From c35cd6cbd4e853da2e9f9e1c1efca3be90c6f03d Mon Sep 17 00:00:00 2001
From: Hanno Cornelius <68783915+jm-clius@users.noreply.github.com>
Date: Wed, 21 Jul 2021 14:22:40 +0200
Subject: [PATCH] Fix topic conversion in bridge (#679)

---
 CHANGELOG.md                  |  1 +
 tests/v2/test_waku_bridge.nim | 18 ++++++++++--------
 waku/common/wakubridge.nim    |  4 +++-
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 89587b4f4..ecfc76c3f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,6 +24,7 @@ This release contains the following:
 #### API
 
 ### Fixes
+- Conversion between topics for the Waku v1 <-> v2 bridge now follows the [RFC recommendation](https://rfc.vac.dev/spec/23/)
 
 ## 2021-06-03 v0.4
 
diff --git a/tests/v2/test_waku_bridge.nim b/tests/v2/test_waku_bridge.nim
index 0defda360..922b3ef6c 100644
--- a/tests/v2/test_waku_bridge.nim
+++ b/tests/v2/test_waku_bridge.nim
@@ -50,7 +50,7 @@ procSuite "WakuBridge":
     v2NodeKey = crypto.PrivateKey.random(Secp256k1, rng[])[]
     v2Node = WakuNode.new(v2NodeKey, ValidIpAddress.init("0.0.0.0"), Port(60002))
 
-    contentTopic = ContentTopic("/waku/1/1a2b3c4d/rlp")
+    contentTopic = ContentTopic("/waku/1/0x1a2b3c4d/rlp")
     topic = [byte 0x1a, byte 0x2b, byte 0x3c, byte 0x4d]
     payloadV1 = "hello from V1".toBytes()
     payloadV2 = "hello from V2".toBytes()
@@ -74,13 +74,15 @@ procSuite "WakuBridge":
     # Expected cases
     
     check:
-      toV1Topic(ContentTopic("/waku/1/00000000/rlp")) == [byte 0x00, byte 0x00, byte 0x00, byte 0x00]
-      toV2ContentTopic([byte 0x00, byte 0x00, byte 0x00, byte 0x00]) == ContentTopic("/waku/1/00000000/rlp")
-      toV1Topic(ContentTopic("/waku/1/ffffffff/rlp")) == [byte 0xff, byte 0xff, byte 0xff, byte 0xff]
-      toV2ContentTopic([byte 0xff, byte 0xff, byte 0xff, byte 0xff]) == ContentTopic("/waku/1/ffffffff/rlp")
+      toV1Topic(ContentTopic("/waku/1/0x00000000/rlp")) == [byte 0x00, byte 0x00, byte 0x00, byte 0x00]
+      toV2ContentTopic([byte 0x00, byte 0x00, byte 0x00, byte 0x00]) == ContentTopic("/waku/1/0x00000000/rlp")
+      toV1Topic(ContentTopic("/waku/1/0xffffffff/rlp")) == [byte 0xff, byte 0xff, byte 0xff, byte 0xff]
+      toV2ContentTopic([byte 0xff, byte 0xff, byte 0xff, byte 0xff]) == ContentTopic("/waku/1/0xffffffff/rlp")
+      toV1Topic(ContentTopic("/waku/1/0x1a2b3c4d/rlp")) == [byte 0x1a, byte 0x2b, byte 0x3c, byte 0x4d]
+      toV2ContentTopic([byte 0x1a, byte 0x2b, byte 0x3c, byte 0x4d]) == ContentTopic("/waku/1/0x1a2b3c4d/rlp")
+      # Topic conversion should still work where '0x' prefix is omitted from <v1 topic byte array>
       toV1Topic(ContentTopic("/waku/1/1a2b3c4d/rlp")) == [byte 0x1a, byte 0x2b, byte 0x3c, byte 0x4d]
-      toV2ContentTopic([byte 0x1a, byte 0x2b, byte 0x3c, byte 0x4d]) == ContentTopic("/waku/1/1a2b3c4d/rlp")
-    
+
     # Invalid cases
 
     expect LPError:
@@ -89,7 +91,7 @@ procSuite "WakuBridge":
     
     expect ValueError:
       # Content topic name too short
-      discard toV1Topic(ContentTopic("/waku/1/112233/rlp"))
+      discard toV1Topic(ContentTopic("/waku/1/0x112233/rlp"))
     
     expect ValueError:
       # Content topic name not hex
diff --git a/waku/common/wakubridge.nim b/waku/common/wakubridge.nim
index 48819e960..8d899233d 100644
--- a/waku/common/wakubridge.nim
+++ b/waku/common/wakubridge.nim
@@ -66,12 +66,14 @@ proc containsOrAdd(sequence: var seq[hashes.Hash], hash: hashes.Hash): bool =
 proc toV2ContentTopic*(v1Topic: waku_protocol.Topic): ContentTopic =
   ## Convert a 4-byte array v1 topic to a namespaced content topic
   ## with format `/waku/1/<v1-topic-bytes-as-hex>/proto`
+  ## 
+  ## <v1-topic-bytes-as-hex> should be prefixed with `0x`
   
   var namespacedTopic = NamespacedTopic()
   
   namespacedTopic.application = "waku"
   namespacedTopic.version = "1"
-  namespacedTopic.topicName = v1Topic.toHex()
+  namespacedTopic.topicName = "0x" & v1Topic.toHex()
   namespacedTopic.encoding = "rlp"
 
   return ContentTopic($namespacedTopic)