Spec compliance: OTEL_PROPAGATORS should still work when OTEL_SDK_DISABLED=false

Author: mikeblum

sdk-extensions/autoconfigure/src/main/java/io/opentelemetry/sdk/autoconfigure/AutoConfiguredOpenTelemetrySdkBuilder.java

@@ -443,7 +443,13 @@ public AutoConfiguredOpenTelemetrySdk build() {
     List<Closeable> closeables = new ArrayList<>();
 
     try {
-      OpenTelemetrySdk openTelemetrySdk = OpenTelemetrySdk.builder().build();
+      OpenTelemetrySdkBuilder sdkBuilder = OpenTelemetrySdk.builder();
+
+      // The propagation system is part of the API and functions in the absence of an SDK.
+      ContextPropagators propagators =
+          PropagatorConfiguration.configurePropagators(config, spiHelper, propagatorCustomizer);
+      sdkBuilder.setPropagators(propagators);
+
       boolean sdkEnabled = !config.getBoolean("otel.sdk.disabled", false);
 
       if (sdkEnabled) {
@@ -489,19 +495,14 @@ public AutoConfiguredOpenTelemetrySdk build() {
         SdkLoggerProvider loggerProvider = loggerProviderBuilder.build();
         closeables.add(loggerProvider);
 
-        ContextPropagators propagators =
-            PropagatorConfiguration.configurePropagators(config, spiHelper, propagatorCustomizer);
-
-        OpenTelemetrySdkBuilder sdkBuilder =
-            OpenTelemetrySdk.builder()
-                .setTracerProvider(tracerProvider)
-                .setLoggerProvider(loggerProvider)
-                .setMeterProvider(meterProvider)
-                .setPropagators(propagators);
-
-        openTelemetrySdk = sdkBuilder.build();
+        sdkBuilder
+            .setTracerProvider(tracerProvider)
+            .setLoggerProvider(loggerProvider)
+            .setMeterProvider(meterProvider);
       }
 
+      OpenTelemetrySdk openTelemetrySdk = sdkBuilder.build();
+
       maybeRegisterShutdownHook(openTelemetrySdk);
       maybeSetAsGlobal(openTelemetrySdk);
       callAutoConfigureListeners(spiHelper, openTelemetrySdk);

sdk-extensions/autoconfigure/src/test/java/io/opentelemetry/sdk/autoconfigure/AutoConfiguredOpenTelemetrySdkTest.java

@@ -67,6 +67,7 @@
 import java.util.Properties;
 import java.util.concurrent.TimeUnit;
 import java.util.function.BiFunction;
+import java.util.function.Consumer;
 import java.util.function.Supplier;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -455,6 +456,39 @@ void disableSdk() {
     verify(logCustomizer, never()).apply(any(), any());
   }
 
+  @Test
+  void disableSdk_PropagatorCustomizer() {
+    Context extracted = Context.root().with(ContextKey.named("animal"), "bear");
+
+    when(propagator2.extract(any(), any(), any())).thenReturn(extracted);
+
+    AutoConfiguredOpenTelemetrySdk autoConfiguredSdk =
+        AutoConfiguredOpenTelemetrySdk.builder()
+            .addPropertiesSupplier(() -> singletonMap("otel.sdk.disabled", "true"))
+            .addPropertiesSupplier(() -> singletonMap("otel.propagators", "tracecontext"))
+            .addPropagatorCustomizer(
+                (previous, config) -> {
+                  assertThat(previous).isSameAs(W3CTraceContextPropagator.getInstance());
+                  return propagator1;
+                })
+            .addPropagatorCustomizer(
+                (previous, config) -> {
+                  assertThat(previous).isSameAs(propagator1);
+                  return propagator2;
+                })
+            .build();
+
+    // When the SDK is disabled, propagators are still configured
+    assertThat(autoConfiguredSdk.getOpenTelemetrySdk().getPropagators()).isNotNull();
+    Consumer<TextMapPropagator> propagatorConsumer =
+        propagator -> {
+          assertThat(propagator.extract(Context.root(), Collections.emptyMap(), getter))
+              .isEqualTo(extracted);
+        };
+    assertThat(autoConfiguredSdk.getOpenTelemetrySdk().getPropagators().getTextMapPropagator())
+        .isInstanceOfSatisfying(TextMapPropagator.class, propagatorConsumer);
+  }
+
   @Test
   void tracerProviderCustomizer() {
     InMemorySpanExporter spanExporter = InMemorySpanExporter.create();