From 7476f5ee0c6d37b31036cf94992f85560c8e2a73 Mon Sep 17 00:00:00 2001
From: christian <christian@deneke.biz>
Date: Tue, 1 Oct 2019 00:57:27 +0200
Subject: [PATCH] Make json_pointer::back const (resolves #1764)

---
 include/nlohmann/detail/json_pointer.hpp | 2 +-
 single_include/nlohmann/json.hpp         | 2 +-
 test/src/unit-json_pointer.cpp           | 4 ++++
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/nlohmann/detail/json_pointer.hpp b/include/nlohmann/detail/json_pointer.hpp
index 9076441c..041408a8 100644
--- a/include/nlohmann/detail/json_pointer.hpp
+++ b/include/nlohmann/detail/json_pointer.hpp
@@ -267,7 +267,7 @@ class json_pointer
 
     @since version 3.6.0
     */
-    const std::string& back()
+    const std::string& back() const
     {
         if (JSON_HEDLEY_UNLIKELY(empty()))
         {
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index d27940b8..f7aedd10 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -10232,7 +10232,7 @@ class json_pointer
 
     @since version 3.6.0
     */
-    const std::string& back()
+    const std::string& back() const
     {
         if (JSON_HEDLEY_UNLIKELY(empty()))
         {
diff --git a/test/src/unit-json_pointer.cpp b/test/src/unit-json_pointer.cpp
index 9746d80d..2fa3033c 100644
--- a/test/src/unit-json_pointer.cpp
+++ b/test/src/unit-json_pointer.cpp
@@ -559,6 +559,10 @@ TEST_CASE("JSON pointers")
         CHECK(!ptr.empty());
         CHECK(j[ptr] == j["answer"]["everything"]);
 
+        // check access via const pointer
+        const auto cptr = ptr;
+        CHECK(cptr.back() == "everything");
+
         ptr.pop_back();
         ptr.pop_back();
         CHECK(ptr.empty());