Uniform interface to truffleposix_get_user_home - always allocate

Author: chrisseaton

src/main/c/truffleposix/truffleposix.c

@@ -202,7 +202,7 @@ char* truffleposix_get_user_home(const char *name) {
     return NULL;
   } else {
     /* ret == 0 && result == NULL means not found */
-    return "";
+    return strdup("");
   }
 }
 

src/main/ruby/core/file.rb

@@ -497,11 +497,8 @@ def self.expand_path(path, dir=nil)
 
         if ptr = Truffle::POSIX.truffleposix_get_user_home(name)
           dir = ptr.read_string
-          if dir.empty?
-            raise ArgumentError, "user #{name} does not exist"
-          else
-            Truffle.invoke_primitive :pointer_free, ptr
-          end
+          Truffle.invoke_primitive :pointer_free, ptr
+          raise ArgumentError, "user #{name} does not exist" if dir.empty?
         else
           Errno.handle
         end