fix: add meter source during migration

pkg/types/dashboardtypes/perses_v1_to_v2_queries.go

@@ -189,7 +189,9 @@ func (d *v1Decoder) collectV1QueryEnvelopes(widget map[string]any, panelKind Pan
 		queries = dropUnrenderableQueries(queries)
 		for _, q := range queries {
 			name := d.readString(q, "queryName")
-			out = append(out, qb.WrapInV5Envelope(name, q, string(qb.QueryTypeBuilder.StringValue())))
+			env := qb.WrapInV5Envelope(name, q, string(qb.QueryTypeBuilder.StringValue()))
+			carryQuerySource(env, q)
+			out = append(out, env)
 			if signal.IsZero() {
 				signal = signalFromDataSource(q["dataSource"])
 			}
@@ -446,3 +448,16 @@ func signalFromDataSource(raw any) telemetrytypes.Signal {
 	}
 	return telemetrytypes.Signal{}
 }
+
+// carryQuerySource copies a v1 builder query's meter source onto the v5 spec.
+// WrapInV5Envelope maps dataSource→signal but ignores the separate `source` field, so a
+// meter query (dataSource metrics + source "meter") would otherwise migrate as plain
+// metrics and read the wrong data. Only "meter" is carried through — the sole non-empty
+// source the v1 UI produces and v5 accepts; anything else stays unspecified.
+func carryQuerySource(env, query map[string]any) {
+	if source, _ := query["source"].(string); source == telemetrytypes.SourceMeter.StringValue() {
+		if spec, ok := env["spec"].(map[string]any); ok {
+			spec["source"] = source
+		}
+	}
+}

pkg/types/dashboardtypes/perses_v1_to_v2_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/SigNoz/signoz/pkg/types/coretypes"
 	qb "github.com/SigNoz/signoz/pkg/types/querybuildertypes/querybuildertypesv5"
 	"github.com/SigNoz/signoz/pkg/types/tagtypes"
+	"github.com/SigNoz/signoz/pkg/types/telemetrytypes"
 	"github.com/SigNoz/signoz/pkg/valuer"
 	"github.com/perses/spec/go/dashboard"
 	"github.com/perses/spec/go/dashboard/variable"
@@ -1779,6 +1780,41 @@ func TestConvertV1WidgetQueryRewritesUnknownMetricValueOrderKey(t *testing.T) {
 	assert.Equal(t, "service.name", spec.Order[1].Key.Name, "valid group-by order key left alone")
 }
 
+// A v1 meter query is dataSource "metrics" with a separate source "meter". The signal
+// maps to metrics, and the meter source must survive onto the v5 spec — otherwise the
+// panel migrates as a plain metrics query and reads the wrong data.
+func TestConvertV1WidgetQueryCarriesMeterSource(t *testing.T) {
+	widget := map[string]any{
+		"id":         "meter-1",
+		"panelTypes": "graph",
+		"query": map[string]any{
+			"queryType": "builder",
+			"builder": map[string]any{
+				"queryData": []any{
+					map[string]any{
+						"queryName":    "A",
+						"expression":   "A",
+						"dataSource":   "metrics",
+						"source":       "meter",
+						"aggregations": []any{map[string]any{"metricName": "signoz.meter.log.size", "spaceAggregation": "sum"}},
+					},
+				},
+			},
+		},
+	}
+
+	queries := (&v1Decoder{}).convertV1WidgetQuery(widget, PanelKindTimeSeries)
+	require.Len(t, queries, 1)
+
+	wrapper, ok := queries[0].Spec.Plugin.Spec.(*BuilderQuerySpec)
+	require.True(t, ok)
+	spec, ok := wrapper.Spec.(qb.QueryBuilderQuery[qb.MetricAggregation])
+	require.True(t, ok, "meter query should dispatch to MetricAggregation, got %T", wrapper.Spec)
+
+	assert.Equal(t, telemetrytypes.SignalMetrics, spec.Signal, "signal maps from dataSource")
+	assert.Equal(t, telemetrytypes.SourceMeter, spec.Source, "meter source carried onto the v5 spec")
+}
+
 func TestConvertV1WidgetQueryInjectsCountForNoopOnAggregationPanel(t *testing.T) {
 	// A logs query with the list-style "noop" operator placed on an aggregation
 	// panel (graph). createAggregationsShapeSafe drops noop, leaving no aggregation;