From 641d946ae775febdd7e5915607d3e122ab594049 Mon Sep 17 00:00:00 2001
From: Kevin Davis <karzak@users.noreply.github.com>
Date: Wed, 16 Sep 2020 20:44:15 -0400
Subject: [PATCH] [R4R] address potential panic in validator vesting (#645)

* emit event instead of panic on undelegation errors
---
 x/validator-vesting/keeper/keeper.go |  9 ++++++++-
 x/validator-vesting/types/errors.go  | 12 ++++++++++++
 x/validator-vesting/types/events.go  |  9 +++++++++
 3 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 x/validator-vesting/types/errors.go
 create mode 100644 x/validator-vesting/types/events.go

diff --git a/x/validator-vesting/keeper/keeper.go b/x/validator-vesting/keeper/keeper.go
index de51ffdf..5469578a 100644
--- a/x/validator-vesting/keeper/keeper.go
+++ b/x/validator-vesting/keeper/keeper.go
@@ -6,6 +6,7 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/codec"
 	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 	stakingexported "github.com/cosmos/cosmos-sdk/x/staking/exported"
 
 	"github.com/tendermint/tendermint/libs/log"
@@ -185,7 +186,13 @@ func (k Keeper) HandleVestingDebt(ctx sdk.Context, addr sdk.AccAddress, blockTim
 		k.stakingKeeper.IterateDelegations(ctx, vv.Address, func(index int64, d stakingexported.DelegationI) (stop bool) {
 			_, err := k.stakingKeeper.Undelegate(ctx, d.GetDelegatorAddr(), d.GetValidatorAddr(), d.GetShares())
 			if err != nil {
-				panic(err)
+				ctx.EventManager().EmitEvent(
+					sdk.NewEvent(
+						types.EventTypeBeginBlockError,
+						sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
+						sdk.NewAttribute(types.AttributeKeyError, fmt.Sprintf("%s", sdkerrors.Wrapf(types.ErrFailedUndelegation, "%s", err.Error()))),
+					),
+				)
 			}
 			return false
 		})
diff --git a/x/validator-vesting/types/errors.go b/x/validator-vesting/types/errors.go
new file mode 100644
index 00000000..260080fb
--- /dev/null
+++ b/x/validator-vesting/types/errors.go
@@ -0,0 +1,12 @@
+package types
+
+import (
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+)
+
+// DONTCOVER
+
+var (
+	// ErrFailedUndelegation error for delegations that fail to unbond
+	ErrFailedUndelegation = sdkerrors.Register(ModuleName, 2, "undelegation failed")
+)
diff --git a/x/validator-vesting/types/events.go b/x/validator-vesting/types/events.go
new file mode 100644
index 00000000..3013f870
--- /dev/null
+++ b/x/validator-vesting/types/events.go
@@ -0,0 +1,9 @@
+package types
+
+// Event types for validator vesting module
+const (
+	EventTypeBeginBlockError = "begin_blocker_error"
+
+	AttributeValueCategory = "validator-vesting"
+	AttributeKeyError      = "error_message"
+)