From: Patrick Donnelly <pdonnell@redhat.com>
Date: Tue, 28 Jun 2022 20:27:14 +0000 (-0400)
Subject: teuthology/misc: avoid copying references of b when list or dict
X-Git-Tag: 1.2.0~154^2~4
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=c546d8dfa822b939ba3da3e529da69e805e28c51;p=teuthology.git

teuthology/misc: avoid copying references of b when list or dict

Otherwise, if b persists in memory (in a cache), it may wrongly
accumulate future merges.

Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>
---

diff --git a/teuthology/misc.py b/teuthology/misc.py
index 6a6651e72..85285cc78 100644
--- a/teuthology/misc.py
+++ b/teuthology/misc.py
@@ -1003,23 +1003,21 @@ def deep_merge(a, b):
     :param a: object items will be merged into
     :param b: object items will be merged from
     """
-    if a is None:
-        return b
     if b is None:
         return a
-    if isinstance(a, list):
+    elif isinstance(a, list):
         assert isinstance(b, list)
         a.extend(b)
         return a
-    if isinstance(a, dict):
+    elif isinstance(a, dict):
         assert isinstance(b, dict)
         for (k, v) in b.items():
-            if k in a:
-                a[k] = deep_merge(a[k], v)
-            else:
-                a[k] = v
+            a[k] = deep_merge(a.get(k), v)
         return a
-    return b
+    elif isinstance(b, dict) or isinstance(b, list):
+        return deep_merge(b.__class__(), b)
+    else:
+        return b
 
 
 def get_valgrind_args(testdir, name, preamble, v, exit_on_first_error=True):