fix(stringlist): allocate string before assignment (#1030)

src/Utilities/CharString.f90

@@ -29,6 +29,7 @@ module CharacterStringModule
     procedure, pass(rhs) :: character_eq_charstring
     procedure, pass(lhs) :: charstring_eq_character
     procedure :: write_unformatted
+    procedure :: strlen
     generic :: assignment(=) => assign_to_charstring, assign_from_charstring
     generic :: operator(==) => character_eq_charstring, charstring_eq_character
     ! not supported by gfortran 5 and 6
@@ -100,4 +101,15 @@ subroutine write_unformatted(this, unit, iostat, iomsg)
     end if
   end subroutine write_unformatted
 
+  function strlen(this) result(length)
+    class(CharacterStringType), intent(in) :: this
+    integer :: length
+
+    if (allocated(this%charstring)) then
+      length = len(this%charstring)
+    else
+      length = 0
+    end if
+  end function strlen
+
 end module CharacterStringModule

src/Utilities/StringList.f90

@@ -63,11 +63,13 @@ function GetStringFromList(list, indx) result(string)
     class(*), pointer :: obj
     type(CharacterStringType), pointer :: charcont
     !
-    string = ''
     obj => list%GetItem(indx)
     charcont => CastAsCharacterStringType(obj)
     if (associated(charcont)) then
-      string = charcont
+      allocate (character(len=charcont%strlen()) :: string)
+      string(:) = charcont
+    else
+      string = ''
     end if
     !
     return