Have user supplied attributes take precedence over exception-derived attributes (#7993)

Author: trask

sdk/logs/src/main/java/io/opentelemetry/sdk/logs/ExtendedSdkLogRecordBuilder.java

@@ -46,7 +46,7 @@ public ExtendedSdkLogRecordBuilder setException(Throwable throwable) {
     loggerSharedState
         .getExceptionAttributeResolver()
         .setExceptionAttributes(
-            this::setAttribute,
+            this::setExceptionAttribute,
             throwable,
             loggerSharedState.getLogLimits().getMaxAttributeValueLength());
 
@@ -144,4 +144,17 @@ protected ReadWriteLogRecord createLogRecord(Context context, long observedTimes
         body,
         extendedAttributes);
   }
+
+  /**
+   * Sets an exception-derived attribute only if it hasn't already been set by the user. This
+   * ensures user-set attributes take precedence over exception-derived attributes.
+   */
+  private <T> void setExceptionAttribute(AttributeKey<T> key, @Nullable T value) {
+    if (key == null || key.getKey().isEmpty() || value == null) {
+      return;
+    }
+    if (extendedAttributes == null || extendedAttributes.get(key) == null) {
+      setAttribute(key, value);
+    }
+  }
 }

sdk/logs/src/testIncubating/java/io/opentelemetry/sdk/logs/ExtendedLoggerBuilderTest.java

@@ -76,4 +76,27 @@ public void setExceptionAttributes(
                         equalTo(EXCEPTION_TYPE, "type"),
                         equalTo(EXCEPTION_STACKTRACE, "stacktrace")));
   }
+
+  @Test
+  void setException_UserAttributesTakePrecedence() {
+    Logger logger = loggerProviderBuilder.build().get("logger");
+
+    ((ExtendedLogRecordBuilder) logger.logRecordBuilder())
+        .setAttribute(EXCEPTION_MESSAGE, "custom message")
+        .setException(new Exception("error"))
+        .emit();
+
+    assertThat(exporter.getFinishedLogRecordItems())
+        .satisfiesExactly(
+            logRecord ->
+                assertThat(logRecord)
+                    .hasAttributesSatisfyingExactly(
+                        equalTo(EXCEPTION_TYPE, "java.lang.Exception"),
+                        equalTo(EXCEPTION_MESSAGE, "custom message"),
+                        satisfies(
+                            EXCEPTION_STACKTRACE,
+                            stacktrace ->
+                                stacktrace.startsWith(
+                                    "java.lang.Exception: error" + System.lineSeparator()))));
+  }
 }