🤜 Doctest 2.5.3

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

.github/workflows/windows.yml

@@ -90,13 +90,11 @@ jobs:
       - name: Get latest CMake and ninja
         uses: lukka/get-cmake@f5b8fbb4d77cec1acc5a5f9f0df4beffaf5d98d9 # v4.3.4
       - name: Set extra CXX_FLAGS for latest std_version
-        # /wd5285 silences C5285 emitted by the bundled third-party doctest.h, which
-        # specializes std::tuple (newly diagnosed by the VS2026 v145 toolset)
         run: |
           if [ "${{ matrix.std_version }}" = "latest" ]; then
-            echo "flags=/permissive- /std:c++latest /utf-8 /W4 /WX /wd5285" >> $GITHUB_ENV
+            echo "flags=/permissive- /std:c++latest /utf-8 /W4 /WX" >> $GITHUB_ENV
           else
-            echo "flags=/W4 /WX /wd5285" >> $GITHUB_ENV
+            echo "flags=/W4 /WX" >> $GITHUB_ENV
           fi
         shell: bash
       - name: Run CMake (Release)

cmake/clang_flags.cmake

@@ -5,7 +5,7 @@
 # -Wno-extra-semi-stmt            The library uses assert which triggers this warning.
 # -Wno-padded                     We do not care about padding warnings.
 # -Wno-covered-switch-default     All switches list all cases and a default case.
-# -Wno-unsafe-buffer-usage        Otherwise Doctest would not compile.
+# -Wno-unsafe-buffer-usage        Otherwise library code (strlen) would not compile.
 # -Wno-missing-noreturn           We found no way to silence this warning otherwise, see PR #4871
 
 set(CLANG_CXXFLAGS

cmake/gcc_flags.cmake

@@ -4,7 +4,6 @@
 # -Wno-aggregate-return  The library uses aggregate returns.
 # -Wno-long-long         The library uses the long long type to interface with system functions.
 # -Wno-namespaces        The library uses namespaces.
-# -Wno-nrvo              Doctest triggers this warning.
 # -Wno-padded            We do not care about padding warnings.
 # -Wno-system-headers    We do not care about warnings in system headers.
 # -Wno-templates         The library uses templates.
@@ -232,7 +231,6 @@ set(GCC_CXXFLAGS
     -Wnonnull
     -Wnonnull-compare
     -Wnormalized=nfkc
-    -Wno-nrvo
     -Wnull-dereference
     -Wodr
     -Wold-style-cast

docs/mkdocs/docs/features/conversions.md

@@ -66,24 +66,6 @@ which forces the explicit `get` form and can catch unintended conversions at com
     floating-point value as an integer truncates it, and narrowing conversions may overflow. See
     [number conversion](types/number_handling.md#number-conversion) for details and how to guard against it.
 
-!!! warning "std::optional direct construction from JSON null throws"
-
-    Constructing or assigning `std::optional<T>` directly from a JSON value does not correctly produce
-    `std::nullopt` for a JSON `null`:
-
-    ```cpp
-    json j_null;
-    std::optional<std::string> opt = j_null;  // ❌ throws type_error 302
-    ```
-
-    This is due to C++ language rules: `std::optional<T>` has its own converting constructor that is chosen over
-    `basic_json::operator T()` when both are viable. Use `get<std::optional<T>>()` or `get_to()` instead:
-
-    ```cpp
-    auto opt = j_null.get<std::optional<std::string>>();  // ✅ std::nullopt
-    j_null.get_to(opt);                                     // ✅ std::nullopt
-    ```
-
 ## Putting values in
 
 The reverse direction works the same way: assigning or constructing a `json` from a C++ value converts it to JSON.

tests/src/unit-conversions.cpp

@@ -1761,27 +1761,16 @@ TEST_CASE("std::filesystem::path")
 }
 #endif
 
+#if !JSON_USE_IMPLICIT_CONVERSIONS
 TEST_CASE("std::optional")
 {
     SECTION("null")
     {
-        const json j_null;
+        json j_null;
-        const std::optional<std::string> opt_null;
+        std::optional<std::string> opt_null;
 
         CHECK(json(opt_null) == j_null);
         CHECK(j_null.get<std::optional<std::string>>() == std::nullopt);
-
-        // Constructing std::optional<T> directly from JSON null throws because
-        // std::optional's own converting constructor is chosen over basic_json's
-        // operator T(). This is a language-level limitation (std::optional<T> is
-        // constructible from T, and T is constructible from basic_json via the
-        // operator); there is no SFINAE path that distinguishes "call from inside
-        // std::optional's constructor" from "direct call". Use get<std::optional<T>>()
-        // or get_to() instead for correct null handling. See #4864 and #5246.
-        CHECK_THROWS_WITH_AS(std::optional<std::string>(j_null),
-                             "[json.exception.type_error.302] type must be string, but is null", json::type_error&);
-        CHECK_THROWS_WITH_AS(std::optional<int>(j_null),
-                             "[json.exception.type_error.302] type must be number, but is null", json::type_error&);
     }
 
     SECTION("string")
@@ -1830,6 +1819,7 @@ TEST_CASE("std::optional")
     }
 }
 #endif
+#endif
 
 #ifdef JSON_HAS_CPP_17
     #undef JSON_HAS_CPP_17