apt: fix disable_components w/ autoinstall

* The mixture of storage for disable_components in and out of the config
  dict was confusing and caused bugs, depending on the flow
* disable_components now solely lives in the dict, like other items

examples/autoinstall.yaml

@@ -19,6 +19,9 @@ apt:
   primary:
     - arches: [default]
       uri: "http://mymirror.local/repository/Apt/ubuntu/"
+  disable_components:
+    - non-free
+    - restricted
 packages:
   - package1
   - package2

scripts/runtests.sh

@@ -155,6 +155,8 @@ timeout --foreground 60 sh -c "LANG=C.UTF-8 python3 -m subiquity.cmd.tui --autoi
                                --kernel-cmdline 'autoinstall' \
                                --source-catalog=examples/install-sources.yaml"
 validate
+python3 scripts/check-yaml-fields.py .subiquity/var/log/installer/subiquity-curtin-apt.conf \
+        apt.disable_components='[non-free, restricted]'
 python3 scripts/check-yaml-fields.py .subiquity/var/log/installer/subiquity-curtin-install.conf \
         debconf_selections.subiquity='"eek"' \
         storage.config[-1].options='"errors=remount-ro"'

subiquity/models/mirror.py

@@ -31,6 +31,7 @@ log = logging.getLogger('subiquitycore.models.mirror')
 
 
 DEFAULT = {
+    "disable_components": [],
     "preserve_sources_list": False,
     "primary": [
         {
@@ -51,12 +52,9 @@ class MirrorModel(object):
         self.config = copy.deepcopy(DEFAULT)
         self.architecture = get_architecture()
         self.default_mirror = self.get_mirror()
-        self.disable_components = set()
 
     def get_apt_config(self):
-        config = copy.deepcopy(self.config)
-        config['disable_components'] = list(self.disable_components)
-        return config
+        return copy.deepcopy(self.config)
 
     def mirror_is_default(self):
         return self.get_mirror() == self.default_mirror

subiquity/models/tests/test_mirror.py

@@ -15,6 +15,8 @@
 
 import unittest
 
+from curtin.config import merge_config
+
 from subiquity.models.mirror import (
     MirrorModel,
     )
@@ -47,8 +49,10 @@ class TestMirrorModel(unittest.TestCase):
         config = MirrorModel().get_apt_config()
         self.assertEqual([], config['disable_components'])
 
-    def test_set_disable_components(self):
+    def test_from_autoinstall(self):
+        # autoinstall loads to the config directly
         model = MirrorModel()
-        model.disable_components = set(['universe'])
+        data = {'disable_components': ['non-free']}
+        merge_config(model.config, data)
         config = model.get_apt_config()
-        self.assertEqual(['universe'], config['disable_components'])
+        self.assertEqual(['non-free'], config['disable_components'])

subiquity/server/controllers/mirror.py

@@ -129,7 +129,7 @@ class MirrorController(SubiquityController):
         await self.configured()
 
     async def disable_components_GET(self) -> List[str]:
-        return list(self.model.disable_components)
+        return self.model.config.get('disable_components', [])
 
     async def disable_components_POST(self, data: List[str]):
-        self.model.disable_components = set(data)
+        self.model.config['disable_components'] = data