merge PR graphql-java#112

andimarek · andimarek · commit b5bb6230223d · 2017-05-20T07:47:12.000+02:00
diff --git a/src/main/java/graphql/relay/SimpleListConnection.java b/src/main/java/graphql/relay/SimpleListConnection.java
@@ -13,7 +13,7 @@
 
 public class SimpleListConnection<T> implements DataFetcher<Connection<T>> {
 
-    private static final String DUMMY_CURSOR_PREFIX = "simple-cursor";
+    static final String DUMMY_CURSOR_PREFIX = "simple-cursor";
     private final String prefix;
     private final List<T> data;
 
@@ -48,6 +48,8 @@ public Connection<T> get(DataFetchingEnvironment environment) {
         int beforeOffset = getOffsetFromCursor(environment.getArgument("before"), edges.size());
         int end = Math.min(beforeOffset, edges.size());
 
+        if (begin > end) begin = end;
+
         edges = edges.subList(begin, end);
         if (edges.size() == 0) {
             return emptyConnection();
diff --git a/src/test/groovy/graphql/relay/SimpleListConnectionTest.groovy b/src/test/groovy/graphql/relay/SimpleListConnectionTest.groovy
@@ -0,0 +1,28 @@
+package graphql.relay
+
+import graphql.schema.DataFetchingEnvironment
+import graphql.schema.DataFetchingEnvironmentImpl
+import spock.lang.Specification
+
+import java.nio.charset.StandardCharsets
+
+class SimpleListConnectionTest extends Specification {
+    def "invalid list indices handled"() {
+        given:
+        def testList = ["a", "b"]
+        def listConnection = new SimpleListConnection(testList)
+        def env = new DataFetchingEnvironmentImpl(null, ["after": createCursor(3)], null, null, null, null, null, null, null, null);
+
+        when:
+        Object item = listConnection.get(env);
+
+        then:
+        item instanceof graphql.relay.Connection
+    }
+
+
+    private String createCursor(int offset) {
+        def string = SimpleListConnection.DUMMY_CURSOR_PREFIX + Integer.toString(offset)
+        return Base64.getEncoder().encodeToString(string.getBytes(StandardCharsets.UTF_8))
+    }
+}
