[471456] Fix regression on editor restoring after session closing

- On editor restoring after session closing the
SessionEditorInput.getSession() must recreate the Session because the
weak reference to the old can be closed. This weak reference could not
be garbage collected yet because the garbage collector is not yet
executed or another object keep reference to this closed Session.
- RestoreSessionFromEditorInputTests has been updated to test this case.

Bug: 471456
Change-Id: Ifb0c8696410feb84911cdf2b7c7db02792c39d65
Signed-off-by: Esteban Dugueperoux <esteban.dugueperoux@obeo.fr>

2 files changed, 44 insertions, 11 deletions

diff --git a/plugins/org.eclipse.sirius.tests.junit/src/org/eclipse/sirius/tests/unit/common/RestoreSessionFromEditorInputTests.java b/plugins/org.eclipse.sirius.tests.junit/src/org/eclipse/sirius/tests/unit/common/RestoreSessionFromEditorInputTests.java
index 496d3e52e4..6f98a1357c 100644
--- a/plugins/org.eclipse.sirius.tests.junit/src/org/eclipse/sirius/tests/unit/common/RestoreSessionFromEditorInputTests.java
+++ b/plugins/org.eclipse.sirius.tests.junit/src/org/eclipse/sirius/tests/unit/common/RestoreSessionFromEditorInputTests.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2010, 2014 THALES GLOBAL SERVICES.
+ * Copyright (c) 2010, 2015 THALES GLOBAL SERVICES.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -32,8 +32,8 @@ import com.google.common.collect.Lists;
  * (especially when reopening an editor from Navigation History).
  * 
  * @author alagarde
- * 
  */
+@SuppressWarnings("restriction")
 public class RestoreSessionFromEditorInputTests extends SiriusDiagramTestCase {
 
     private static final String SEMANTIC_ROOT = "/vp-2067/2067.ecore";
@@ -69,16 +69,45 @@ public class RestoreSessionFromEditorInputTests extends SiriusDiagramTestCase {
     public void testRestoreSessionFromHistory() {
         if (TestsUtil.shouldSkipUnreliableTests()) {
             /*
-            junit.framework.AssertionFailedError: Wrong initial state: expecting only one active session expected:<1> but was:<2>
-            at junit.framework.Assert.fail(Assert.java:57)
-            at junit.framework.Assert.failNotEquals(Assert.java:329)
-            at junit.framework.Assert.assertEquals(Assert.java:78)
-            at junit.framework.Assert.assertEquals(Assert.java:234)
-            at junit.framework.TestCase.assertEquals(TestCase.java:401)
-            at org.eclipse.sirius.tests.unit.common.RestoreSessionFromEditorInputTests.testRestoreSessionFromHistory(RestoreSessionFromEditorInputTests.java:61)
-            */
+             * junit.framework.AssertionFailedError: Wrong initial state:
+             * expecting only one active session expected:<1> but was:<2> at
+             * junit.framework.Assert.fail(Assert.java:57) at
+             * junit.framework.Assert.failNotEquals(Assert.java:329) at
+             * junit.framework.Assert.assertEquals(Assert.java:78) at
+             * junit.framework.Assert.assertEquals(Assert.java:234) at
+             * junit.framework.TestCase.assertEquals(TestCase.java:401) at
+             * org.eclipse.sirius.tests.unit.common.
+             * RestoreSessionFromEditorInputTests.testRestoreSessionFromHistory(
+             * RestoreSessionFromEditorInputTests.java:61)
+             */
             return;
         }
+        testRestoreSessionFromHistory(false);
+    }
+
+    /**
+     * Same test as previous but close the session before restoring the editor.
+     */
+    public void testRestoreSessionFromHistoryWithClosedSession() {
+        if (TestsUtil.shouldSkipUnreliableTests()) {
+            /*
+             * junit.framework.AssertionFailedError: Wrong initial state:
+             * expecting only one active session expected:<1> but was:<2> at
+             * junit.framework.Assert.fail(Assert.java:57) at
+             * junit.framework.Assert.failNotEquals(Assert.java:329) at
+             * junit.framework.Assert.assertEquals(Assert.java:78) at
+             * junit.framework.Assert.assertEquals(Assert.java:234) at
+             * junit.framework.TestCase.assertEquals(TestCase.java:401) at
+             * org.eclipse.sirius.tests.unit.common.
+             * RestoreSessionFromEditorInputTests.testRestoreSessionFromHistory(
+             * RestoreSessionFromEditorInputTests.java:61)
+             */
+            return;
+        }
+        testRestoreSessionFromHistory(true);
+    }
+
+    private void testRestoreSessionFromHistory(boolean closeSession) {
         assertEquals("Wrong initial state: expecting only one active session", 1, SessionManager.INSTANCE.getSessions().size());
 
         // Step 1: open editor on the controlled representation
@@ -89,6 +118,10 @@ public class RestoreSessionFromEditorInputTests extends SiriusDiagramTestCase {
         DialectUIManager.INSTANCE.closeEditor(editor, false);
         TestsUtil.synchronizationWithUIThread();
 
+        if (closeSession) {
+            closeSession(session);
+        }
+
         // Step 3: restore editor from navigation history
         new NavigationHistoryAction(PlatformUI.getWorkbench().getActiveWorkbenchWindow(), false).run();
         TestsUtil.synchronizationWithUIThread();
diff --git a/plugins/org.eclipse.sirius.ui/src/org/eclipse/sirius/ui/business/api/session/SessionEditorInput.java b/plugins/org.eclipse.sirius.ui/src/org/eclipse/sirius/ui/business/api/session/SessionEditorInput.java
index c2c5145beb..18b940bbb8 100644
--- a/plugins/org.eclipse.sirius.ui/src/org/eclipse/sirius/ui/business/api/session/SessionEditorInput.java
+++ b/plugins/org.eclipse.sirius.ui/src/org/eclipse/sirius/ui/business/api/session/SessionEditorInput.java
@@ -108,7 +108,7 @@ public class SessionEditorInput extends URIEditorInput {
      */
     private Session getSession(boolean restore) {
         Session session = sessionRef != null ? sessionRef.get() : null;
-        if (session == null) {
+        if (session == null || !session.isOpen()) {
             URI sessionModelURI = getURI().trimFragment();
             if (sessionResourceURI != null) {
                 sessionModelURI = sessionResourceURI;