Merge pull request #8 from Goddard-Fortran-Ecosystem/hotfix/value-of-…

…iterator-of-empty-container

Fix for bug with empty containers.

include/templates/altSet_impl.inc

@@ -830,7 +830,11 @@
       class(__iterator), target, intent(in) :: this
       __type_declare_result, pointer :: value
 
-      value=>this%reference%items%at(this%current)
+      if (this%current == UNINITIALIZED) then
+         value => null()
+      else
+         value=>this%reference%items%at(this%current)
+      end if
 
       end function __PROC(value)
 

include/templates/map_impl.inc

@@ -332,7 +332,11 @@
          type(__pair), pointer :: p
 
          p => this%setIter%value()
-         res => p%value
+         if (associated(p)) then
+            res => p%value
+         else
+            res => null()
+         end if
 
       end function __PROC(value)
 

include/templates/set_impl.inc

@@ -642,7 +642,11 @@
       class(__iterator), intent(in) :: this
       __type_declare_result, pointer :: value
 
-      value=>this%node%value
+      if (associated(this%node)) then
+         value =>this%node%value
+      else
+         value => null()
+      end if
 
       end function __PROC(value)
 

tests/Map/Test_Map.m4

@@ -103,6 +103,16 @@ contains
 
    end subroutine test_at
 
+@test
+   subroutine test_value_empty_is_null()
+      type (Map), target :: m
+      type (MapIterator) :: iter
+
+      iter = m%find(KEY1)
+      @assertFalse(associated(iter%value()))
+
+   end subroutine test_value_empty_is_null
+
 @test
    subroutine test_find()
       type (Map), target :: m