Add multi-prefix comment support for SQL scripts

Update `ResourceDatabasePopulator` and `ScriptUtils` so that more than
one comment prefix can be used when processing SQL scripts. This
feature is particularly useful when dealing with scripts provided by
Quartz since they often use a mix `--` and `#`.

Closes gh-23289

Author: philwebb

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

@@ -60,7 +60,7 @@ public class ResourceDatabasePopulator implements DatabasePopulator {
 
 	private String separator = ScriptUtils.DEFAULT_STATEMENT_SEPARATOR;
 
-	private String commentPrefix = ScriptUtils.DEFAULT_COMMENT_PREFIX;
+	private String[] commentPrefixes = ScriptUtils.DEFAULT_COMMENT_PREFIXES;
 
 	private String blockCommentStartDelimiter = ScriptUtils.DEFAULT_BLOCK_COMMENT_START_DELIMITER;
 
@@ -171,9 +171,22 @@ public void setSeparator(String separator) {
 	 * Set the prefix that identifies single-line comments within the SQL scripts.
 	 * <p>Defaults to {@code "--"}.
 	 * @param commentPrefix the prefix for single-line comments
+	 * @see #setCommentPrefixes(String...)
 	 */
 	public void setCommentPrefix(String commentPrefix) {
-		this.commentPrefix = commentPrefix;
+		Assert.hasText(commentPrefix, "CommentPrefix must not be null or empty");
+		this.commentPrefixes = new String[] { commentPrefix };
+	}
+
+	/**
+	 * Set the prefixes that identify single-line comments within the SQL scripts.
+	 * <p>Defaults to {@code "--"}.
+	 * @param commentPrefixes the prefixes for single-line comments
+	 * @since 5.2
+	 */
+	public void setCommentPrefixes(String... commentPrefixes) {
+		Assert.notNull(commentPrefixes, "CommentPrefixes must not be null");
+		this.commentPrefixes = commentPrefixes;
 	}
 
 	/**
@@ -236,7 +249,7 @@ public void populate(Connection connection) throws ScriptException {
 		for (Resource script : this.scripts) {
 			EncodedResource encodedScript = new EncodedResource(script, this.sqlScriptEncoding);
 			ScriptUtils.executeSqlScript(connection, encodedScript, this.continueOnError, this.ignoreFailedDrops,
-					this.commentPrefix, this.separator, this.blockCommentStartDelimiter, this.blockCommentEndDelimiter);
+					this.commentPrefixes, this.separator, this.blockCommentStartDelimiter, this.blockCommentEndDelimiter);
 		}
 	}
 

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

@@ -80,6 +80,12 @@ public abstract class ScriptUtils {
 	 */
 	public static final String DEFAULT_COMMENT_PREFIX = "--";
 
+	/**
+	 * Default prefixes for single-line comments within SQL scripts: {@code ["--"]}.
+	 * @since 5.2
+	 */
+	public static final String[] DEFAULT_COMMENT_PREFIXES = { DEFAULT_COMMENT_PREFIX };
+
 	/**
 	 * Default start delimiter for block comments within SQL scripts: {@code "/*"}.
 	 */
@@ -170,9 +176,46 @@ public static void splitSqlScript(@Nullable EncodedResource resource, String scr
 			String separator, String commentPrefix, String blockCommentStartDelimiter,
 			String blockCommentEndDelimiter, List<String> statements) throws ScriptException {
 
