De-duplicate the diagnostic-positions test files via define-based recompilation

tests/src/unit-class_parser_diagnostic_positions.cpp and
tests/src/unit-diagnostic-positions-only.cpp were maintained as near-copies
of unit-class_parser.cpp and unit-diagnostic-positions.cpp respectively, and
had drifted: trailing-comma handling, the #5342 filter-array/filter-value
sections, and the cross-input-adapter diagnostics test were never ported to
the positions-enabled copy.

Fold the position-specific assertions into the base files, guarded by
#if JSON_DIAGNOSTIC_POSITIONS / #if JSON_DIAGNOSTICS, and compile each base
file a second time with the relevant macro set via CMake COMPILE_DEFINITIONS
(mirroring the existing test-comparison_legacy pattern) instead of
maintaining a separate source file. This removes the duplication and, as a
side effect, closes the coverage gaps above since the full test file now
compiles under JSON_DIAGNOSTIC_POSITIONS=1 as well.

Fixes #5417

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

tests/CMakeLists.txt

@@ -177,6 +177,24 @@ json_test_add_test_for(src/unit-comparison.cpp
     MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
 )
 
+# test the parser again with JSON_DIAGNOSTIC_POSITIONS enabled
+json_test_set_test_options(test-class_parser_diagnostic_positions
+    COMPILE_DEFINITIONS JSON_DIAGNOSTIC_POSITIONS=1
+)
+json_test_add_test_for(src/unit-class_parser.cpp
+    NAME test-class_parser_diagnostic_positions
+    MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
+)
+
+# test diagnostic positions again without regular diagnostics (JSON pointer paths)
+json_test_set_test_options(test-diagnostic-positions_only
+    COMPILE_DEFINITIONS JSON_DIAGNOSTICS=0
+)
+json_test_add_test_for(src/unit-diagnostic-positions.cpp
+    NAME test-diagnostic-positions_only
+    MAIN test_main CXX_STANDARDS ${test_cxx_standards} ${test_force}
+)
+
 # *DO NOT* use json_test_set_test_options() below this line
 
 #############################################################################

tests/src/unit-bson.cpp

@@ -38,26 +38,6 @@ class huge_binary_t : public std::vector<std::uint8_t>
 using huge_binary_json = nlohmann::basic_json <
                          std::map, std::vector, std::string, bool, std::int64_t, std::uint64_t,
                          double, std::allocator, nlohmann::adl_serializer, huge_binary_t, void >;
-
-// a string type that reports a size beyond INT32_MAX without allocating that
-// much memory, so BSON length overflow can be tested for strings and
-// (embedded) documents as well, following the same idea as huge_binary_t
-class huge_string_t : public std::string
-{
-  public:
-    using std::string::string;
-    huge_string_t(const std::string& s) : std::string(s) {} // NOLINT(google-explicit-constructor,hicpp-explicit-conversions)
-
-    size_type size() const noexcept // NOLINT(readability-convert-member-functions-to-static)
-    {
-        // one byte more than the BSON length field can represent
-        return static_cast<size_type>((std::numeric_limits<std::int32_t>::max)()) + 1;
-    }
-};
-
-using huge_string_json = nlohmann::basic_json <
-                         std::map, std::vector, huge_string_t, bool, std::int64_t, std::uint64_t,
-                         double, std::allocator, nlohmann::adl_serializer, std::vector<std::uint8_t>, void >;
 } // namespace
 
 TEST_CASE("BSON")
@@ -125,36 +105,10 @@ TEST_CASE("BSON")
 
     SECTION("lengths exceeding INT32_MAX cannot be serialized to BSON")
     {
-        // out_of_range.412 is thrown from a single shared helper
-        // (to_bson_length) that guards the BSON length fields of binary
-        // values, strings, and (embedded) documents alike
-        SECTION("binary")
-        {
-            huge_binary_json j;
-            j["b"] = huge_binary_json::binary(huge_binary_t{});
+        huge_binary_json j;
+        j["b"] = huge_binary_json::binary(huge_binary_t{});
 
