Allow commands to be hidden from help after construction.

spring-shell-core/src/main/java/org/springframework/shell/core/command/AbstractCommand.java

@@ -46,7 +46,7 @@ public abstract class AbstractCommand implements Command {
 
 	private final String group;
 
-	private final boolean hidden;
+	private boolean hidden;
 
 	private AvailabilityProvider availabilityProvider = AvailabilityProvider.alwaysAvailable();
 
@@ -105,6 +105,10 @@ public boolean isHidden() {
 		return this.hidden;
 	}
 
+	public void setHidden(boolean hidden) {
+		this.hidden = hidden;
+	}
+
 	@Override
 	public List<String> getAliases() {
 		return this.aliases;

spring-shell-core/src/test/java/org/springframework/shell/core/command/HelpTests.java

@@ -18,6 +18,7 @@
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 import org.springframework.shell.core.InputReader;
+import org.springframework.shell.core.utils.Utils;
 
 import java.io.PrintWriter;
 import java.io.StringWriter;
@@ -51,6 +52,35 @@ void testDefaultHelpMessage() throws Exception {
 		Assertions.assertEquals(expectedOutput.replaceAll("\\R", "\n"), actualOutput.replaceAll("\\R", "\n"));
 	}
 
+	@Test
+	void testDefaultHelpMessageWithoutQuit() throws Exception {
+		// given
+		CommandRegistry commandRegistry = new CommandRegistry();
+		StringWriter stringWriter = new StringWriter();
+		PrintWriter outputWriter = new PrintWriter(stringWriter);
+		InputReader inputReader = new InputReader() {
+		};
+		ParsedInput parsedInput = ParsedInput.builder().build();
+		CommandContext commandContext = new CommandContext(parsedInput, commandRegistry, outputWriter, inputReader);
+
+		((AbstractCommand) Utils.QUIT_COMMAND).setHidden(true);
+
+		// when
+		Help help = new Help();
+		help.execute(commandContext);
+
+		// then
+		String actualOutput = stringWriter.toString();
+		String expectedOutput = """
+				AVAILABLE COMMANDS
+
+
+				""";
+		Assertions.assertEquals(expectedOutput.replaceAll("\\R", "\n"), actualOutput.replaceAll("\\R", "\n"));
+
+		((AbstractCommand) Utils.QUIT_COMMAND).setHidden(false);
+	}
+
 	@Test
 	void testHelpMessageForCommand() throws Exception {
 		// given
@@ -352,4 +382,4 @@ void testHelpMessageForCommandAlias() throws Exception {
 		Assertions.assertEquals(expectedOutput.replaceAll("\\R", "\n"), actualOutput.replaceAll("\\R", "\n"));
 	}
 
-}
+}