fix: url_view memcpy with null source when size is zero

Author: alandefreitas

include/boost/url/impl/url_view.hpp

@@ -67,9 +67,10 @@ persist() const
     auto p = std::allocate_shared<T>(
         detail::over_allocator<T, Alloc>(
             size(), a), url_view(impl()));
-    std::memcpy(
-        reinterpret_cast<char*>(
-            p.get() + 1), data(), size());
+    if(size())
+        std::memcpy(
+            reinterpret_cast<char*>(
+                p.get() + 1), data(), size());
     return p;
 }
 

test/unit/url_view.cpp

@@ -217,6 +217,16 @@ class url_view_test
         }
         }
 
+        // persist() with null data() and zero size()
+        {
+            url_view u;
+            BOOST_TEST(u.empty());
+            auto sp = u.persist();
+            BOOST_TEST(sp->empty());
+            BOOST_TEST_EQ(sp->size(), 0u);
+            BOOST_TEST_EQ(sp->buffer(), "");
+        }
+
         // operator core::string_view()
         {
             auto const f = []( core::string_view ) {};