Merge branch 'claude/issue-5387-duplicate-check-bd7853' into claude/issue-5387-comparison-binary

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

single_include/nlohmann/json.hpp

@@ -3195,6 +3195,10 @@ void templated_json_throw(ExceptionType exception)
     #define JSON_BRACE_INIT_COPY_SEMANTICS 0
 #endif
 
+#ifndef JSON_STRICT_NUL_HANDLING
+    #define JSON_STRICT_NUL_HANDLING 0
+#endif
+
 #if JSON_HAS_THREE_WAY_COMPARISON
     #include <compare> // partial_ordering
 #endif
@@ -7912,6 +7916,21 @@ contiguous_bytes_input_adapter input_adapter(CharT b)
 template<typename T, std::size_t N>
 auto input_adapter(T (&array)[N]) -> decltype(input_adapter(array, array + N)) // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
 {
+#if JSON_STRICT_NUL_HANDLING
+    // A `char` array from string-literal initialization (e.g. json::parse("123"))
+    // carries a trailing '\0' contributed by the compiler, not by the source
+    // text; drop exactly that one byte so it is not mistaken for real trailing
+    // data. Every other element type (unsigned char, std::uint8_t, ...) keeps
+    // the full extent unconditionally, since a trailing zero byte there is
+    // genuine data (e.g. CBOR/MessagePack). This intentionally does not
+    // strlen()-scan the array (as the pointer overload above does for a
+    // null-delimited string): for a `char` array that is not NUL-terminated
+    // within its bounds, that would read past the end of the array.
+    if (std::is_same<typename std::remove_cv<T>::type, char>::value && N > 0 && array[N - 1] == 0)
+    {
+        return input_adapter(array, array + N - 1);
+    }
+#endif
     return input_adapter(array, array + N);
 }
 
@@ -9521,7 +9540,9 @@ class lexer : public lexer_base<BasicJsonType>
                         case '\n':
                         case '\r':
                         case char_traits<char_type>::eof():
+#if !JSON_STRICT_NUL_HANDLING
                         case '\0':
+#endif
                             return true;
 
                         default:
@@ -9539,8 +9560,10 @@ class lexer : public lexer_base<BasicJsonType>
                 {
                     switch (get())
                     {
-                        case char_traits<char_type>::eof():
+#if !JSON_STRICT_NUL_HANDLING
                         case '\0':
+#endif
+                        case char_traits<char_type>::eof():
                         {
                             error_message = "invalid comment; missing closing '*/'";
                             return false;
@@ -10722,9 +10745,12 @@ scan_number_done:
             case '9':
                 return scan_number_dispatch(std::integral_constant<bool, bulk_scan> {});
 
-            // end of input (the null byte is needed when parsing from
-            // string literals)
+#if !JSON_STRICT_NUL_HANDLING
             case '\0':
+#endif
+            // end of input; by default, a null byte is also treated as end of
+            // input for backwards compatibility (see JSON_STRICT_NUL_HANDLING
+            // to opt into rejecting a null byte in the input instead)
             case char_traits<char_type>::eof():
                 return token_type::end_of_input;
 
@@ -30627,6 +30653,7 @@ struct formatter<nlohmann::NLOHMANN_BASIC_JSON_TPL, char> // NOLINT(cert-dcl58-c
 #undef JSON_DISABLE_ENUM_SERIALIZATION
 #undef JSON_USE_GLOBAL_UDLS
 #undef JSON_BRACE_INIT_COPY_SEMANTICS
+#undef JSON_STRICT_NUL_HANDLING
 
 #ifndef JSON_TEST_KEEP_MACROS
     #undef JSON_CATCH