Merge branch 'develop' into claude/issue-5066-24ba30

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

include/nlohmann/detail/input/lexer.hpp

@@ -975,15 +975,10 @@ class lexer : public lexer_base<BasicJsonType>
                         case '\n':
                         case '\r':
                         case char_traits<char_type>::eof():
-                            return true;
-
 #if !JSON_STRICT_NUL_HANDLING
                         case '\0':
-                            // a NUL byte is the end of the input (see scan()),
-                            // so leave it for scan() to see
-                            unget();
-                            return true;
 #endif
+                            return true;
 
                         default:
                             break;

single_include/nlohmann/json.hpp

@@ -10067,15 +10067,10 @@ class lexer : public lexer_base<BasicJsonType>
                         case '\n':
                         case '\r':
                         case char_traits<char_type>::eof():
-                            return true;
-
 #if !JSON_STRICT_NUL_HANDLING
                         case '\0':
-                            // a NUL byte is the end of the input (see scan()),
-                            // so leave it for scan() to see
-                            unget();
-                            return true;
 #endif
+                            return true;
 
                         default:
                             break;

tests/src/unit-class_parser.cpp

@@ -592,45 +592,6 @@ TEST_CASE("parser class")
 
                 // parsing from a string literal is unaffected either way
                 CHECK(json::parse("123") == json(123));
-
-                // a NUL byte that ends a // comment ends the input just
-                // like a NUL byte anywhere else (issue #5659); before the
-                // fix, the NUL was consumed as part of the comment, and
-                // scanning continued with whatever followed it
-                {
-                    // same as "//c" alone (real end of input after the
-                    // comment), rather than continuing with "[1]"
-                    std::string s1 = "//c";
-                    s1.push_back('\0');
-                    s1 += "[1]";
-                    json _; // NOLINT(readability-identifier-naming)
-                    CHECK_THROWS_WITH_AS(_ = json::parse(s1, nullptr, true, true),
-                                         "[json.exception.parse_error.101] parse error at line 1, column 4: syntax error while parsing value - unexpected end of input; expected '[', '{', or a literal",
-                                         json::parse_error&);
-                    CHECK_FALSE(json::accept(s1, true, true));
-                }
-
-                {
-                    // same as "[1, //c" alone, rather than continuing with " 2]"
-                    std::string s2 = "[1, //c";
-                    s2.push_back('\0');
-                    s2 += " 2]";
-                    json _; // NOLINT(readability-identifier-naming)
-                    CHECK_THROWS_WITH_AS(_ = json::parse(s2, nullptr, true, true),
-                                         "[json.exception.parse_error.101] parse error at line 1, column 8: syntax error while parsing value - unexpected end of input; expected '[', '{', or a literal",
-                                         json::parse_error&);
-                    CHECK_FALSE(json::accept(s2, true, true));
-                }
-
-                {
-                    // same as "1 //c" alone: the comment (and the NUL that
-                    // ends it) is ignored, and "x" is never reached
-                    std::string s3 = "1 //c";
-                    s3.push_back('\0');
-                    s3 += "x";
-                    CHECK(json::parse(s3, nullptr, true, true) == json(1));
-                    CHECK(json::accept(s3, true, true));
-                }
             }
 #endif
 

tests/src/unit-regression2.cpp

@@ -766,6 +766,25 @@ TEST_CASE("regression tests 2")
         CHECK(j == k);
     }
 
+#ifdef JSON_HAS_CPP_17
+    SECTION("issue #5066 - MSVC converts json to std::variant<json> via the conversion operator")
+    {
+        // std::variant<json> must not be retrievable via get<>(), because otherwise the
+        // implicit conversion operator becomes a candidate that MSVC picks over the variant's
+        // converting constructor, routing a number through the string from_json overload
+        static_assert(!nlohmann::detail::is_detected<nlohmann::detail::get_template_function, const json&, std::variant<json>>::value,
+                      "std::variant<json> must not be retrievable via get<>()");
+
+        // clang before 7 cannot instantiate libstdc++'s std::variant<json>
+#if !(defined(__clang__) && __clang_major__ < 7)
+        // push_back, not emplace_back: #5066 needs the implicit conversion
+        // from json to the vector's value type
+        std::vector<std::variant<json>> v;
+        v.push_back(json(1)); // NOLINT(hicpp-use-emplace,modernize-use-emplace)
+        CHECK(std::get<0>(v[0]) == 1);
+#endif
+    }
+#endif
 }
 
 TEST_CASE("regression test - parser callback must not lose a duplicate key's prior value")