From f9ee39f0b2b9c548ea74c207567e9a2643d2c9dd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?colin=20axn=C3=A9r?=
 <25233464+colin-axner@users.noreply.github.com>
Date: Thu, 21 Jan 2021 16:10:07 +0100
Subject: [PATCH] Reorder IBC channel callbacks (#8404)

* reorder chan callbacks

* add changelog

* Update CHANGELOG.md

Co-authored-by: Federico Kunze <31522760+fedekunze@users.noreply.github.com>
---
 CHANGELOG.md                    |  1 +
 x/ibc/core/keeper/msg_server.go | 16 ++++++++--------
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f2bc793c0..3cfe96782 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -38,6 +38,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Improvements
 
+* (x/ibc) [\#8404](https://github.com/cosmos/cosmos-sdk/pull/8404) Reorder IBC `ChanOpenAck` and `ChanOpenConfirm` handler execution to perform core handler first, followed by application callbacks. 
 
 ### Bug Fixes
 
diff --git a/x/ibc/core/keeper/msg_server.go b/x/ibc/core/keeper/msg_server.go
index 5ea590fea..dcddcaed1 100644
--- a/x/ibc/core/keeper/msg_server.go
+++ b/x/ibc/core/keeper/msg_server.go
@@ -326,15 +326,15 @@ func (k Keeper) ChannelOpenAck(goCtx context.Context, msg *channeltypes.MsgChann
 		return nil, sdkerrors.Wrapf(porttypes.ErrInvalidRoute, "route not found to module: %s", module)
 	}
 
-	if err = cbs.OnChanOpenAck(ctx, msg.PortId, msg.ChannelId, msg.CounterpartyVersion); err != nil {
-		return nil, sdkerrors.Wrap(err, "channel open ack callback failed")
-	}
-
 	_, err = channel.HandleMsgChannelOpenAck(ctx, k.ChannelKeeper, cap, msg)
 	if err != nil {
 		return nil, err
 	}
 
+	if err = cbs.OnChanOpenAck(ctx, msg.PortId, msg.ChannelId, msg.CounterpartyVersion); err != nil {
+		return nil, sdkerrors.Wrap(err, "channel open ack callback failed")
+	}
+
 	return &channeltypes.MsgChannelOpenAckResponse{}, nil
 }
 
@@ -354,15 +354,15 @@ func (k Keeper) ChannelOpenConfirm(goCtx context.Context, msg *channeltypes.MsgC
 		return nil, sdkerrors.Wrapf(porttypes.ErrInvalidRoute, "route not found to module: %s", module)
 	}
 
-	if err = cbs.OnChanOpenConfirm(ctx, msg.PortId, msg.ChannelId); err != nil {
-		return nil, sdkerrors.Wrap(err, "channel open confirm callback failed")
-	}
-
 	_, err = channel.HandleMsgChannelOpenConfirm(ctx, k.ChannelKeeper, cap, msg)
 	if err != nil {
 		return nil, err
 	}
 
+	if err = cbs.OnChanOpenConfirm(ctx, msg.PortId, msg.ChannelId); err != nil {
+		return nil, sdkerrors.Wrap(err, "channel open confirm callback failed")
+	}
+
 	return &channeltypes.MsgChannelOpenConfirmResponse{}, nil
 }