Shelly: no return energy register on gen1 relay and plug meters (#33112)

meter/shelly/gen1.go

@@ -149,9 +149,11 @@ func (c *gen1) IsReversed() bool {
 	return false
 }
 
-// HasReturnEnergy reports whether the device measures energy in the return direction
+// HasReturnEnergy reports whether the device measures energy in the return direction.
+// Only the EM variants have a total_returned register, relay/plug meters don't.
 func (c *gen1) HasReturnEnergy() bool {
-	return true
+	res, err := c.status.Get()
+	return err == nil && c.channel >= len(res.Meters) && c.channel < len(res.EMeters)
 }
 
 // IsThreePhase reports whether the device is a three-phase energy meter.

meter/shelly/gen1_test.go

@@ -3,7 +3,9 @@ package shelly
 import (
 	"encoding/json"
 	"testing"
+	"time"
 
+	"github.com/evcc-io/evcc/util"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -46,3 +48,21 @@ func TestUnmarshalGen1Status(t *testing.T) {
 		assert.Equal(t, -620.34, res.EMeters[0].Power)
 	}
 }
+
+// TestGen1HasReturnEnergy asserts that only the EM variants report a return
+// register - a 1PM's production must not be booked in return direction (#33062).
+func TestGen1HasReturnEnergy(t *testing.T) {
+	status := func(s string) util.Cacheable[Gen1Status] {
+		var res Gen1Status
+		require.NoError(t, json.Unmarshal([]byte(s), &res))
+		return util.ResettableCached(func() (Gen1Status, error) { return res, nil }, time.Minute)
+	}
+
+	// Shelly 1PM: meters without total_returned
+	g := &gen1{status: status(`{"meters":[{"power":198.0,"total":31510486}]}`)}
+	assert.False(t, g.HasReturnEnergy(), "1PM has no return register")
+
+	// Shelly EM: emeters with total_returned
+	g = &gen1{status: status(`{"emeters":[{"power":-620.34,"total":401472.9,"total_returned":653673.7}]}`)}
+	assert.True(t, g.HasReturnEnergy())
+}