[cmd/mdatagen] Fix entity extra_attributes emission

Fixes #14778

Fix `mdatagen` entity code generation so `extra_attributes` are emitted
as resource attributes instead of entity descriptive attributes.

Author: dmitryax

.chloggen/fix-mdatagen-entity-builder.yaml

@@ -0,0 +1,4 @@
+change_type: bug_fix
+component: cmd/mdatagen
+note: Fix entity code generation so `extra_attributes` are emitted as resource attributes instead of entity descriptive attributes.
+issues: [14778]

cmd/mdatagen/internal/sampleconnector/internal/metadata/generated_entity_metrics_test.go

@@ -128,11 +128,11 @@ func (e *{{ $entityStructType }}) copyToResource(cfg ResourceAttributesConfig, r
 		{{- $attr := index $resourceAttributes $extraAttr.Ref }}
 		if cfg.{{ publicVar $extraAttr.Ref.Render }}.Enabled {
 			{{- if eq $attr.Type.ValueType.String "Str" }}
-			ent.DescriptiveAttributes().PutStr("{{ $extraAttr.Ref }}", e.{{ $extraAttr.Ref.RenderUnexported }})
+			res.Attributes().PutStr("{{ $extraAttr.Ref }}", e.{{ $extraAttr.Ref.RenderUnexported }})
 			{{- else if or (eq $attr.Type.ValueType.String "Map") (eq $attr.Type.ValueType.String "Slice") (eq $attr.Type.ValueType.String "Bytes") }}
-			ent.DescriptiveAttributes().PutEmpty("{{ $extraAttr.Ref }}").SetEmpty{{ $attr.Type.ValueType }}().FromRaw(e.{{ $extraAttr.Ref.RenderUnexported }})
+			res.Attributes().PutEmpty("{{ $extraAttr.Ref }}").SetEmpty{{ $attr.Type.ValueType }}().FromRaw(e.{{ $extraAttr.Ref.RenderUnexported }})
 			{{- else }}
-			ent.DescriptiveAttributes().PutEmpty("{{ $extraAttr.Ref }}").Set{{ $attr.Type.ValueType }}(e.{{ $extraAttr.Ref.RenderUnexported }})
+			res.Attributes().PutEmpty("{{ $extraAttr.Ref }}").Set{{ $attr.Type.ValueType }}(e.{{ $extraAttr.Ref.RenderUnexported }})
 			{{- end }}
 		}
 		{{- end }}

cmd/mdatagen/internal/sampleentityreceiver/internal/metadata/generated_entity_metrics.go

@@ -97,6 +97,20 @@ func TestEntityBuilders(t *testing.T) {
 		require.True(t, ok)
 		assert.Equal(t, {{ $attr.TestValue }}, attrVal.Str())
 		{{- end }}
+		{{- range $descAttr := $ent.Description }}
+		{{- $attr := index $resourceAttributes $descAttr.Ref }}
+		attrVal, ok := entityVal.DescriptiveAttributes().Get("{{ $descAttr.Ref }}")
+		require.True(t, ok)
+		assert.Equal(t, {{ $attr.TestValue }}, attrVal.Str())
+		{{- end }}
+		{{- range $extraAttr := $ent.ExtraAttributes }}
+		{{- $attr := index $resourceAttributes $extraAttr.Ref }}
+		_, ok = entityVal.DescriptiveAttributes().Get("{{ $extraAttr.Ref }}")
+		assert.False(t, ok)
+		attrVal, ok := rm.Resource().Attributes().Get("{{ $extraAttr.Ref }}")
+		require.True(t, ok)
+		assert.Equal(t, {{ $attr.TestValue }}, attrVal.Str())
+		{{- end }}
 
 		require.Equal(t, 1, rm.ScopeMetrics().Len())
 		ms := rm.ScopeMetrics().At(0).Metrics()