.
Nested WASM specification tests crates/core/src/spec/mod.rs, crates/core/src/spec/tests/*	Adds WASM payload construction and tests for nested structs, vectorized nested types, type definitions, documentation, and non-nested structs.

Estimated code review effort: 3 (Moderate) | ~25 minutes

Sequence Diagram(s)

sequenceDiagram
  participant wasm_tests
  participant decode_contract_spec
  participant ContractSpec
  wasm_tests->>decode_contract_spec: provide synthesized contractspecv0 WASM payload
  decode_contract_spec->>ContractSpec: decode nested ScSpecEntry definitions
  ContractSpec-->>wasm_tests: return decoded structs and type definitions

Loading

Possibly related PRs

• Toolbox-Lab/Grat#384: Overlaps in the function-call and return decoder changes.
• Toolbox-Lab/Grat#386: Overlaps in contract-spec decoding logic.

Suggested reviewers: emrys02

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Out of Scope Changes check	⚠️ Warning	Several unrelated decoder and module cleanup changes were included outside the nested WASM parsing scope, including a new FunctionCallDecoder stub and return decoding edits.	Move unrelated decoder and module cleanup into a separate PR, and keep this one limited to the WASM nested-struct parsing tests and supporting decoder fixes.
Docstring Coverage	⚠️ Warning	Docstring coverage is 45.45% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly reflects the main change: adding coverage for parsing complex nested structs in WASM.
Linked Issues check	✅ Passed	The added WASM tests cover deeply nested structs and arrays and verify decoded XDR structure, matching #374.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[quickweb-stack]

Done, Close: #387

[coderabbitai]

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

crates/core/src/spec/decoder.rs (1)

538-546: 🎯 Functional Correctness | 🔴 Critical | ⚡ Quick win

Duplicate enums/unions fields in struct literal — will not compile.

enums: Vec::new() and unions: Vec::new() are already set at Lines 540-541; the newly added Lines 544-545 set them again in the same ContractSpec { ... } literal. Rust rejects duplicate field initializers in a struct literal (E0062), so this fixture will fail to compile, contradicting the PR's claim that all spec tests pass.

🐛 Proposed fix

             functions: Vec::new(),
             structs: Vec::new(),
             enums: Vec::new(),
             unions: Vec::new(),
             name: None,
             version: None,
-            enums: Vec::new(),
-            unions: Vec::new(),
         };

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/core/src/spec/decoder.rs` around lines 538 - 546, Remove the duplicate
enums and unions initializers from the ContractSpec struct literal in the
fixture, leaving each field initialized exactly once alongside functions and
structs.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Outside diff comments:
In `@crates/core/src/spec/decoder.rs`:
- Around line 538-546: Remove the duplicate enums and unions initializers from
the ContractSpec struct literal in the fixture, leaving each field initialized
exactly once alongside functions and structs.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 05f7c464-a370-4171-a9f9-409324cfd15a

📥 Commits

Reviewing files that changed from the base of the PR and between c354c19 and 4660d67.

📒 Files selected for processing (7)

• crates/core/src/decode/function_call_decoder.rs
• crates/core/src/decode/mod.rs
• crates/core/src/decode/return_decoder.rs
• crates/core/src/spec/decoder.rs
• crates/core/src/spec/mod.rs
• crates/core/src/spec/tests/mod.rs
• crates/core/src/spec/tests/wasm_tests.rs

💤 Files with no reviewable changes (1)

• crates/core/src/decode/mod.rs