Don't clear branch cache

This keeps the branch cache continuously populated.  When part of
the cache is invalidated by a branch creation/deletion event, instead
of clearing the cache, this updates the data.

That can be slightly more efficient in that it may reduce the number
of ZK transactions, and it may also help us when adding layout loading
to zuul-web, in that those connections will not need to make any remote
calls to the code review system.

Change-Id: I0ad3ea0ecab50ae5261f9510e34ffb27ca83ac1e

1 files changed, 66 insertions, 3 deletions

diff --git a/tests/unit/test_zk.py b/tests/unit/test_zk.py
index 9ed950282..e74117ac6 100644
--- a/tests/unit/test_zk.py
+++ b/tests/unit/test_zk.py
@@ -1599,7 +1599,7 @@ class TestZKObject(ZooKeeperBaseTestCase):
 
 
 class TestBranchCache(ZooKeeperBaseTestCase):
-    def test_branch_cache(self):
+    def test_branch_cache_protected_then_all(self):
         conn = DummyConnection()
         cache = BranchCache(self.zk_client, conn)
 
@@ -1634,8 +1634,18 @@ class TestBranchCache(ZooKeeperBaseTestCase):
             test_data['project1']['all']
         )
 
-        # Clear them to start over
-        cache.clearProjectCache('project1')
+    def test_branch_cache_all_then_protected(self):
+        conn = DummyConnection()
+        cache = BranchCache(self.zk_client, conn)
+
+        test_data = {
+            'project1': {
+                'all': ['protected1', 'protected2',
+                        'unprotected1', 'unprotected2'],
+                'protected': ['protected1', 'protected2'],
+            },
+        }
+
         self.assertEqual(
             cache.getProjectBranches('project1', True),
             None
@@ -1667,3 +1677,56 @@ class TestBranchCache(ZooKeeperBaseTestCase):
             sorted(cache.getProjectBranches('project1', False)),
             test_data['project1']['all']
         )
+
+    def test_branch_cache_change_protected(self):
+        conn = DummyConnection()
+        cache = BranchCache(self.zk_client, conn)
+
+        data1 = {
+            'project1': {
+                'all': ['newbranch', 'protected'],
+                'protected': ['protected'],
+            },
+        }
+        data2 = {
+            'project1': {
+                'all': ['newbranch', 'protected'],
+                'protected': ['newbranch', 'protected'],
+            },
+        }
+
+        # Create a new unprotected branch
+        cache.setProjectBranches('project1', False,
+                                 data1['project1']['all'])
+        cache.setProjectBranches('project1', True,
+                                 data1['project1']['protected'])
+        self.assertEqual(
+            cache.getProjectBranches('project1', True),
+            data1['project1']['protected']
+        )
+        self.assertEqual(
+            sorted(cache.getProjectBranches('project1', False)),
+            data1['project1']['all']
+        )
+
+        # Change it to protected
+        cache.setProtected('project1', 'newbranch', True)
+        self.assertEqual(
+            sorted(cache.getProjectBranches('project1', True)),
+            data2['project1']['protected']
+        )
+        self.assertEqual(
+            sorted(cache.getProjectBranches('project1', False)),
+            data2['project1']['all']
+        )
+
+        # Change it back
+        cache.setProtected('project1', 'newbranch', False)
+        self.assertEqual(
+            sorted(cache.getProjectBranches('project1', True)),
+            data1['project1']['protected']
+        )
+        self.assertEqual(
+            sorted(cache.getProjectBranches('project1', False)),
+            data1['project1']['all']
+        )