Make convert_null_to() take the container type as a template argument

Passing array_t or object_t instead of a value_t makes an invalid target a compile error instead of a runtime assertion, and removes the branch. Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Re-enable bugprone-use-after-move/hicpp-invalid-access-moved
2026-10-02 20:50:32 +00:00 · 2026-09-30 21:31:58 +02:00 · 2026-09-30 19:05:07 +02:00 · 2026-09-30 19:05:05 +02:00 · 2026-09-30 19:05:05 +02:00 · 2026-09-30 19:05:03 +02:00
18 changed files with 808 additions and 1474 deletions
@@ -1,11 +1,9 @@
-# TODO: The first three checks are only removed to get the CI going. They have to be addressed at some point.
+# TODO: portability-template-virtual-member-function is only removed to get the CI going. It has to be addressed at some point.
 # TODO: portability-avoid-pragma-once: should be fixed eventually

 Checks: '*,

         -portability-template-virtual-member-function,
-         -bugprone-use-after-move,
-         -hicpp-invalid-access-moved,

         -altera-id-dependent-backward-branch,
         -altera-struct-pack-align,
@@ -13,7 +13,7 @@ JSON object holding version information

 | key         | description                                                                                                                                                                                                                                                                    |
 |-------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| `compiler`  | Information on the used compiler. It is an object with the following keys: `c++` (the used C++ standard), `family` (the compiler family; possible values are `clang`, `icc`, `gcc`, `ilecpp`, `msvc`, `pgcpp`, `sunpro`, and `unknown`), and `version` (the compiler version). On HP aCC compilers, `compiler` is instead the plain string `hp`. |
+| `compiler`  | Information on the used compiler. It is an object with the following keys: `c++` (the used C++ standard), `family` (the compiler family; possible values are `clang`, `icc`, `gcc`, `hp`, `ilecpp`, `msvc`, `pgcpp`, `sunpro`, and `unknown`), and `version` (the compiler version). |
 | `copyright` | The copyright line for the library as string.                                                                                                                                                                                                                                  |
 | `name`      | The name of the library as string.                                                                                                                                                                                                                                             |
 | `platform`  | The used platform as string. Possible values are `win32`, `linux`, `apple`, `unix`, and `unknown`.                                                                                                                                                                             |
@@ -55,10 +55,6 @@ This implementation does exactly follow this approach, as it uses double precisi
 smaller than `-1.79769313486232e+308` and values greater than `1.79769313486232e+308` will be stored as NaN internally
 and be serialized to `null`.

-During deserialization (from JSON text or any of the binary formats), a finite number that does not fit into
-`number_float_t` is rejected with [`out_of_range.406`](../../home/exceptions.md#jsonexceptionout_of_range406), for
-example a double-precision number in a binary format when `number_float_t` is `#!cpp float`.
-
 #### Storage

 Floating-point number values are stored directly inside a `basic_json` type.
@@ -47,9 +47,8 @@ With the default values for `NumberIntegerType` (`std::int64_t`), the default va

 When the default type is used, the maximal integer number that can be stored is `9223372036854775807` (INT64_MAX) and
 the minimal integer number that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers that are out of
-range will yield over/underflow when used in a constructor. During deserialization (from JSON text or any of the binary
-formats), too large or small integer numbers will automatically be stored as [`number_unsigned_t`](number_unsigned_t.md)
-or [`number_float_t`](number_float_t.md).
+range will yield over/underflow when used in a constructor. During deserialization, too large or small integer numbers
+will automatically be stored as [`number_unsigned_t`](number_unsigned_t.md) or [`number_float_t`](number_float_t.md).

 [RFC 8259](https://tools.ietf.org/html/rfc8259) further states:
 > Note that when such software is used, numbers that are integers and are in the range $[-2^{53}+1, 2^{53}-1]$ are
@@ -48,9 +48,8 @@ With the default values for `NumberUnsignedType` (`std::uint64_t`), the default

 When the default type is used, the maximal integer number that can be stored is `18446744073709551615` (UINT64_MAX) and
 the minimal integer number that can be stored is `0`. Integer numbers that are out of range will yield over/underflow
-when used in a constructor. During deserialization (from JSON text or any of the binary formats), too large or small
-integer numbers will automatically be stored as [`number_integer_t`](number_integer_t.md) or
-[`number_float_t`](number_float_t.md).
+when used in a constructor. During deserialization, too large or small integer numbers will automatically be stored
+as [`number_integer_t`](number_integer_t.md) or [`number_float_t`](number_float_t.md).

 [RFC 8259](https://tools.ietf.org/html/rfc8259) further states:
 > Note that when such software is used, numbers that are integers and are in the range $[-2^{53}+1, 2^{53}-1]$ are
@@ -168,9 +168,9 @@ The library maps CBOR types to JSON value types as follows:
 !!! warning "Negative integer overflow"

    CBOR negative integers (major type 1) are decoded as `-1 - n`. If the encoded magnitude `n` is too large for the
-    result to fit into `number_integer_t` (`std::int64_t` by default), the result is stored as `number_float_t`, like
-    a too small integer in JSON text. For example, `-18446744073709551616` (`0x3B` followed by eight `0xFF` bytes) is
-    stored as `-1.8446744073709552e+19`.
+    result to fit into `number_integer_t` (`std::int64_t` by default), parsing fails with a
+    [`parse_error.112`](../../home/exceptions.md#jsonexceptionparse_error112) exception rather than overflowing
+    silently.

 !!! warning "Object keys"

@@ -331,6 +331,9 @@ An unexpected byte was read in a [binary format](../features/binary_formats/inde
    [json.exception.parse_error.112] parse error at byte 15: syntax error while parsing BSON binary: byte array length cannot be negative, is -1
    ```
    ```
+    [json.exception.parse_error.112] parse error at byte 9: syntax error while parsing CBOR value: negative integer overflow
+    ```
+    ```
    [json.exception.parse_error.112] parse error at byte 5: syntax error while parsing BSON document: document size 6 does not match the number of bytes read (5)
    ```

@@ -851,18 +854,13 @@ The JSON Patch operations 'remove' and 'add' cannot be applied to the root eleme

 ### json.exception.out_of_range.406

-A parsed number could not be stored without changing it to NaN or INF. For the binary formats, this happens when a
-finite floating-point number does not fit into [`number_float_t`](../api/basic_json/number_float_t.md), for example a
-double-precision number when `number_float_t` is `#!cpp float`.
+A parsed number could not be stored as without changing it to NaN or INF.

