[453037] Avoid to reopen a session in the SessionEditorInput

Avoid to reopen a session in the SessionEditorInput when restore is not
asked.

Bug: 453037
Change-Id: Ia0fbafc8bf36cbceeea246c4998d2d4af91d4528
Signed-off-by: Maxime Porhel <maxime.porhel@obeo.fr>

2 files changed, 30 insertions, 13 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 6f98a1357c..779ef44b72 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
@@ -13,6 +13,7 @@ package org.eclipse.sirius.tests.unit.common;
 import java.util.Collections;
 
 import org.eclipse.core.runtime.NullProgressMonitor;
+import org.eclipse.sirius.business.api.session.Session;
 import org.eclipse.sirius.business.api.session.SessionManager;
 import org.eclipse.sirius.tests.SiriusTestsPlugin;
 import org.eclipse.sirius.tests.support.api.SiriusDiagramTestCase;
@@ -120,6 +121,7 @@ public class RestoreSessionFromEditorInputTests extends SiriusDiagramTestCase {
 
         if (closeSession) {
             closeSession(session);
+            assertTrue("Session should be closed and removed from the manager", SessionManager.INSTANCE.getSessions().isEmpty() && !session.isOpen());
         }
 
         // Step 3: restore editor from navigation history
@@ -130,6 +132,12 @@ public class RestoreSessionFromEditorInputTests extends SiriusDiagramTestCase {
 
         // => This should not have created a new session but use the current one
         assertEquals("No new session should have been opened while restoring editor from navigation history", 1, SessionManager.INSTANCE.getSessions().size());
+        Session currentSession = SessionManager.INSTANCE.getSessions().iterator().next();
+        if (closeSession) {
+            assertNotSame(session, currentSession);
+        } else {
+            assertEquals(session, currentSession);
+        }
         activePage.closeAllEditors(false);
         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 8c4fdb5db1..59bf4ad437 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
@@ -108,8 +108,9 @@ public class SessionEditorInput extends URIEditorInput {
      */
     private Session getSession(boolean restore) {
         Session session = sessionRef != null ? sessionRef.get() : null;
-        // Avoid to create a new session if the default editor name is used:
-        // GoToMarker case.
+        // Avoid to create a new session if the default editor name is used: we
+        // do not known yet for which representation the input is, like
+        // in the GotoMarker case for example.
         if (session == null || (!session.isOpen() && !DEFAULT_EDITOR_NAME.equals(name))) {
             URI sessionModelURI = getURI().trimFragment();
             if (sessionResourceURI != null) {
@@ -218,21 +219,29 @@ public class SessionEditorInput extends URIEditorInput {
     private Session getSession(URI sessionModelURI, boolean restore) {
         Session sessionFromURI;
         try {
-            sessionFromURI = null;
-            if (restore) {
+            sessionFromURI = SessionManager.INSTANCE.getExistingSession(sessionModelURI);
+
+            // A session adds and removes itself from the session manager during
+            // open()/close()
+            // If restore, we try to create a new one and open it only in this
+            // case: the session lifecycle is not safe enough to try to open a
+            // previously closed session.
+            if (sessionFromURI == null && restore) {
                 sessionFromURI = SessionManager.INSTANCE.getSession(sessionModelURI, new NullProgressMonitor());
-            } else {
-                sessionFromURI = SessionManager.INSTANCE.getExistingSession(sessionModelURI);
-            }
-            if (sessionFromURI != null) {
-                if (!sessionFromURI.isOpen()) {
+                if (sessionFromURI != null && !sessionFromURI.isOpen()) {
                     sessionFromURI.open(new NullProgressMonitor());
                 }
-                IEditingSession uiSession = null;
-                if (restore) {
+            }
+
+            if (sessionFromURI != null && sessionFromURI.isOpen()) {
+                // The SessionUIManager creates and open an IEditingSession when
+                // a session is added to the SessionManager. This
+                // IEditingSession is closed and removed from the ui manager
+                // when the corresponding session is removed from the session
+                // manager (closed).
+                IEditingSession uiSession = SessionUIManager.INSTANCE.getUISession(sessionFromURI);
+                if (uiSession == null && restore) {
                     uiSession = SessionUIManager.INSTANCE.getOrCreateUISession(sessionFromURI);
-                } else {
-                    uiSession = SessionUIManager.INSTANCE.getUISession(sessionFromURI);
                 }
                 if (uiSession != null && !uiSession.isOpen()) {
                     uiSession.open();