-            CHECK_THROWS_WITH_AS(huge_binary_json::to_bson(j), "[json.exception.out_of_range.412] BSON length 2147483661 exceeds maximum of 2147483647", huge_binary_json::out_of_range&);
-        }
-
-        SECTION("string")
-        {
-            huge_string_json j;
-            j["s"] = huge_string_json::string_t("value");
-
-            CHECK_THROWS_WITH_AS(huge_string_json::to_bson(j), "[json.exception.out_of_range.412] BSON length 4294967308 exceeds maximum of 2147483647", huge_string_json::out_of_range&);
-        }
-
-        SECTION("document")
-        {
-            // an oversized string nested one level deep makes the
-            // *embedded* document's own length exceed INT32_MAX as well
-            huge_string_json nested;
-            nested["s"] = huge_string_json::string_t("value");
-            huge_string_json j;
-            j["nested"] = nested;
-
-            CHECK_THROWS_WITH_AS(huge_string_json::to_bson(j), "[json.exception.out_of_range.412] BSON length 6442450963 exceeds maximum of 2147483647", huge_string_json::out_of_range&);
-        }
+        CHECK_THROWS_WITH_AS(huge_binary_json::to_bson(j), "[json.exception.out_of_range.412] BSON length 2147483661 exceeds maximum of 2147483647", huge_binary_json::out_of_range&);
     }
 
     SECTION("string length must be at least 1")
@@ -239,23 +193,6 @@ TEST_CASE("BSON")
             CHECK(json::from_bson(result, true, false) == j);
         }
 
-        SECTION("non-empty object with bool from a non-0/1 byte (lenient parsing)")
-        {
-            // documented lenient behavior (see gh-5333): any non-zero byte
-            // is accepted as `true`, not just 0x01
-            std::vector<std::uint8_t> const input =
-            {
-                0x0D, 0x00, 0x00, 0x00, // size (little endian)
-                0x08,               // entry: boolean
-                'e', 'n', 't', 'r', 'y', '\x00',
-                0x02,           // value = 0x02 (neither 0x00 nor 0x01)
-                0x00                    // end marker
-            };
-
-            const json expected = { { "entry", true } };
-            CHECK(json::from_bson(input) == expected);
-        }
-
         SECTION("non-empty object with double")
         {
             json const j =
@@ -562,29 +499,6 @@ TEST_CASE("BSON")
             CHECK(json::from_bson(result, true, false) == j);
         }
 
-        SECTION("array elements with non-conforming keys (lenient parsing)")
-        {
-            // documented lenient behavior (see gh-5333): BSON array element
-            // keys are not checked against the required decimal sequence
-            // "0", "1", "2", ... - elements are taken in encoded order
-            std::vector<std::uint8_t> const input =
-            {
-                0x26, 0x00, 0x00, 0x00, // size (little endian)
-                0x04, 'e', 'n', 't', 'r', 'y', '\x00', // entry: embedded array
-
-                0x1A, 0x00, 0x00, 0x00, // size (little endian)
-                0x10, '5', 0x00, 0x0A, 0x00, 0x00, 0x00, // key "5" (bogus)      -> 10
-                0x10, 'x', 0x00, 0x14, 0x00, 0x00, 0x00, // key "x" (non-numeric) -> 20
-                0x10, '1', 0x00, 0x1E, 0x00, 0x00, 0x00, // key "1" (out of order) -> 30
-                0x00, // end marker (embedded array)
-
-                0x00 // end marker
-            };
-
-            const json expected = { { "entry", json::array({10, 20, 30}) } };
-            CHECK(json::from_bson(input) == expected);
-        }
-
         SECTION("non-empty object with binary member")
         {
             const size_t N = 10;
@@ -680,31 +594,6 @@ TEST_CASE("BSON")
             CHECK(json::from_bson(result, true, false) == j);
         }
 