-!!! failure "Example messages"
+!!! failure "Example message"

    ```
    number overflow parsing '10E1000'
    ```
-    ```
-    [json.exception.out_of_range.406] syntax error while parsing CBOR value: number overflow
-    ```

 ### json.exception.out_of_range.407

@@ -353,7 +353,7 @@ template < typename BasicJsonType, typename T, std::size_t... Idx >
 std::array<T, sizeof...(Idx)> from_json_inplace_array_impl(BasicJsonType&& j,
                     identity_tag<std::array<T, sizeof...(Idx)>> /*unused*/, index_sequence<Idx...> /*unused*/)
 {
-    return { { std::forward<BasicJsonType>(j).at(Idx).template get<T>()... } };
+    return { { j.at(Idx).template get<T>()... } };
 }

 template < typename BasicJsonType, typename T, std::size_t N >
@@ -502,7 +502,7 @@ using tuple_type = std::tuple < decltype(from_json_tuple_get_impl(std::declval<B
 template<std::size_t PTagValue, typename... Args, typename BasicJsonType, std::size_t... Idx>
 tuple_type<PTagValue, BasicJsonType, Args...> from_json_tuple_impl_base(BasicJsonType&& j, index_sequence<Idx...> /*unused*/)
 {
-    return tuple_type<PTagValue, BasicJsonType, Args...>(from_json_tuple_get_impl(std::forward<BasicJsonType>(j).at(Idx), detail::identity_tag<Args> {}, detail::priority_tag<PTagValue> {})...);
+    return tuple_type<PTagValue, BasicJsonType, Args...>(from_json_tuple_get_impl(j.at(Idx), detail::identity_tag<Args> {}, detail::priority_tag<PTagValue> {})...);
 }

 template<std::size_t PTagValue, typename BasicJsonType>
@@ -514,8 +514,8 @@ std::tuple<> from_json_tuple_impl_base(BasicJsonType& /*unused*/, index_sequence
 template < typename BasicJsonType, class A1, class A2 >
 std::pair<A1, A2> from_json_tuple_impl(BasicJsonType&& j, identity_tag<std::pair<A1, A2>> /*unused*/, priority_tag<0> /*unused*/)
 {
-    return {std::forward<BasicJsonType>(j).at(0).template get<A1>(),
-            std::forward<BasicJsonType>(j).at(1).template get<A2>()};
+    return {j.at(0).template get<A1>(),
+            j.at(1).template get<A2>()};
 }

 template<typename BasicJsonType, typename A1, typename A2>
@@ -559,7 +559,7 @@ class binary_reader
            case 0x01: // double
            {
                double number{};
-                return get_number<double, true>(input_format_t::bson, number) && emit_float(input_format_t::bson, number);
+                return get_number<double, true>(input_format_t::bson, number) && sax->number_float(static_cast<number_float_t>(number), "");
            }

            case 0x02: // string
@@ -600,19 +600,19 @@ class binary_reader
            case 0x10: // int32
            {
                std::int32_t value{};
-                return get_number<std::int32_t, true>(input_format_t::bson, value) && emit_signed(input_format_t::bson, value);
+                return get_number<std::int32_t, true>(input_format_t::bson, value) && sax->number_integer(value);
            }

            case 0x12: // int64
            {
                std::int64_t value{};
-                return get_number<std::int64_t, true>(input_format_t::bson, value) && emit_signed(input_format_t::bson, value);
+                return get_number<std::int64_t, true>(input_format_t::bson, value) && sax->number_integer(value);
            }

            case 0x11: // uint64
            {
                std::uint64_t value{};
-                return get_number<std::uint64_t, true>(input_format_t::bson, value) && emit_unsigned(input_format_t::bson, value);
+                return get_number<std::uint64_t, true>(input_format_t::bson, value) && sax->number_unsigned(value);
            }

            default: // anything else is not supported (yet)
@@ -638,19 +638,14 @@ class binary_reader
        {
            return false;
        }
-
-        // the value is -1 - number, which fits into number_integer_t
-        // whenever number does
-        if (JSON_HEDLEY_LIKELY(value_in_range_of<number_integer_t>(number)))
+        const auto max_val = static_cast<NumberType>((std::numeric_limits<number_integer_t>::max)());
+        if (number > max_val)
        {
-            return sax->number_integer(static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(number));
+            return sax->parse_error(chars_read, get_token_string(),
+                                    parse_error::create(112, chars_read,
+                                            exception_message(input_format_t::cbor, "negative integer overflow", "value"), nullptr));
        }
-
-        // like the lexer does for JSON text, store a value too small for
-        // number_integer_t as number_float_t; compute it as long double so
-        // that emit_float sees a finite value and can detect an overflow of
-        // number_float_t
-        return emit_float(input_format_t::cbor, static_cast<long double>(-1) - static_cast<long double>(number));
+        return sax->number_integer(static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(number));
    }

    /*!
@@ -707,25 +702,25 @@ class binary_reader
            case 0x18: // Unsigned integer (one-byte uint8_t follows)
            {
                std::uint8_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
            }

            case 0x19: // Unsigned integer (two-byte uint16_t follows)
            {
                std::uint16_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
            }

            case 0x1A: // Unsigned integer (four-byte uint32_t follows)
            {
                std::uint32_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
            }

            case 0x1B: // Unsigned integer (eight-byte uint64_t follows)
            {
                std::uint64_t number{};
-                return get_number(input_format_t::cbor, number) && emit_unsigned(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_unsigned(number);
            }

            // Negative integer -1-0x00..-1-0x17 (-1..-24)
@@ -1170,13 +1165,13 @@ class binary_reader
            case 0xFA: // Single-Precision Float (four-byte IEEE 754)
            {
                float number{};
-                return get_number(input_format_t::cbor, number) && emit_float(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_float(static_cast<number_float_t>(number), "");
            }

            case 0xFB: // Double-Precision Float (eight-byte IEEE 754)
            {
                double number{};
-                return get_number(input_format_t::cbor, number) && emit_float(input_format_t::cbor, number);
+                return get_number(input_format_t::cbor, number) && sax->number_float(static_cast<number_float_t>(number), "");
            }

            default: // anything else (0xFF is handled inside the other types)
@@ -1940,61 +1935,61 @@ class binary_reader
            case 0xCA: // float 32
            {
                float number{};
-                return get_number(input_format_t::msgpack, number) && emit_float(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_float(static_cast<number_float_t>(number), "");
            }

            case 0xCB: // float 64
            {
                double number{};
-                return get_number(input_format_t::msgpack, number) && emit_float(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_float(static_cast<number_float_t>(number), "");
            }

            case 0xCC: // uint 8
            {
                std::uint8_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
            }

            case 0xCD: // uint 16
            {
                std::uint16_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
            }

            case 0xCE: // uint 32
            {
                std::uint32_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
            }

            case 0xCF: // uint 64
            {
                std::uint64_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_unsigned(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_unsigned(number);
            }

            case 0xD0: // int 8
            {
                std::int8_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
            }

            case 0xD1: // int 16
            {
                std::int16_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
            }

            case 0xD2: // int 32
            {
                std::int32_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
            }

            case 0xD3: // int 64
            {
                std::int64_t number{};
-                return get_number(input_format_t::msgpack, number) && emit_signed(input_format_t::msgpack, number);
+                return get_number(input_format_t::msgpack, number) && sax->number_integer(number);
            }

