Handle multiline subquery removal.

Closes #2582.
Related: #2563, #2557, #2603

Author: c-fraser

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

@@ -78,6 +78,8 @@
  * @author Jędrzej Biedrzycki
  * @author Darin Manica
  * @author Simon Paradies
+ * @author Vladislav Yukharin
+ * @author Chris Fraser
  */
 public abstract class QueryUtils {
 
@@ -103,7 +105,7 @@ public abstract class QueryUtils {
 	private static final Pattern ALIAS_MATCH;
 	private static final Pattern COUNT_MATCH;
 	private static final Pattern STARTS_WITH_PAREN = Pattern.compile("^\\s*\\(");
-	private static final Pattern PARENS_TO_REMOVE = Pattern.compile("(\\(.*\\bfrom\\b[^)]+\\))", CASE_INSENSITIVE);
+	private static final Pattern PARENS_TO_REMOVE = Pattern.compile("(\\(.*\\bfrom\\b[^)]+\\))", CASE_INSENSITIVE | DOTALL | MULTILINE);
 	private static final Pattern PROJECTION_CLAUSE = Pattern.compile("select\\s+(?:distinct\\s+)?(.+)\\s+from",
 			Pattern.CASE_INSENSITIVE);
 

Diff for: src/test/java/org/springframework/data/jpa/repository/query/QueryUtilsUnitTests.java

@@ -45,6 +45,7 @@
  * @author Greg Turnquist
  * @author Jędrzej Biedrzycki
  * @author Darin Manica
+ * @author Chris Fraser
  */
 class QueryUtilsUnitTests {
 
@@ -180,6 +181,56 @@ void testRemoveSubqueries() throws Exception {
 						.isEqualTo("(select u from User u where not exists ( ))");
 	}
 
+	@Test // GH-2581
+	void testRemoveMultilineSubqueries() {
+
+		assertThat(normalizeWhitespace(removeSubqueries("select u from User u\n"
+				+ "    where not exists (\n"
+				+ "        from User u2\n"
+				+ "    )")))
+				.isEqualTo("select u from User u where not exists");
+		assertThat(normalizeWhitespace(removeSubqueries("(\n"
+				+ "    select u from User u \n"
+				+ "        where not exists (\n"
+				+ "            from User u2\n"
+				+ "        )\n"
+				+ ")")))
+				.isEqualTo("( select u from User u where not exists )");
+		assertThat(normalizeWhitespace(
+				removeSubqueries("select u from User u \n"
+						+ "    where not exists (\n"
+						+ "        from User u2 \n"
+						+ "            where not exists (\n"
+						+ "                from User u3\n"
+						+ "            )\n"
+						+ "    )")))
+				.isEqualTo("select u from User u where not exists");
+		assertThat(normalizeWhitespace(
+				removeSubqueries("select u from User u \n"
+						+ "    where not exists (\n"
+						+ "        (\n"
+						+ "            from User u2 \n"
+						+ "                where not exists (\n"
+						+ "                    from User u3\n"
+						+ "                )\n"
+						+ "        )\n"
+						+ "    )")))
+				.isEqualTo("select u from User u where not exists ( )");
+		assertThat(normalizeWhitespace(
+				removeSubqueries("(\n"
+						+ "    select u from User u \n"
+						+ "        where not exists (\n"
+						+ "            (\n"
+						+ "                from User u2 \n"
+						+ "                    where not exists (\n"
+						+ "                        from User u3\n"
+						+ "                    )\n"
+						+ "            )\n"
+						+ "        )\n"
+						+ ")")))
+				.isEqualTo("( select u from User u where not exists ( ) )");
+	}
+
 	private String normalizeWhitespace(String s) {
 		Matcher matcher = MULTI_WHITESPACE.matcher(s);
 		if (matcher.find()) {