feat(sdk): add default tracer configuration

[Debashismitra01]

Description

Adds support for setting a default TracerConfig on SdkTracerProviderBuilder.

This provides a way to configure the default behavior of tracers created by the provider without requiring a condition for each instrumentation scope. Scope-specific tracer configurations can still override the default configuration.

Changes

• Add setDefaultTracerConfig(TracerConfig) to SdkTracerProviderBuilder.
• Configure the default tracer behavior through the existing ScopeConfigurator.
• Preserve existing scope-specific configuration behavior.
• Add tests covering the default tracer configuration.

Testing

• SdkTracerProviderBuilderTest
• SdkTracerProviderTest
• OpenTelemetrySdkTest

Fixes #8740

[otelbot]

⚠️ API changes detected — additional maintainer review required

@jack-berg @jkwatson

This PR modifies the public API surface area of the following module(s):

• opentelemetry-sdk-trace

Please review the changes in docs/apidiffs/current_vs_latest/ carefully before approving.

[opentelemetry-pr-dashboard]

Pull request dashboard status

Waiting on the author · refreshed 2026-09-08 22:27 UTC

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.28%. Comparing base (c87b50e) to head (d9f1a79).

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #8772      +/-   ##
============================================
- Coverage     91.29%   91.28%   -0.01%     
- Complexity    10498    10502       +4     
============================================
  Files          1006     1006              
  Lines         28338    28342       +4     
  Branches       3581     3581              
============================================
+ Hits          25870    25873       +3     
- Misses         1675     1676       +1     
  Partials        793      793              

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[jack-berg]

This isn't how we should fix #8740. Instead, we should adjust the SdkTracerProvider behavior to have a noop-like behavior when no processors are registered.