            case 0xDC: // array 16
@@ -2927,7 +2922,7 @@ class binary_reader
                        {
                            return sax->parse_error(chars_read, get_token_string(), out_of_range::create(408, exception_message(input_format, "excessive ndarray size caused overflow", "size"), nullptr));
                        }
-                        if (JSON_HEDLEY_UNLIKELY(!emit_unsigned(input_format, i)))
+                        if (JSON_HEDLEY_UNLIKELY(!sax->number_unsigned(static_cast<number_unsigned_t>(i))))
                        {
                            return false;
                        }
@@ -3059,37 +3054,37 @@ class binary_reader
                    break;
                }
                std::uint8_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
            }

            case 'U':
            {
                std::uint8_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
            }

            case 'i':
            {
                std::int8_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
            }

            case 'I':
            {
                std::int16_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
            }

            case 'l':
            {
                std::int32_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
            }

            case 'L':
            {
                std::int64_t number{};
-                return get_number(input_format, number) && emit_signed(input_format, number);
+                return get_number(input_format, number) && sax->number_integer(number);
            }

            case 'u':
@@ -3099,7 +3094,7 @@ class binary_reader
                    break;
                }
                std::uint16_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
            }

            case 'm':
@@ -3109,7 +3104,7 @@ class binary_reader
                    break;
                }
                std::uint32_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
            }

            case 'M':
@@ -3119,7 +3114,7 @@ class binary_reader
                    break;
                }
                std::uint64_t number{};
-                return get_number(input_format, number) && emit_unsigned(input_format, number);
+                return get_number(input_format, number) && sax->number_unsigned(number);
            }

            case 'h':
@@ -3177,13 +3172,13 @@ class binary_reader
            case 'd':
            {
                float number{};
-                return get_number(input_format, number) && emit_float(input_format, number);
+                return get_number(input_format, number) && sax->number_float(static_cast<number_float_t>(number), "");
            }

            case 'D':
            {
                double number{};
-                return get_number(input_format, number) && emit_float(input_format, number);
+                return get_number(input_format, number) && sax->number_float(static_cast<number_float_t>(number), "");
            }

            case 'H':
@@ -3650,13 +3645,13 @@ class binary_reader
            case 0x8E: // binary32
            {
                float number{};
-                return get_number(input_format_t::bon8, number) && emit_float(input_format_t::bon8, number);
+                return get_number(input_format_t::bon8, number) && sax->number_float(static_cast<number_float_t>(number), "");
            }

            case 0x8F: // binary64
            {
                double number{};
-                return get_number(input_format_t::bon8, number) && emit_float(input_format_t::bon8, number);
+                return get_number(input_format_t::bon8, number) && sax->number_float(static_cast<number_float_t>(number), "");
            }

            case 0xF8:
@@ -3722,9 +3717,7 @@ class binary_reader
    @brief pass an integer to the SAX parser

    Non-negative integers are passed as unsigned, negative integers as signed
-    numbers, like the other binary formats do. A value that does not fit the
-    number type is passed as described for @ref emit_unsigned and
-    @ref emit_signed.
+    numbers, like the other binary formats do.

    @param[in] number  the integer
    @return whether the SAX parser accepted the value
@@ -3733,9 +3726,9 @@ class binary_reader
    {
        if (number >= 0)
        {
-            return emit_unsigned(input_format_t::bon8, static_cast<std::uint64_t>(number));
+            return sax->number_unsigned(static_cast<number_unsigned_t>(number));
        }
-        return emit_signed(input_format_t::bon8, number);
+        return sax->number_integer(static_cast<number_integer_t>(number));
    }

    /*!
@@ -3792,7 +3785,8 @@ class binary_reader
            value = (value << 8) | static_cast<std::int64_t>(current);
        }

-        return emit_bon8_integer(negative ? -(value + offset) : value + offset);
+        return negative ? sax->number_integer(static_cast<number_integer_t>(-(value + offset)))
+               : sax->number_unsigned(static_cast<number_unsigned_t>(value + offset));
    }

    /*!
@@ -4089,88 +4083,6 @@ class binary_reader
        return true;
    }

-    /*!
-    @brief pass a signed integer read from the input to the SAX parser
-
-    Like the lexer does for JSON text, a value that does not fit into
-    number_integer_t is passed as number_unsigned_t if it is non-negative and
-    fits there, and as number_float_t otherwise. With the default number
-    types, every integer the binary formats can encode fits, so this only
-    matters for narrower custom number types.
-
-    @tparam NumberType a signed integer type
-    @param[in] format  the current format (for diagnostics)
-    @param[in] number  the integer
-    @return whether the SAX parser accepted the value
-
-    @throw out_of_range.406 if @a number overflows number_float_t (see
-           @ref emit_float)
-    */
-    template<typename NumberType>
-    bool emit_signed(const input_format_t format, const NumberType number)
-    {
-        if (JSON_HEDLEY_LIKELY(value_in_range_of<number_integer_t>(number)))
-        {
-            return sax->number_integer(static_cast<number_integer_t>(number));
-        }
-        if (value_in_range_of<number_unsigned_t>(number))
-        {
-            return sax->number_unsigned(static_cast<number_unsigned_t>(number));
-        }
-        return emit_float(format, number);
-    }
-
-    /*!
-    @brief pass an unsigned integer read from the input to the SAX parser
-
-    Like the lexer does for JSON text, a value that does not fit into
-    number_unsigned_t is passed as number_float_t.
-
-    @tparam NumberType an unsigned integer type
-    @param[in] format  the current format (for diagnostics)
-    @param[in] number  the integer
-    @return whether the SAX parser accepted the value
-
-    @throw out_of_range.406 if @a number overflows number_float_t (see
-           @ref emit_float)
-    */
-    template<typename NumberType>
-    bool emit_unsigned(const input_format_t format, const NumberType number)
-    {
-        if (JSON_HEDLEY_LIKELY(value_in_range_of<number_unsigned_t>(number)))
-        {
-            return sax->number_unsigned(static_cast<number_unsigned_t>(number));
-        }
-        return emit_float(format, number);
-    }
-
-    /*!
-    @brief pass a floating-point number read from the input to the SAX parser
-
-    Like the lexer does for JSON text, a finite value that overflows
-    number_float_t is rejected instead of silently becoming infinity. Infinity
-    and NaN in the input are passed on unchanged. Integers only overflow if
-    number_float_t cannot represent 2^64, e.g., a half-precision type.
-
-    @tparam NumberType a floating-point or integer type
-    @param[in] format  the current format (for diagnostics)
-    @param[in] number  the number
-    @return whether the SAX parser accepted the value
-
-    @throw out_of_range.406 if a finite @a number overflows number_float_t
-    */
-    template<typename NumberType>
-    bool emit_float(const input_format_t format, const NumberType number)
-    {
-        const auto result = static_cast<number_float_t>(number);
-        if (JSON_HEDLEY_UNLIKELY(std::isfinite(number) && !std::isfinite(result)))
-        {
-            return sax->parse_error(chars_read, get_token_string(),
-                                    out_of_range::create(406, exception_message(format, "number overflow", "value"), nullptr));
-        }
-        return sax->number_float(result, "");
-    }
-
    /*!
    @brief create a string by reading characters from the input

