Fix command highlighter

pom.xml

@@ -63,9 +63,9 @@
 		<awaitility.version>4.3.0</awaitility.version>
 		<log4j.version>2.25.2</log4j.version>
 
-        <!-- samples dependencies -->
-        <h2-database.version>2.4.240</h2-database.version>
-        <logback.version>1.5.21</logback.version>
+		<!-- samples dependencies -->
+		<h2-database.version>2.4.240</h2-database.version>
+		<logback.version>1.5.21</logback.version>
 
 		<!-- documentation dependencies -->
 		<antora-maven-plugin.version>1.0.0-alpha.5</antora-maven-plugin.version>

spring-shell-core-autoconfigure/src/main/java/org/springframework/shell/core/autoconfigure/JLineShellAutoConfiguration.java

@@ -19,11 +19,9 @@
 import java.io.IOException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
-import java.util.regex.Pattern;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.jline.reader.Highlighter;
 import org.jline.reader.LineReader;
 import org.jline.reader.LineReaderBuilder;
 import org.jline.reader.Parser;
@@ -32,7 +30,6 @@
 import org.jline.terminal.TerminalBuilder;
 import org.jline.terminal.TerminalBuilder.SystemOutput;
 import org.jline.utils.AttributedString;
-import org.jline.utils.AttributedStringBuilder;
 import org.jline.utils.AttributedStyle;
 
 import org.springframework.beans.factory.BeanCreationException;
@@ -50,6 +47,7 @@
 import org.springframework.shell.core.command.CommandRegistry;
 import org.springframework.shell.core.config.UserConfigPathProvider;
 import org.springframework.shell.jline.CommandCompleter;
+import org.springframework.shell.jline.CommandHighlighter;
 import org.springframework.shell.jline.ExtendedDefaultParser;
 import org.springframework.shell.jline.JLineInputProvider;
 import org.springframework.shell.jline.PromptProvider;
@@ -62,6 +60,7 @@
  * @author Eric Bottard
  * @author Florent Biville
  * @author Mahmoud Ben Hassine
+ * @author Piotr Olaszewski
  */
 @AutoConfiguration
 @EnableConfigurationProperties(SpringShellProperties.class)
@@ -98,36 +97,7 @@ public LineReader lineReader(Terminal terminal, Parser parser, CommandCompleter
 			.appName("Spring Shell")
 			.completer(commandCompleter)
 			.history(jLineHistory)
-			.highlighter(new Highlighter() {
-
-				@Override
-				public AttributedString highlight(LineReader reader, String buffer) {
-					int l = 0;
-					String best = null;
-					for (Command command : commandRegistry.getCommands()) {
-						if (buffer.startsWith(command.getName()) && command.getName().length() > l) {
-							l = command.getName().length();
-							best = command.getName();
-						}
-					}
-					if (best != null) {
-						return new AttributedStringBuilder(buffer.length()).append(best, AttributedStyle.BOLD)
-							.append(buffer.substring(l))
-							.toAttributedString();
-					}
-					else {
-						return new AttributedString(buffer, AttributedStyle.DEFAULT.foreground(AttributedStyle.RED));
-					}
-				}
-
-				@Override
-				public void setErrorPattern(Pattern errorPattern) {
-				}
-
-				@Override
-				public void setErrorIndex(int errorIndex) {
-				}
-			})
+			.highlighter(new CommandHighlighter(commandRegistry))
 			.parser(parser);
 
 		LineReader lineReader = lineReaderBuilder.build();

spring-shell-jline/src/main/java/org/springframework/shell/jline/CommandHighlighter.java

