From bc524d70253a4ab2fe40c3ca3e5666e267c0a4d1 Mon Sep 17 00:00:00 2001 From: Lexi Winter Date: Sun, 29 Jun 2025 19:25:29 +0100 Subject: import catch2 3.8.1 --- src/catch2/internal/catch_decomposer.hpp | 457 +++++++++++++++++++++++++++++++ 1 file changed, 457 insertions(+) create mode 100644 src/catch2/internal/catch_decomposer.hpp (limited to 'src/catch2/internal/catch_decomposer.hpp') diff --git a/src/catch2/internal/catch_decomposer.hpp b/src/catch2/internal/catch_decomposer.hpp new file mode 100644 index 0000000..adce89f --- /dev/null +++ b/src/catch2/internal/catch_decomposer.hpp @@ -0,0 +1,457 @@ + +// Copyright Catch2 Authors +// Distributed under the Boost Software License, Version 1.0. +// (See accompanying file LICENSE.txt or copy at +// https://www.boost.org/LICENSE_1_0.txt) + +// SPDX-License-Identifier: BSL-1.0 +#ifndef CATCH_DECOMPOSER_HPP_INCLUDED +#define CATCH_DECOMPOSER_HPP_INCLUDED + +#include +#include +#include +#include +#include +#include + +#include +#include + +/** \file + * Why does decomposing look the way it does: + * + * Conceptually, decomposing is simple. We change `REQUIRE( a == b )` into + * `Decomposer{} <= a == b`, so that `Decomposer{} <= a` is evaluated first, + * and our custom operator is used for `a == b`, because `a` is transformed + * into `ExprLhs` and then into `BinaryExpr`. + * + * In practice, decomposing ends up a mess, because we have to support + * various fun things. + * + * 1) Types that are only comparable with literal 0, and they do this by + * comparing against a magic type with pointer constructor and deleted + * other constructors. Example: `REQUIRE((a <=> b) == 0)` in libstdc++ + * + * 2) Types that are only comparable with literal 0, and they do this by + * comparing against a magic type with consteval integer constructor. + * Example: `REQUIRE((a <=> b) == 0)` in current MSVC STL. + * + * 3) Types that have no linkage, and so we cannot form a reference to + * them. Example: some implementations of traits. + * + * 4) Starting with C++20, when the compiler sees `a == b`, it also uses + * `b == a` when constructing the overload set. For us this means that + * when the compiler handles `ExprLhs == b`, it also tries to resolve + * the overload set for `b == ExprLhs`. + * + * To accomodate these use cases, decomposer ended up rather complex. + * + * 1) These types are handled by adding SFINAE overloads to our comparison + * operators, checking whether `T == U` are comparable with the given + * operator, and if not, whether T (or U) are comparable with literal 0. + * If yes, the overload compares T (or U) with 0 literal inline in the + * definition. + * + * Note that for extra correctness, we check that the other type is + * either an `int` (literal 0 is captured as `int` by templates), or + * a `long` (some platforms use 0L for `NULL` and we want to support + * that for pointer comparisons). + * + * 2) For these types, `is_foo_comparable` is true, but letting + * them fall into the overload that actually does `T == int` causes + * compilation error. Handling them requires that the decomposition + * is `constexpr`, so that P2564R3 applies and the `consteval` from + * their accompanying magic type is propagated through the `constexpr` + * call stack. + * + * However this is not enough to handle these types automatically, + * because our default is to capture types by reference, to avoid + * runtime copies. While these references cannot become dangling, + * they outlive the constexpr context and thus the default capture + * path cannot be actually constexpr. + * + * The solution is to capture these types by value, by explicitly + * specializing `Catch::capture_by_value` for them. Catch2 provides + * specialization for `std::foo_ordering`s, but users can specialize + * the trait for their own types as well. + * + * 3) If a type has no linkage, we also cannot capture it by reference. + * The solution is once again to capture them by