+		Assert.hasText(commentPrefix, "'commentPrefix' must not be null or empty");
+		splitSqlScript(resource, script, separator, new String[] { commentPrefix },
+				blockCommentStartDelimiter, blockCommentEndDelimiter, statements);
+	}
+
+	/**
+	 * Split an SQL script into separate statements delimited by the provided
+	 * separator string. Each individual statement will be added to the provided
+	 * {@code List}.
+	 * <p>Within the script, the provided {@code commentPrefix} will be honored:
+	 * any text beginning with the comment prefix and extending to the end of the
+	 * line will be omitted from the output. Similarly, the provided
+	 * {@code blockCommentStartDelimiter} and {@code blockCommentEndDelimiter}
+	 * delimiters will be honored: any text enclosed in a block comment will be
+	 * omitted from the output. In addition, multiple adjacent whitespace characters
+	 * will be collapsed into a single space.
+	 * @param resource the resource from which the script was read
+	 * @param script the SQL script
+	 * @param separator text separating each statement
+	 * (typically a ';' or newline character)
+	 * @param commentPrefixes the prefixes that identify SQL line comments
+	 * (typically "--")
+	 * @param blockCommentStartDelimiter the <em>start</em> block comment delimiter;
+	 * never {@code null} or empty
+	 * @param blockCommentEndDelimiter the <em>end</em> block comment delimiter;
+	 * never {@code null} or empty
+	 * @param statements the list that will contain the individual statements
+	 * @throws ScriptException if an error occurred while splitting the SQL script
+	 * @since 5.2
+	 */
+	public static void splitSqlScript(@Nullable EncodedResource resource, String script,
+			String separator, String[] commentPrefixes, String blockCommentStartDelimiter,
+			String blockCommentEndDelimiter, List<String> statements) throws ScriptException {
+
 		Assert.hasText(script, "'script' must not be null or empty");
 		Assert.notNull(separator, "'separator' must not be null");
-		Assert.hasText(commentPrefix, "'commentPrefix' must not be null or empty");
+		Assert.notNull(commentPrefixes, "'commentPrefixes' must not be null");
+		for (int i = 0; i < commentPrefixes.length; i++) {
+			Assert.hasText(commentPrefixes[i], "'commentPrefixes' must not contain null or empty elements");
+		}
 		Assert.hasText(blockCommentStartDelimiter, "'blockCommentStartDelimiter' must not be null or empty");
 		Assert.hasText(blockCommentEndDelimiter, "'blockCommentEndDelimiter' must not be null or empty");
 
@@ -210,7 +253,7 @@ else if (!inSingleQuote && (c == '"')) {
 					i += separator.length() - 1;
 					continue;
 				}
-				else if (script.startsWith(commentPrefix, i)) {
+				else if (startsWithAny(script, commentPrefixes, i)) {
 					// Skip over any content from the start of the comment to the EOL
 					int indexOfNextNewline = script.indexOf('\n', i);
 					if (indexOfNextNewline > i) {
@@ -260,7 +303,7 @@ else if (c == ' ' || c == '\r' || c == '\n' || c == '\t') {
 	 * @throws IOException in case of I/O errors
 	 */
 	static String readScript(EncodedResource resource) throws IOException {
-		return readScript(resource, DEFAULT_COMMENT_PREFIX, DEFAULT_STATEMENT_SEPARATOR, DEFAULT_BLOCK_COMMENT_END_DELIMITER);
+		return readScript(resource, DEFAULT_COMMENT_PREFIXES, DEFAULT_STATEMENT_SEPARATOR, DEFAULT_BLOCK_COMMENT_END_DELIMITER);
 	}
 
 	/**
@@ -271,19 +314,19 @@ static String readScript(EncodedResource resource) throws IOException {
 	 * a statement &mdash; will be included in the results.
 	 * @param resource the {@code EncodedResource} containing the script
 	 * to be processed
-	 * @param commentPrefix the prefix that identifies comments in the SQL script
+	 * @param commentPrefixes 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,
+	private static String readScript(EncodedResource resource, @Nullable String[] commentPrefixes,
 			@Nullable String separator, @Nullable String blockCommentEndDelimiter) throws IOException {
 
 		LineNumberReader lnr = new LineNumberReader(resource.getReader());
 		try {
-			return readScript(lnr, commentPrefix, separator, blockCommentEndDelimiter);
+			return readScript(lnr, commentPrefixes, separator, blockCommentEndDelimiter);
 		}
 		finally {
 			lnr.close();
@@ -309,11 +352,35 @@ private static String readScript(EncodedResource resource, @Nullable String comm
 	public static String readScript(LineNumberReader lineNumberReader, @Nullable String lineCommentPrefix,
 			@Nullable String separator, @Nullable String blockCommentEndDelimiter) throws IOException {
 