@@ -0,0 +1,39 @@
+package org.springframework.shell.jline;
+
+import java.util.Comparator;
+import java.util.stream.Stream;
+
+import org.jline.reader.Highlighter;
+import org.jline.reader.LineReader;
+import org.jline.utils.AttributedString;
+import org.jline.utils.AttributedStringBuilder;
+import org.jline.utils.AttributedStyle;
+
+import org.springframework.shell.core.command.CommandRegistry;
+
+/**
+ * @author Piotr Olaszewski
+ * @since 4.0.1
+ */
+public class CommandHighlighter implements Highlighter {
+
+	private final CommandRegistry commandRegistry;
+
+	public CommandHighlighter(CommandRegistry commandRegistry) {
+		this.commandRegistry = commandRegistry;
+	}
+
+	@Override
+	public AttributedString highlight(LineReader reader, String buffer) {
+		return commandRegistry.getCommands()
+			.stream()
+			.flatMap(command -> Stream.concat(Stream.of(command.getName()), command.getAliases().stream()))
+			.filter(buffer::startsWith)
+			.max(Comparator.comparingInt(String::length))
+			.map(bestMatch -> new AttributedStringBuilder(buffer.length()).append(bestMatch, AttributedStyle.BOLD)
+				.append(buffer.substring(bestMatch.length()))
+				.toAttributedString())
+			.orElseGet(() -> new AttributedString(buffer, AttributedStyle.DEFAULT.foreground(AttributedStyle.RED)));
+	}
+
+}

spring-shell-jline/src/main/java/org/springframework/shell/jline/command/package-info.java

@@ -0,0 +1,4 @@
+@NullMarked
+package org.springframework.shell.jline.command;
+
+import org.jspecify.annotations.NullMarked;

spring-shell-jline/src/test/java/org/springframework/shell/jline/CommandCompleterTests.java

@@ -72,7 +72,7 @@ else if ("last".equals(option.longName()) || 'l' == option.shortName()) {
 	};
 
 	@BeforeEach
-	public void before() {
+	void before() {
 		command = mock(Command.class);
 		when(command.getName()).thenReturn("hello");
 		when(command.getCompletionProvider()).thenReturn(completionProvider);
@@ -86,7 +86,7 @@ private List<String> toCandidateNames(List<Candidate> candidates) {
 
 	@ParameterizedTest
 	@MethodSource("completeData")
-	public void testComplete(List<String> words, List<String> expectedValues) {
+	void testComplete(List<String> words, List<String> expectedValues) {
 		// given
 		when(command.getName()).thenReturn("hello");
 		when(command.getOptions())
@@ -173,7 +173,7 @@ static Stream<Arguments> completeData() {
 
 	@ParameterizedTest
 	@MethodSource("completeCommandWithLongNamesData")
-	public void testCompleteCommandWithLongNames(List<String> words, List<String> expectedValues) {
+	void testCompleteCommandWithLongNames(List<String> words, List<String> expectedValues) {
 		// given
 		when(command.getOptions()).thenReturn(List.of(new CommandOption.Builder().longName("first").build(),
 				new CommandOption.Builder().longName("last").build()));
@@ -227,7 +227,7 @@ static Stream<Arguments> completeCommandWithLongNamesData() {
 
 	@ParameterizedTest
 	@MethodSource("completeCommandWithShortNamesData")
-	public void testCompleteCommandWithShortNames(List<String> words, List<String> expectedValues) {
+	void testCompleteCommandWithShortNames(List<String> words, List<String> expectedValues) {
 		// given
 		when(command.getOptions()).thenReturn(List.of(new CommandOption.Builder().shortName('f').build(),
 				new CommandOption.Builder().shortName('l').build()));
@@ -279,7 +279,7 @@ static Stream<Arguments> completeCommandWithShortNamesData() {
 
 	@ParameterizedTest
 	@MethodSource("completeWithSubCommandsData")
-	public void testCompleteWithSubCommands(List<String> words, List<String> expectedValues) {
+	void testCompleteWithSubCommands(List<String> words, List<String> expectedValues) {
 		// given
 		when(command.getName()).thenReturn("hello world");
 		when(command.getOptions())
@@ -328,7 +328,7 @@ static Stream<Arguments> completeWithSubCommandsData() {
 
