json_view: address review of the exception diagnostics

- value_path(): check for the empty stack where the last frame is popped,
  so that the loop is `for (;;)`; update the frame only after the target
  check; document that the frame reference is not used after pop_back()
  or push_back() (and add a test with deep documents to run under a
  sanitizer)
- value_range(): flip the container check to remove a level of nesting
- diagnostics(): wrap the whole function in the macro check, and compute
  the path before the bytes, so that nothing is computed when there is no
  path; the function stays a template
- error_site: separate constructors for the two configurations
- site_of(): static_assert that it is called with a view
- document why the throw helpers without an error_site have none
- pointer.hpp: do not split a comment around the template header
- docs: "when materialize() sets them"; list the effects of
  JSON_DIAGNOSTICS and JSON_DIAGNOSTIC_POSITIONS separately

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

docs/mkdocs/docs/api/basic_json_view/at.md

@@ -70,7 +70,7 @@ Strong guarantee: there are no changes to the view or the document it refers to.
 
 As for `BasicJsonType`, with [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) these exceptions name the JSON
 Pointer path of the value within the document, and with
-[`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) its bytes in the source text (where
+[`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) its bytes in the source text (when
 [`materialize()`](materialize.md) sets them).
 
 ## Complexity

docs/mkdocs/docs/api/basic_json_view/back.md

@@ -22,7 +22,7 @@ Throws [`invalid_iterator.214`](../../home/exceptions.md#jsonexceptioninvalid_it
 
 As for `BasicJsonType`, with [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) the exception names the JSON Pointer
 path of the value within the document, and with [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md)
-its bytes in the source text (where [`materialize()`](materialize.md) sets them).
+its bytes in the source text (when [`materialize()`](materialize.md) sets them).
 
 ## Complexity
 

docs/mkdocs/docs/api/basic_json_view/front.md

@@ -22,7 +22,7 @@ Throws [`invalid_iterator.214`](../../home/exceptions.md#jsonexceptioninvalid_it
 
 As for `BasicJsonType`, with [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) the exception names the JSON Pointer
 path of the value within the document, and with [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md)
-its bytes in the source text (where [`materialize()`](materialize.md) sets them).
+its bytes in the source text (when [`materialize()`](materialize.md) sets them).
 
 ## Complexity
 

docs/mkdocs/docs/api/basic_json_view/get_string.md

@@ -24,7 +24,7 @@ Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) i
 
 As for `BasicJsonType`, with [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) the exception names the JSON Pointer
 path of the value within the document, and with [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md)
-its bytes in the source text (where [`materialize()`](materialize.md) sets them).
+its bytes in the source text (when [`materialize()`](materialize.md) sets them).
 
 ## Complexity
 

docs/mkdocs/docs/api/basic_json_view/number_token.md

@@ -24,7 +24,7 @@ Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) i
 
 As for `BasicJsonType`, with [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) the exception names the JSON Pointer
 path of the value within the document, and with [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md)
-its bytes in the source text (where [`materialize()`](materialize.md) sets them).
+its bytes in the source text (when [`materialize()`](materialize.md) sets them).
 
 ## Complexity
 

docs/mkdocs/docs/api/basic_json_view/operator[].md

@@ -75,7 +75,7 @@ Strong guarantee: there are no changes to the view or the document it refers to.
 
 As for `BasicJsonType`, with [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) these exceptions name the JSON
 Pointer path of the value within the document, and with
-[`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) its bytes in the source text (where
+[`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) its bytes in the source text (when
 [`materialize()`](materialize.md) sets them).
 
 ## Complexity

docs/mkdocs/docs/api/basic_json_view/value.md

@@ -63,7 +63,7 @@ Strong guarantee: there are no changes to the view or the document it refers to.
 
 As for `BasicJsonType`, with [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) these exceptions name the JSON
 Pointer path of the value within the document, and with
-[`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) its bytes in the source text (where
+[`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) its bytes in the source text (when
 [`materialize()`](materialize.md) sets them).
 
