From e99720344e5998ec6c0b0dc56055b1496816cb3e Mon Sep 17 00:00:00 2001
From: lisa neigut <niftynei@gmail.com>
Date: Tue, 20 Aug 2019 21:46:32 -0500
Subject: [PATCH] wire-gen: ensure that tlv messages are correctly ordered

Our TLV serializer relies on TLV outputs to be ordered by type
number. Prior to this commit we relied on 1) the ordering in the
RFC to be correct and 2) users to be using a version of Python that
respects stable ordering of dicts (i.e. Python 3.7+)

Instead of relying on these implicitly, we now explicitly sort messages
by type number when the TLV sets.

Resolves #2956.

Thanks-To: @ScottTre for the sort function
Reported-By: @ZmnSCPxj
---
 tools/gen/impl_template | 2 +-
 tools/generate-wire.py  | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/gen/impl_template b/tools/gen/impl_template
index bee9323aa..735f97fcb 100644
--- a/tools/gen/impl_template
+++ b/tools/gen/impl_template
@@ -203,7 +203,7 @@ static void fromwire_${msg.struct_name()}(const u8 **cursor, size_t *plen, void
 <% static = '' if tlv.name in options.expose_tlv_type else 'static '
 %>\
 ${static}const struct tlv_record_type tlvs_${tlv.name}[] = {
-    % for msg in tlv.messages.values():
+    % for msg in tlv.ordered_msgs():
 	{ ${msg.number}, towire_${msg.struct_name()}, fromwire_${msg.struct_name()} },
     % endfor
 };
diff --git a/tools/generate-wire.py b/tools/generate-wire.py
index 4b6926b42..71ec01744 100755
--- a/tools/generate-wire.py
+++ b/tools/generate-wire.py
@@ -377,6 +377,9 @@ class Tlv(object):
     def find_message(self, name):
         return self.messages[name]
 
+    def ordered_msgs(self):
+        return sorted(self.messages.values(), key=lambda item: int(item.number))
+
 
 class Master(object):
     types = {}