ADFA-4330: Fix TermuxService shellManager NPE on OS service auto-restart

termux/termux-app/src/main/java/com/termux/app/TermuxService.java

@@ -122,7 +122,10 @@ public void onCreate() {
         // load and TermuxActivity handles reloads
         mProperties = TermuxAppSharedProperties.getProperties();
 
-        mShellManager = TermuxShellManager.getShellManager();
+        // Use init() instead of getShellManager() so the singleton is lazily created if the
+        // OS auto-restarted the service after process death (TermuxApplication.onCreate did not
+        // run, leaving the static singleton null and causing an NPE in buildNotification()).
+        mShellManager = TermuxShellManager.init(getApplicationContext());
 
         runStartForeground();
 

termux/termux-app/src/test/java/com/termux/app/TermuxServiceShellManagerNpeTest.java

@@ -0,0 +1,69 @@
+package com.termux.app;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+import com.termux.shared.termux.shell.TermuxShellManager;
+
+import java.lang.reflect.Field;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.Robolectric;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.android.controller.ServiceController;
+
+/**
+ * Repro for ADFA-4330: when the OS auto-restarts {@link TermuxService} after process death,
+ * {@code TermuxApplication.onCreate()} does NOT run, so the static
+ * {@link TermuxShellManager} singleton is still {@code null}.
+ *
+ * <p>On the pre-fix baseline, {@code TermuxService.onCreate()} assigned
+ * {@code mShellManager = TermuxShellManager.getShellManager()} (which returns the null
+ * singleton), then immediately called {@code runStartForeground() -> buildNotification() ->
+ * getTermuxSessionsSize()}, dereferencing the null {@code mShellManager} and throwing a
+ * {@link NullPointerException}.
+ *
+ * <p>The fix changes that assignment to {@code TermuxShellManager.init(applicationContext)},
+ * which lazily creates the singleton, so the service starts cleanly.
+ *
+ * <p>This test simulates the auto-restart by forcing the static singleton back to {@code null}
+ * before creating the service, then asserts the service comes up and
+ * {@link TermuxService#getTermuxSessionsSize()} returns 0 instead of NPE-ing.
+ */
+@RunWith(RobolectricTestRunner.class)
+public class TermuxServiceShellManagerNpeTest {
+
+    /**
+     * Reset the static singleton to null to mimic a fresh process where
+     * TermuxApplication.onCreate() (which would normally call init()) never ran.
+     */
+    @Before
+    public void clearShellManagerSingleton() throws Exception {
+        Field f = TermuxShellManager.class.getDeclaredField("shellManager");
+        f.setAccessible(true);
+        f.set(null, null);
+    }
+
+    /** Service onCreate() with a null shell-manager singleton must not NPE and must expose usable sessions. */
+    @Test
+    public void onCreateWithNullSingleton_doesNotNpe_andSessionsAreUsable() {
+        // Sanity: the auto-restart precondition — singleton is null going in.
+        assertEquals(null, TermuxShellManager.getShellManager());
+
+        // Drive the REAL service lifecycle. On stage this throws NullPointerException inside
+        // onCreate() -> runStartForeground() -> buildNotification() -> getTermuxSessionsSize().
+        ServiceController<TermuxService> controller =
+            Robolectric.buildService(TermuxService.class).create();
+        TermuxService service = controller.get();
+
+        // After a clean onCreate(), the shell manager must be wired up and queryable.
+        assertNotNull("mShellManager must be initialized after onCreate()",
+            TermuxShellManager.getShellManager());
+        assertEquals("A freshly created service manages zero sessions",
+            0, service.getTermuxSessionsSize());
+
+        controller.destroy();
+    }
+}