Fixes #4854 Explicitly handle nullptr in sax_parse (#4873)

* handle nullptr explicitly Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * add test Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * make amalgamate Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * Fix formatting Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * move sax parse test to relevant unit test file Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * extend exceptions.md to include other_error.502 Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * Better exception messages Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * link sax_parse function Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * fix string Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * amalgamate Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * fix clang-tidy checks Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * cover valid handler with no throw Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * Add tests for other two overloads Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * cover overload with valid sax handler Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * pass an rvalue Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * ignore -Wtautological-pointer-compare Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * ignore clang-analyzer-core.NonNullParamChecker Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * ignore gcc -Wnonnull-compare Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * ignore undefined-behaviour-sanitizer Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * nest directives to ignore sanitizer errors Signed-off-by: Nikhil <nikhilreddydev@gmail.com> * use elif Signed-off-by: Nikhil <nikhilreddydev@gmail.com> --------- Signed-off-by: Nikhil <nikhilreddydev@gmail.com>
2025-10-27 23:35:55 +03:00 · 2025-08-03 00:36:01 +05:30
parent 55abcb5c0f
commit efcf9efb4f
4 changed files with 133 additions and 0 deletions
--- a/docs/mkdocs/docs/home/exceptions.md
+++ b/docs/mkdocs/docs/home/exceptions.md
@@ -900,3 +900,13 @@ A JSON Patch operation 'test' failed. The unsuccessful operation is also printed
    ```
    [json.exception.other_error.501] unsuccessful: {"op":"test","path":"/baz","value":"bar"}
    ```
+
+### json.exception.other_error.502
+
+This exception occurs when a null pointer is passed as SAX handler in [sax_parse](../api/basic_json/sax_parse.md) function.
+
+!!! failure "Example message"
+
+    ```
+    [json.exception.other_error.502] SAX handler must not be null
+    ```
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -4122,6 +4122,22 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                          const bool ignore_comments = false,
                          const bool ignore_trailing_commas = false)
    {
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wtautological-pointer-compare"
+#elif defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wnonnull-compare"
+#endif
+        if (sax == nullptr)
+        {
+            JSON_THROW(other_error::create(502, "SAX handler must not be null", nullptr));
+        }
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#elif defined(__GNUC__)
+#pragma GCC diagnostic pop
+#endif
        auto ia = detail::input_adapter(std::forward<InputType>(i));
        return format == input_format_t::json
               ? parser(std::move(ia), nullptr, true, ignore_comments, ignore_trailing_commas).sax_parse(sax, strict)
@@ -4138,6 +4154,22 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                          const bool ignore_comments = false,
                          const bool ignore_trailing_commas = false)
    {
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wtautological-pointer-compare"
+#elif defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wnonnull-compare"
+#endif
+        if (sax == nullptr)
+        {
+            JSON_THROW(other_error::create(502, "SAX handler must not be null", nullptr));
+        }
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#elif defined(__GNUC__)
+#pragma GCC diagnostic pop
+#endif
        auto ia = detail::input_adapter(std::move(first), std::move(last));
        return format == input_format_t::json
               ? parser(std::move(ia), nullptr, true, ignore_comments, ignore_trailing_commas).sax_parse(sax, strict)
@@ -4158,6 +4190,22 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                          const bool ignore_comments = false,
                          const bool ignore_trailing_commas = false)
    {
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wtautological-pointer-compare"
+#elif defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wnonnull-compare"
+#endif
+        if (sax == nullptr)
+        {
+            JSON_THROW(other_error::create(502, "SAX handler must not be null", nullptr));
+        }
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#elif defined(__GNUC__)
+#pragma GCC diagnostic pop
