[#381] Bugfix: Prevent NPE when adding programmatically created subco…

…mmands to CommandLine.

Closes #381

RELEASE-NOTES.md

@@ -1,5 +1,37 @@
 # picocli Release Notes
 
+# <a name="3.0.2"></a> Picocli 3.0.2
+The picocli community is pleased to announce picocli 3.0.2.
+
+This release fixes a bug for programmatic configuration.
+
+This is the thirty-first public release.
+Picocli follows [semantic versioning](http://semver.org/).
+
+## <a name="3.0.2"></a> Table of Contents
+* [New and noteworthy](#3.0.2-new)
+* [Promoted features](#3.0.2-promoted)
+* [Fixed issues](#3.0.2-fixes)
+* [Deprecations](#3.0.2-deprecated)
+* [Potential breaking changes](#3.0.2-breaking-changes)
+
+## <a name="3.0.2-new"></a> New and Noteworthy
+
+## <a name="3.0.2-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="3.0.2-fixes"></a> Fixed issues
+- [#381] Bugfix: Prevent NPE when adding programmatically created subcommands to CommandLine. Thanks to [Mikusch](https://github.com/Mikusch) for the bug report.
+
+## <a name="3.0.2-deprecated"></a> Deprecations
+No features were deprecated in this release.
+
+## <a name="3.0.2-breaking-changes"></a> Potential breaking changes
+This release has no breaking changes.
+
+
 # <a name="3.0.1"></a> Picocli 3.0.1
 The picocli community is pleased to announce picocli 3.0.1.
 

src/main/java/picocli/CommandLine.java

@@ -4171,6 +4171,7 @@ private static void initSubcommands(Command cmd, CommandSpec parent, IFactory fa
                 }
             }
             static void initParentCommand(Object subcommand, Object parent) {
+                if (subcommand == null) { return; }
                 try {
                     Class<?> cls = subcommand.getClass();
                     while (cls != null) {

src/test/java/picocli/CommandLineModelTest.java

@@ -1572,4 +1572,24 @@ public <T> T set(T value) throws Exception {
         assertEquals(null, values.get(0));
         assertEquals("2", values.get(1));
     }
+
+    @Test
+    public void test381_NPE_whenAddingSubcommand() {
+        CommandSpec toplevel = CommandSpec.create();
+        toplevel.addOption(OptionSpec.builder("-o").description("o option").build());
+
+        CommandSpec sub = CommandSpec.create();
+        sub.addOption(OptionSpec.builder("-x").description("x option").build());
+
+        CommandLine commandLine = new CommandLine(toplevel);
+        commandLine.addSubcommand("sub", sub); // NPE here
+        commandLine.usage(System.out);
+
+        String expected = String.format("" +
+                "Usage: <main class> [-o] [COMMAND]%n" +
+                "  -o     o option%n" +
+                "Commands:%n" +
+                "  sub%n");
+        assertEquals(expected, systemOutRule.getLog());
+    }
 }