+		String[] lineCommentPrefixes = (lineCommentPrefix != null) ? new String[] { lineCommentPrefix } : null;
+		return readScript(lineNumberReader, lineCommentPrefixes, separator, blockCommentEndDelimiter);
+	}
+
+	/**
+	 * Read a script from the provided {@code LineNumberReader}, using the supplied
+	 * comment prefix and statement separator, and build a {@code String} containing
+	 * the lines.
+	 * <p>Lines <em>beginning</em> with the comment prefix are excluded from the
+	 * results; however, line comments anywhere else &mdash; for example, within
+	 * a statement &mdash; will be included in the results.
+	 * @param lineNumberReader the {@code LineNumberReader} containing the script
+	 * to be processed
+	 * @param lineCommentPrefixes the prefixes that identify 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
+	 * @since 5.2
+	 */
+	public static String readScript(LineNumberReader lineNumberReader, @Nullable String[] lineCommentPrefixes,
+			@Nullable String separator, @Nullable String blockCommentEndDelimiter) throws IOException {
+
 		String currentStatement = lineNumberReader.readLine();
 		StringBuilder scriptBuilder = new StringBuilder();
 		while (currentStatement != null) {
 			if ((blockCommentEndDelimiter != null && currentStatement.contains(blockCommentEndDelimiter)) ||
-				(lineCommentPrefix != null && !currentStatement.startsWith(lineCommentPrefix))) {
+				(lineCommentPrefixes != null && !startsWithAny(currentStatement, lineCommentPrefixes, 0))) {
 				if (scriptBuilder.length() > 0) {
 					scriptBuilder.append('\n');
 				}
@@ -340,6 +407,15 @@ private static void appendSeparatorToScriptIfNecessary(StringBuilder scriptBuild
 		}
 	}
 
+	private static boolean startsWithAny(String script, String[] prefixes, int toffset) {
+		for (String prefix : prefixes) {
+			if (script.startsWith(prefix, toffset)) {
+				return true;
+			}
+		}
+		return false;
+	}
+
 	/**
 	 * Does the provided SQL script contain the specified delimiter?
 	 * @param script the SQL script
@@ -454,6 +530,46 @@ public static void executeSqlScript(Connection connection, EncodedResource resou
 			boolean ignoreFailedDrops, String commentPrefix, @Nullable String separator,
 			String blockCommentStartDelimiter, String blockCommentEndDelimiter) throws ScriptException {
 
+		executeSqlScript(connection, resource, continueOnError, ignoreFailedDrops,
+				new String[] { commentPrefix }, separator, blockCommentStartDelimiter,
+				blockCommentEndDelimiter);
+	}
+
+	/**
+	 * Execute the given SQL script.
+	 * <p>Statement separators and comments will be removed before executing
+	 * individual statements within the supplied script.
+	 * <p><strong>Warning</strong>: this method does <em>not</em> release the
+	 * provided {@link Connection}.
+	 * @param connection the JDBC connection to use to execute the script; already
+	 * configured and ready to use
+	 * @param resource the resource (potentially associated with a specific encoding)
+	 * to load the SQL script from
+	 * @param continueOnError whether or not to continue without throwing an exception
+	 * in the event of an error
+	 * @param ignoreFailedDrops whether or not to continue in the event of specifically
+	 * an error on a {@code DROP} statement
+	 * @param commentPrefixes the prefixes that identify single-line comments in the
+	 * SQL script (typically "--")
+	 * @param separator the script statement separator; defaults to
+	 * {@value #DEFAULT_STATEMENT_SEPARATOR} if not specified and falls back to
+	 * {@value #FALLBACK_STATEMENT_SEPARATOR} as a last resort; may be set to
+	 * {@value #EOF_STATEMENT_SEPARATOR} to signal that the script contains a
+	 * single statement without a separator
+	 * @param blockCommentStartDelimiter the <em>start</em> block comment delimiter
+	 * @param blockCommentEndDelimiter the <em>end</em> block comment delimiter
+	 * @throws ScriptException if an error occurred while executing the SQL script
+	 * @since 5.2
+	 * @see #DEFAULT_STATEMENT_SEPARATOR
+	 * @see #FALLBACK_STATEMENT_SEPARATOR
+	 * @see #EOF_STATEMENT_SEPARATOR
+	 * @see org.springframework.jdbc.datasource.DataSourceUtils#getConnection
+	 * @see org.springframework.jdbc.datasource.DataSourceUtils#releaseConnection
+	 */
+	public static void executeSqlScript(Connection connection, EncodedResource resource, boolean continueOnError,
+			boolean ignoreFailedDrops, String[] commentPrefixes, @Nullable String separator,
+			String blockCommentStartDelimiter, String blockCommentEndDelimiter) throws ScriptException {
+
 		try {
 			if (logger.isDebugEnabled()) {
 				logger.debug("Executing SQL script from " + resource);
@@ -462,7 +578,7 @@ public static void executeSqlScript(Connection connection, EncodedResource resou
 
