From a55d2a93c9599766446a37d7cc508f9ad9f39531 Mon Sep 17 00:00:00 2001
From: Hubert Chathi <hubert@uhoreg.ca>
Date: Thu, 8 Oct 2020 11:57:20 -0400
Subject: [PATCH 1/4] invalidate the cache when a fallback key is uploaded

---
 .../storage/databases/main/end_to_end_keys.py |  4 ++++
 tests/handlers/test_e2e_keys.py               | 20 +++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/synapse/storage/databases/main/end_to_end_keys.py b/synapse/storage/databases/main/end_to_end_keys.py
index 359dc6e968c6..44159094147e 100644
--- a/synapse/storage/databases/main/end_to_end_keys.py
+++ b/synapse/storage/databases/main/end_to_end_keys.py
@@ -398,6 +398,10 @@ async def set_e2e_fallback_keys(
                 desc="set_e2e_fallback_key",
             )
 
+        await self.invalidate_cache_and_stream(
+            "get_e2e_unused_fallback_key_types", (user_id, device_id)
+        )
+
     @cached(max_entries=10000)
     async def get_e2e_unused_fallback_key_types(
         self, user_id: str, device_id: str
diff --git a/tests/handlers/test_e2e_keys.py b/tests/handlers/test_e2e_keys.py
index 4e9e3dcbc267..b0ed3cbf4d09 100644
--- a/tests/handlers/test_e2e_keys.py
+++ b/tests/handlers/test_e2e_keys.py
@@ -33,6 +33,7 @@ def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.hs = None  # type: synapse.server.HomeServer
         self.handler = None  # type: synapse.handlers.e2e_keys.E2eKeysHandler
+        self.store = None # type: synapse.storage.Storage
 
     @defer.inlineCallbacks
     def setUp(self):
@@ -40,6 +41,7 @@ def setUp(self):
             self.addCleanup, handlers=None, federation_client=mock.Mock()
         )
         self.handler = synapse.handlers.e2e_keys.E2eKeysHandler(self.hs)
+        self.store = self.hs.get_datastore()
 
     @defer.inlineCallbacks
     def test_query_local_devices_no_devices(self):
@@ -178,6 +180,12 @@ def test_fallback_key(self):
         fallback_key = {"alg1:k1": "key1"}
         otk = {"alg1:k2": "key2"}
 
+        # we shouldn't have any unused fallback keys yet
+        res = yield defer.ensureDeferred(
+            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
+        )
+        self.assertEqual(res, [])
+
         yield defer.ensureDeferred(
             self.handler.upload_keys_for_user(
                 local_user,
@@ -186,6 +194,12 @@ def test_fallback_key(self):
             )
         )
 
+        # we should now have an unused alg1 key
+        res = yield defer.ensureDeferred(
+            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
+        )
+        self.assertEqual(res, ["alg1"])
+
         # claiming an OTK when no OTKs are available should return the fallback
         # key
         res = yield defer.ensureDeferred(
@@ -198,6 +212,12 @@ def test_fallback_key(self):
             {"failures": {}, "one_time_keys": {local_user: {device_id: fallback_key}}},
         )
 
+        # we shouldn't have any unused fallback keys again
+        res = yield defer.ensureDeferred(
+            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
+        )
+        self.assertEqual(res, [])
+
         # claiming an OTK again should return the same fallback key
         res = yield defer.ensureDeferred(
             self.handler.claim_one_time_keys(

From 1737c78d10798032393fe9d246741f2f1c2372e3 Mon Sep 17 00:00:00 2001
From: Hubert Chathi <hubert@uhoreg.ca>
Date: Thu, 8 Oct 2020 12:05:43 -0400
Subject: [PATCH 2/4] add changelog

---
 changelog.d/8501.bugfix | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/8501.bugfix

diff --git a/changelog.d/8501.bugfix b/changelog.d/8501.bugfix
new file mode 100644
index 000000000000..0fb825281bb7
--- /dev/null
+++ b/changelog.d/8501.bugfix
@@ -0,0 +1 @@
+Invalidate the cache when a fallback key is uploaded.

From 17e19692ec99a5f0482da201384611caac7c3a51 Mon Sep 17 00:00:00 2001
From: Hubert Chathi <hubert@uhoreg.ca>
Date: Thu, 8 Oct 2020 12:12:16 -0400
Subject: [PATCH 3/4] black

---
 tests/handlers/test_e2e_keys.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/handlers/test_e2e_keys.py b/tests/handlers/test_e2e_keys.py
index b0ed3cbf4d09..e79d612f7ae2 100644
--- a/tests/handlers/test_e2e_keys.py
+++ b/tests/handlers/test_e2e_keys.py
@@ -33,7 +33,7 @@ def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.hs = None  # type: synapse.server.HomeServer
         self.handler = None  # type: synapse.handlers.e2e_keys.E2eKeysHandler
-        self.store = None # type: synapse.storage.Storage
+        self.store = None  # type: synapse.storage.Storage
 
     @defer.inlineCallbacks
     def setUp(self):

From c14a7a32856c82f674ff248cd3048f34aae25946 Mon Sep 17 00:00:00 2001
From: Hubert Chathi <hubert@uhoreg.ca>
Date: Thu, 8 Oct 2020 12:31:41 -0400
Subject: [PATCH 4/4] fix changelog so it gets grouped with original fallback
 implementation

---
 changelog.d/8501.bugfix  | 1 -
 changelog.d/8501.feature | 1 +
 2 files changed, 1 insertion(+), 1 deletion(-)
 delete mode 100644 changelog.d/8501.bugfix
 create mode 100644 changelog.d/8501.feature

diff --git a/changelog.d/8501.bugfix b/changelog.d/8501.bugfix
deleted file mode 100644
index 0fb825281bb7..000000000000
--- a/changelog.d/8501.bugfix
+++ /dev/null
@@ -1 +0,0 @@
-Invalidate the cache when a fallback key is uploaded.
diff --git a/changelog.d/8501.feature b/changelog.d/8501.feature
new file mode 100644
index 000000000000..5220ddd48252
--- /dev/null
+++ b/changelog.d/8501.feature
@@ -0,0 +1 @@
+Add support for olm fallback keys ([MSC2732](https://github.com/matrix-org/matrix-doc/pull/2732)).