 ## Complexity

docs/mkdocs/docs/features/json_view.md

@@ -134,14 +134,21 @@ document: `#!cpp auto v = json_document::parse(text).root();` does not compile.
 - **Macros.** [`JSON_STRICT_NUL_HANDLING`](../api/macros/json_strict_nul_handling.md) and
   [`JSON_NOEXCEPTION`](../api/macros/json_noexception.md)/[`JSON_THROW_USER`](../api/macros/json_throw_user.md)
   behave the same way they do for `<nlohmann/json.hpp>`. These are the macros that change what the parser accepts or
-  how it reports errors. With [`JSON_DIAGNOSTICS`](../api/macros/json_diagnostics.md) and
-  [`JSON_DIAGNOSTIC_POSITIONS`](../api/macros/json_diagnostic_positions.md), the exceptions of views name the path
-  and the bytes of the value as those of `#!cpp basic_json` do; as a view has neither parent pointers nor stored
-  positions, both are found from the document's index when the exception is thrown, which takes time linear in the
-  size of the document (only for an exception). One exception has neither: `key()` of an iterator over an array or a
-  primitive value ([`invalid_iterator.207`](../home/exceptions.md#jsonexceptioninvalid_iterator207)), as a view's
-  iterator does not know the value it iterates over. The other macros only affect the values `materialize()` produces,
-  through `BasicJsonType`.
+  how it reports errors. Two more macros add context to the exceptions of views, as they do for those of
+  `#!cpp basic_json`:
+
+    - With [`JSON_DIAGNOSTICS`](../api/macros/json_diagnostics.md), an exception names the JSON Pointer path of the
+      value within the document.
+    - With [`JSON_DIAGNOSTIC_POSITIONS`](../api/macros/json_diagnostic_positions.md), an exception names the bytes of
+      the value in the source text.
+
+    A view has neither parent pointers nor stored positions, so both are found from the document's index when the
+    exception is thrown. This takes time linear in the size of the document. One exception has neither:
+    `key()` of an iterator over an array or a primitive value
+    ([`invalid_iterator.207`](../home/exceptions.md#jsonexceptioninvalid_iterator207)), because a view's iterator does
+    not know the value it iterates over.
+
+    The other macros only affect the values `materialize()` produces, through `BasicJsonType`.
 
 ## What is different
 

include/nlohmann/detail/view/errors.hpp

@@ -40,16 +40,11 @@ class error_site
   public:
     error_site() noexcept = default;
 
+#if JSON_DIAGNOSTICS || JSON_DIAGNOSTIC_POSITIONS
     error_site(const document_data* d, const node* n) noexcept
-#if JSON_DIAGNOSTICS || JSON_DIAGNOSTIC_POSITIONS
         : m_doc(d), m_node(n)
-#endif
-    {
-        static_cast<void>(d);
-        static_cast<void>(n);
-    }
+    {}
 
-#if JSON_DIAGNOSTICS || JSON_DIAGNOSTIC_POSITIONS
     const document_data* doc() const noexcept
     {
         return m_doc;
@@ -62,6 +57,8 @@ class error_site
   private:
     const document_data* m_doc = nullptr;
     const node* m_node = nullptr;
+#else
+    error_site(const document_data* /*d*/, const node* /*n*/) noexcept {}
 #endif
 };
 
@@ -78,6 +75,7 @@ struct view_access
 template<typename View>
 error_site site_of(const View& v) noexcept
 {
+    static_assert(is_json_view<View>::value, "the site of a value is only defined for views");
     return view_access::site(v);
 }
 
