Function findMissingRequiredExport

lib/validator/component_validator.cpp:128–157

Returns the first export in `RequiredIT` missing from the instance at `ProvidedInstIdx`, or whose stored SortType doesn't match the required sort kind. nullopt ⇒ Provided is a sort-kind subtype of RequiredIT. Only the sort kind is compared; deep structural subtype between the required externdesc and the provided export's inferred type is not yet implemented.

// required externdesc and the provided export's inferred type is not yet
// implemented.
std::optional<std::string>
findMissingRequiredExport(const ComponentContext &Ctx, uint32_t ProvidedInstIdx,
                          const AST::Component::InstanceType &RequiredIT) {
  const auto &Exports = Ctx.getInstance(ProvidedInstIdx);
  for (const auto &Decl : RequiredIT.getDecl()) {
    if (!Decl.isExportDecl()) {
      continue;
    }
    const auto &Exp = Decl.getExport();
    auto It = Exports.find(std::string(Exp.getName()));
    if (It == Exports.end()) {
      return std::string(Exp.getName());
    }
    auto RequiredST = descTypeToSortType(Exp.getExternDesc().getDescType());
    if (!RequiredST.has_value()) {
      // `(core module)` required-exports can't be compared against
      // InstanceExport::ST (component-side only). Skip symmetrically with
      // populateInstanceFromType; will be revisited when InstanceExport
      // gains a core-sort variant.
      spdlog::debug("    findMissingRequiredExport: skipping `(core module)` "
                    "required-export '{}'"sv,
                    Exp.getName());
      continue;
    }
    if (It->second.ST != *RequiredST) {
      return std::string(Exp.getName());
    }
  }
  return std::nullopt;
}

// Resolve a type index in `Comp`'s own type index space to an InstanceType.
// Returns nullptr when the index does not refer to an inline InstanceType