 			String script;
 			try {
-				script = readScript(resource, commentPrefix, separator, blockCommentEndDelimiter);
+				script = readScript(resource, commentPrefixes, separator, blockCommentEndDelimiter);
 			}
 			catch (IOException ex) {
 				throw new CannotReadScriptException(resource, ex);
@@ -476,7 +592,7 @@ public static void executeSqlScript(Connection connection, EncodedResource resou
 			}
 
 			List<String> statements = new ArrayList<>();
-			splitSqlScript(resource, script, separator, commentPrefix, blockCommentStartDelimiter,
+			splitSqlScript(resource, script, separator, commentPrefixes, blockCommentStartDelimiter,
 					blockCommentEndDelimiter, statements);
 
 			int stmtNumber = 0;

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

@@ -25,6 +25,9 @@
 import org.springframework.core.io.support.EncodedResource;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.jdbc.datasource.init.ScriptUtils.DEFAULT_BLOCK_COMMENT_END_DELIMITER;
+import static org.springframework.jdbc.datasource.init.ScriptUtils.DEFAULT_BLOCK_COMMENT_START_DELIMITER;
+import static org.springframework.jdbc.datasource.init.ScriptUtils.DEFAULT_COMMENT_PREFIXES;
 import static org.springframework.jdbc.datasource.init.ScriptUtils.DEFAULT_STATEMENT_SEPARATOR;
 import static org.springframework.jdbc.datasource.init.ScriptUtils.containsSqlScriptDelimiters;
 import static org.springframework.jdbc.datasource.init.ScriptUtils.splitSqlScript;
@@ -117,18 +120,25 @@ public void readAndSplitScriptWithMultipleNewlinesAsSeparator() throws Exception
 	@Test
 	public void readAndSplitScriptContainingComments() throws Exception {
 		String script = readScript("test-data-with-comments.sql");
-		splitScriptContainingComments(script);
+		splitScriptContainingComments(script, DEFAULT_COMMENT_PREFIXES);
 	}
 
 	@Test
 	public void readAndSplitScriptContainingCommentsWithWindowsLineEnding() throws Exception {
 		String script = readScript("test-data-with-comments.sql").replaceAll("\n", "\r\n");
-		splitScriptContainingComments(script);
+		splitScriptContainingComments(script, DEFAULT_COMMENT_PREFIXES);
 	}
 
-	private void splitScriptContainingComments(String script) throws Exception {
+	@Test
+	public void readAndSplitScriptContainingCommentsWithMultiplePrefixes() throws Exception {
+		String script = readScript("test-data-with-multi-prefix-comments.sql");
+		splitScriptContainingComments(script, "--", "#", "^");
+	}
+
+	private void splitScriptContainingComments(String script, String... commentPrefixes) throws Exception {
 		List<String> statements = new ArrayList<>();
-		splitSqlScript(script, ';', statements);
+		splitSqlScript(null, script, ";", commentPrefixes, DEFAULT_BLOCK_COMMENT_START_DELIMITER,
+				DEFAULT_BLOCK_COMMENT_END_DELIMITER, statements);
 
 		String statement1 = "insert into customer (id, name) values (1, 'Rod; Johnson'), (2, 'Adrian Collier')";
 		String statement2 = "insert into orders(id, order_date, customer_id) values (1, '2008-01-02', 2)";

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

@@ -0,0 +1,18 @@
+-- The next comment line has no text after the '--' prefix.
+--
+-- The next comment line starts with a space.
+ -- x, y, z...
+
+insert into customer (id, name)
+values	(1, 'Rod; Johnson'), (2, 'Adrian Collier');
+-- This is also a comment.
+insert into orders(id, order_date, customer_id)
+values (1, '2008-01-02', 2);
+# A comment with a different prefix
+insert into orders(id, order_date, customer_id) values (1, '2008-01-02', 2);
+INSERT INTO persons( person_id--
+                   , name)
+^ A comment with yet another different prefix
+VALUES( 1      -- person_id
+      , 'Name' --name
+);--