@@ -115,16 +113,18 @@ bool value_path(const document_data& d, const node* target, std::vector<std::str
     std::vector<frame> stack;
     stack.push_back(frame{nav::first(d, root), nav::end(d, root), 0, root->kind == node_kind::object});
     // (tokens[i] leads from stack[i] to stack[i + 1], or to the target)
-    while (!stack.empty())
+    for (;;)
     {
+        // (f is not used after the stack changes: pop_back() below, push_back() at the end)
         frame& f = stack.back();
         if (f.pos == f.end)
         {
             stack.pop_back();
-            if (!tokens.empty())
+            if (stack.empty())
             {
-                tokens.pop_back();
+                return false;
             }
+            tokens.pop_back();
             continue;
         }
         const node* entry = f.pos;
@@ -145,20 +145,19 @@ bool value_path(const document_data& d, const node* target, std::vector<std::str
             token = std::to_string(f.index);
         }
         const node* const child = nav::value(entry);
-        f.pos = document_data::after(entry);
-        ++f.index;
         if (child == target)
         {
             tokens.push_back(token);
             return true;
         }
+        f.pos = document_data::after(entry);
+        ++f.index;
         if (is_container(*child) && (nav::editable() || (target > child && target < child + child->next)))
         {
             tokens.push_back(token);
             stack.push_back(frame{nav::first(d, child), nav::end(d, child), 0, child->kind == node_kind::object});
         }
     }
-    return false;
 }
 #endif
 
@@ -195,32 +194,31 @@ void value_range(const document_data& d, const node* n, std::size_t& start, std:
     std::size_t pos = std::string::npos;
     for (const node* c = n;;)
     {
-        if (is_container(*c))
+        if (!is_container(*c))
         {
-            if ((c->flags & node_flags::is_new) != 0 || c->off >= d.size)
-            {
-                return;
-            }
-            ++closing;
-            const node* const first = nav::first(d, c);
-            const node* const last_end = nav::end(d, c);
-            if (first == last_end)
-            {
-                pos = std::size_t{c->off} + 1;
-                break;
-            }
-            const std::size_t value_offset = c->kind == node_kind::object ? 1 : 0;
-            const node* last = first;
-            for (const node* e = document_data::after(first + value_offset); e != last_end; e = document_data::after(e + value_offset))
-            {
-                last = e;
-            }
-            c = nav::value(last + value_offset);
-            continue;
+            p.set_scalar(d, *c);
+            pos = p.end;
+            break;
         }
-        p.set_scalar(d, *c);
-        pos = p.end;
-        break;
+        if ((c->flags & node_flags::is_new) != 0 || c->off >= d.size)
+        {
+            return;
+        }
+        ++closing;
+        const node* const first = nav::first(d, c);
+        const node* const last_end = nav::end(d, c);
+        if (first == last_end)
+        {
+            pos = std::size_t{c->off} + 1;
+            break;
+        }
+        const std::size_t value_offset = c->kind == node_kind::object ? 1 : 0;
+        const node* last = first;
+        for (const node* e = document_data::after(first + value_offset); e != last_end; e = document_data::after(e + value_offset))
+        {
+            last = e;
+        }
+        c = nav::value(last + value_offset);
     }
     for (; closing != 0 && pos != std::string::npos; --closing)
     {
@@ -245,33 +243,17 @@ void value_range(const document_data& d, const node* n, std::size_t& start, std:
 /// function makes it), it changed GCC's early inlining of unrelated view
 /// functions, so that GCC 13 no longer inlined a recursive walk over a view
 /// into itself (2.7 times the instructions).
+#if JSON_DIAGNOSTICS || JSON_DIAGNOSTIC_POSITIONS
 template<typename Unused = void>
 std::string diagnostics(const error_site site)
 {
-#if JSON_DIAGNOSTICS || JSON_DIAGNOSTIC_POSITIONS
     if (site.doc() == nullptr || site.value() == nullptr)
     {
         return "";
     }
     const document_data& d = *site.doc();
     const bool edited = d.edits != nullptr;
-    std::string bytes;
-#if JSON_DIAGNOSTIC_POSITIONS
-    std::size_t start = 0;
-    std::size_t end = 0;
-    if (edited)
-    {
-        value_range<true>(d, site.value(), start, end);
-    }
-    else
-    {
-        value_range<false>(d, site.value(), start, end);
-    }
-    if (start != std::string::npos && end != std::string::npos)
-    {
-        bytes = concat("(bytes ", std::to_string(start), "-", std::to_string(end), ") ");
-    }
-#endif
+    std::string context;
 #if JSON_DIAGNOSTICS
     std::vector<std::string> tokens;
     const bool found = edited ? value_path<true>(d, site.value(), tokens) : value_path<false>(d, site.value(), tokens);
@@ -285,15 +267,33 @@ std::string diagnostics(const error_site site)
         path.push_back('/');
         path += detail::escape(token);
     }
-    return concat('(', path, ") ", bytes);
-#else
-    return bytes;
+    context = concat('(', path, ") ");
 #endif
-#else
-    static_cast<void>(site);
-    return "";
+#if JSON_DIAGNOSTIC_POSITIONS
+    std::size_t start = 0;
+    std::size_t end = 0;
+    if (edited)
+    {
+        value_range<true>(d, site.value(), start, end);
+    }
+    else
+    {
+        value_range<false>(d, site.value(), start, end);
+    }
+    if (start != std::string::npos && end != std::string::npos)
+    {
+        context += concat("(bytes ", std::to_string(start), "-", std::to_string(end), ") ");
+    }
 #endif
+    return context;
 }
+#else
+template<typename Unused = void>
+std::string diagnostics(const error_site /*site*/)
+{
+    return "";
+}
+#endif
 