-        SECTION("binary member with subtype 0x02 (old binary) keeps its inner length prefix (lenient parsing)")
-        {
-            // documented lenient behavior (see gh-5333): the payload for
-            // binary subtype 0x02 ("old binary") is returned as-is,
-            // including its own inner 4-byte length prefix; it is not
-            // stripped or reinterpreted
-            std::vector<std::uint8_t> const input =
-            {
-                0x17, 0x00, 0x00, 0x00, // size (little endian)
-                0x05, 'e', 'n', 't', 'r', 'y', '\x00', // entry: binary
-
-                0x06, 0x00, 0x00, 0x00, // size of binary (little endian)
-                0x02, // "old binary" subtype
-                0x02, 0x00, 0x00, 0x00, // inner length prefix (part of the old-binary payload)
-                0x68, 0x69, // payload ('h', 'i')
-
-                0x00 // end marker
-            };
-
-            // the inner length prefix is part of the (unmodified) payload
-            const std::vector<std::uint8_t> expected_payload = {0x02, 0x00, 0x00, 0x00, 0x68, 0x69};
-            const json expected = { { "entry", json::binary(expected_payload, 0x02) } };
-            CHECK(json::from_bson(input) == expected);
-        }
-
         SECTION("Some more complex document")
         {
             json const j =

tests/src/unit-class_parser.cpp

@@ -344,6 +344,50 @@ void trailing_comma_helper(const std::string& s)
     }
 }
 
+#if JSON_DIAGNOSTIC_POSITIONS
+/**
+ * Validates that the generated JSON object is the same as expected
+ * Validates that the start position and end position match the start and end of the string
+ *
+ * This check assumes that there is no whitespace around the json object in the original string.
+ */
+void validate_generated_json_and_start_end_pos_helper(const std::string& original_string, const json& j, const json& check)
+{
+    CHECK(j == check);
+    CHECK(j.start_pos() == 0);
+    CHECK(j.end_pos() == original_string.size());
+}
+
+/**
+ * Parses the root object from the given root string and validates that the start and end positions for the nested object are correct.
+ *
+ * This checks that whitespace around the nested object is included in the start and end positions of the root object.
+ */
+void validate_start_end_pos_for_nested_obj_helper(const std::string& nested_type_json_str, const std::string& root_type_json_str, const json& expected_json, const json::parser_callback_t& cb = nullptr)
+{
+    json j;
+
+    // 1. If callback is provided, use callback version of parse()
+    if (cb)
+    {
+        j = json::parse(root_type_json_str, cb);
+    }
+    else
+    {
+        j = json::parse(root_type_json_str);
+    }
+
+    // 2. Check if the generated JSON is as expected
+    // Assumptions: The root_type_json_str does not have any whitespace around the json object
+    validate_generated_json_and_start_end_pos_helper(root_type_json_str, j, expected_json);
+
+    // 3. Get the nested object
+    const auto& nested = j["nested"];
+    // 4. Check if the start and end positions are generated correctly for nested objects and arrays
+    CHECK(nested_type_json_str == root_type_json_str.substr(nested.start_pos(), nested.end_pos() - nested.start_pos()));
+}
+#endif
+
 } // namespace
 
