Fix empty and commented lines within script execution #1315 #1316

Signed-off-by: David Pilar <david@czpilar.net>

Author: czpilar

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

@@ -19,6 +19,7 @@
 import java.io.*;
 
 import org.jspecify.annotations.Nullable;
+import org.springframework.util.StringUtils;
 
 /**
  * An {@link InputProvider} that reads input from a file.
@@ -59,9 +60,12 @@ public FileInputProvider(File file) throws FileNotFoundException {
 			sb.append(line.replaceFirst(BACKSLASH_AT_EOL_REGEX, "$1 "));
 		}
 		while (continued);
-		if (line == null || isComment(line)) {
+		if (line == null) {
 			return null;
 		}
+		else if (!StringUtils.hasLength(line) || isComment(line)) {
+			return readInput();
+		}
 		else {
 			return sb.toString();
 		}

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

@@ -0,0 +1,40 @@
+package org.springframework.shell.core;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.CleanupMode;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.File;
+import java.nio.file.Files;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+class FileInputProviderTests {
+
+	@TempDir(cleanup = CleanupMode.ALWAYS)
+	private File tempDir;
+
+	@Test
+	void testReadInput() throws Exception {
+		// given
+		File inputFile = new File(tempDir, "input.txt");
+		String inputContent = """
+				echo Hello World
+				// This is a comment
+				echo Line 1\\
+				Line 2
+
+				echo Line 3""";
+		Files.writeString(inputFile.toPath(), inputContent);
+
+		// when & then
+		try (FileInputProvider inputProvider = new FileInputProvider(inputFile)) {
+			assertEquals("echo Hello World", inputProvider.readInput());
+			assertEquals("echo Line 1 Line 2", inputProvider.readInput());
+			assertEquals("echo Line 3", inputProvider.readInput());
+			assertNull(inputProvider.readInput());
+		}
+	}
+
+}