[thswlsqls]

Fixes #8958

Description

• Otel2PrometheusConverter.convertAttributes() added exemplar trace_id/span_id with putIfAbsent after the filtered attributes, so a filtered attribute with the same label name (trace_id, or trace.id after escaping) replaced the span context ids.
• Use put instead so the span context ids win. Scope and resource labels keep putIfAbsent; only exemplar conversion passes additional attributes.
• Spec: Exemplar Conversion says trace_id/span_id MUST take precedence over filtered attributes (Prometheus: Stabilize OpenTelemetry Exemplar to Prometheus Exemplar opentelemetry-specification#4964).

Testing done

• Added Otel2PrometheusConverterTest#exemplarSpanContextLabelsTakePrecedence with two cases: trace_id/span_id keys and trace.id/span.id keys.
• Before the fix both cases fail (expected: "00000000000000000000000000000001" but was: "bogus"); after the fix both pass.
• ./gradlew :exporters:prometheus:check passed (221 tests, 0 failures, 3 skipped).

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Pull request dashboard status

Merged · refreshed 2026-10-19 19:14 UTC

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.41%. Comparing base (b32298a) to head (2984190).

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #8959   +/-   ##
=========================================
  Coverage     90.40%   90.41%           
- Complexity    10898    10901    +3     
=========================================
  Files          1015     1015           
  Lines         29843    29842    -1     
  Branches       3896     3896           
=========================================
+ Hits          26981    26982    +1     
  Misses         1910     1910           
+ Partials        952      950    -2     

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