Close data files after reading

Starting with Python 3.8, the interpreter raises a ResourceWarning
exception during garbage collection if it finds an unclosed file
descriptor. Because of where this exception gets raised, it's
ignored (but a warning is emitted on stderr).

Use a typical context block in our loop to load data files, so that
this condition won't occur.

diff --git a/mudpy/data.py b/mudpy/data.py
index b73959a..eeea8fb 100644 (file)
--- a/mudpy/data.py
+++ b/mudpy/data.py
@@ -1,6 +1,6 @@
 """Data interface functions for the mudpy engine."""
 
-# Copyright (c) 2004-2018 mudpy authors. Permission to use, copy,
+# Copyright (c) 2004-2021 mudpy authors. Permission to use, copy,
 # modify, and distribute this software is granted under terms
 # provided in the LICENSE file distributed with this software.
 
@@ -57,7 +57,8 @@ class Data:
         self.source = find_file(
                 self.source, relative=self.relative, universe=self.universe)
         try:
-            self.data = yaml.safe_load(open(self.source))
+            with open(self.source) as datafd:
+                self.data = yaml.safe_load(datafd)
             log_entry = ("Loaded file %s into memory." % self.source, 5)
         except FileNotFoundError:
             # it's normal if the file is one which doesn't exist yet