8341342: Elements.getAllModuleElements() does not work properly before JavacTask.analyze()

Reviewed-by: vromero, liach

src/jdk.compiler/share/classes/com/sun/tools/javac/model/JavacElements.java

@@ -128,6 +128,7 @@ public class JavacElements implements Elements {
 
     @Override @DefinedBy(Api.LANGUAGE_MODEL)
     public Set<? extends ModuleElement> getAllModuleElements() {
+        ensureEntered("getAllModuleElements");
         if (allowModules)
             return Collections.unmodifiableSet(modules.allModules());
         else

test/jdk/tools/sincechecker/SinceChecker.java

@@ -297,7 +297,6 @@ public class SinceChecker {
                         Collections.singletonList(SimpleJavaFileObject.forSource(URI.create("myfo:/Test.java"), "")));
                 ct.analyze();
                 Elements elements = ct.getElements();
-                elements.getModuleElement("java.base");
                 try (EffectiveSourceSinceHelper javadocHelper = EffectiveSourceSinceHelper.create(ct, List.of(root), this)) {
                     processModuleCheck(elements.getModuleElement(moduleName), ct, moduleDirectory, javadocHelper);
                 } catch (Exception e) {

test/langtools/tools/javac/processing/model/util/elements/TestElementsProgrammatic.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8341342
+ * @summary Test Elements methods programmatically
+ * @modules jdk.compiler
+ * @run junit TestElementsProgrammatic
+ */
+
+import com.sun.source.util.JavacTask;
+import java.net.URI;
+import java.util.List;
+import java.util.function.Consumer;
+import javax.tools.JavaCompiler;
+import javax.tools.JavaFileObject;
+import javax.tools.SimpleJavaFileObject;
+import javax.tools.ToolProvider;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * Programmatically test workings of various methods of Elements.
+ */
+public class TestElementsProgrammatic {
+
+    private final JavaCompiler systemCompiler = ToolProvider.getSystemJavaCompiler();
+
+    @ParameterizedTest
+    @MethodSource
+    public void automaticallyEnter(Consumer<JavacTask> verify) {
+        //make sure the get{All,}{Module,Package,Type}Element{s,} methods will automatically enter:
+        JavaFileObject input =
+                SimpleJavaFileObject.forSource(URI.create("mem://Test.java"), "");
+        List<JavaFileObject> inputs = List.of(input);
+        JavacTask task = (JavacTask) systemCompiler.getTask(null, null, null, null, null, inputs);
+        verify.accept(task);
+    }
+
+    private static List<Consumer<JavacTask>> automaticallyEnter() {
+        return List.of(
+            task -> assertFalse(task.getElements().getAllModuleElements().isEmpty()),
+            task -> assertNotNull(task.getElements().getModuleElement("java.base")),
+            task -> assertNotNull(task.getElements().getPackageElement("java.lang")),
+            task -> assertFalse(task.getElements().getAllPackageElements("java.lang").isEmpty()),
+            task -> assertNotNull(task.getElements().getTypeElement("java.lang.Object")),
+            task -> assertFalse(task.getElements().getAllTypeElements("java.lang.Object").isEmpty())
+        );
+    }
+}