value. We handle + * the common cases by using `std::is_arithmetic` as the default + * for `Catch::capture_by_value`, but that is only a some-effort + * heuristic. But as with 2), users can specialize `capture_by_value` + * for their own types as needed. + * + * 4) To support C++20 and make the SFINAE on our decomposing operators + * work, the SFINAE has to happen in return type, rather than in + * a template type. This is due to our use of logical type traits + * (`conjunction`/`disjunction`/`negation`), that we use to workaround + * an issue in older (9-) versions of GCC. I still blame C++20 for + * this, because without the comparison order switching, the logical + * traits could still be used in template type. + * + * There are also other side concerns, e.g. supporting both `REQUIRE(a)` + * and `REQUIRE(a == b)`, or making `REQUIRE_THAT(a, IsEqual(b))` slot + * nicely into the same expression handling logic, but these are rather + * straightforward and add only a bit of complexity (e.g. common base + * class for decomposed expressions). + */ + +#ifdef _MSC_VER +#pragma warning(push) +#pragma warning(disable:4389) // '==' : signed/unsigned mismatch +#pragma warning(disable:4018) // more "signed/unsigned mismatch" +#pragma warning(disable:4312) // Converting int to T* using reinterpret_cast (issue on x64 platform) +#pragma warning(disable:4180) // qualifier applied to function type has no meaning +#pragma warning(disable:4800) // Forcing result to true or false +#endif + +#ifdef __clang__ +# pragma clang diagnostic push +# pragma clang diagnostic ignored "-Wsign-compare" +# pragma clang diagnostic ignored "-Wnon-virtual-dtor" +#elif defined __GNUC__ +# pragma GCC diagnostic push +# pragma GCC diagnostic ignored "-Wsign-compare" +# pragma GCC diagnostic ignored "-Wnon-virtual-dtor" +#endif + +#if defined(CATCH_CPP20_OR_GREATER) && __has_include() +# include +# if defined( __cpp_lib_three_way_comparison ) && \ + __cpp_lib_three_way_comparison >= 201907L +# define CATCH_CONFIG_CPP20_COMPARE_OVERLOADS +# endif +#endif + +namespace Catch { + + namespace Detail { + // This was added in C++20, but we require only C++14 for now. + template + using RemoveCVRef_t = std::remove_cv_t>; + } + + // Note: There is nothing that stops us from extending this, + // e.g. to `std::is_scalar`, but the more encompassing + // traits are usually also more expensive. For now we + // keep this as it used to be and it can be changed later. + template + struct capture_by_value + : std::integral_constant{}> {}; + +#if defined( CATCH_CONFIG_CPP20_COMPARE_OVERLOADS ) + template <> + struct capture_by_value : std::true_type {}; + template <> + struct capture_by_value : std::true_type {}; + template <> + struct capture_by_value : std::true_type {}; +#endif + + template + struct always_false : std::false_type {}; + + class ITransientExpression { + bool m_isBinaryExpression; + bool m_result; + + protected: + ~ITransientExpression() = default; + + public: + constexpr auto isBinaryExpression() const -> bool { return m_isBinaryExpression; } + constexpr auto getResult() const -> bool { return m_result; } + //! This function **has** to be overriden by the derived class. + virtual void streamReconstructedExpression( std::ostream& os ) const; + + constexpr ITransientExpression( bool isBinaryExpression, bool result ) + : m_isBinaryExpression( isBinaryExpression ), + m_result( result ) + {} + + constexpr ITransientExpression( ITransientExpression const& ) = default; + constexpr ITransientExpression& operator=( ITransientExpression const& ) = default; + + friend std::ostream& operator<<(std::ostream& out, ITransientExpression const& expr) { + expr.streamReconstructedExpression(out); + return out; + } + }; + + void formatReconstructedExpression( std::ostream &os, std::string const& lhs, StringRef op, std::string const& rhs ); + + template + class BinaryExpr : public ITransientExpression { + LhsT m_lhs; + StringRef m_op; + RhsT