Support backticks for quoted identifiers in spring-r2dbc

NamedParameterUtils in spring-r2dbc now supports MySQL-style backticks
for quoted identifiers for consistency with spring-jdbc.

See gh-31944
Closes gh-32285

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

@@ -56,12 +56,12 @@ abstract class NamedParameterUtils {
 	/**
 	 * Set of characters that qualify as comment or quote starting characters.
 	 */
-	private static final String[] START_SKIP = {"'", "\"", "--", "/*"};
+	private static final String[] START_SKIP = {"'", "\"", "--", "/*", "`"};
 
 	/**
 	 * Set of characters that are the corresponding comment or quote ending characters.
 	 */
-	private static final String[] STOP_SKIP = {"'", "\"", "\n", "*/"};
+	private static final String[] STOP_SKIP = {"'", "\"", "\n", "*/", "`"};
 
 	/**
 	 * Set of characters that qualify as parameter separators,

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

@@ -251,6 +251,7 @@ void variableAssignmentOperator() {
 			"SELECT /*:doo*/':foo', :xxx FROM DUAL",
 			"SELECT ':foo'/*:doo*/, :xxx FROM DUAL",
 			"SELECT \":foo\"\":doo\", :xxx FROM DUAL",
+			"SELECT `:foo``:doo`, :xxx FROM DUAL"
 		})
 	void parseSqlStatementWithParametersInsideQuotesAndComments(String sql) {
 		ParsedSql parsedSql = NamedParameterUtils.parseSqlStatement(sql);
@@ -289,6 +290,14 @@ void namedParamMapReference() {
 		assertThat(psql.getParameterNames()).containsExactly("headers[id]");
 	}
 
+	@Test  // gh-31944 / gh-32285
+	void parseSqlStatementWithBackticks() {
+		String sql = "select * from `tb&user` where id = :id";
+		ParsedSql parsedSql = NamedParameterUtils.parseSqlStatement(sql);
+		assertThat(parsedSql.getParameterNames()).containsExactly("id");
+		assertThat(expand(parsedSql)).isEqualTo("select * from `tb&user` where id = $1");
+	}
+
 	@Test
 	void shouldAllowParsingMultipleUseOfParameter() {
 		String sql = "SELECT * FROM person where name = :id or lastname = :id";