Properly expand reused collection parameters in R2DBC NamedParameterUtils

Prior to this commit, NamedParameterUtils in spring-r2dbc did not
properly expand reused collection parameters. Specifically, values in a
supplied collection were only expanded in the resulting query once, for
the first occurrence of the named parameter.

To address that, this commit effectively reinstates the original logic
for ExpandedQuery from NamedParameterUtils in the Spring Data R2DBC
project.

https://github.com/spring-projects/spring-data-relational/blob/94958f5eb66cbe2e8e025155cd99abf36f6f91f4/spring-data-r2dbc/src/main/java/org/springframework/data/r2dbc/core/NamedParameterUtils.java#L486

Closes gh-34768

Author: sbrannen

spring-r2dbc/src/main/java/org/springframework/r2dbc/core/NamedParameterUtils.java

@@ -49,6 +49,7 @@
  * @author Juergen Hoeller
  * @author Mark Paluch
  * @author Anton Naydenov
+ * @author Sam Brannen
  * @since 5.3
  */
 abstract class NamedParameterUtils {
@@ -545,41 +546,43 @@ public void bindTo(BindTarget target) {
 		}
 
 		private void bindNull(BindTarget target, String identifier, Parameter parameter) {
-			List<BindMarker> bindMarkers = getBindMarkers(identifier);
+			List<List<BindMarker>> bindMarkers = getBindMarkers(identifier);
 			if (bindMarkers == null) {
 				target.bind(identifier, parameter);
 				return;
 			}
-			for (BindMarker bindMarker : bindMarkers) {
-				bindMarker.bind(target, parameter);
+			for (List<BindMarker> outer : bindMarkers) {
+				for (BindMarker bindMarker : outer) {
+					bindMarker.bind(target, parameter);
+				}
 			}
 		}
 
-		@SuppressWarnings({"rawtypes", "unchecked"})
 		private void bind(BindTarget target, String identifier, Parameter parameter) {
-			List<BindMarker> bindMarkers = getBindMarkers(identifier);
+			List<List<BindMarker>> bindMarkers = getBindMarkers(identifier);
 			if (bindMarkers == null) {
 				target.bind(identifier, parameter);
 				return;
 			}
-			if (parameter.getValue() instanceof Collection collection) {
-				Iterator<Object> iterator = collection.iterator();
-				Iterator<BindMarker> markers = bindMarkers.iterator();
-				while (iterator.hasNext()) {
-					Object valueToBind = iterator.next();
-					if (valueToBind instanceof Object[] objects) {
-						for (Object object : objects) {
-							bind(target, markers, object);
+
+			for (List<BindMarker> outer : bindMarkers) {
+				if (parameter.getValue() instanceof Collection<?> collection) {
+					Iterator<BindMarker> markers = outer.iterator();
+					for (Object valueToBind : collection) {
+						if (valueToBind instanceof Object[] objects) {
+							for (Object object : objects) {
+								bind(target, markers, object);
+							}
+						}
+						else {
+							bind(target, markers, valueToBind);
 						}
-					}
-					else {
-						bind(target, markers, valueToBind);
 					}
 				}
-			}
-			else {
-				for (BindMarker bindMarker : bindMarkers) {
-					bindMarker.bind(target, parameter);
+				else {
+					for (BindMarker bindMarker : outer) {
+						bindMarker.bind(target, parameter);
+					}
 				}
 			}
 		}
@@ -592,14 +595,14 @@ private void bind(BindTarget target, Iterator<BindMarker> markers, Object valueT
 		}
 
 		@Nullable
-		private List<BindMarker> getBindMarkers(String identifier) {
+		private List<List<BindMarker>> getBindMarkers(String identifier) {
 			List<NamedParameters.NamedParameter> parameters = this.parameters.getMarker(identifier);
 			if (parameters == null) {
 				return null;
 			}
-			List<BindMarker> markers = new ArrayList<>();
+			List<List<BindMarker>> markers = new ArrayList<>();
 			for (NamedParameters.NamedParameter parameter : parameters) {
-				markers.addAll(parameter.placeholders);
+				markers.add(new ArrayList<>(parameter.placeholders));
 			}
 			return markers;
 		}

spring-r2dbc/src/test/java/org/springframework/r2dbc/core/NamedParameterUtilsTests.java

@@ -21,7 +21,6 @@
 import java.util.Map;
 
 import io.r2dbc.spi.Parameters;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.ValueSource;
@@ -350,7 +349,6 @@ void multipleEqualCollectionParameterReferencesForIndexedMarkersBindsValuesOnce(
 	}
 
 	@Test  // gh-34768
-	@Disabled("Disabled until gh-34768 is addressed")
 	void multipleEqualCollectionParameterReferencesForAnonymousMarkersBindsValuesTwice() {
 		String sql = "SELECT * FROM fund_info WHERE fund_code IN (:fundCodes) OR fund_code IN (:fundCodes)";