1 files changed, 3 insertions, 0 deletions

diff --git a/src/mailman/chains/base.py b/src/mailman/chains/base.py
index fdf9477da..59125ba69 100644
--- a/src/mailman/chains/base.py
+++ b/src/mailman/chains/base.py
@@ -21,6 +21,7 @@ from mailman.config import config
 from mailman.interfaces.chain import (
     IChain, IChainIterator, IChainLink, IMutableChain, LinkAction)
 from mailman.interfaces.rules import IRule
+from mailman.utilities.modules import abstract_component
 from public import public
 from zope.interface import implementer
 
@@ -55,6 +56,7 @@ class Link:
 
 
 @public
+@abstract_component
 @implementer(IChain, IChainIterator)
 class TerminalChainBase:
     """A base chain that always matches and executes a method.
@@ -85,6 +87,7 @@ class TerminalChainBase:
 
 
 @public
+@abstract_component
 @implementer(IMutableChain)
 class Chain:
     """Generic chain base class."""