 TEST_CASE("parser class")
@@ -1779,6 +1823,228 @@ TEST_CASE("parser class")
         CHECK_THROWS_WITH_AS(_ = json::parse("/a", nullptr, true, true), "[json.exception.parse_error.101] parse error at line 1, column 2: syntax error while parsing value - invalid comment; expecting '/' or '*' after '/'; last read: '/a'", json::parse_error);
         CHECK_THROWS_WITH_AS(_ = json::parse("/*", nullptr, true, true), "[json.exception.parse_error.101] parse error at line 1, column 3: syntax error while parsing value - invalid comment; missing closing '*/'; last read: '/*<U+0000>'", json::parse_error);
     }
+
+#if JSON_DIAGNOSTIC_POSITIONS
+    // Macro for all test cases for start_pos and end_pos
+#define SETUP_TESTCASES() \
+    SECTION("with callback") \
+    { \
+        SECTION("filter nothing") \
+        { \
+            json::parser_callback_t const cb = [](int /*unused*/, json::parse_event_t /*unused*/, json& /*unused*/) noexcept \
+            { \
+                return true; \
+            }; \
+            validate_start_end_pos_for_nested_obj_helper(nested_type_json_str, root_type_json_str, expected, cb); \
+        } \
+        SECTION("filter element") \
+        { \
+            json::parser_callback_t const cb = [](int /*unused*/, json::parse_event_t event, json& j) noexcept \
+            { \
+                return (event != json::parse_event_t::key && event != json::parse_event_t::value) || j != json("a"); \
+            }; \
+            validate_start_end_pos_for_nested_obj_helper(nested_type_json_str, root_type_json_str, filteredExpected, cb); \
+        } \
+    } \
+    SECTION("without callback") \
+    { \
+        validate_start_end_pos_for_nested_obj_helper(nested_type_json_str, root_type_json_str, expected); \
+    }
+
+    SECTION("retrieve start position and end position")
+    {
+        SECTION("for object")
+        {
+            // Create an object with spaces to test the start and end positions. Spaces will not be included in the
+            // JSON object, however, the start and end positions should include the spaces from the input JSON string.
+            const std::string nested_type_json_str =  R"({    "a":       1,"b"      : "test1"})";
+            const std::string root_type_json_str =  R"({    "nested": )" + nested_type_json_str + R"(, "anotherValue": "test2"})";
+            auto expected = json({{"nested", {{"a", 1}, {"b", "test1"}}}, {"anotherValue", "test2"}});
+            auto filteredExpected = expected;
+            filteredExpected["nested"].erase("a");
+
+            SETUP_TESTCASES()
+        }
+
+        SECTION("for array")
+        {
+            const std::string nested_type_json_str =  R"(["a", "test", 45])";
+            const std::string root_type_json_str =  R"({   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
+            auto expected = json({{"nested", {"a", "test", 45}}, {"anotherValue", "test"}});
+            auto filteredExpected = expected;
+            filteredExpected["nested"] = json({"test", 45});
+            SETUP_TESTCASES()
+        }
+
+        SECTION("for array with objects")
+        {
+            const std::string nested_type_json_str =  R"([{"a": 1, "b": "test"}, {"c": 2, "d": "test2"}])";
+            const std::string root_type_json_str =  R"({   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
+            auto expected = json({{"nested", {{{"a", 1}, {"b", "test"}}, {{"c", 2}, {"d", "test2"}}}}, {"anotherValue", "test"}});
+            auto filteredExpected = expected;
+            filteredExpected["nested"][0].erase("a");
+            SETUP_TESTCASES()
+
+            auto j = json::parse(root_type_json_str);
+            auto nested_array = j["nested"];
+            const auto& nested_obj = nested_array[0];
+            CHECK(nested_type_json_str.substr(1, 21) == root_type_json_str.substr(nested_obj.start_pos(), nested_obj.end_pos() - nested_obj.start_pos()));
+            CHECK(nested_type_json_str.substr(24, 22) == root_type_json_str.substr(nested_array[1].start_pos(), nested_array[1].end_pos() - nested_array[1].start_pos()));
+        }
+
+        SECTION("for two levels of nesting objects")
+        {
+            const std::string nested_type_json_str =  R"({"nested2": {"b": "test"}})";
+            const std::string root_type_json_str =  R"({   "a": 2, "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
+            auto expected = json({{"a", 2}, {"nested", {{"nested2", {{"b", "test"}}}}}, {"anotherValue", "test"}});
+            auto filteredExpected = expected;
+            filteredExpected.erase("a");
+            SETUP_TESTCASES()
+
+            auto j = json::parse(root_type_json_str);
+            auto nested_obj = j["nested"]["nested2"];
+            CHECK(nested_type_json_str.substr(12, 13) == root_type_json_str.substr(nested_obj.start_pos(), nested_obj.end_pos() - nested_obj.start_pos()));
+        }
+
+        SECTION("for simple types")
+        {
+            SECTION("no nested")
+            {
+                SECTION("with callback")
+                {
+                    json::parser_callback_t const cb = [](int /*unused*/, json::parse_event_t /*unused*/, json& /*unused*/) noexcept
+                    {
+                        return true;
+                    };
+
+                    // 1. string type
+                    std::string json_str =  R"("test")";
+                    auto j = json::parse(json_str, cb);
+                    validate_generated_json_and_start_end_pos_helper(json_str, j, "test");
+
+                    // 2. number type
+                    json_str =  R"(1)";
+                    j = json::parse(json_str, cb);
+                    validate_generated_json_and_start_end_pos_helper(json_str, j, 1);
+
+                    // 3. boolean type
+                    json_str =  R"(true)";
+                    j = json::parse(json_str, cb);
+                    validate_generated_json_and_start_end_pos_helper(json_str, j, true);
+
+                    // 4. null type
+                    json_str =  R"(null)";
+                    j = json::parse(json_str, cb);
+                    validate_generated_json_and_start_end_pos_helper(json_str, j, nullptr);
+                }
+
+                SECTION("without callback")
+                {
+                    // 1. string type
+                    std::string json_str =  R"("test")";
+                    auto j = json::parse(json_str);
+                    validate_generated_json_and_start_end_pos_helper(json_str, j, "test");
+
+                    // 2. number type
+                    json_str =  R"(1)";
+                    j = json::parse(json_str);
+                    validate_generated_json_and_start_end_pos_helper(json_str, j, 1);
+
+                    json_str = R"(1.001239923)";
+                    j = json::parse(json_str);
+                    validate_generated_json_and_start_end_pos_helper(json_str, j, 1.001239923);
+
+                    json_str = R"(1.123812389000000)";
+                    j = json::parse(json_str);
+                    validate_generated_json_and_start_end_pos_helper(json_str, j, 1.123812389);
+
+                    // 3. boolean type
+                    json_str =  R"(true)";
+                    j = json::parse(json_str);
+                    validate_generated_json_and_start_end_pos_helper(json_str, j, true);
+
+                    json_str =  R"(false)";
+                    j = json::parse(json_str);
+                    validate_generated_json_and_start_end_pos_helper(json_str, j, false);
+
+                    // 4. null type
+                    json_str =  R"(null)";
+                    j = json::parse(json_str);
+                    validate_generated_json_and_start_end_pos_helper(json_str, j, nullptr);
+                }
+            }
+
+            SECTION("string type")
+            {
+                const std::string nested_type_json_str =  R"("test")";
+                const std::string root_type_json_str =  R"({ "a": 1,   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
+                auto expected = json({{"nested", "test"}, {"anotherValue", "test"}, {"a", 1}});
+                auto filteredExpected = expected;
+                filteredExpected.erase("a");
+                SETUP_TESTCASES()
+            }
+
+            SECTION("number type")
+            {
+                const std::string nested_type_json_str =  R"(2)";
+                const std::string root_type_json_str =  R"({ "a": 1,   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
+                auto expected = json({{"nested", 2}, {"anotherValue", "test"}, {"a", 1}});
+                auto filteredExpected = expected;
+                filteredExpected.erase("a");
+                SETUP_TESTCASES()
+            }
+
+            SECTION("boolean type")
+            {
+                const std::string nested_type_json_str =  R"(true)";
+                const std::string root_type_json_str =  R"({ "a": 1,   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
+                auto expected = json({{"nested", true}, {"anotherValue", "test"}, {"a", 1}});
+                auto filteredExpected = expected;
+                filteredExpected.erase("a");
+                SETUP_TESTCASES()
+            }
+
+            SECTION("null type")
+            {
+                const std::string nested_type_json_str =  R"(null)";
+                const std::string root_type_json_str =  R"({ "a": 1,   "nested": )" + nested_type_json_str + R"(, "anotherValue": "test" })";
+                auto expected = json({{"nested", nullptr}, {"anotherValue", "test"}, {"a", 1}});
+                auto filteredExpected = expected;
+                filteredExpected.erase("a");
+                SETUP_TESTCASES()
+            }
+        }
+        SECTION("with leading whitespace and newlines around root JSON")
+        {
+            const std::string initial_whitespace = R"(
+                
+            )";
+            const std::string nested_type_json_str = R"({
+                "a": 1,
+                "nested": {
+                    "b": "test"
+                },
+                "anotherValue": "test"
+            })";
+            const std::string end_whitespace = R"(
+                
+            )";
+            const std::string root_type_json_str = initial_whitespace + nested_type_json_str + end_whitespace;
+
+            auto expected = json({{"a", 1}, {"nested", {{"b", "test"}}}, {"anotherValue", "test"}});
+
+            auto j = json::parse(root_type_json_str);
+
+            // 2. Check if the generated JSON is as expected
+            CHECK(j == expected);
+
+            // 3. Check if the start and end positions do not include the surrounding whitespace
+            CHECK(j.start_pos() == initial_whitespace.size());
+            CHECK(j.end_pos() == root_type_json_str.size() - end_whitespace.size());
+        }
+    }
+#undef SETUP_TESTCASES
+#endif
 }
 