@@ -763,6 +763,7 @@ struct container_input_adapter_factory< ContainerType,

           static adapter_type create(ContainerType&& container)
 {
+    // NOLINTNEXTLINE(bugprone-use-after-move,hicpp-invalid-access-moved) forwarded twice on purpose, so begin() and end() see the same value category and yield matching iterator types
    return input_adapter(begin(std::forward<ContainerType>(container)), end(std::forward<ContainerType>(container)));
 }
       };
@@ -39,7 +39,6 @@ inline std::size_t concat_length(const char /*c*/, const Args& ... rest)
 template<typename... Args>
 inline std::size_t concat_length(const char* cstr, const Args& ... rest)
 {
-    // cppcheck-suppress ignoredReturnValue
    return ::strlen(cstr) + concat_length(rest...);
 }

@@ -70,14 +70,41 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,
        return *this;
    }

+private:
+    /// @brief find the entry for @a key, for either constness of @a self
+    /// @note the single place that performs the linear key search
+    template<typename Self, typename KeyType>
+    static auto find_impl(Self& self, KeyType&& key) -> decltype(self.begin())
+    {
+        for (auto it = self.begin(); it != self.end(); ++it)
+        {
+            if (self.m_compare(it->first, key))
+            {
+                return it;
+            }
+        }
+        return self.end();
+    }
+
+    /// @brief remove the entry @a it points to, preserving order
+    /// @note keys are not movable, so the tail is destroyed and re-constructed in place
+    void erase_at(iterator it)
+    {
+        for (auto next = it; ++next != this->end(); ++it)
+        {
+            it->~value_type(); // Destroy but keep allocation
+            new (&*it) value_type{std::move(*next)};
+        }
+        Container::pop_back();
+    }
+
+public:
    std::pair<iterator, bool> emplace(const key_type& key, T&& t)
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
+        const auto it = find_impl(*this, key);
+        if (it != this->end())
        {
-            if (m_compare(it->first, key))
-            {
-                return {it, false};
-            }
+            return {it, false};
        }
        Container::emplace_back(key, std::forward<T>(t));
        return {std::prev(this->end()), true};
@@ -87,12 +114,10 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    std::pair<iterator, bool> emplace(KeyType && key, T && t)
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
+        const auto it = find_impl(*this, key);
+        if (it != this->end())
        {
-            if (m_compare(it->first, key))
-            {
-                return {it, false};
-            }
+            return {it, false};
        }
        Container::emplace_back(std::forward<KeyType>(key), std::forward<T>(t));
        return {std::prev(this->end()), true};
@@ -124,75 +149,55 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,

    T& at(const key_type& key)
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
+        const auto it = find_impl(*this, key);
+        if (it == this->end())
        {
-            if (m_compare(it->first, key))
-            {
-                return it->second;
-            }
+            JSON_THROW(std::out_of_range("key not found"));
        }
-
-        JSON_THROW(std::out_of_range("key not found"));
+        return it->second;
    }

    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    T & at(KeyType && key) // NOLINT(cppcoreguidelines-missing-std-forward)
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
+        const auto it = find_impl(*this, key);
+        if (it == this->end())
        {
-            if (m_compare(it->first, key))
-            {
-                return it->second;
-            }
+            JSON_THROW(std::out_of_range("key not found"));
        }
-
-        JSON_THROW(std::out_of_range("key not found"));
+        return it->second;
    }

    const T& at(const key_type& key) const
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
+        const auto it = find_impl(*this, key);
+        if (it == this->end())
        {
-            if (m_compare(it->first, key))
-            {
-                return it->second;
-            }
+            JSON_THROW(std::out_of_range("key not found"));
        }
-
-        JSON_THROW(std::out_of_range("key not found"));
+        return it->second;
    }

    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    const T & at(KeyType && key) const // NOLINT(cppcoreguidelines-missing-std-forward)
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
+        const auto it = find_impl(*this, key);
+        if (it == this->end())
        {
-            if (m_compare(it->first, key))
-            {
-                return it->second;
-            }
+            JSON_THROW(std::out_of_range("key not found"));
        }
-
-        JSON_THROW(std::out_of_range("key not found"));
+        return it->second;
    }

    size_type erase(const key_type& key)
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
+        const auto it = find_impl(*this, key);
+        if (it != this->end())
        {
-            if (m_compare(it->first, key))
-            {
-                // Since we cannot move const Keys, re-construct them in place
-                for (auto next = it; ++next != this->end(); ++it)
-                {
-                    it->~value_type(); // Destroy but keep allocation
-                    new (&*it) value_type{std::move(*next)};
-                }
-                Container::pop_back();
-                return 1;
-            }
+            erase_at(it);
+            return 1;
        }
        return 0;
    }
@@ -201,19 +206,11 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    size_type erase(KeyType && key) // NOLINT(cppcoreguidelines-missing-std-forward)
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
+        const auto it = find_impl(*this, key);
+        if (it != this->end())
        {
-            if (m_compare(it->first, key))
-            {
-                // Since we cannot move const Keys, re-construct them in place
-                for (auto next = it; ++next != this->end(); ++it)
-                {
-                    it->~value_type(); // Destroy but keep allocation
-                    new (&*it) value_type{std::move(*next)};
-                }
-                Container::pop_back();
-                return 1;
-            }
+            erase_at(it);
+            return 1;
        }
        return 0;
    }
@@ -278,80 +275,38 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,

    size_type count(const key_type& key) const
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
-        {
-            if (m_compare(it->first, key))
-            {
-                return 1;
-            }
-        }
-        return 0;
+        return find_impl(*this, key) != this->end() ? 1 : 0;
    }

    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    size_type count(KeyType && key) const // NOLINT(cppcoreguidelines-missing-std-forward)
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
-        {
-            if (m_compare(it->first, key))
-            {
-                return 1;
-            }
-        }
-        return 0;
+        return find_impl(*this, key) != this->end() ? 1 : 0;
    }

    iterator find(const key_type& key)
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
-        {
-            if (m_compare(it->first, key))
-            {
-                return it;
-            }
-        }
-        return Container::end();
+        return find_impl(*this, key);
    }

