fix stack overflow issue with recursive schema

tangiel · tangiel · commit 03a19038d18c · 2017-02-28T15:43:48.000-08:00
Currently, if you add a self-referencing type to multiple APIs, a
StackOverflowError will occur. This change fixes that by not attempting
to add a type to an API that's already added.
diff --git a/endpoints-framework/src/main/java/com/google/api/server/spi/config/model/SchemaRepository.java b/endpoints-framework/src/main/java/com/google/api/server/spi/config/model/SchemaRepository.java
@@ -170,6 +170,9 @@ private Schema getOrCreateTypeForConfig(
   }
 
   private void addSchemaToApi(ApiKey key, Schema schema) {
+    if (schemaByApiKeys.containsEntry(key, schema)) {
+      return;
+    }
     schemaByApiKeys.put(key, schema);
     for (Field f : schema.fields().values()) {
       while (f.type() == FieldType.ARRAY) {
diff --git a/endpoints-framework/src/test/java/com/google/api/server/spi/config/model/SchemaRepositoryTest.java b/endpoints-framework/src/test/java/com/google/api/server/spi/config/model/SchemaRepositoryTest.java
@@ -114,6 +114,25 @@ public void getOrAdd_enum() throws Exception {
             .build());
   }
 
+  @Test
+  public void getOrAdd_recursiveSchema() throws Exception {
+    TypeToken<SelfReferencingObject> type = TypeToken.of(SelfReferencingObject.class);
+    // This test checks the case where a schema is added multiple times. The second time it's added
+    // to an API, it recurses through the schema. If the schema is self-referencing, we must not
+    // stack overflow.
+    repo.getOrAdd(type, config);
+    assertThat(repo.getOrAdd(type, config))
+        .isEqualTo(Schema.builder()
+            .setName("SelfReferencingObject")
+            .setType("object")
+            .addField("foo", Field.builder()
+                .setName("foo")
+                .setType(FieldType.OBJECT)
+                .setSchemaReference(SchemaReference.create(repo, config, type))
+                .build())
+            .build());
+  }
+
   @Test
   public void get() {
     TypeToken<Parameterized<Integer>> type = new TypeToken<Parameterized<Integer>>() {};
@@ -204,6 +223,12 @@ public Parameterized<Short> transformFrom(Parameterized<String> in) {
     }
   }
 
+  private static class SelfReferencingObject {
+    public SelfReferencingObject getFoo() {
+      return null;
+    }
+  }
+
   private ApiMethodConfig fooEndpointSetParameterized() throws Exception {
     return getMethodConfig("setParameterized", Parameterized.class);
   }

Original file line number	Diff line number	Diff line change
`@@ -170,6 +170,9 @@ private Schema getOrCreateTypeForConfig(`
`170`	`170`	`}`
`171`	`171`
`172`	`172`	`private void addSchemaToApi(ApiKey key, Schema schema) {`
	`173`	`+ if (schemaByApiKeys.containsEntry(key, schema)) {`
	`174`	`+ return;`
	`175`	`+ }`
`173`	`176`	`schemaByApiKeys.put(key, schema);`
`174`	`177`	`for (Field f : schema.fields().values()) {`
`175`	`178`	`while (f.type() == FieldType.ARRAY) {`