 // this test relies on parse errors being thrown, so it is skipped when

tests/src/unit-diagnostic-positions-only.cpp

@@ -1,44 +0,0 @@
-//     __ _____ _____ _____
-//  __|  |   __|     |   | |  JSON for Modern C++ (supporting code)
-// |  |  |__   |  |  | | | |  version 3.12.0
-// |_____|_____|_____|_|___|  https://github.com/nlohmann/json
-//
-// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
-// SPDX-License-Identifier: MIT
-
-#include "doctest_compatibility.h"
-
-#ifdef JSON_DIAGNOSTICS
-    #undef JSON_DIAGNOSTICS
-#endif
-
-#define JSON_DIAGNOSTICS 0
-#define JSON_DIAGNOSTIC_POSITIONS 1
-#include <nlohmann/json.hpp>
-
-using json = nlohmann::json;
-
-TEST_CASE("Better diagnostics with positions only")
-{
-    SECTION("invalid type")
-    {
-        const std::string json_invalid_string = R"(
-        {
-            "address": {
-                "street": "Fake Street",
-                "housenumber": "1"
-            }
-        }
-        )";
-        json j = json::parse(json_invalid_string);
-        CHECK_THROWS_WITH_AS(j.at("address").at("housenumber").get<int>(),
-                             "[json.exception.type_error.302] (bytes 108-111) type must be number, but is string", json::type_error);
-    }
-
-    SECTION("invalid type without positions")
-    {
-        const json j = "foo";
-        CHECK_THROWS_WITH_AS(j.get<int>(),
-                             "[json.exception.type_error.302] type must be number, but is string", json::type_error);
-    }
-}

tests/src/unit-diagnostic-positions.cpp

@@ -8,7 +8,9 @@
 
 #include "doctest_compatibility.h"
 
-#define JSON_DIAGNOSTICS 1
+#ifndef JSON_DIAGNOSTICS
+    #define JSON_DIAGNOSTICS 1
+#endif
 #define JSON_DIAGNOSTIC_POSITIONS 1
 #include <nlohmann/json.hpp>
 
@@ -27,8 +29,13 @@ TEST_CASE("Better diagnostics with positions")
         }
         )";
         json j = json::parse(json_invalid_string);
+#if JSON_DIAGNOSTICS
         CHECK_THROWS_WITH_AS(j.at("address").at("housenumber").get<int>(),
                              "[json.exception.type_error.302] (/address/housenumber) (bytes 108-111) type must be number, but is string", json::type_error);
+#else
+        CHECK_THROWS_WITH_AS(j.at("address").at("housenumber").get<int>(),
+                             "[json.exception.type_error.302] (bytes 108-111) type must be number, but is string", json::type_error);
+#endif
     }
 
     SECTION("invalid type without positions")
@@ -74,7 +81,12 @@ TEST_CASE("Better diagnostics with positions")
         // (/foo/bar); the position of that parent is reported in the message
         const json doc = json::parse(R"({"foo":{"bar":"a string"}})");
         const json patch = json::parse(R"([{"op":"add","path":"/foo/bar/baz","value":1}])");
+#if JSON_DIAGNOSTICS
         CHECK_THROWS_WITH_AS(doc.patch(patch),
                              "[json.exception.out_of_range.411] (/foo/bar) (bytes 14-24) cannot add value: the JSON Patch 'add' target's parent is of type string, but must be an object or array", json::out_of_range);
+#else
+        CHECK_THROWS_WITH_AS(doc.patch(patch),
+                             "[json.exception.out_of_range.411] (bytes 14-24) cannot add value: the JSON Patch 'add' target's parent is of type string, but must be an object or array", json::out_of_range);
+#endif
     }
 }