    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    iterator find(KeyType && key) // NOLINT(cppcoreguidelines-missing-std-forward)
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
-        {
-            if (m_compare(it->first, key))
-            {
-                return it;
-            }
-        }
-        return Container::end();
+        return find_impl(*this, key);
    }

    const_iterator find(const key_type& key) const
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
-        {
-            if (m_compare(it->first, key))
-            {
-                return it;
-            }
-        }
-        return Container::end();
+        return find_impl(*this, key);
    }

    template<class KeyType, detail::enable_if_t<
                 detail::is_usable_as_key_type<key_compare, key_type, KeyType>::value, int> = 0>
    const_iterator find(KeyType && key) const // NOLINT(cppcoreguidelines-missing-std-forward)
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
-        {
-            if (m_compare(it->first, key))
-            {
-                return it;
-            }
-        }
-        return Container::end();
+        return find_impl(*this, key);
    }

    std::pair<iterator, bool> insert( value_type&& value )
@@ -361,12 +316,10 @@ template <class Key, class T, class IgnoredLess = std::less<Key>,

    std::pair<iterator, bool> insert( const value_type& value )
    {
-        for (auto it = this->begin(); it != this->end(); ++it)
+        const auto it = find_impl(*this, value.first);
+        if (it != this->end())
        {
-            if (m_compare(it->first, value.first))
-            {
-                return {it, false};
-            }
+            return {it, false};
        }
        Container::push_back(value);
        return {--this->end(), true};
@@ -11,12 +11,7 @@
 #include <nlohmann/json.hpp>
 using nlohmann::json;

-#include <cmath>
 #include <fstream>
-#include <limits>
-#include <map>
-#include <string>
-#include <vector>
 #include "make_test_data_available.hpp"

 TEST_CASE("Binary Formats" * doctest::skip())
@@ -229,139 +224,3 @@ TEST_CASE("Binary Formats" * doctest::skip())
        CHECK((100.0 * double(ubjson_3_size) / double(json_size)) == Approx(89.450));
    }
 }
-
-namespace
-{
-// the binary formats as function pointers for "Binary formats with narrow number types";
-// named functions rather than lambdas, because clang 3.5 cannot convert a lambda
-// to a function pointer in the braced initializer of the format table
-using narrow_json = nlohmann::basic_json<std::map, std::vector, std::string, bool, std::int32_t, std::uint32_t, float>;
-using bytes = std::vector<std::uint8_t>;
-
-bytes encode_cbor(const json& j)
-{
-    return json::to_cbor(j);
-}
-narrow_json decode_cbor(const bytes& v, bool allow_exceptions)
-{
-    return narrow_json::from_cbor(v, true, allow_exceptions);
-}
-
-bytes encode_msgpack(const json& j)
-{
-    return json::to_msgpack(j);
-}
-narrow_json decode_msgpack(const bytes& v, bool allow_exceptions)
-{
-    return narrow_json::from_msgpack(v, true, allow_exceptions);
-}
-
-bytes encode_ubjson(const json& j)
-{
-    return json::to_ubjson(j);
-}
-narrow_json decode_ubjson(const bytes& v, bool allow_exceptions)
-{
-    return narrow_json::from_ubjson(v, true, allow_exceptions);
-}
-
-bytes encode_bjdata(const json& j)
-{
-    return json::to_bjdata(j);
-}
-narrow_json decode_bjdata(const bytes& v, bool allow_exceptions)
-{
-    return narrow_json::from_bjdata(v, true, allow_exceptions);
-}
-
-// BSON can only store numbers as object members
-bytes encode_bson(const json& j)
-{
-    return json::to_bson(json{{"a", j}});
-}
-narrow_json decode_bson(const bytes& v, bool allow_exceptions)
-{
-    const auto result = narrow_json::from_bson(v, true, allow_exceptions);
-    return result.is_discarded() ? result : result.at("a");
-}
-
-bytes encode_bon8(const json& j)
-{
-    return json::to_bon8(j);
-}
-narrow_json decode_bon8(const bytes& v, bool allow_exceptions)
-{
-    return narrow_json::from_bon8(v, true, allow_exceptions);
-}
-
-} // namespace
-
-TEST_CASE("Binary formats with narrow number types")
-{
-    // Numbers that do not fit the number types are handled like the lexer
-    // handles them in JSON text: an integer that fits neither integer type is
-    // stored as a floating-point number, and a finite floating-point number
-    // that overflows number_float_t is rejected with out_of_range.406.
-    struct binary_format
-    {
-        const char* name;
-        bytes (*encode)(const json&);
-        narrow_json (*decode)(const bytes&, bool);
-    };
-
-    const std::vector<binary_format> formats =
-    {
-        {"CBOR", encode_cbor, decode_cbor},
-        {"MessagePack", encode_msgpack, decode_msgpack},
-        {"UBJSON", encode_ubjson, decode_ubjson},
-        {"BJData", encode_bjdata, decode_bjdata},
-        {"BSON", encode_bson, decode_bson},
-        {"BON8", encode_bon8, decode_bon8},
-    };
-
-    for (const auto& format : formats)
-    {
-        const std::string name = format.name;
-        INFO("format := ", name);
-        const auto roundtrip = [&format](const json & j)
-        {
-            return format.decode(format.encode(j), true);
-        };
-
-        // integers that fit keep their type
-        CHECK(roundtrip(json(-5)).is_number_integer());
-        CHECK(roundtrip(json(-5)).get<std::int32_t>() == -5);
-        CHECK(roundtrip(json(3000000000u)).is_number_unsigned());
-        CHECK(roundtrip(json(3000000000u)).get<std::uint32_t>() == 3000000000u);
-
-        // integers that fit neither integer type are stored as float
-        CHECK(roundtrip(json(5000000000u)).is_number_float());
-        CHECK(roundtrip(json(5000000000u)).get<float>() == 5000000000.0f);
-        if (name != "BON8") // BON8 cannot encode integers above INT64_MAX
-        {
-            CHECK(roundtrip(json(10000000000000000000u)).is_number_float());
-            CHECK(roundtrip(json(10000000000000000000u)).get<float>() == 10000000000000000000.0f);
-        }
-        CHECK(roundtrip(json(-3000000000LL)).is_number_float());
-        CHECK(roundtrip(json(-3000000000LL)).get<float>() == -3000000000.0f);
-        CHECK(roundtrip(json(-5000000000LL)).is_number_float());
-        CHECK(roundtrip(json(-5000000000LL)).get<float>() == -5000000000.0f);
-
-        // floating-point numbers that fit
-        CHECK(roundtrip(json(1.5)).get<float>() == 1.5f);
-        const auto just_above_max = std::nextafter(static_cast<double>((std::numeric_limits<float>::max)()),
-                                    std::numeric_limits<double>::infinity());
-        CHECK(roundtrip(json(just_above_max)).get<float>() == (std::numeric_limits<float>::max)());
-
-        // infinity and NaN are passed on
-        CHECK(std::isinf(roundtrip(json(std::numeric_limits<double>::infinity())).get<float>()));
-        CHECK(std::isnan(roundtrip(json(std::numeric_limits<double>::quiet_NaN())).get<float>()));
-
-        // finite floating-point numbers that overflow number_float_t are rejected
-        const std::string message = "[json.exception.out_of_range.406] syntax error while parsing " + name
-                                    + " value: number overflow";
-        CHECK_THROWS_WITH_AS(roundtrip(json(1e300)), message.c_str(), narrow_json::out_of_range&);
-        CHECK_THROWS_WITH_AS(roundtrip(json(-1e300)), message.c_str(), narrow_json::out_of_range&);
-        CHECK(format.decode(format.encode(json(1e300)), false).is_discarded());
-    }
-}
@@ -3187,8 +3187,7 @@ TEST_CASE("Tagged values")
        // CBOR encodes negative integers as: result = -1 - n
        // For type 0x3B, n is an 8-byte uint64_t. Valid range for n with
        // the default int64_t is [0, INT64_MAX], producing results in [INT64_MIN, -1].
-        // When n > INT64_MAX, the result exceeds int64_t range and is stored
-        // as a floating-point number, as the lexer does for JSON text.
+        // When n > INT64_MAX, the result exceeds int64_t range and is rejected.

