fix: incorrect noexcept in segments_base::front() and back()

Author: alandefreitas

include/boost/url/impl/segments_base.hpp

@@ -180,7 +180,7 @@ size() const noexcept
 inline
 std::string
 segments_base::
-front() const noexcept
+front() const
 {
     BOOST_ASSERT(! empty());
     return *begin();
@@ -189,7 +189,7 @@ front() const noexcept
 inline
 std::string
 segments_base::
-back() const noexcept
+back() const
 {
     BOOST_ASSERT(! empty());
     return *--end();

include/boost/url/segments_base.hpp

@@ -244,7 +244,7 @@ class BOOST_SYMBOL_VISIBLE segments_base
         @return The first segment.
     */
     std::string
-    front() const noexcept;
+    front() const;
 
     /** Return the last segment
 
@@ -277,7 +277,7 @@ class BOOST_SYMBOL_VISIBLE segments_base
         @return The last segment.
     */
     std::string
-    back() const noexcept;
+    back() const;
 
     /** Return an iterator to the beginning
 

test/unit/segments_base.cpp

@@ -273,11 +273,30 @@ struct segments_base_test
         }
     }
 
+    void
+    testFrontBackNonEmpty()
+    {
+        // front()/back() on single-element segments
+        // (noexcept removal regression)
+        {
+            auto rv = parse_uri_reference("/only");
+            BOOST_TEST(rv.has_value());
+            if(rv.has_value())
+            {
+                segments_base const& ps(
+                    segments_view(rv->encoded_segments()));
+                BOOST_TEST_EQ(ps.front(), "only");
+                BOOST_TEST_EQ(ps.back(), "only");
+            }
+        }
+    }
+
     void
     run()
     {
         testObservers();
         testRange();
+        testFrontBackNonEmpty();
         testJavadoc();
     }
 };