filesystem: look-ahead on reset-partition-only

The identity controller shouldn't own the logic for determining
if the filesystem controller will only install the reset partition.
Creates a utility function that can be called by the identity
controller to determine if only installing the reset partition.

subiquity/server/controllers/filesystem.py

@@ -294,6 +294,16 @@ class FilesystemController(SubiquityController, FilesystemManipulator):
         # log.debug("self.ai_data = %s", data)
         self.ai_data = data
 
+    # The identity and user-data section are optional if we are only installing
+    # the reset partition, however the identity controller needs to know this
+    # before the filesystem controller naturally sets this. So this is a
+    # function to inspect the outcome early.
+    # See: https://github.com/canonical/subiquity/pull/1965
+    def is_reset_partition_only(self):
+        storage_config = self.app.autoinstall_config.get(self.autoinstall_key, {})
+        layout = storage_config.get("layout", {})
+        return layout.get("reset-partition-only", False)
+
     async def configured(self):
         self._configured = True
         if self._info is None:

subiquity/server/controllers/identity.py

@@ -89,14 +89,7 @@ class IdentityController(SubiquityController):
         if self.app.base_model.source.current.variant != "server":
             return
         # 3. we are only refreshing the reset partition
-        # (The identity controller doesn't figure this out until the apply
-        # step, so we are going to cheat and inspect the situation here)
-        storage_config = self.app.autoinstall_config.get("storage")
-        if (
-            storage_config is not None
-            and storage_config.get("layout") is not None
-            and storage_config["layout"].get("reset-partition-only")
-        ):
+        if self.app.controllers.Filesystem.is_reset_partition_only():
             return
         # 4. identity section is interactive
         if self.interactive():

subiquity/server/controllers/tests/test_filesystem.py

@@ -1660,3 +1660,50 @@ class TestMatchingDisks(IsolatedAsyncioTestCase):
         # overhead
         actual = self.fsc.get_bootable_matching_disk({"path": "/dev/md/*"})
         self.assertEqual(r1, actual)
+
+
+class TestResetPartitionLookAhead(IsolatedAsyncioTestCase):
+    def setUp(self):
+        self.app = make_app()
+        self.app.opts.bootloader = None
+        self.fsc = FilesystemController(app=self.app)
+
+    @parameterized.expand(
+        # (config, is reset only)
+        (
+            ({}, False),
+            (
+                {
+                    "storage": {},
+                },
+                False,
+            ),
+            (
+                {
+                    "storage": {
+                        "layout": {
+                            "name": "direct",
+                            "reset-partition": True,
+                        },
+                    },
+                },
+                False,
+            ),
+            (
+                {
+                    "storage": {
+                        "layout": {
+                            "reset-partition-only": True,
+                        },
+                    },
+                },
+                True,
+            ),
+        )
+    )
+    def test_is_reset_partition_only_utility(self, config, expected):
+        """Test is_reset_partition_only utility"""
+
+        self.app.autoinstall_config = config
+
+        self.assertEqual(self.fsc.is_reset_partition_only(), expected)

subiquity/server/controllers/tests/test_identity.py

@@ -17,6 +17,7 @@ import jsonschema
 from jsonschema.validators import validator_for
 
 from subiquity.server.autoinstall import AutoinstallError
+from subiquity.server.controllers.filesystem import FilesystemController
 from subiquity.server.controllers.identity import IdentityController
 from subiquitycore.tests import SubiTestCase
 from subiquitycore.tests.mocks import make_app
@@ -39,6 +40,8 @@ class TestControllerUserCreationFlows(SubiTestCase):
     # See subiquity/models/tests/test_subiquity.py for details.
     def setUp(self):
         self.app = make_app()
+        self.app.opts.bootloader = False
+        self.app.controllers.Filesystem = FilesystemController(self.app)
         self.ic = IdentityController(self.app)
         self.ic.model.user = None
 
@@ -54,9 +57,9 @@ class TestControllerUserCreationFlows(SubiTestCase):
         ({"interactive-sections": ["*"]}, True),
         # No Autoinstall => interactive
         ({}, True),
-        # Can be missing if reset-parition-only specified
+        # Can be missing if reset-partition-only specified
         ({"storage": {"layout": {"reset-partition-only": True}}}, True),
-        # Can't be missing if reset-parition-only is not specified
+        # Can't be missing if reset-partition-only is not specified
         ({"storage": {"layout": {}}}, False),
         # user-data passed instead
         ({"user-data": "..."}, True),