[#444] Bugfix: Usage help shows duplicate aliases if registered with …

…same alias multiple times.

RELEASE-NOTES.md

@@ -1,5 +1,38 @@
 # picocli Release Notes
 
+# <a name="3.6.0"></a> Picocli 3.6.0 (UNRELEASED)
+The picocli community is pleased to announce picocli 3.6.0.
+
+This is a bugfix release.
+
+This is the thirty-nineth public release.
+Picocli follows [semantic versioning](http://semver.org/).
+
+## <a name="3.6.0"></a> Table of Contents
+* [New and noteworthy](#3.6.0-new)
+* [Promoted features](#3.6.0-promoted)
+* [Fixed issues](#3.6.0-fixes)
+* [Deprecations](#3.6.0-deprecated)
+* [Potential breaking changes](#3.6.0-breaking-changes)
+
+## <a name="3.6.0-new"></a> New and Noteworthy
+
+
+## <a name="3.6.0-promoted"></a> Promoted Features
+Promoted features are features that were incubating in previous versions of picocli but are now supported and subject to backwards compatibility. 
+
+No features have been promoted in this picocli release.
+
+## <a name="3.6.0-fixes"></a> Fixed issues
+- [#444] Bugfix: Usage help shows duplicate aliases if registered with same alias multiple times.
+
+## <a name="3.6.0-deprecated"></a> Deprecations
+No features were deprecated in this release.
+
+## <a name="3.6.0-breaking-changes"></a> Potential breaking changes
+This release has no breaking changes.
+
+
 # <a name="3.5.2"></a> Picocli 3.5.2
 The picocli community is pleased to announce picocli 3.5.2.
 

src/main/java/picocli/CommandLine.java

@@ -241,9 +241,7 @@ public CommandLine addSubcommand(String name, Object command) {
      */
     public CommandLine addSubcommand(String name, Object command, String... aliases) {
         CommandLine subcommandLine = toCommandLine(command, factory);
-        List<String> update = new ArrayList<String>(Arrays.asList(subcommandLine.getCommandSpec().aliases()));
-        update.addAll(Arrays.asList(aliases));
-        subcommandLine.getCommandSpec().aliases(update.toArray(new String[0]));
+        subcommandLine.getCommandSpec().aliases.addAll(Arrays.asList(aliases));
         getCommandSpec().addSubcommand(name, subcommandLine);
         CommandLine.Model.CommandReflection.initParentCommand(subcommandLine.getCommandSpec().userObject(), getCommandSpec().userObject());
         return this;
@@ -3111,7 +3109,7 @@ public static class CommandSpec {
             private CommandSpec parent;
 
             private String name;
-            private String[] aliases = {};
+            private Set<String> aliases = new LinkedHashSet<String>();
             private Boolean isHelpCommand;
             private IVersionProvider versionProvider;
             private String[] version;
@@ -3359,7 +3357,7 @@ public CommandSpec addMixin(String name, CommandSpec mixin) {
 
             /** Returns the alias command names of this subcommand.
              * @since 3.1 */
-            public String[] aliases() { return aliases.clone(); }
+            public String[] aliases() { return aliases.toArray(new String[0]); }
 
             /** Returns the String to use as the program name in the synopsis line of the help message:
              * this command's {@link #name() name}, preceded by the qualified name of the parent command, if any.
@@ -3410,7 +3408,10 @@ public String[] version() {
             /** Sets the alternative names by which this subcommand is recognized on the command line.
              * @return this CommandSpec for method chaining
              * @since 3.1 */
-            public CommandSpec aliases(String... aliases) { this.aliases = aliases == null ? new String[0] : aliases.clone(); return this; }
+            public CommandSpec aliases(String... aliases) {
+                this.aliases = new LinkedHashSet<String>(Arrays.asList(aliases == null ? new String[0] : aliases));
+                return this;
+            }
 
             /** Sets version information literals for this command, to print to the console when the user specifies an
              * {@linkplain OptionSpec#versionHelp() option} to request version help. Only used if no {@link #versionProvider() versionProvider} is set.
@@ -7358,7 +7359,7 @@ private static String join(String[] names, int offset, int length, String separa
             return result.toString();
         }
         private static String stringOf(char chr, int length) {
-            char[] buff = new char[length];
+                             char[] buff = new char[length];
             Arrays.fill(buff, chr);
             return new String(buff);
         }

src/test/java/picocli/CommandLineTest.java

@@ -2264,7 +2264,7 @@ public void run() {
         }
     }
 
-    @Command(name = "task", aliases = {"t"})
+    @Command(name = "task", aliases = {"t"}, description = "subcommand with alias")
     static class SubCommandWithAlias implements Runnable {
         boolean subWasExecuted;
         public void run() {
@@ -2283,6 +2283,20 @@ public void testIssue443SubcommandWithAliasAnnotation() {
         assertTrue("sub was executed", sub.subWasExecuted);
     }
 
+    @Test
+    public void testIssue444SubcommandWithDuplicateAliases() {
+        Issue443TopLevelCommand top = new Issue443TopLevelCommand();
+        SubCommandWithAlias sub = new SubCommandWithAlias();
+        CommandLine cmd = new CommandLine(top).addSubcommand("task", sub, "t", "t");
+        Model.CommandSpec subSpec = cmd.getSubcommands().get("task").getCommandSpec();
+        String expected = String.format("" +
+                "Usage: cb [COMMAND]%n" +
+                "Commands:%n" +
+                "  task, t  subcommand with alias%n");
+        assertEquals(expected, cmd.getUsageMessage());
+        assertArrayEquals(new String[]{"t"}, subSpec.aliases());
+    }
+
     public static <T> Set<T> setOf(T... elements) {
         Set<T> result = new HashSet<T>();
         for (T t : elements) { result.add(t); }