        SECTION("n = 0 is valid (result = -1)")
        {
@@ -3209,34 +3208,33 @@ TEST_CASE("Tagged values")
            CHECK(result.get<int64_t>() == (std::numeric_limits<int64_t>::min)());
        }

-        SECTION("n = INT64_MAX + 1 is stored as float")
+        SECTION("n = INT64_MAX + 1 is rejected (overflow)")
        {
            // n = INT64_MAX + 1 (0x8000000000000000)
-            // result = -1 - n = -9223372036854775809, which exceeds int64_t range;
-            // the nearest double is -9223372036854775808.0
+            // result = -1 - n = -9223372036854775809, which exceeds int64_t range
            const std::vector<uint8_t> input = {0x3B, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
-            const auto result = json::from_cbor(input);
-            CHECK(result.is_number_float());
-            CHECK(result.get<double>() == -9223372036854775808.0);
-            CHECK(result == json::parse("-9223372036854775809"));
+            json _;
+            CHECK_THROWS_WITH_AS(_ = json::from_cbor(input),
+                                 "[json.exception.parse_error.112] parse error at byte 9: syntax error while parsing CBOR value: negative integer overflow",
+                                 json::parse_error);
        }

-        SECTION("n = UINT64_MAX is stored as float")
+        SECTION("n = UINT64_MAX is rejected (overflow)")
        {
            // n = UINT64_MAX (0xFFFFFFFFFFFFFFFF)
            // result = -1 - n = -18446744073709551616, which exceeds int64_t range
            const std::vector<uint8_t> input = {0x3B, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};
-            const auto result = json::from_cbor(input);
-            CHECK(result.is_number_float());
-            CHECK(result.get<double>() == -18446744073709551616.0);
-            CHECK(result == json::parse("-18446744073709551616"));
+            json _;
+            CHECK_THROWS_WITH_AS(_ = json::from_cbor(input),
+                                 "[json.exception.parse_error.112] parse error at byte 9: syntax error while parsing CBOR value: negative integer overflow",
+                                 json::parse_error);
        }

-        SECTION("overflow with allow_exceptions=false is not an error")
+        SECTION("overflow with allow_exceptions=false returns discarded")
        {
            const std::vector<uint8_t> input = {0x3B, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
            const auto result = json::from_cbor(input, true, false);
-            CHECK(result.is_number_float());
+            CHECK(result.is_discarded());
        }
    }

@@ -2525,12 +2525,10 @@ TEST_CASE("diagnostic positions: value lifetime, input adapters, and SAX")

        SECTION("move constructor resets the moved-from value to npos")
        {
-            // basic_json(basic_json&&) (json.hpp, around line 1265) copies
+            // basic_json(basic_json&&) (json.hpp, around line 1944) copies
            // other's start_position/end_position into *this and then resets
-            // other's to npos (see the cppcheck-suppress[accessForwarded]
-            // annotation there, which flags this reset as worth a second
-            // look). Only the top-level moved-from value is affected; its
-            // (moved-away) children are gone along with it.
+            // other's to npos. Only the top-level moved-from value is
+            // affected; its (moved-away) children are gone along with it.
            const std::string s = R"({"a":1,"b":[1,2,3]})";
            json a = json::parse(s);
            const auto a_start = a.start_pos();
@@ -618,6 +618,49 @@ TEST_CASE("modifiers")
            }
        }

