Parse commented lines like an empty lines

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

@@ -66,7 +66,13 @@ public Input readInput() {
         if (line == null) {
             return null;
         } else {
-            ParsedLine parsedLine = parser.parse(sb.toString(), sb.toString().length());
+			// gh-277: if it's a commented line then skip as it is equal to NO_INPUT
+			ParsedLine parsedLine;
+			if (isCommentedLine(line)) {
+				parsedLine = parser.parse("", -1, Parser.ParseContext.COMPLETE);
+			} else {
+				parsedLine = parser.parse(sb.toString(), sb.toString().length());
+			}
             return new ParsedLineInput(parsedLine);
         }
     }
@@ -75,4 +81,8 @@ public Input readInput() {
     public void close() throws IOException {
         reader.close();
     }
+
+	private boolean isCommentedLine(String line) {
+		return line.matches("\\s*//.*");
+	}
 }

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

@@ -0,0 +1,83 @@
+package org.springframework.shell.jline;
+
+import org.jline.reader.EOFError;
+import org.jline.reader.impl.DefaultParser;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.io.Reader;
+import java.io.StringReader;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class FileInputProviderTests {
+	private final ExtendedDefaultParser springParser = new ExtendedDefaultParser();
+	private final DefaultParser jlineParser = new DefaultParser();
+	private FileInputProvider fileInputProvider;
+
+	static Stream<Arguments> regularLinesUnclosedQuotes() {
+		return Stream.of(
+				Arguments.of("Regular line with unclosed 'quote"),
+				Arguments.of("Regular line with unclosed \"quote")
+		);
+	}
+
+	static Stream<Arguments> commentsUnclosedQuotes() {
+		return Stream.of(
+				Arguments.of("//Commented line with unclosed 'quote"),
+				Arguments.of("//Commented line with unclosed \"quote")
+		);
+	}
+
+	@ParameterizedTest
+	@MethodSource("regularLinesUnclosedQuotes")
+	void shouldThrowOnUnclosedQuoteDefaultParser(String line) {
+		jlineParser.setEofOnUnclosedQuote(true);
+		Reader reader = new StringReader(line);
+		fileInputProvider = new FileInputProvider(reader, jlineParser);
+		Exception exception = assertThrows(EOFError.class, () -> {
+			fileInputProvider.readInput();
+		});
+		String expectedExceptionMessage = "Missing closing quote";
+		String actualExceptionMessage = exception.getMessage();
+		assertTrue(actualExceptionMessage.contains(expectedExceptionMessage));
+	}
+
+	@ParameterizedTest
+	@MethodSource("regularLinesUnclosedQuotes")
+	void shouldThrowOnUnclosedQuoteExtendedParser(String line) {
+		springParser.setEofOnUnclosedQuote(true);
+		Reader reader = new StringReader(line);
+		fileInputProvider = new FileInputProvider(reader, springParser);
+		Exception exception = assertThrows(EOFError.class, () -> {
+			fileInputProvider.readInput();
+		});
+		String expectedExceptionMessage = "Missing closing quote";
+		String actualExceptionMessage = exception.getMessage();
+		assertTrue(actualExceptionMessage.contains(expectedExceptionMessage));
+	}
+
+	@ParameterizedTest
+	@MethodSource("commentsUnclosedQuotes")
+	void shoulNotThrowOnUnclosedQuoteDefaultParser(String line) {
+		jlineParser.setEofOnUnclosedQuote(true);
+		Reader reader = new StringReader(line);
+		fileInputProvider = new FileInputProvider(reader, jlineParser);
+		assertDoesNotThrow(() -> {
+			fileInputProvider.readInput();
+		});
+	}
+
+	@ParameterizedTest
+	@MethodSource("commentsUnclosedQuotes")
+	void shouldNotThrowOnUnclosedQuoteExtendedParser(String line) {
+		springParser.setEofOnUnclosedQuote(true);
+		Reader reader = new StringReader(line);
+		fileInputProvider = new FileInputProvider(reader, springParser);
+		assertDoesNotThrow(() -> {
+			fileInputProvider.readInput();
+		});
+	}
+}