Fix HttpExporterBuilder.copy() to preserve componentLoader field

[Copilot]

Summary

Fixes a class loader mismatch issue in OtlpHttpMetricExporter.toBuilder() where the HttpExporterBuilder.copy() method was not preserving the componentLoader field, causing new instances to use default values instead of the original configuration.

Problem

When extending OtlpMetricExporterProvider to dynamically inject authentication headers, calling OtlpHttpMetricExporter.toBuilder() caused a class loader mismatch. The issue occurred because:

1. The original exporter was configured with a custom ComponentLoader (e.g., MultipleParentClassLoader in agent scenarios)
2. toBuilder() internally calls HttpExporterBuilder.copy()
3. The copy() method was not preserving the componentLoader field
4. The new builder instance would use the default AgentClassLoader instead
5. This caused the JDK sender to become unavailable, breaking metric export

Example usage that failed before this fix:

public class AuthenticatedOtlpMetricExporterProvider extends OtlpMetricExporterProvider {
    @Override
    public MetricExporter createExporter(ConfigProperties config) {
        ClientCredentialsAuthenticator auth = ...;
        MetricExporter metricExporter = super.createExporter(config);

        if (metricExporter instanceof OtlpHttpMetricExporter) {
            // This would fail with class loader mismatch
            OtlpHttpMetricExporter.Builder otlpHttpBuilder =
                ((OtlpHttpMetricExporter) metricExporter).toBuilder();
            otlpHttpBuilder.setHeaders(auth::getHeaders);
            return otlpHttpBuilder.build();
        }
        // ...
    }
}

Solution

Fixed the HttpExporterBuilder.copy() method to preserve the componentLoader field:

copy.componentLoader = componentLoader;

Note: The executorService field is intentionally not copied to allow each exporter instance to manage its own executor lifecycle.

Testing

Added comprehensive tests to verify the fix:

1. Unit tests in HttpExporterBuilderTest to ensure copy() preserves the componentLoader field
2. Integration test in OtlpHttpMetricExporterBuilderTest to verify toBuilder() works correctly with custom component loaders
3. Regression tests to ensure existing functionality remains intact

The fix ensures that when toBuilder() is called on an OTLP HTTP exporter, the resulting builder maintains the same component loader configuration, preventing class loader mismatches in agent environments.

---

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[trask]

@copilot Don't copy executor service

[trask]

@copilot don't copy over the executor service

[Copilot]

@copilot Don't copy executor service

Done. Removed the executorService copying from HttpExporterBuilder.copy() method and its associated test. Only the componentLoader field is now preserved to fix the class loader mismatch issue. See commit 26f9e7d.

@copilot don't copy over the executor service

Done. Removed the executorService copying from HttpExporterBuilder.copy() method and its associated test. Only the componentLoader field is now preserved to fix the class loader mismatch issue. See commit 26f9e7d.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• dl.google.com
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED --add-opens=java.xml/javax.xml.namespace=ALL-UNNAMED -XX:MaxMetaspaceSize=512m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -cp /home/REDACTED/.gradle/wrapper/dists/gradle-8.14.3-bin/cv11ve7ro1n3o1j4so8xd9n66/gradle-8.14.3/lib/gradle-daemon-main-8.14.3.jar -javaagent:/home/REDACTED/.gradle/wrapper/dists/gradle-8.14.3-bin/cv11ve7ro1n3o1j4so8xd9n66/gradle-8.14.3/lib/agents/gradle-instrumentation-agent-8.14.3.jar org.gradle.launcher.daemon.bootstrap.GradleDaemon 8.14.3 (dns block)
• scans-in.gradle.com
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED --add-opens=java.xml/javax.xml.namespace=ALL-UNNAMED -XX:MaxMetaspaceSize=512m -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -cp /home/REDACTED/.gradle/wrapper/dists/gradle-8.14.3-bin/cv11ve7ro1n3o1j4so8xd9n66/gradle-8.14.3/lib/gradle-daemon-main-8.14.3.jar -javaagent:/home/REDACTED/.gradle/wrapper/dists/gradle-8.14.3-bin/cv11ve7ro1n3o1j4so8xd9n66/gradle-8.14.3/lib/agents/gradle-instrumentation-agent-8.14.3.jar org.gradle.launcher.daemon.bootstrap.GradleDaemon 8.14.3 (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
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[trask]

if there aren't other similar tests for other HttpExporter fields, then remove this

[trask]

why not merge this into above verifyToBuilderPreservesSettings?