Bug 559465 - Correctly handle memento on ImportDeclaration without alias

Change-Id: I35da71a4ecb051bb18454fa00442fe552789714b
Signed-off-by: Dawid Pakuła <zulus@w3des.net>
diff --git a/core/plugins/org.eclipse.dltk.core/model/org/eclipse/dltk/internal/core/ImportContainer.java b/core/plugins/org.eclipse.dltk.core/model/org/eclipse/dltk/internal/core/ImportContainer.java
index 55ac557..fb12083 100644
--- a/core/plugins/org.eclipse.dltk.core/model/org/eclipse/dltk/internal/core/ImportContainer.java
+++ b/core/plugins/org.eclipse.dltk.core/model/org/eclipse/dltk/internal/core/ImportContainer.java
@@ -75,6 +75,9 @@
 				String importName = memento.nextToken();
 				String version = memento.nextToken();
 				String alias = memento.nextToken();
+				if (alias.length() == 0) {
+					alias = null;
+				}
 				int type = Integer.parseInt(memento.nextToken());
 				int flags = Integer.parseInt(memento.nextToken());
 				if (version.length() == 0) {
diff --git a/core/plugins/org.eclipse.dltk.core/model/org/eclipse/dltk/internal/core/ImportDeclaration.java b/core/plugins/org.eclipse.dltk.core/model/org/eclipse/dltk/internal/core/ImportDeclaration.java
index d2067c6..f13b9cd 100644
--- a/core/plugins/org.eclipse.dltk.core/model/org/eclipse/dltk/internal/core/ImportDeclaration.java
+++ b/core/plugins/org.eclipse.dltk.core/model/org/eclipse/dltk/internal/core/ImportDeclaration.java
@@ -98,7 +98,9 @@
 		buff.append(JEM_COUNT);
 		escapeMementoName(buff, version);
 		buff.append(JEM_COUNT);
-		escapeMementoName(buff, alias);
+		if (alias != null) {
+			escapeMementoName(buff, alias);
+		}
 		buff.append(JEM_COUNT);
 		buff.append(type);
 		buff.append(JEM_COUNT);