template engine: no session available fix #3941

Author: jknack

jooby/src/main/java/io/jooby/DefaultContext.java

@@ -167,6 +167,10 @@ default Session session() {
     if (session == null) {
       Router router = getRouter();
       SessionStore store = router.getSessionStore();
+      // edge-case: user ask for session or null, treat unsupported as null
+      if (store == SessionStore.UNSUPPORTED) {
+        return null;
+      }
       session = store.findSession(this);
       if (session != null) {
         getAttributes().put(Session.NAME, session);

jooby/src/test/java/io/jooby/DefaultContextTest.java

@@ -211,6 +211,13 @@ void sessionOrNullExisting() {
     assertSame(sessionMock, attributes.get(Session.NAME));
   }
 
+  @Test
+  void sessionOrNullUnsupported() {
+    when(router.getSessionStore()).thenReturn(SessionStore.UNSUPPORTED);
+
+    assertNull(ctx.sessionOrNull());
+  }
+
   @Test
   void sessionMissingValues() {
     // Session is null -> session(String) returns missing, session(String, String) returns default

tests/src/test/java/io/jooby/i3936/Issue3936.java

@@ -40,7 +40,8 @@ void shouldUnderstandHtmxRequest(ServerTestRunner runner) {
                                   "isError",
                                   true));
               app.install(new HtmxModule(globalErrorHandler));
-              app.install(new HandlebarsModule(TestUtil.userdir("src/test/resources/htmx")));
+              app.install(
+                  new HandlebarsModule(TestUtil.userdir("src", "test", "resources", "htmx")));
               app.install(new HibernateValidatorModule());
 
               app.mvc(new TaskUIHtmx_(new TaskRepo3936()));

tests/src/test/java/io/jooby/i3941/Issue3941.java

@@ -0,0 +1,40 @@
+/*
+ * Jooby https://jooby.io
+ * Apache License Version 2.0 https://jooby.io/LICENSE.txt
+ * Copyright 2014 Edgar Espina
+ */
+package io.jooby.i3941;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Map;
+
+import io.jooby.ModelAndView;
+import io.jooby.SessionStore;
+import io.jooby.handlebars.HandlebarsModule;
+import io.jooby.junit.ServerTest;
+import io.jooby.junit.ServerTestRunner;
+import io.jooby.test.TestUtil;
+
+public class Issue3941 {
+
+  @ServerTest
+  public void shouldTriggerNoSessionError(ServerTestRunner runner) {
+    runner
+        .define(
+            app -> {
+              app.setSessionStore(SessionStore.UNSUPPORTED);
+              app.install(
+                  new HandlebarsModule(TestUtil.userdir("src", "test", "resources", "views")));
+              app.get("/3814", ctx -> ModelAndView.map("index.hbs", Map.of("name", "3941")));
+            })
+        .ready(
+            http -> {
+              http.get(
+                  "/3814",
+                  rsp -> {
+                    assertEquals("Hello 3941!", rsp.body().string().trim());
+                  });
+            });
+  }
+}