Semconv metric helper caller-slice mutation fix

[MrAlias]

This PR addresses issue #7987 (issue (1)): generated semconv metric helpers should not risk mutating caller-provided attrs backing arrays when required attributes are appended.

Update the generator logic to merge required-attribute using capacity clamping before append:

append(attrs[:len(attrs):len(attrs)], requiredAttrs...)

This guarantees append allocates a new backing array for the merged slice instead of writing into caller memory when there are attributes appended. It makes not allocations in the case attributes are not appended.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.6%. Comparing base (8c91c83) to head (9f707e8).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #7993     +/-   ##
=======================================
- Coverage   81.6%   81.6%   -0.1%     
=======================================
  Files        304     304             
  Lines      23385   23385             
=======================================
- Hits       19093   19089      -4     
- Misses      3905    3907      +2     
- Partials     387     389      +2     

see 2 files with indirect coverage changes

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[Copilot]

Pull request overview

This PR updates the Go semconv metric helper generation to avoid mutating caller-provided attrs backing arrays when required semantic attributes are appended, and includes regenerated v1.40.0 metric helper outputs.

Changes:

• Update the Weaver Go template to cap attrs capacity before appending required attributes (attrs[:len(attrs):len(attrs)]).
• Regenerate affected semconv/v1.40.0/*conv/metric.go files to apply the new append behavior.
• Replace direct append(attrs, ...) patterns with the capacity-clamped variant across the regenerated outputs.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
semconv/templates/registry/go/instrument.j2	Adjusts generated helper attribute merging to avoid mutating caller slices.
semconv/v1.40.0/azureconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/cicdconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/dbconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/dnsconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/genaiconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/httpconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/hwconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/k8sconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/mcpconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/messagingconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/openshiftconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/rpcconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.
semconv/v1.40.0/vcsconv/metric.go	Regenerated to use capacity-clamped attrs before appending required attrs.

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