 	@ParameterizedTest
 	@MethodSource("completeWithTwoOptionsWhereOneIsSubsetOfOtherData")
-	public void testCompleteWithTwoOptionsWhereOneIsSubsetOfOther(List<String> words, List<String> expectedValues) {
+	void testCompleteWithTwoOptionsWhereOneIsSubsetOfOther(List<String> words, List<String> expectedValues) {
 		// given
 		when(command.getOptions()).thenReturn(List.of(new CommandOption.Builder().longName("first").build(),
 				new CommandOption.Builder().longName("firstname").build()));
@@ -373,7 +373,7 @@ static Stream<Arguments> completeWithTwoOptionsWhereOneIsSubsetOfOtherData() {
 
 	@ParameterizedTest
 	@MethodSource("completeWithHiddenCommandsData")
-	public void testCompleteWithHiddenCommands(List<String> words, List<String> expectedValues) {
+	void testCompleteWithHiddenCommands(List<String> words, List<String> expectedValues) {
 		// given
 		when(command.getName()).thenReturn("hello visible");
 		when(command.getOptions()).thenReturn(List.of());

spring-shell-jline/src/test/java/org/springframework/shell/jline/CommandHighlighterTest.java

@@ -0,0 +1,68 @@
+package org.springframework.shell.jline;
+
+import java.util.Collections;
+import java.util.List;
+
+import org.jline.reader.LineReader;
+import org.jline.utils.AttributedString;
+import org.jline.utils.AttributedStyle;
+import org.jline.utils.Colors;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.shell.core.command.Command;
+import org.springframework.shell.core.command.CommandRegistry;
+import org.springframework.shell.jline.tui.style.ThemeResolver;
+import static org.assertj.core.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+/**
+ * @author Piotr Olaszewski
+ */
+class CommandHighlighterTest {
+
+	private final LineReader lineReader = mock(LineReader.class);
+
+	private final CommandRegistry commandRegistry = new CommandRegistry();
+
+	private final CommandHighlighter highlighter = new CommandHighlighter(commandRegistry);
+
+	@Test
+	void shouldHighlightCommandNameInBold() {
+		Command command = mock(Command.class);
+		when(command.getName()).thenReturn("help");
+		when(command.getAliases()).thenReturn(Collections.emptyList());
+
+		commandRegistry.registerCommand(command);
+
+		AttributedString result = highlighter.highlight(lineReader, "help argument");
+
+		assertThat(result).hasToString("help argument");
+		assertThat(result.styleAt(0).getStyle()).isEqualTo(AttributedStyle.BOLD.getStyle());
+		assertThat(result.styleAt(5).getStyle()).isNotEqualTo(AttributedStyle.BOLD.getStyle());
+	}
+
+	@Test
+	void shouldHighlightAliasInBold() {
+		Command command = mock(Command.class);
+		when(command.getName()).thenReturn("help");
+		when(command.getAliases()).thenReturn(List.of("h"));
+
+		commandRegistry.registerCommand(command);
+
+		AttributedString result = highlighter.highlight(lineReader, "h argument");
+
+		assertThat(result).hasToString("h argument");
+		assertThat(result.styleAt(0).getStyle()).isEqualTo(AttributedStyle.BOLD.getStyle());
+		assertThat(result.styleAt(2).getStyle()).isNotEqualTo(AttributedStyle.BOLD.getStyle());
+	}
+
+	@Test
+	void shouldHighlightRedWhenNoMatchFound() {
+		AttributedString result = highlighter.highlight(lineReader, "unknown");
+
+		assertThat(result).hasToString("unknown");
+		assertThat(ThemeResolver.resolveValues(result.styleAt(0)).foreground())
+			.isEqualTo(Colors.DEFAULT_COLORS_256[AttributedStyle.RED]);
+	}
+
+}