Fix for ScriptUtils failure when '--' occurs inside a multi-line comment on the same line as '*/' (#22392)

* Test for multi-line comment block where the comment end delimiter occurs on a line starting with the single-line comment prefix
* ScriptUtils successfully parses a SQL script containing a multi-line comment block where the comment-end delimiter occurs on a line starting with the single-line comment prefix.

spring-jdbc/src/main/java/org/springframework/jdbc/datasource/init/ScriptUtils.java

@@ -259,7 +259,7 @@ public abstract class ScriptUtils {
 	 * @throws IOException in case of I/O errors
 	 */
 	static String readScript(EncodedResource resource) throws IOException {
-		return readScript(resource, DEFAULT_COMMENT_PREFIX, DEFAULT_STATEMENT_SEPARATOR);
+		return readScript(resource, DEFAULT_COMMENT_PREFIX, DEFAULT_STATEMENT_SEPARATOR, DEFAULT_BLOCK_COMMENT_END_DELIMITER);
 	}
 
 	/**
@@ -273,15 +273,16 @@ public abstract class ScriptUtils {
 	 * @param commentPrefix the prefix that identifies comments in the SQL script —
 	 * typically "--"
 	 * @param separator the statement separator in the SQL script — typically ";"
+	 * @param blockCommentEndDelimiter the <em>end</em> block comment delimiter
 	 * @return a {@code String} containing the script lines
 	 * @throws IOException in case of I/O errors
 	 */
 	private static String readScript(EncodedResource resource, @Nullable String commentPrefix,
-			@Nullable String separator) throws IOException {
+									 @Nullable String separator, @Nullable String blockCommentEndDelimiter) throws IOException {
 
 		LineNumberReader lnr = new LineNumberReader(resource.getReader());
 		try {
-			return readScript(lnr, commentPrefix, separator);
+			return readScript(lnr, commentPrefix, separator, blockCommentEndDelimiter);
 		}
 		finally {
 			lnr.close();
@@ -297,19 +298,21 @@ public abstract class ScriptUtils {
 	 * a statement &mdash; will be included in the results.
 	 * @param lineNumberReader the {@code LineNumberReader} containing the script
 	 * to be processed
-	 * @param commentPrefix the prefix that identifies comments in the SQL script &mdash;
+	 * @param lineCommentPrefix the prefix that identifies comments in the SQL script &mdash;
 	 * typically "--"
 	 * @param separator the statement separator in the SQL script &mdash; typically ";"
+	 * @param blockCommentEndDelimiter the <em>end</em> block comment delimiter
 	 * @return a {@code String} containing the script lines
 	 * @throws IOException in case of I/O errors
 	 */
-	public static String readScript(LineNumberReader lineNumberReader, @Nullable String commentPrefix,
+	public static String readScript(LineNumberReader lineNumberReader, @Nullable String lineCommentPrefix,
-			@Nullable String separator) throws IOException {
+									@Nullable String separator, @Nullable String blockCommentEndDelimiter) throws IOException {
 
 		String currentStatement = lineNumberReader.readLine();
 		StringBuilder scriptBuilder = new StringBuilder();
 		while (currentStatement != null) {
-			if (commentPrefix != null && !currentStatement.startsWith(commentPrefix)) {
+			if ((blockCommentEndDelimiter != null && currentStatement.contains(blockCommentEndDelimiter)) ||
+				(lineCommentPrefix != null && !currentStatement.startsWith(lineCommentPrefix))) {
 				if (scriptBuilder.length() > 0) {
 					scriptBuilder.append('\n');
 				}
@@ -460,7 +463,7 @@ public abstract class ScriptUtils {
 
 			String script;
 			try {
-				script = readScript(resource, commentPrefix, separator);
+				script = readScript(resource, commentPrefix, separator, blockCommentEndDelimiter);
 			}
 			catch (IOException ex) {
 				throw new CannotReadScriptException(resource, ex);

spring-jdbc/src/test/java/org/springframework/jdbc/datasource/init/ScriptUtilsUnitTests.java

@@ -162,6 +162,20 @@ public class ScriptUtilsUnitTests {
 		assertEquals("statement 2 not split correctly", statement2, statements.get(1));
 	}
 
+	@Test
+	public void readAndSplitScriptContainingMultiLineNestedComments() throws Exception {
+		String script = readScript("test-data-with-multi-line-nested-comments.sql");
+		List<String> statements = new ArrayList<>();
+		splitSqlScript(script, ';', statements);
+
+		String statement1 = "INSERT INTO users(first_name, last_name) VALUES('Juergen', 'Hoeller')";
+		String statement2 = "INSERT INTO users(first_name, last_name) VALUES( 'Sam' , 'Brannen' )";
+
+		assertEquals("wrong number of statements", 2, statements.size());
+		assertEquals("statement 1 not split correctly", statement1, statements.get(0));
+		assertEquals("statement 2 not split correctly", statement2, statements.get(1));
+	}
+
 	@Test
 	public void containsDelimiters() {
 		assertFalse(containsSqlScriptDelimiters("select 1\n select ';'", ";"));

spring-jdbc/src/test/resources/org/springframework/jdbc/datasource/init/test-data-with-multi-line-nested-comments.sql

@@ -0,0 +1,23 @@
+/* This is a multi line comment
+ * The next comment line has no text
+
+ * The next comment line starts with a space.
+ *  x, y, z...
+ */
+
+INSERT INTO users(first_name, last_name) VALUES('Juergen', 'Hoeller');
+-- This is also a comment.
+/*-------------------------------------------
+-- A fancy multi-line comments that puts
+-- single line comments inside of a multi-line
+-- comment block.
+Moreover, the block commend end delimiter
+appears on a line that can potentially also
+be a single-line comment if we weren't
+already inside a multi-line comment run.
+-------------------------------------------*/
+ INSERT INTO
+users(first_name, last_name)    -- This is a single line comment containing the block-end-comment sequence here */ but it's still a single-line comment
+VALUES( 'Sam'     -- first_name
+      , 'Brannen' -- last_name
+);--