From: Jeremy Stanley <fungi@yuggoth.org>
Date: Mon, 31 Jul 2017 15:00:33 +0000 (+0000)
Subject: Refuse to alter read-only elements at runtime
X-Git-Tag: 0.0.1~138
X-Git-Url: https://mudpy.org/gitweb?p=mudpy.git;a=commitdiff_plain;h=7a0a96095780b29d58a9d5aa8ece1fabaab72a2c

Refuse to alter read-only elements at runtime

In the Element.set() method, check whether the element being altered
is from a read-only file. That should only ever happen when
(re)loading of files is underway, either at start time or because
the reload command/SIGHUP has been issued. If an attempt is made to
change a read-only element at any other time, raise a
PermissionError exception instead of setting the new value in memory
(altered values were never written to the backing file, but prior to
this it was possible to modify the in-memory copies).
---

diff --git a/mudpy/misc.py b/mudpy/misc.py
index 4e32ccc..157096c 100644
--- a/mudpy/misc.py
+++ b/mudpy/misc.py
@@ -154,6 +154,12 @@ class Element:
 
     def set(self, facet, value):
         """Set values."""
+        if not self.origin.is_writeable() and not self.universe.loading:
+            # break if there is an attempt to update an element from a
+            # read-only file, unless the universe is in the midst of loading
+            # updated data from files
+            raise PermissionError("Altering elements in read-only files is "
+                                  "disallowed")
         if facet in ["loglevel"]:
             value = int(value)
         if not self.has_facet(facet) or not self.get(facet) == value: