Tests: skip the parse() allocation sweep with MSVC iterator debugging

With _ITERATOR_DEBUG_LEVEL > 0 (MSVC STL debug builds, clang-cl), containers
allocate inside noexcept functions, so a failing allocation terminates the
program: "test case CRASHED: Terminate handler called" in the sax_parse
subcase of #5985. The sweep test of #6000 has the same guard.

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

include/nlohmann/detail/view/builder.hpp

@@ -1174,9 +1174,8 @@ indent_done:
             {
                 ++p;
             }
-            else if (!negative || NLOHMANN_VIEW_LIKELY(cur() >= '1' && cur() <= '9'))
+            else if (NLOHMANN_VIEW_LIKELY(cur() >= '1' && cur() <= '9'))
             {
-                // (without a sign, the dispatch saw a digit)
                 p = skip_digits(p + 1, e);
             }
             else

include/nlohmann/detail/view/errors.hpp

@@ -251,8 +251,12 @@ std::string diagnostics(const error_site site)
     std::string context;
 #if JSON_DIAGNOSTICS
     std::vector<std::string> tokens;
-    // a value that is not found leaves no tokens, like the root
-    static_cast<void>(edited ? value_path<true>(d, site.value(), tokens) : value_path<false>(d, site.value(), tokens));
+    const bool found = edited ? value_path<true>(d, site.value(), tokens) : value_path<false>(d, site.value(), tokens);
+    if (!found)
+    {
+        // a value that is not found has no path, and with it no bytes
+        return context;
+    }
     if (!tokens.empty())
     {
         // the root value has no path, but still has a byte range

single_include/nlohmann/json_view.hpp

@@ -2479,9 +2479,8 @@ indent_done:
             {
                 ++p;
             }
-            else if (!negative || NLOHMANN_VIEW_LIKELY(cur() >= '1' && cur() <= '9'))
+            else if (NLOHMANN_VIEW_LIKELY(cur() >= '1' && cur() <= '9'))
             {
-                // (without a sign, the dispatch saw a digit)
                 p = skip_digits(p + 1, e);
             }
             else
@@ -5080,8 +5079,12 @@ std::string diagnostics(const error_site site)
     std::string context;
 #if JSON_DIAGNOSTICS
     std::vector<std::string> tokens;
-    // a value that is not found leaves no tokens, like the root
-    static_cast<void>(edited ? value_path<true>(d, site.value(), tokens) : value_path<false>(d, site.value(), tokens));
+    const bool found = edited ? value_path<true>(d, site.value(), tokens) : value_path<false>(d, site.value(), tokens);
+    if (!found)
+    {
+        // a value that is not found has no path, and with it no bytes
+        return context;
+    }
     if (!tokens.empty())
     {
         // the root value has no path, but still has a byte range

tests/src/unit-allocator.cpp

@@ -1026,7 +1026,10 @@ TEST_CASE("insert() provides its documented exception guarantees (#5986)")
 }
 #endif
 
-#if !defined(JSON_NOEXCEPTION)
+// the no-exceptions CI job has no std::bad_alloc to catch; with iterator
+// debugging (MSVC STL debug builds) containers allocate inside noexcept
+// functions, so failing an allocation there terminates the program
+#if !defined(JSON_NOEXCEPTION) && !(defined(_ITERATOR_DEBUG_LEVEL) && _ITERATOR_DEBUG_LEVEL > 0)
 namespace
 {
 // the allocation numbered sweep_fail_at (counted from 1) throws; 0 never fails