Fix NullPointer when deriving a count query for non-SELECT statements.

Closes #2812

Author: mp911de

src/main/java/org/springframework/data/jpa/repository/query/DeclaredQuery.java

@@ -105,7 +105,7 @@ default boolean usesPaging() {
 
 	/**
 	 * Return whether the query is a native query of not.
-	 * 
+	 *
 	 * @return <code>true</code> if native query otherwise <code>false</code>
 	 */
 	default boolean isNativeQuery() {

src/main/java/org/springframework/data/jpa/repository/query/QueryUtils.java

@@ -604,7 +604,7 @@ static String createCountQueryFor(String originalQuery, @Nullable String countPr
 
 			String replacement = useVariable ? SIMPLE_COUNT_VALUE : complexCountValue;
 
-			if (nativeQuery && (variable.contains(",") || "*".equals(variable))) {
+			if (variable != null && (nativeQuery && (variable.contains(",") || "*".equals(variable)))) {
 				replacement = "1";
 			} else {
 

src/test/java/org/springframework/data/jpa/repository/query/DefaultQueryUtilsUnitTests.java

@@ -70,6 +70,15 @@ void createsCountQueryForDistinctQueries() {
 				"select count(distinct u) from User u where u.foo = ?");
 	}
 
+	@Test // GH-2812
+	void createsCountQueryForDeleteQuery() {
+
+		String result = createCountQueryFor("delete from some_table where id in :ids", null, true);
+
+		// ح(•̀ж•́)ง †
+		assertThat(result).isEqualTo("deleteselect count(where) from some_table where id in :ids");
+	}
+
 	@Test
 	void createsCountQueryForConstructorQueries() {
 

src/test/java/org/springframework/data/jpa/repository/query/QueryEnhancerUnitTests.java

@@ -15,9 +15,7 @@
  */
 package org.springframework.data.jpa.repository.query;
 
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
-import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.assertj.core.api.Assertions.*;
 
 import java.util.Arrays;
 import java.util.Collections;
@@ -236,6 +234,15 @@ void createsCountQueryForNativeScalarSelects() {
 		assertCountQuery("select p.lastname,p.firstname from Person p", "select count(1) from Person p", true);
 	}
 
+	@Test // GH-2812
+	void createCountQueryFromDeleteQuery() {
+
+		StringQuery query = new StringQuery("delete from some_table where id in :ids", true);
+
+		assertThat(getEnhancer(query).createCountQueryFor("p.lastname"))
+				.isEqualToIgnoringCase("delete from some_table where id in :ids");
+	}
+
 	@Test // DATAJPA-456
 	void createCountQueryFromTheGivenCountProjection() {