Result and Issues

Header: swaggercpp/result.hpp

swaggercpp uses a return-type-based error channel instead of exceptions for expected failures.

`Issue`

cpp

enum class IssueSeverity { warning, error };

struct Issue {
    IssueSeverity severity { IssueSeverity::error };
    std::string   path;      // JSON Pointer-style path, e.g. "/paths/~1pets/get"
    std::string   message;   // human-readable description
};

path follows RFC 6901 encoding: / is escaped as ~1, ~ as ~0. An empty path refers to the document root.

`Result<T>`

cpp

template <typename T>
class Result {
public:
    static Result success(T value, std::vector<Issue> issues = {});
    static Result failure(std::vector<Issue> issues);

    [[nodiscard]] bool ok() const noexcept;          // value present AND no errors
    [[nodiscard]] explicit operator bool() const noexcept;
    [[nodiscard]] bool has_errors() const noexcept;

    [[nodiscard]] const T&  value() const;           // throws logic_error if absent
    [[nodiscard]]       T&  value();

    [[nodiscard]] const std::vector<Issue>& issues() const noexcept;
};

Semantics

State	`ok()`	`value()`	`issues()`
Success, no issues	true	returns value	empty
Success, warnings	true	returns value	warning entries
Failure, with errors	false	throws	error (+ warning) entries

TIP

ok() is stricter than "has a value" — it returns false when any issue has IssueSeverity::error. Use if (result) as the go-to guard; it already delegates to ok().

`ValidationReport`

A lighter sibling used by DocumentValidator:

cpp

struct ValidationReport {
    std::vector<Issue> issues;
    [[nodiscard]] bool ok() const noexcept;   // true iff no errors
};

There is no "value" here — validation's only output is the list of issues.

Idioms

Short-circuit on failure

cpp

auto r = swaggercpp::DocumentReader::read_file("spec.yaml");
if (!r) return 1;

Inspect issues on success

cpp

for (const auto& issue : r.issues()) {
    // warnings only; errors already sent us down the failure path
}

Accumulate across a pipeline

cpp

std::vector<swaggercpp::Issue> collected;

auto r = swaggercpp::DocumentReader::read_file("spec.yaml");
collected.insert(collected.end(), r.issues().begin(), r.issues().end());

if (r) {
    swaggercpp::DocumentValidator v;
    auto report = v.validate(r.value());
    collected.insert(collected.end(), report.issues.begin(), report.issues.end());
}

std::ranges::sort(collected, {}, &swaggercpp::Issue::path);

Result and Issues ​

Issue ​

Result<T> ​

Semantics ​

ValidationReport ​

Idioms ​

Short-circuit on failure ​

Inspect issues on success ​

Accumulate across a pipeline ​

See also ​