m_rhs; + + void streamReconstructedExpression( std::ostream &os ) const override { + formatReconstructedExpression + ( os, Catch::Detail::stringify( m_lhs ), m_op, Catch::Detail::stringify( m_rhs ) ); + } + + public: + constexpr BinaryExpr( bool comparisonResult, LhsT lhs, StringRef op, RhsT rhs ) + : ITransientExpression{ true, comparisonResult }, + m_lhs( lhs ), + m_op( op ), + m_rhs( rhs ) + {} + + template + auto operator && ( T ) const -> BinaryExpr const { + static_assert(always_false::value, + "chained comparisons are not supported inside assertions, " + "wrap the expression inside parentheses, or decompose it"); + } + + template + auto operator || ( T ) const -> BinaryExpr const { + static_assert(always_false::value, + "chained comparisons are not supported inside assertions, " + "wrap the expression inside parentheses, or decompose it"); + } + + template + auto operator == ( T ) const -> BinaryExpr const { + static_assert(always_false::value, + "chained comparisons are not supported inside assertions, " + "wrap the expression inside parentheses, or decompose it"); + } + + template + auto operator != ( T ) const -> BinaryExpr const { + static_assert(always_false::value, + "chained comparisons are not supported inside assertions, " + "wrap the expression inside parentheses, or decompose it"); + } + + template + auto operator > ( T ) const -> BinaryExpr const { + static_assert(always_false::value, + "chained comparisons are not supported inside assertions, " + "wrap the expression inside parentheses, or decompose it"); + } + + template + auto operator < ( T ) const -> BinaryExpr const { + static_assert(always_false::value, + "chained comparisons are not supported inside assertions, " + "wrap the expression inside parentheses, or decompose it"); + } + + template + auto operator >= ( T ) const -> BinaryExpr const { + static_assert(always_false::value, + "chained comparisons are not supported inside assertions, " + "wrap the expression inside parentheses, or decompose it"); + } + + template + auto operator <= ( T ) const -> BinaryExpr const { + static_assert(always_false::value, + "chained comparisons are not supported inside assertions, " + "wrap the expression inside parentheses, or decompose it"); + } + }; + + template + class UnaryExpr : public ITransientExpression { + LhsT m_lhs; + + void streamReconstructedExpression( std::ostream &os ) const override { + os << Catch::Detail::stringify( m_lhs ); + } + + public: + explicit constexpr UnaryExpr( LhsT lhs ) + : ITransientExpression{ false, static_cast(lhs) }, + m_lhs( lhs ) + {} + }; + + + template + class ExprLhs { + LhsT m_lhs; + public: + explicit constexpr ExprLhs( LhsT lhs ) : m_lhs( lhs ) {} + +#define CATCH_INTERNAL_DEFINE_EXPRESSION_EQUALITY_OPERATOR( id, op ) \ + template \ + constexpr friend auto operator op( ExprLhs&& lhs, RhsT&& rhs ) \ + -> std::enable_if_t< \ + Detail::conjunction, \ + Detail::negation>>>::value, \ + BinaryExpr> { \ + return { \ + static_cast( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \ + } \ + template \ + constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs ) \ + -> std::enable_if_t< \ + Detail::conjunction, \ + capture_by_value>::value, \ + BinaryExpr> { \ + return { \ + static_cast( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \ + } \ + template \ + constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs ) \ + -> std::enable_if_t< \ + Detail::conjunction< \ + Detail::negation>, \ + Detail::is_eq_0_comparable, \ + /* We allow long because we want `ptr op NULL` to be accepted */ \ + Detail::disjunction, \ + std::is_same>>::value, \ + BinaryExpr> { \ + if ( rhs != 0 ) { throw_test_failure_exception(); } \ + return { \ + static_cast( lhs.m_lhs op 0 ), lhs.m_lhs, #op##_sr, rhs }; \ + } \ + template \ + constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs ) \ + -> std::enable_if_t< \ + Detail::conjunction< \ + Detail::negation>, \ + Detail::is_eq_0_comparable, \ + /* We allow long because we want `ptr op NULL` to be accepted */ \ + Detail::disjunction, \ + std::is_same>>::value, \ + BinaryExpr> { \ + if ( lhs.m_lhs != 0 ) { throw_test_failure_exception(); } \ + return { static_cast( 0 op rhs ), lhs.m_lhs, #op##_sr, rhs }; \ + } + + CATCH_INTERNAL_DEFINE_EXPRESSION_EQUALITY_OPERATOR( eq, == ) + CATCH_INTERNAL_DEFINE_EXPRESSION_EQUALITY_OPERATOR( ne, != ) + + #undef CATCH_INTERNAL_DEFINE_EXPRESSION_EQUALITY_OPERATOR + + +#define CATCH_INTERNAL_DEFINE_EXPRESSION_COMPARISON_OPERATOR( id, op ) \ + template \ + constexpr friend auto operator op( ExprLhs&& lhs, RhsT&& rhs ) \ + -> std::enable_if_t< \ + Detail::conjunction, \ + Detail::negation>>>::value, \ + BinaryExpr> { \ + return { \ + static_cast( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \ + } \ + template \ + constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs ) \ + -> std::enable_if_t< \ + Detail::conjunction, \ + capture_by_value>::value, \ + BinaryExpr> { \ + return { \ + static_cast( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \ + } \ + template \ + constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs ) \ + -> std::enable_if_t< \ + Detail::conjunction< \ + Detail::negation>, \ + Detail::is_##id##_0_comparable, \ + std::is_same>::value, \ + BinaryExpr> { \ + if ( rhs != 0 ) { throw_test_failure_exception(); } \ + return { \ + static_cast( lhs.m_lhs op 0 ), lhs.m_lhs, #op##_sr, rhs }; \ + } \ + template \ + constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs ) \ + -> std::enable_if_t< \ + Detail::conjunction< \ + Detail::negation>, \ + Detail::is_##id##_0_comparable, \ + std::is_same>::value, \ + BinaryExpr> { \ + if ( lhs.m_lhs != 0 ) { throw_test_failure_exception(); } \ + return { static_cast( 0 op rhs ), lhs.m_lhs, #op##_sr, rhs }; \ + } + + CATCH_INTERNAL_DEFINE_EXPRESSION_COMPARISON_OPERATOR( lt, < ) + CATCH_INTERNAL_DEFINE_EXPRESSION_COMPARISON_OPERATOR( le, <= ) + CATCH_INTERNAL_DEFINE_EXPRESSION_COMPARISON_OPERATOR( gt, > ) + CATCH_INTERNAL_DEFINE_EXPRESSION_COMPARISON_OPERATOR( ge, >= ) + + #undef CATCH_INTERNAL_DEFINE_EXPRESSION_COMPARISON_OPERATOR + + +#define CATCH_INTERNAL_DEFINE_EXPRESSION_OPERATOR( op ) \ + template \ + constexpr friend auto operator op( ExprLhs&& lhs, RhsT&& rhs ) \ + -> std::enable_if_t< \ + !capture_by_value>::value, \ + BinaryExpr> { \ + return { \ + static_cast( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \ + } \ + template \ + constexpr friend auto operator op( ExprLhs&& lhs, RhsT rhs ) \ + -> std::enable_if_t::value, \ + BinaryExpr> { \ + return { \ + static_cast( lhs.m_lhs op rhs ), lhs.m_lhs, #op##_sr, rhs }; \ + } + + CATCH_INTERNAL_DEFINE_EXPRESSION_OPERATOR(|) + CATCH_INTERNAL_DEFINE_EXPRESSION_OPERATOR(&) + CATCH_INTERNAL_DEFINE_EXPRESSION_OPERATOR(^) + + #undef CATCH_INTERNAL_DEFINE_EXPRESSION_OPERATOR + + template + friend auto operator && ( ExprLhs &&, RhsT && ) -> BinaryExpr { + static_assert(always_false::value, + "operator&& is not supported inside assertions, " + "wrap the expression inside parentheses, or decompose it"); + } + + template + friend auto operator || ( ExprLhs &&, RhsT && ) -> BinaryExpr { + static_assert(always_false::value, + "operator|| is not supported inside assertions, " + "wrap the expression inside parentheses, or decompose it"); + } + + constexpr auto makeUnaryExpr() const -> UnaryExpr { + return UnaryExpr{ m_lhs }; + } + }; + + struct Decomposer { + template >::value, + int> = 0> + constexpr friend auto operator <= ( Decomposer &&, T && lhs ) -> ExprLhs { + return ExprLhs{ lhs }; + } + + template ::value, int> = 0> + constexpr friend auto operator <= ( Decomposer &&, T value ) -> ExprLhs { + return ExprLhs{ value }; + } + }; + +} // end namespace Catch + +#ifdef _MSC_VER +#pragma warning(pop) +#endif +#ifdef __clang__ +# pragma clang diagnostic pop +#elif defined __GNUC__ +# pragma GCC diagnostic pop +#endif + +#endif // CATCH_DECOMPOSER_HPP_INCLUDED -- cgit v1.2.3