From fb86e6da299405824cc6eda431726bbd8c22b346 Mon Sep 17 00:00:00 2001
From: Francois Chabot <francois.chabot.dev@gmail.com>
Date: Tue, 22 Jan 2019 17:15:59 -0500
Subject: [PATCH] added zero-length array check, and better test coverage

---
 .../nlohmann/detail/input/input_adapters.hpp  |  2 +-
 single_include/nlohmann/json.hpp              |  2 +-
 test/src/unit-class_parser.cpp                | 20 +++++++++++++++
 test/src/unit-deserialization.cpp             | 25 +++++++++++++++++++
 4 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/include/nlohmann/detail/input/input_adapters.hpp b/include/nlohmann/detail/input/input_adapters.hpp
index 949b8397c..490c05877 100644
--- a/include/nlohmann/detail/input/input_adapters.hpp
+++ b/include/nlohmann/detail/input/input_adapters.hpp
@@ -399,7 +399,7 @@ class input_adapter
     /// input adapter for array
     template<class T, std::size_t N>
     input_adapter(T (&array)[N])
-        : input_adapter(std::begin(array), array[N - 1] == 0 ? std::prev(std::end(array)) : std::end(array)) {}
+        : input_adapter(std::begin(array), (N > 0 && array[N - 1]) == 0 ? std::prev(std::end(array)) : std::end(array)) {}
 
     /// input adapter for contiguous container
     template<class ContiguousContainer, typename
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 3f15880e1..a0bcc3d75 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -2554,7 +2554,7 @@ class input_adapter
     /// input adapter for array
     template<class T, std::size_t N>
     input_adapter(T (&array)[N])
-        : input_adapter(std::begin(array), array[N - 1] == 0 ? std::prev(std::end(array)) : std::end(array)) {}
+        : input_adapter(std::begin(array), (N > 0 && array[N - 1]) == 0 ? std::prev(std::end(array)) : std::end(array)) {}
 
     /// input adapter for contiguous container
     template<class ContiguousContainer, typename
diff --git a/test/src/unit-class_parser.cpp b/test/src/unit-class_parser.cpp
index f3d30690c..72a26251e 100644
--- a/test/src/unit-class_parser.cpp
+++ b/test/src/unit-class_parser.cpp
@@ -1626,6 +1626,17 @@ TEST_CASE("parser class")
             CHECK(j == json(true));
         }
 
+        SECTION("from padded std::array")
+        {
+            std::array<uint8_t, 5> v { {'t', 'r', 'u', 'e'} };
+            json j;
+            json::parser(nlohmann::detail::input_adapter(std::begin(v), std::end(v))).parse(false, j);
+            CHECK(j == json(true));
+
+            CHECK_THROWS_WITH(json::parser(nlohmann::detail::input_adapter(std::begin(v), std::end(v))).parse(true, j),
+            "[json.exception.parse_error.101] parse error at line 1, column 5: syntax error while parsing value - invalid literal; last read: 'true<U+0000>'; expected end of input");
+        }
+
         SECTION("from array")
         {
             uint8_t v[] = {'t', 'r', 'u', 'e'};
@@ -1634,6 +1645,15 @@ TEST_CASE("parser class")
             CHECK(j == json(true));
         }
 
+        SECTION("from zero-length array")
+        {
+            uint8_t v[] = {};
+            json j;
+            CHECK_THROWS_WITH(json::parser(nlohmann::detail::input_adapter(v)).parse(true, j),
+            "[json.exception.parse_error.101] parse error at line 1, column 1: syntax error while parsing value - unexpected end of input; expected '[', '{', or a literal");
+        }
+
+
         SECTION("from char literal")
         {
             CHECK(parser_helper("true") == json(true));
diff --git a/test/src/unit-deserialization.cpp b/test/src/unit-deserialization.cpp
index 875147f8b..bf88e21d8 100644
--- a/test/src/unit-deserialization.cpp
+++ b/test/src/unit-deserialization.cpp
@@ -368,6 +368,19 @@ TEST_CASE("deserialization")
                 CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
             }
 
+            SECTION("from padded std::array")
+            {
+                std::array<uint8_t, 5> v { {'t', 'r', 'u', 'e'} };
+
+                SaxEventLogger l;
+                CHECK(json::sax_parse(v, &l, json::input_format_t::json, false));
+                CHECK(l.events.size() == 1);
+                CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
+
+                CHECK(not json::accept(v));
+                CHECK(not json::sax_parse(v, &l));
+            }
+
             SECTION("from array")
             {
                 uint8_t v[] = {'t', 'r', 'u', 'e'};
@@ -380,6 +393,18 @@ TEST_CASE("deserialization")
                 CHECK(l.events == std::vector<std::string>({"boolean(true)"}));
             }
 
+            SECTION("from zero-length array")
+            {
+                uint8_t v[] = {};
+                CHECK_THROWS_AS(json::parse(v), json::parse_error&);
+                CHECK(not json::accept(v));
+
+                SaxEventLogger l;
+                CHECK(not json::sax_parse(v, &l));
+                CHECK(l.events.size() == 1);
+                CHECK(l.events == std::vector<std::string>({"parse_error(1)"}));
+            }
+
             SECTION("from chars")
             {
                 uint8_t* v = new uint8_t[5];