fix: Allow ScheduleUpgrade to come from same block (#260)

* Cherry-pick of cosmos#11551

Allow ScheduleUpgrade to come from same block

* Fix test

x/upgrade/abci_test.go

@@ -68,9 +68,9 @@ func TestRequireName(t *testing.T) {
 	require.True(t, errors.Is(sdkerrors.ErrInvalidRequest, err), err)
 }
 
-func TestRequireFutureBlock(t *testing.T) {
+func TestRequireNotPastBlock(t *testing.T) {
 	s := setupTest(10, map[int64]bool{})
-	err := s.handler(s.ctx, &types.SoftwareUpgradeProposal{Title: "prop", Plan: types.Plan{Name: "test", Height: s.ctx.BlockHeight()}})
+	err := s.handler(s.ctx, &types.SoftwareUpgradeProposal{Title: "prop", Plan: types.Plan{Name: "test", Height: s.ctx.BlockHeight() - 1}})
 	require.NotNil(t, err)
 	require.True(t, errors.Is(sdkerrors.ErrInvalidRequest, err), err)
 }

x/upgrade/keeper/keeper.go

@@ -145,14 +145,16 @@ func (k Keeper) getModuleVersion(ctx sdk.Context, name string) (uint64, bool) {
 // ScheduleUpgrade schedules an upgrade based on the specified plan.
 // If there is another Plan already scheduled, it will overwrite it
 // (implicitly cancelling the current plan)
-// ScheduleUpgrade will also write the upgraded client to the upgraded client path
-// if an upgraded client is specified in the plan
+// ScheduleUpgrade will also write the upgraded IBC ClientState to the upgraded client
+// path if it is specified in the plan.
 func (k Keeper) ScheduleUpgrade(ctx sdk.Context, plan types.Plan) error {
 	if err := plan.ValidateBasic(); err != nil {
 		return err
 	}
 
-	if plan.Height <= ctx.BlockHeight() {
+	// NOTE: allow for the possibility of chains to schedule upgrades in begin block of the same block
+	// as a strategy for emergency hard fork recoveries
+	if plan.Height < ctx.BlockHeight() {
 		return sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "upgrade cannot be scheduled in the past")
 	}