+#endif
        auto ia = i.get();
        return format == input_format_t::json
               // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -24225,6 +24225,22 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                          const bool ignore_comments = false,
                          const bool ignore_trailing_commas = false)
    {
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wtautological-pointer-compare"
+#elif defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wnonnull-compare"
+#endif
+        if (sax == nullptr)
+        {
+            JSON_THROW(other_error::create(502, "SAX handler must not be null", nullptr));
+        }
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#elif defined(__GNUC__)
+#pragma GCC diagnostic pop
+#endif
        auto ia = detail::input_adapter(std::forward<InputType>(i));
        return format == input_format_t::json
               ? parser(std::move(ia), nullptr, true, ignore_comments, ignore_trailing_commas).sax_parse(sax, strict)
@@ -24241,6 +24257,22 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                          const bool ignore_comments = false,
                          const bool ignore_trailing_commas = false)
    {
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wtautological-pointer-compare"
+#elif defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wnonnull-compare"
+#endif
+        if (sax == nullptr)
+        {
+            JSON_THROW(other_error::create(502, "SAX handler must not be null", nullptr));
+        }
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#elif defined(__GNUC__)
+#pragma GCC diagnostic pop
+#endif
        auto ia = detail::input_adapter(std::move(first), std::move(last));
        return format == input_format_t::json
               ? parser(std::move(ia), nullptr, true, ignore_comments, ignore_trailing_commas).sax_parse(sax, strict)
@@ -24261,6 +24293,22 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                          const bool ignore_comments = false,
                          const bool ignore_trailing_commas = false)
    {
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wtautological-pointer-compare"
+#elif defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wnonnull-compare"
+#endif
+        if (sax == nullptr)
+        {
+            JSON_THROW(other_error::create(502, "SAX handler must not be null", nullptr));
+        }
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#elif defined(__GNUC__)
+#pragma GCC diagnostic pop
+#endif
        auto ia = i.get();
        return format == input_format_t::json
               // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
--- a/tests/src/unit-class_parser.cpp
+++ b/tests/src/unit-class_parser.cpp
@@ -1644,6 +1644,33 @@ TEST_CASE("parser class")

        SECTION("SAX parser")
        {
+            SECTION("null sax handler")
+            {
+# if defined(__has_feature)
+#if !__has_feature(undefined_behavior_sanitizer)
+                const std::string s = "some_string";
+                SaxCountdown* p = nullptr;
+                CHECK_THROWS_WITH_AS(json::sax_parse(s, p), "[json.exception.other_error.502] SAX handler must not be null", json::other_error&); // NOLINT(clang-analyzer-core.NonNullParamChecker)
+                CHECK_THROWS_WITH_AS(json::sax_parse(s.begin(), s.end(), p), "[json.exception.other_error.502] SAX handler must not be null", json::other_error&); // NOLINT(clang-analyzer-core.NonNullParamChecker)
+                CHECK_THROWS_WITH_AS(json::sax_parse(nlohmann::detail::span_input_adapter(s.c_str(), s.size()), p), "[json.exception.other_error.502] SAX handler must not be null", json::other_error&); // NOLINT(clang-analyzer-core.NonNullParamChecker)
+#endif
+#else
+                const std::string s = "some_string";
+                SaxCountdown* p = nullptr;
+                CHECK_THROWS_WITH_AS(json::sax_parse(s, p), "[json.exception.other_error.502] SAX handler must not be null", json::other_error&); // NOLINT(clang-analyzer-core.NonNullParamChecker)
+                CHECK_THROWS_WITH_AS(json::sax_parse(s.begin(), s.end(), p), "[json.exception.other_error.502] SAX handler must not be null", json::other_error&); // NOLINT(clang-analyzer-core.NonNullParamChecker)
+                CHECK_THROWS_WITH_AS(json::sax_parse(nlohmann::detail::span_input_adapter(s.c_str(), s.size()), p), "[json.exception.other_error.502] SAX handler must not be null", json::other_error&); // NOLINT(clang-analyzer-core.NonNullParamChecker)
+#endif
+            }
+
+            SECTION("valid sax handler")
+            {
+                const std::string str = "some_string";
+                SaxCountdown s(1);
+                CHECK(json::sax_parse(str, &s) == false);
+                CHECK(json::sax_parse(nlohmann::detail::span_input_adapter(str.c_str(), str.size()), &s) == false);
+            }
+
            SECTION("} without value")
            {
                SaxCountdown s(1);