Merge ~ltrager/maas:lp1749246_2.3 into maas:2.3

[Lee Trager]

Backport of 583a8cc: LP: #1749246 - Only create generic hardlink for ga generic kernels.

[Lee Trager (ltrager)]

Approved in https://code.launchpad.net/~ltrager/maas/+git/maas/+merge/337677

review: Approve

diff --git a/src/provisioningserver/import_images/download_resources.py b/src/provisioningserver/import_images/download_resources.py
index 5062b85..f423a76 100644
--- a/src/provisioningserver/import_images/download_resources.py
+++ b/src/provisioningserver/import_images/download_resources.py
@@ -1,4 +1,4 @@
-# Copyright 2014-2017 Canonical Ltd.  This software is licensed under the
+# Copyright 2014-2018 Canonical Ltd.  This software is licensed under the
 # GNU Affero General Public License version 3 (see the file LICENSE).
 
 """Simplestreams code to download boot resources."""
@@ -302,8 +302,10 @@ class RepoWriter(BasicMirrorWriter):
         if 'subarch' in item:
             # MAAS uses the 'generic' subarch when it doesn't know which
             # subarch to use. This happens during enlistment and commissioning.
-            # Allow the 'generic' kflavor to own the 'generic' hardlink.
-            if item.get('kflavor') == 'generic':
+            # Allow the 'generic' kflavor to own the 'generic' hardlink. The
+            # generic kernel should always be the ga kernel.
+            if (item['subarch'].startswith('ga-') and
+                    item.get('kflavor') == 'generic'):
                 subarches = {item['subarch'], 'generic'}
             else:
                 subarches = {item['subarch']}
diff --git a/src/provisioningserver/import_images/tests/test_download_resources.py b/src/provisioningserver/import_images/tests/test_download_resources.py
index f13b392..f1e7759 100644
--- a/src/provisioningserver/import_images/tests/test_download_resources.py
+++ b/src/provisioningserver/import_images/tests/test_download_resources.py
@@ -1,4 +1,4 @@
-# Copyright 2014-2016 Canonical Ltd.  This software is licensed under the
+# Copyright 2014-2018 Canonical Ltd.  This software is licensed under the
 # GNU Affero General Public License version 3 (see the file LICENSE).
 
 """Tests for `provisioningserver.import_images.download_resources`."""
@@ -361,7 +361,7 @@ class TestRepoWriter(MAASTestCase):
                 label=product['label'], subarches={'ga-16.04'},
                 bootloader_type=None))
 
-    def test_inserts_generic_link_for_generic_kflavor(self):
+    def test_inserts_generic_link_for_generic_ga_kflavor(self):
         product_mapping = ProductMapping()
         product = self.make_product(subarch='ga-16.04', kflavor='generic')
         product_mapping.add(product, 'ga-16.04')
@@ -391,6 +391,37 @@ class TestRepoWriter(MAASTestCase):
                 label=product['label'], subarches={'ga-16.04', 'generic'},
                 bootloader_type=None))
 
+    def test_inserts_no_generic_link_for_generic_non_ga_kflavor(self):
+        # Regression test for LP:1749246
+        product_mapping = ProductMapping()
+        product = self.make_product(subarch='hwe-16.04', kflavor='generic')
+        product_mapping.add(product, 'hwe-16.04')
+        repo_writer = download_resources.RepoWriter(
+            None, None, product_mapping)
+        self.patch(
+            download_resources, 'products_exdata').return_value = product
+        # Prevent MAAS from trying to actually write the file.
+        mock_insert_file = self.patch(download_resources, 'insert_file')
+        mock_link_resources = self.patch(download_resources, 'link_resources')
+        # We only need to provide the product as the other fields are only used
+        # when writing the actual files to disk.
+        repo_writer.insert_item(product, None, None, None, None)
+        # None is used for the store and the content source as we're not
+        # writing anything to disk.
+        self.assertThat(
+            mock_insert_file,
+            MockCalledOnceWith(
+                None, os.path.basename(product['path']), product['sha256'],
+                {'sha256': product['sha256']}, product['size'], None))
+        # links are mocked out by the mock_insert_file above.
+        self.assertThat(
+            mock_link_resources,
+            MockCalledOnceWith(
+                snapshot_path=None, links=mock.ANY, osystem=product['os'],
+                arch=product['arch'], release=product['release'],
+                label=product['label'], subarches={'hwe-16.04'},
+                bootloader_type=None))
+
 
 class TestLinkResources(MAASTestCase):
     """Tests for `LinkResources`()."""