fix: generated semconv helpers skipping attributes

CHANGELOG.md

@@ -17,6 +17,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 ### Fixed
 
 - Fix missing `request.GetBody` in `go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp` to correctly handle HTTP2 GOAWAY frame. (#7931)
+- Fix semconv v1.39.0 generated metric helpers skipping required attributes when extra attributes were empty. (#7964)
 
 ### Removed
 

semconv/templates/registry/go/instrument.j2

@@ -116,7 +116,15 @@ func (m {{ name }}) Add(
 {{ params(metric.attributes, pkg=pkg, prefix="\t") }}
 ) {
 	if len(attrs) == 0 {
+{%- if req_attr | length > 0 %}
+		m.{{ inst }}.Add(ctx, incr, metric.WithAttributes(
+{%- for attr in req_attr %}
+			{{ to_attribute(attr, pkg) }}
+{%- endfor %}
+		))
+{%- else %}
 		m.{{ inst }}.Add(ctx, incr)
+{%- endif %}
 		return
 	}
 
@@ -201,7 +209,15 @@ func (m {{ name }}) Record(
 {{ params(metric.attributes, pkg=pkg, prefix="\t") }}
 ) {
 	if len(attrs) == 0 {
+{%- if req_attr | length > 0 %}
+		m.{{ inst }}.Record(ctx, val, metric.WithAttributes(
+{%- for attr in req_attr %}
+			{{ to_attribute(attr, pkg) }}
+{%- endfor %}
+		))
+{%- else %}
 		m.{{ inst }}.Record(ctx, val)
+{%- endif %}
 		return
 	}