Fixed issue: #96

core/src/main/java/org/luaj/vm2/WeakTable.java

@@ -119,8 +119,12 @@ public class WeakTable implements Metatable {
 			if ( key != null && value != null ) {
 				return new LuaTable.NormalEntry(key, value);
 			} else {
-				this.key = null;
-				this.value = null;
+				if ( key == null ) {
+					this.key = null;
+				}
+				if ( value == null ) {
+					this.value = null;
+				}
 				return null;
 			}
 		}

jse/src/test/java/org/luaj/vm2/WeakTableTest.java

@@ -104,6 +104,23 @@ abstract public class WeakTableTest extends TableTest {
 			assertEquals(LuaValue.NIL, t.get(1));
 			assertFalse("strings should not be in weak references", t.get("string").isnil());
 		}
+
+		public void testWeakValueRehashAfterGcDoesNotDropStrongKeyOrThrow() {
+			LuaTable t = new_Table();
+
+			for ( int i = 0; i < 100; i++ ) {
+				t.set("dead-" + i, new LuaTable());
+			}
+
+			collectGarbage();
+
+			for ( int i = 0; i < 100; i++ ) {
+				assertEquals(LuaValue.NIL, t.get("dead-" + i));
+			}
+
+			t.set("survivor", LuaValue.valueOf("ok"));
+			assertEquals(LuaValue.valueOf("ok"), t.get("survivor"));
+		}
 	}
 	
 	public static class WeakKeyTableTest extends WeakTableTest {