Make configuration-extensions have a default value

This saves a check (and an indentation) in the deployment plugin,
making the code a tiny bit simpler.

Suggested-By: Sam Thursfield

2 files changed, 11 insertions, 12 deletions

diff --git a/morphlib/morph2.py b/morphlib/morph2.py
index 3a3ad679..6e24765e 100644
--- a/morphlib/morph2.py
+++ b/morphlib/morph2.py
@@ -49,7 +49,8 @@ class Morphology(object):
             ('strata', []),
             ('description', ''),
             ('arch', None),
-            ('system-kind', None)
+            ('system-kind', None),
+            ('configuration-extensions', []),
         ]
     }
 
diff --git a/morphlib/plugins/deploy_plugin.py b/morphlib/plugins/deploy_plugin.py
index e921b0af..fbc8f145 100644
--- a/morphlib/plugins/deploy_plugin.py
+++ b/morphlib/plugins/deploy_plugin.py
@@ -137,17 +137,15 @@ class DeployPlugin(cliapp.Plugin):
 
         # Run configuration extensions.
         self.app.status(msg='Configure system')
-        m = artifact.source.morphology
-        if 'configuration-extensions' in m:
-            names = m['configuration-extensions']
-            for name in names:
-                self._run_extension(
-                    branch_dir,
-                    build_ref,
-                    name,
-                    '.configure',
-                    [system_tree],
-                    env)
+        names = artifact.source.morphology['configuration-extensions']
+        for name in names:
+            self._run_extension(
+                branch_dir,
+                build_ref,
+                name,
+                '.configure',
+                [system_tree],
+                env)
         
         # Run write extension.
         self.app.status(msg='Writing to device')