 /// the context of an exception about view @a v (see exception_prefix())
 template<typename View>
@@ -305,6 +305,13 @@ std::string diagnostics_of(const View& v)
 // Exceptions are thrown out of line, so that the accessors that may throw stay
 // small enough to be inlined. The overloads with an error_site put its context
 // in front of the message.
+//
+// The overloads without one are for exceptions that are not about a value of a
+// document: limits and invalid input of the editing and image functions, a
+// discarded view (it has no node), a view of another document (its path would
+// be one in that document), and those that basic_json creates without a
+// context too (the errors of json_pointer, invalid UTF-8). The one exception
+// about a value that has no site is key(), see view_iterator::key().
 
 [[noreturn]] NLOHMANN_VIEW_NOINLINE inline void throw_type_error(exception_id id, const char* prefix, const char* type)
 {

include/nlohmann/detail/view/pointer.hpp

@@ -44,8 +44,8 @@ index_status array_index(const StringType& s, std::size_t& idx) noexcept
 }
 
 /// throws the exception json_pointer::array_index throws for this status
-template<typename StringType>
 /// (without a context, as json_pointer::array_index)
+template<typename StringType>
 [[noreturn]] NLOHMANN_VIEW_NOINLINE void throw_array_index_error(index_status status, const StringType& s)
 {
     switch (status)

single_include/nlohmann/json_view.hpp

@@ -4546,16 +4546,11 @@ class error_site
   public:
     error_site() noexcept = default;
 
+#if JSON_DIAGNOSTICS || JSON_DIAGNOSTIC_POSITIONS
     error_site(const document_data* d, const node* n) noexcept
-#if JSON_DIAGNOSTICS || JSON_DIAGNOSTIC_POSITIONS
         : m_doc(d), m_node(n)
-#endif
-    {
-        static_cast<void>(d);
-        static_cast<void>(n);
-    }
+    {}
 
-#if JSON_DIAGNOSTICS || JSON_DIAGNOSTIC_POSITIONS
     const document_data* doc() const noexcept
     {
         return m_doc;
@@ -4568,6 +4563,8 @@ class error_site
   private:
     const document_data* m_doc = nullptr;
     const node* m_node = nullptr;
+#else
+    error_site(const document_data* /*d*/, const node* /*n*/) noexcept {}
 #endif
 };
 
@@ -4584,6 +4581,7 @@ struct view_access
 template<typename View>
 error_site site_of(const View& v) noexcept
 {
+    static_assert(is_json_view<View>::value, "the site of a value is only defined for views");
     return view_access::site(v);
 }
 