+        SECTION("rvalue at position moves rather than copies")
+        {
+            // regression test: insert(pos, basic_json&&) used to forward to
+            // insert(pos, const basic_json&) because the named rvalue
+            // reference parameter is itself an lvalue, so it always
+            // deep-copied its argument instead of moving it
+            json j_big = std::string(1000, 'x');
+            const auto* const original_buffer = j_big.get_ref<const std::string&>().data();
+
+            auto it = j_array.insert(j_array.begin(), std::move(j_big));
+            CHECK(j_array.size() == 5);
+            CHECK(*it == json(std::string(1000, 'x')));
+            CHECK((*it).get_ref<const std::string&>().data() == original_buffer);
+
+            // the moved-from value is null, the same as after push_back(&&)
+            CHECK(j_big.is_null()); // NOLINT(bugprone-use-after-move,hicpp-invalid-access-moved)
+        }
+
+        SECTION("self-aliasing insertion")
+        {
+            SECTION("without reallocation")
+            {
+                json j_self = {1, 2, 3, 4};
+                j_self.get_ref<json::array_t&>().reserve(j_self.size() + 1);
+
+                auto it = j_self.insert(j_self.begin(), std::move(j_self[1]));
+                CHECK(j_self.size() == 5);
+                CHECK(*it == json(2));
+                CHECK(j_self == json({2, 1, nullptr, 3, 4}));
+            }
+
+            SECTION("with reallocation")
+            {
+                json j_self = {1, 2, 3, 4};
+                j_self.get_ref<json::array_t&>().shrink_to_fit();
+
+                auto it = j_self.insert(j_self.begin(), std::move(j_self[1]));
+                CHECK(j_self.size() == 5);
+                CHECK(*it == json(2));
+                CHECK(j_self == json({2, 1, nullptr, 3, 4}));
+            }
+        }
+
        SECTION("copies at position")
        {
            SECTION("insert before begin()")
Author	SHA1	Message	Date
Niels Lohmann	3a04f78507	Make convert_null_to() take the container type as a template argument Passing array_t or object_t instead of a value_t makes an invalid target a compile error instead of a runtime assertion, and removes the branch. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 21:31:58 +02:00
Niels Lohmann	09d41a894b	Re-enable bugprone-use-after-move/hicpp-invalid-access-moved These two checks (and portability-template-virtual-member-function) were disabled in #4489 (November 2024) "only removed to get the CI going". portability-template-virtual-member-function is a separate, still-open cleanup (#5725 item 3 on its own branch) and stays disabled here; this commit only re-enables the move/forward checks and cleans up what they flag on this branch. The move constructor (json.hpp) already casts to the base type instead of forwarding the whole object (#5724 item 9), so it no longer trips either check. The at(KeyType&&) double-forward this check used to flag was reduced to a single forward with the now-unforwarded reuse annotated by a NOLINTNEXTLINE in #5724 item 3's object_at() helper (clang-tidy 22 still flags that reuse even after a single forward; see that commit's message). What is left here: - from_json_inplace_array_impl(), from_json_tuple_impl_base() and the std::pair overload of from_json_tuple_impl() forwarded j into every j.at(...) call in a pack expansion or a pair of calls. at() has no ref-qualified overloads, so the forward was a no-op; call j.at(...) directly. - container_input_adapter_factory::create() forwards container twice on purpose, into begin() and end(), so both see the same value category and produce matching iterator types. Annotate it with NOLINTNEXTLINE and a comment instead of changing it. - unit-class_parser.cpp's "move constructor resets the moved-from value to npos" test still pointed at the pre-static_cast move constructor by line number and mentioned the cppcheck-suppress annotation that #5724 item 9 already removed; update the comment. No behavior change anywhere in include/. Verified with clang-tidy 22.1.8 (Docker silkeh/clang:22, --platform linux/amd64) against a TU including json.hpp with the repo's .clang-tidy: bugprone-use-after-move and hicpp-invalid-access-moved report nothing unsuppressed. Overlaps #5737 (open PR for the rest of #5725 item 3: the from_json.hpp/input_adapters.hpp cleanup above, and portability-template-virtual-member-function), which currently keeps both checks disabled pending this move-constructor change; whichever of this commit and that PR lands second will need a small rebase of .clang-tidy. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 19:05:07 +02:00
Niels Lohmann	3e771c2ad7	Deduplicate the linear key search in ordered_map emplace, at, erase(key), count and find each repeated the same "for (auto it = begin(); it != end(); ++it) if (m_compare(it->first, key)) ..." loop (15 copies across their key_type and transparent KeyType&& overloads), and both erase(key) overloads additionally repeated the exception-sensitive in-place reconstruction (destroy, placement-new, pop_back) used to remove an element while keeping the const Key non-movable. Add two private helpers: find_impl(Self&, KeyType&&), a static member template that runs the search once for either constness of the receiver, and erase_at(iterator), which keeps the existing pop_back-based reconstruction instead of switching to erase()/resize() (which would add a DefaultInsertable requirement). Route find, at, count, emplace, insert(const value_type&) and both erase(key) overloads through them. Same signatures, is_usable_as_key_type constraints and exception messages/types. Overlaps #5609 and #5685, which both rewrite emplace (#5609 also touches insert and adds private members at the end of the class); whichever of this commit and those PRs lands second will need a rebase. #5724 item 6 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 19:05:05 +02:00
Niels Lohmann	51233dc17d	Deduplicate the null-to-container conversion into convert_null_to() Nine sites wrote out the same "turn a null value into an empty array or object" logic with two different idioms: operator[](size_type), operator[](key_type), operator[](KeyType&&) and update() set m_type then assigned m_value.array/object directly via create<T>(), while the three push_back() overloads, emplace_back() and emplace() set m_type then assigned m_value = value_t::array/object (going through json_value's converting constructor and a temporary). Both idioms end up calling create<T>() and produce the same state, just via a different path; both also share a latent exception-safety bug, since m_type is written before the (possibly throwing) allocation, so a throwing allocator leaves m_type == array/object with a null pointer behind it, violating the class invariant and crashing on the next access to, or destruction of, the value. Add a private convert_null_to(value_t) helper and call it from all nine sites. Unlike the idioms it replaces, it allocates the container first and only then writes m_type, so a throwing allocation leaves the value as a valid null instead of a mistyped, half-constructed one; verified with a throwing allocator (see unit-allocator.cpp's bad_allocator) that j["x"] = ... on a null j now stays null, and no longer trips assert_invariant()/crashes, when create<object_t>() throws. Same allocator usage and assert_invariant() call as before, otherwise. Overlaps #5585, which reorders these same nine blocks for exception safety; whichever of this commit and that PR lands second will need a small rebase. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 19:05:05 +02:00
Niels Lohmann	03d53596f9	Deduplicate the lookup/default/throw body of value() The six non-deprecated value() overloads each held a full copy of the same body: the four key-based overloads looked up the key and either returned the found element converted to the requested type or the default value (throwing type_error.306 if this is not an object), and the two json_pointer overloads did the same via ptr.get_checked_or_null(), throwing type_error.306 unless is_structured(). Replace the duplicated bodies with two private helpers, value_member() and value_pointee(), that return a const basic_json* (null when not found) and do the type check/throw once each. Every value() overload now just picks between the found pointer's get<T>() and the default. Same signatures, template parameters, SFINAE conditions, exception id, message and this context on every overload. Overlaps #5689 (routes find() through lookup_key()) and #5705 (adds a deleted integral-key value() next to these overloads); whichever of this commit and those PRs lands second will need a small rebase. #5724 item 4 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 19:05:03 +02:00
