3.4.x: Fix empty and commented lines within script execution -> 3.4.x

spring-shell-core/src/main/java/org/springframework/shell/jline/FileInputProvider.java

@@ -20,6 +20,7 @@
 import org.jline.reader.Parser;
 import org.springframework.shell.Input;
 import org.springframework.shell.InputProvider;
+import org.springframework.util.StringUtils;
 
 import java.io.BufferedReader;
 import java.io.Closeable;
@@ -33,6 +34,7 @@
  * of line to signal line continuation.</p>
  *
  * @author Eric Bottard
+ * @author David Pilar
  */
 public class FileInputProvider implements InputProvider, Closeable {
 
@@ -63,9 +65,13 @@ public Input readInput() {
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
-        if (line == null || isComment(line)) {
+        if (line == null) {
             return null;
-        } else {
+        }
+        else if (!StringUtils.hasLength(line) || isComment(line)) {
+            return readInput();
+        }
+        else {
 			ParsedLine parsedLine = parser.parse(sb.toString(), sb.toString().length());
 			return new ParsedLineInput(parsedLine);
         }

spring-shell-core/src/test/java/org/springframework/shell/jline/FileInputProviderTests.java

@@ -17,15 +17,20 @@
 
 import org.jline.reader.EOFError;
 import org.jline.reader.impl.DefaultParser;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
+import org.springframework.shell.Input;
+
 import java.io.Reader;
 import java.io.StringReader;
 import java.util.stream.Stream;
 
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
@@ -98,4 +103,27 @@ void shouldNotThrowOnUnclosedQuoteExtendedParser(String line) {
 			fileInputProvider.readInput();
 		});
 	}
+
+	@Test
+	void shouldSkipEmptyAndCommentedLines() {
+		String inputContent = """
+				echo Hello World
+				// This is a comment
+				echo Line 1\\
+				Line 2
+
+				echo Line 3""";
+		Reader reader = new StringReader(inputContent);
+		fileInputProvider = new FileInputProvider(reader, springParser);
+
+		Input first = fileInputProvider.readInput();
+		Input second = fileInputProvider.readInput();
+		Input third = fileInputProvider.readInput();
+		Input fourth = fileInputProvider.readInput();
+
+		assertEquals("echo Hello World", first.rawText());
+		assertEquals("echo Line 1 Line 2", second.rawText());
+		assertEquals("echo Line 3", third.rawText());
+		assertNull(fourth);
+	}
 }