@@ -4621,16 +4619,18 @@ bool value_path(const document_data& d, const node* target, std::vector<std::str
     std::vector<frame> stack;
     stack.push_back(frame{nav::first(d, root), nav::end(d, root), 0, root->kind == node_kind::object});
     // (tokens[i] leads from stack[i] to stack[i + 1], or to the target)
-    while (!stack.empty())
+    for (;;)
     {
+        // (f is not used after the stack changes: pop_back() below, push_back() at the end)
         frame& f = stack.back();
         if (f.pos == f.end)
         {
             stack.pop_back();
-            if (!tokens.empty())
+            if (stack.empty())
             {
-                tokens.pop_back();
+                return false;
             }
+            tokens.pop_back();
             continue;
         }
         const node* entry = f.pos;
@@ -4651,20 +4651,19 @@ bool value_path(const document_data& d, const node* target, std::vector<std::str
             token = std::to_string(f.index);
         }
         const node* const child = nav::value(entry);
-        f.pos = document_data::after(entry);
-        ++f.index;
         if (child == target)
         {
             tokens.push_back(token);
             return true;
         }
+        f.pos = document_data::after(entry);
+        ++f.index;
         if (is_container(*child) && (nav::editable() || (target > child && target < child + child->next)))
         {
             tokens.push_back(token);
             stack.push_back(frame{nav::first(d, child), nav::end(d, child), 0, child->kind == node_kind::object});
         }
     }
-    return false;
 }
 #endif
 
@@ -4701,32 +4700,31 @@ void value_range(const document_data& d, const node* n, std::size_t& start, std:
     std::size_t pos = std::string::npos;
     for (const node* c = n;;)
     {
-        if (is_container(*c))
+        if (!is_container(*c))
         {
-            if ((c->flags & node_flags::is_new) != 0 || c->off >= d.size)
-            {
-                return;
-            }
-            ++closing;
-            const node* const first = nav::first(d, c);
-            const node* const last_end = nav::end(d, c);
-            if (first == last_end)
-            {
-                pos = std::size_t{c->off} + 1;
-                break;
-            }
-            const std::size_t value_offset = c->kind == node_kind::object ? 1 : 0;
-            const node* last = first;
-            for (const node* e = document_data::after(first + value_offset); e != last_end; e = document_data::after(e + value_offset))
-            {
-                last = e;
-            }
-            c = nav::value(last + value_offset);
-            continue;
+            p.set_scalar(d, *c);
+            pos = p.end;
+            break;
         }
-        p.set_scalar(d, *c);
-        pos = p.end;
-        break;
+        if ((c->flags & node_flags::is_new) != 0 || c->off >= d.size)
+        {
+            return;
+        }
+        ++closing;
+        const node* const first = nav::first(d, c);
+        const node* const last_end = nav::end(d, c);
+        if (first == last_end)
+        {
+            pos = std::size_t{c->off} + 1;
+            break;
+        }
+        const std::size_t value_offset = c->kind == node_kind::object ? 1 : 0;
+        const node* last = first;
+        for (const node* e = document_data::after(first + value_offset); e != last_end; e = document_data::after(e + value_offset))
+        {
+            last = e;
+        }
+        c = nav::value(last + value_offset);
     }
     for (; closing != 0 && pos != std::string::npos; --closing)
     {
@@ -4751,33 +4749,17 @@ void value_range(const document_data& d, const node* n, std::size_t& start, std:
 /// function makes it), it changed GCC's early inlining of unrelated view
 /// functions, so that GCC 13 no longer inlined a recursive walk over a view
 /// into itself (2.7 times the instructions).
+#if JSON_DIAGNOSTICS || JSON_DIAGNOSTIC_POSITIONS
 template<typename Unused = void>
 std::string diagnostics(const error_site site)
 {
-#if JSON_DIAGNOSTICS || JSON_DIAGNOSTIC_POSITIONS
     if (site.doc() == nullptr || site.value() == nullptr)
     {
         return "";
     }
     const document_data& d = *site.doc();
     const bool edited = d.edits != nullptr;
-    std::string bytes;
-#if JSON_DIAGNOSTIC_POSITIONS
-    std::size_t start = 0;
-    std::size_t end = 0;
-    if (edited)
-    {
-        value_range<true>(d, site.value(), start, end);
-    }
-    else
-    {
-        value_range<false>(d, site.value(), start, end);
-    }
-    if (start != std::string::npos && end != std::string::npos)
-    {
-        bytes = concat("(bytes ", std::to_string(start), "-", std::to_string(end), ") ");
-    }
-#endif
+    std::string context;
 #if JSON_DIAGNOSTICS
     std::vector<std::string> tokens;
     const bool found = edited ? value_path<true>(d, site.value(), tokens) : value_path<false>(d, site.value(), tokens);
@@ -4791,15 +4773,33 @@ std::string diagnostics(const error_site site)
         path.push_back('/');
         path += detail::escape(token);
     }
-    return concat('(', path, ") ", bytes);
-#else
-    return bytes;
+    context = concat('(', path, ") ");
 #endif
-#else
-    static_cast<void>(site);
-    return "";
+#if JSON_DIAGNOSTIC_POSITIONS
+    std::size_t start = 0;
+    std::size_t end = 0;
+    if (edited)
+    {
+        value_range<true>(d, site.value(), start, end);
+    }
+    else
+    {
+        value_range<false>(d, site.value(), start, end);
+    }
+    if (start != std::string::npos && end != std::string::npos)
+    {
+        context += concat("(bytes ", std::to_string(start), "-", std::to_string(end), ") ");
+    }
 #endif
+    return context;
 }
+#else
+template<typename Unused = void>
+std::string diagnostics(const error_site /*site*/)
+{
+    return "";
+}
+#endif
 
