CommandLine.addArgs(String) should not allow a null String

Author: garydgregory

src/changes/changes.xml

@@ -55,6 +55,9 @@
       <action dev="ggregory" type="fix" due-to="Dilraj Singh, Gary Gregory" issue="CLI-283">
         CommandLine.addOption(Option) should not allow a null Option.
       </action>
+      <action dev="ggregory" type="fix" due-to="Gary Gregory" issue="CLI-283">
+        CommandLine.addArgs(String) should not allow a null String.
+      </action>
       <!-- ADD -->
       <action type="update" dev="ggregory" due-to="Dependabot, Gary Gregory">
         Add github/codeql-action.

src/main/java/org/apache/commons/cli/CommandLine.java

@@ -99,7 +99,9 @@ protected CommandLine() {
      * @param arg the unrecognized option/argument.
      */
     protected void addArg(final String arg) {
-        args.add(arg);
+        if (arg != null) {
+            args.add(arg);
+        }
     }
 
     /**

src/test/java/org/apache/commons/cli/CommandLineTest.java

@@ -41,10 +41,23 @@ public void testBuilder() {
     }
 
     @Test
-    public void testBuilderNulls() {
+    public void testBuilderNullArgs() {
+        final CommandLine.Builder builder = new CommandLine.Builder();
+        builder.addArg(null).addArg(null);
+        builder.addOption(Option.builder("T").build());
+        final CommandLine cmd = builder.build();
+
+        assertEquals(0, cmd.getArgs().length);
+        assertEquals("T", cmd.getOptions()[0].getOpt());
+    }
+
+    @Test
+    public void testBuilderNullOption() {
         final CommandLine.Builder builder = new CommandLine.Builder();
         builder.addArg("foo").addArg("bar");
         builder.addOption(null);
+        builder.addOption(null);
+        builder.addOption(null);
         final CommandLine cmd = builder.build();
 
         assertEquals("foo", cmd.getArgs()[0]);