fix map converter (#13972)

instrumentation/spring/spring-boot-autoconfigure/src/main/java/io/opentelemetry/instrumentation/spring/autoconfigure/OpenTelemetryAutoConfiguration.java

@@ -41,6 +41,7 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.DependsOn;
 import org.springframework.core.env.Environment;
 
 /**
@@ -62,18 +63,26 @@ public class OpenTelemetryAutoConfiguration {
 
   public OpenTelemetryAutoConfiguration() {}
 
+  @Bean
+  @ConfigurationPropertiesBinding
+  OtelMapConverter otelMapConverter() {
+    // This is needed for otlp exporter headers and OtelResourceProperties.
+
+    // We need this converter, even if the SDK is disabled,
+    // because the properties are parsed before the SDK is disabled.
+
+    // We also need this converter if the OpenTelemetry bean is user supplied,
+    // because the environment variables may still contain a value that needs to be converted,
+    // even if the SDK is disabled (and the value thus ignored).
+    return new OtelMapConverter();
+  }
+
   @Configuration
   @Conditional(SdkEnabled.class)
+  @DependsOn("otelMapConverter")
   @ConditionalOnMissingBean(OpenTelemetry.class)
   static class OpenTelemetrySdkConfig {
 
-    @Bean
-    @ConfigurationPropertiesBinding
-    public OtelMapConverter otelMapConverter() {
-      // needed for otlp exporter headers and OtelResourceProperties
-      return new OtelMapConverter();
-    }
-
     @Bean
     public OpenTelemetrySdkComponentLoader openTelemetrySdkComponentLoader(
         ApplicationContext applicationContext) {
@@ -139,21 +148,10 @@ public class OpenTelemetryAutoConfiguration {
   }
 
   @Configuration
+  @DependsOn("otelMapConverter")
   @ConditionalOnMissingBean(OpenTelemetry.class)
   @ConditionalOnProperty(name = "otel.sdk.disabled", havingValue = "true")
   static class DisabledOpenTelemetrySdkConfig {
-
-    @Bean
-    @ConfigurationPropertiesBinding
-    // Duplicated in OpenTelemetrySdkConfig and DisabledOpenTelemetrySdkConfig to not expose the
-    // converter in the public API
-    public OtelMapConverter otelMapConverter() {
-      // needed for otlp exporter headers and OtelResourceProperties
-      // we need this converter, even if the SDK is disabled,
-      // because the properties are parsed before the SDK is disabled
-      return new OtelMapConverter();
-    }
-
     @Bean
     public OpenTelemetry openTelemetry() {
       logger.info("OpenTelemetry Spring Boot starter has been disabled");

instrumentation/spring/spring-boot-autoconfigure/src/test/java/io/opentelemetry/instrumentation/spring/autoconfigure/internal/properties/SpringConfigPropertiesTest.java

@@ -8,6 +8,7 @@ package io.opentelemetry.instrumentation.spring.autoconfigure.internal.propertie
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.entry;
 
+import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.instrumentation.spring.autoconfigure.OpenTelemetryAutoConfiguration;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
 import io.opentelemetry.sdk.autoconfigure.spi.internal.DefaultConfigProperties;
@@ -77,6 +78,19 @@ class SpringConfigPropertiesTest {
                     .containsExactly(entry("a", "1"), entry("b", "2")));
   }
 
+  @ParameterizedTest
+  @MethodSource("headerKeys")
+  @DisplayName("should map headers from spring properties with user supplied OpenTelemetry bean")
+  void mapFlatHeadersWithUserSuppliedOtelBean(String key) {
+    this.contextRunner
+        .withSystemProperties(key + "=a=1,b=2")
+        .withBean(OpenTelemetry.class, OpenTelemetry::noop)
+        .run(
+            context ->
+                assertThat(getConfig(context).getMap(key))
+                    .containsExactly(entry("a", "1"), entry("b", "2")));
+  }
+
   @ParameterizedTest
   @MethodSource("headerKeys")
   @DisplayName("should map headers from spring application.yaml")