 /// the context of an exception about view @a v (see exception_prefix())
 template<typename View>
@@ -4811,6 +4811,13 @@ std::string diagnostics_of(const View& v)
 // Exceptions are thrown out of line, so that the accessors that may throw stay
 // small enough to be inlined. The overloads with an error_site put its context
 // in front of the message.
+//
+// The overloads without one are for exceptions that are not about a value of a
+// document: limits and invalid input of the editing and image functions, a
+// discarded view (it has no node), a view of another document (its path would
+// be one in that document), and those that basic_json creates without a
+// context too (the errors of json_pointer, invalid UTF-8). The one exception
+// about a value that has no site is key(), see view_iterator::key().
 
 [[noreturn]] NLOHMANN_VIEW_NOINLINE inline void throw_type_error(exception_id id, const char* prefix, const char* type)
 {
@@ -8019,8 +8026,8 @@ index_status array_index(const StringType& s, std::size_t& idx) noexcept
 }
 
 /// throws the exception json_pointer::array_index throws for this status
-template<typename StringType>
 /// (without a context, as json_pointer::array_index)
+template<typename StringType>
 [[noreturn]] NLOHMANN_VIEW_NOINLINE void throw_array_index_error(index_status status, const StringType& s)
 {
     switch (status)

tests/src/unit-json_view_positions.cpp

@@ -512,6 +512,26 @@ TEST_CASE("json_view exceptions name the path and the bytes of the value")
         CHECK(exception_of_call([&] { static_cast<void>(d.root()["a"][2]["n"][0].get<int>()); }) == expected);
     }
 
+    SECTION("deep documents with siblings after every nested container")
+    {
+        // the search for the path pushes and pops one frame per level (the
+        // stack reallocates while it grows, and shrinks again at every
+        // sibling): run under a sanitizer, a reference to a popped or moved
+        // frame would show here
+        std::string text = "7";
+        for (int level = 0; level < 40; ++level)
+        {
+            text = R"([[1, [2]], )" + text + R"(, {"k": [3, {"l": [4]}]}, [5, [6, [7]]]])";
+        }
+        CAPTURE(text)
+        const json j = json::parse(text);
+        const json_document d = json_document::parse(text);
+        check_exceptions(d.root(), j);
+        json_editable_document e = json_editable_document::parse(text);
+        e.set(e.root()[0][0], 9);
+        check_exceptions(e.root(), e.root().materialize());
+    }
+
     SECTION("examples")
     {
         const std::string text = R"({"people": [{"name": "a", "age": 1}, {"name": "c", "age": "x"}], "o": {"k": 1}})";