Niels Lohmann	a0e01e3b9c	Deduplicate object key lookup and checked at() access at()/find()/count()/contains()/const operator[]/erase_internal() each repeated the raw object lookup (m_value.object->find(key)), and the six at() overloads additionally repeated the type_error.304 check and out_of_range.401/403 throw. Route them all through two new private helpers, object_lookup()/object_at() (plus array_at() for the index overloads of at()), templated on the constness of the receiver so one body serves both the const and non-const overload. count() is left untouched, since it already goes through object_t::count() rather than a second find(). The at(KeyType&&) overloads used to forward the same key twice: once into object->find() and again, on the not-found path, into the string_t() conversion for the exception message. object_at() now forwards it only into the lookup and reuses the (unmoved) key for the message. clang-tidy 22 (Docker silkeh/clang:22) still flags that reuse under bugprone-use-after-move/hicpp-invalid-access-moved even with the single forward, since it cannot see that object_t::find() (a plain std::map or ordered_map) never actually moves from its argument; add a NOLINTNEXTLINE with that reasoning rather than avoid the pattern. No signature, exception id/message, or set_parent() behavior changes. Overlaps #5689, #5705, #5606, #5687 and #5585, which touch the same hunks; whichever of this commit and those PRs lands second will need a small rebase. Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 19:05:02 +02:00
Niels Lohmann	0c0d5edda3	Make insert(pos, basic_json&&) move its argument instead of copying it insert(const_iterator pos, basic_json&& val) delegated to insert(pos, val), but val is a named rvalue reference, so inside the function it is an lvalue: the call always resolved to insert(const_iterator, const basic_json&) and deep-copied the value. This has been the case since the overload was introduced, in every release. push_back(basic_json&&), by contrast, already moves. Give the rvalue overload its own body with the same two checks (type_error.309, invalid_iterator.202), then move the argument into a local before inserting it. Moving into a local first, rather than inserting std::move(val) directly, keeps this safe even when val aliases an element of the same array (e.g. arr.insert(arr.begin(), std::move(arr[1]))), since std::vector::insert(pos, T&&) is not guaranteed to handle an argument that aliases one of its own elements. This is a deliberate, small behavior change: the moved-from argument now ends up null afterwards, the same as after push_back(&&), instead of keeping its old value unchanged. No signature changes, so the public API and ABI are unaffected. Add unit-modifiers coverage for the moved-from state and for self-aliasing insertion, both with and without reallocation of the underlying array. Part of #5724 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 11:11:16 +02:00
Niels Lohmann	ff2ec8116d	Deduplicate the 16 copied from_cbor/msgpack/ubjson/bjdata/bon8/bson bodies Each of the 16 binary deserialization overloads (from_cbor, from_msgpack, from_ubjson, from_bjdata, from_bon8, from_bson, each in an InputType&& and an iterator/sentinel version, plus the deprecated span overloads of from_cbor/from_msgpack/from_ubjson/from_bson) had the same body, differing only in the input_format_t value. Every copy built a temporary binary_reader from std::move(ia) and called sax_parse on it in the same expression, which also produced a false-positive cppcheck accessMoved on all 16 lines and needed a NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg) on the four span overloads. Add a private from_binary_impl() helper that builds the reader as a named local instead, and make each of the 16 overloads a one-line forward to it. All public signatures, default arguments, JSON_HEDLEY_WARN_UNUSED_RESULT and JSON_HEDLEY_DEPRECATED_FOR attributes are unchanged, tag_handler keeps defaulting to cbor_tag_handler_t::error for the non-CBOR formats (matching binary_reader::sax_parse's own default), and the helper is placed in the existing private section before the binary section banner rather than between the from_* overloads, so from_binary_impl() itself does not collide with #5688's insertion point. Collapsing the from_bjdata/from_bon8 bodies into one-line forwards does rewrite the "return result; }" context lines that #5688 inserts its two deprecated overloads after, so that PR will need a small manual rebase (reinserting its overloads after the new one-line bodies) rather than applying cleanly. Part of #5724 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 11:11:15 +02:00
Niels Lohmann	b591304d04	Fix stale and copy-pasted comments in basic_json Several comments no longer match the code: the class invariant and assert_invariant()'s doc still named the members m_value/m_type (now m_data.m_value/m_data.m_type) and did not mention the binary invariant that assert_invariant() already checks; the json_value note and the get<PointerType>() @tparam list omitted binary_t even though binary is a variable-length, pointer-stored type like the others; the key-based value() overload's brief said "via JSON Pointer", which is the other overload; and swap(binary_t&)/swap(binary_t::container_type&) both carried "swap only works for strings", copied from swap(string_t&). Comment-only change; behavior, the public API and the ABI are unchanged. The private get_impl() doxygen and the emplace() comments that border #5585's hunk are intentionally left alone. Part of #5724 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 10:42:29 +02:00
Niels Lohmann	c2553bac5a	Deduplicate the string/binary cleanup in the two erase() overloads erase(pos) and erase(first, last) each carried a byte-identical 14-line block that destroys and deallocates a string or binary value before resetting the type to null. That reimplements the string/binary cases of json_value::destroy(), so any future change to how those values are freed would have to be made in three places instead of one. Both overloads now just call destroy() and reset the union; for the other primitive types (boolean, numbers) destroy() is a no-op, so behavior is unchanged. Also fix erase(first, last)'s error-path branch hint, which used JSON_HEDLEY_LIKELY where erase(pos), the iterator-range constructor, and every other error path in the class use JSON_HEDLEY_UNLIKELY. This only affects code layout, not semantics. Part of #5724 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 10:40:04 +02:00
Niels Lohmann	1274e0f250	Remove stale cppcheck suppressions and name the local parser in parse() Running the pinned cppcheck (ci_cppcheck's invocation) without --inline-suppr across all configurations reports no syntaxError, no ignoredReturnValue and no assertWithSideEffect, so the corresponding suppressions in json_fwd.hpp, string_concat.hpp and assert_invariant() no longer match anything (json_fwd.hpp's is kept, since downstream users who run an older cppcheck against it could still hit the warning it once silenced). The three basic_json::parse() overloads still trigger a false-positive accessMoved/accessForwarded because they build a temporary parser and call .parse() on it in the same expression; giving that parser a name makes the warning go away without changing behavior, and removes the last of the inline suppressions on these functions. Part of #5724 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 10:37:48 +02:00
Niels Lohmann	ffd3a3722b	Remove four cppcheck accessForwarded suppressions in the move constructor basic_json(basic_json&&) built its base subobject with std::forward<json_base_class_t>(other), so cppcheck saw the whole of other as forwarded and flagged every subsequent access to it as accessForwarded, three of them still marked "TODO check". Only the base subobject is actually moved from; cast explicitly to the base type instead, the way ordered_map already does, so cppcheck can tell the two are unrelated. Behavior is unchanged: for a non-reference T, std::forward<T>(x) is defined as static_cast<T&&>(x). Part of #5724 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 10:36:41 +02:00
Niels Lohmann	f5e4b9b8cf	Stop the noexcept null constructor delegating to a throwing one basic_json(std::nullptr_t) delegated to basic_json(value_t), whose underlying json_value(value_t) constructor allocates for other types and can therefore throw, which is why the noexcept had a NOLINT(bugprone-exception-escape). The delegated-to constructor also called assert_invariant() a second time. The default member initializers of data already produce the same null state (a value-initialized, i.e. zeroed, union with object == nullptr), so the delegation and its NOLINT can simply be dropped. Part of #5724 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 10:34:05 +02:00
Niels Lohmann	e5c3e81279	Fix meta()'s dead, syntactically invalid HP aCC branch The HP aCC branch of basic_json::meta() was missing a semicolon and has therefore never compiled; adding only a semicolon would also make it throw type_error.305, since it assigned a plain string to result["compiler"] and then indexed into it like the other branches do into an object. Make the branch consistent with the others by assigning an object with "family" and "version" keys, narrow the condition to __HP_aCC (a C compiler cannot build this header-only library), and fix meta.md, which documented the old (impossible) plain-string behavior. Part of #5724 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 10:32:07 +02:00
Niels Lohmann	1d98396a19	Remove unused private aliases from basic_json The private aliases primitive_iterator_t, internal_iterator and output_adapter_t are not used anywhere: iter_impl, binary_writer and the tests refer to the detail:: names directly. As the aliases are private, no user or derived class can depend on them. The internal_iterator.hpp include stays because iter_impl needs it. Part of #5724 Signed-off-by: Niels Lohmann <mail@nlohmann.me>	2026-09-30 09:47:00 +02:00