Discard empty args

- Take 2 of #763
- Revert changes in 06e89dc
  what comes for `ExtendedDefaultParser`.
- Discard empty args in a `Shell` coming from `ExtendedDefaultParser`
- `ExtendedDefaultParserTests` has more tests, some commented out, to
  see some differences for jline default parser impl. Something
  to get handled in #517

Author: jvalkeal

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

@@ -195,7 +195,9 @@ protected Object evaluate(Input input) {
 			return NO_INPUT;
 		}
 
-		List<String> words = input.words();
+		// List<String> words = input.words();
+		// gh-763
+		List<String> words = input.words().stream().filter(w -> w.length() > 0).collect(Collectors.toList());
 		String line = words.stream().collect(Collectors.joining(" ")).trim();
 		String command = findLongestCommand(line, false);
 

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

@@ -126,12 +126,10 @@ else if (!isEscapeChar(line, i)) {
 		}
 
 		if (current.length() > 0 || (line != null && cursor == line.length())) {
-			if (current.length() > 0) {
-				words.add(current.toString());
-			}
+			words.add(current.toString());
 		}
 
-		if (line != null && cursor == line.length() && words.size() > 0) {
+		if (line != null && cursor == line.length()) {
 			wordIndex = words.size() - 1;
 			wordCursor = words.get(words.size() - 1).length();
 		}

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

@@ -15,38 +15,90 @@
  */
 package org.springframework.shell.jline;
 
-import org.junit.jupiter.api.Test;
+import java.util.stream.Stream;
+
+import org.jline.reader.ParsedLine;
+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 static org.assertj.core.api.Assertions.assertThat;
 
 public class ExtendedDefaultParserTests {
 
-	@Test
-	void wordsParsing() {
-		ExtendedDefaultParser parser = new ExtendedDefaultParser();
+	private final ExtendedDefaultParser springParser = new ExtendedDefaultParser();
+	private final DefaultParser jlineParser = new DefaultParser();
+
+	static Stream<Arguments> args() {
+		// cursor words wordIndex wordCursor line
+		// We've left these tests here to show issues
+		// differences between DefaultParser and
+		// ExtendedDefaultParser. relates gh517
+		return Stream.of(
+			Arguments.of(0, 1, 0, 0, "one"),
+			Arguments.of(3, 1, 0, 3, "one "),
+			Arguments.of(4, 2, 1, 0, "one "),
 
-		assertThat(parser.parse("one", 0).words()).hasSize(1);
-		assertThat(parser.parse("one", 3).words()).hasSize(1);
+			Arguments.of(0, 2, 0, 0, "one two"),
+			Arguments.of(1, 2, 0, 1, "one two"),
+			Arguments.of(2, 2, 0, 2, "one two"),
+			Arguments.of(3, 2, 0, 3, "one two"),
+			Arguments.of(7, 2, 1, 3, "one two"),
+			Arguments.of(7, 2, 1, 3, "one two "),
+			Arguments.of(8, 3, 2, 0, "one two "),
 
-		assertThat(parser.parse("one two", 0).words()).hasSize(2);
-		assertThat(parser.parse("one two", 7).words()).hasSize(2);
+			Arguments.of(0, 1, 0, 0, "'one'"),
+			// Arguments.of(5, 1, 0, 3, "'one' "),
+			Arguments.of(6, 2, 1, 0, "'one' "),
 
-		assertThat(parser.parse("'one'", 0).words()).hasSize(1);
-		assertThat(parser.parse("'one'", 5).words()).hasSize(1);
+			Arguments.of(0, 1, 0, 0, "'one'"),
+			Arguments.of(1, 1, 0, 0, "'one'"),
+			Arguments.of(2, 1, 0, 1, "'one'"),
+			Arguments.of(3, 1, 0, 2, "'one'"),
+			Arguments.of(4, 1, 0, 3, "'one'"),
+			// Arguments.of(5, 1, 0, 3, "'one'"),
 
-		assertThat(parser.parse("'one' two", 0).words()).hasSize(2);
-		assertThat(parser.parse("'one' two", 9).words()).hasSize(2);
+			Arguments.of(0, 1, 0, 0, "'one' "),
+			Arguments.of(1, 1, 0, 0, "'one' "),
+			Arguments.of(2, 1, 0, 1, "'one' "),
+			Arguments.of(3, 1, 0, 2, "'one' "),
+			Arguments.of(4, 1, 0, 3, "'one' "),
+			// Arguments.of(5, 1, 0, 3, "'one' "),
+			Arguments.of(6, 2, 1, 0, "'one' "),
 
-		assertThat(parser.parse("one 'two'", 0).words()).hasSize(2);
-		assertThat(parser.parse("one 'two'", 9).words()).hasSize(2);
+			Arguments.of(0, 1, 0, 0, "\"one\""),
+			Arguments.of(1, 1, 0, 0, "\"one\""),
+			Arguments.of(2, 1, 0, 1, "\"one\""),
+			Arguments.of(3, 1, 0, 2, "\"one\""),
+			Arguments.of(4, 1, 0, 3, "\"one\""),
+			// Arguments.of(5, 1, 0, 3, "\"one\""),
 
-		assertThat(parser.parse("\"one\"", 0).words()).hasSize(1);
-		assertThat(parser.parse("\"one\"", 5).words()).hasSize(1);
+			Arguments.of(0, 1, 0, 0, "\"one\" "),
+			Arguments.of(1, 1, 0, 0, "\"one\" "),
+			Arguments.of(2, 1, 0, 1, "\"one\" "),
+			Arguments.of(3, 1, 0, 2, "\"one\" "),
+			Arguments.of(4, 1, 0, 3, "\"one\" "),
+			// Arguments.of(5, 1, 0, 3, "\"one\" "),
+			Arguments.of(6, 2, 1, 0, "\"one\" ")
+			);
+	}
 
-		assertThat(parser.parse("\"one\" two", 0).words()).hasSize(2);
-		assertThat(parser.parse("\"one\" two", 9).words()).hasSize(2);
+	@ParameterizedTest
+	@MethodSource("args")
+	void testSpringExtendedDefaultParser(int cursor, int words, int wordIndex, int wordCursor, String line) {
+		ParsedLine parse = springParser.parse(line, cursor);
+		assertThat(parse.words()).as("words").hasSize(words);
+		assertThat(parse.wordIndex()).as("wordIndex").isEqualTo(wordIndex);
+		assertThat(parse.wordCursor()).as("wordCursor").isEqualTo(wordCursor);
+	}
 
-		assertThat(parser.parse("one \"two\"", 0).words()).hasSize(2);
-		assertThat(parser.parse("one \"two\"", 9).words()).hasSize(2);
+	@ParameterizedTest
+	@MethodSource("args")
+	void testJlineDefaultParser(int cursor, int words, int wordIndex, int wordCursor, String line) {
+		ParsedLine parse = jlineParser.parse(line, cursor);
+		assertThat(parse.words()).as("words").hasSize(words);
+		assertThat(parse.wordIndex()).as("wordIndex").isEqualTo(wordIndex);
+		assertThat(parse.wordCursor()).as("wordCursor").isEqualTo(wordCursor);
 	}
 }