Log an error when an app loads duplicate dex files

Creating a class loader with duplicate dex files in its classpath is most
likely an unintended bug. That leads to rejecting any compiled code and
hurts performance by extracting in memory.

Test: run-test gtest
Bug: 149410951

Change-Id: Ieebb69c6bd03acbe95dd8bedb6101d70390b92d8

1 files changed, 19 insertions, 0 deletions

diff --git a/runtime/class_loader_context_test.cc b/runtime/class_loader_context_test.cc
index 4d7e390b9a..e2e6075d22 100644
--- a/runtime/class_loader_context_test.cc
+++ b/runtime/class_loader_context_test.cc
@@ -1637,4 +1637,23 @@ TEST_F(ClassLoaderContextTest, CreateContextForClassLoaderWithSharedLibraries) {
             ClassLoaderContext::VerificationResult::kVerifies);
 }
 
+TEST_F(ClassLoaderContextTest, CheckForDuplicateDexFiles) {
+  jobject class_loader_a = LoadDexInPathClassLoader("Main", nullptr);
+  jobject class_loader_b =
+      LoadDexInInMemoryDexClassLoader("MyClass", class_loader_a);
+
+  std::unique_ptr<ClassLoaderContext> context =
+      CreateContextForClassLoader(class_loader_b);
+
+  std::vector<const DexFile*> result = context->CheckForDuplicateDexFiles(
+      std::vector<const DexFile*>());
+  ASSERT_EQ(0u, result.size());
+
+  std::vector<std::unique_ptr<const DexFile>> dex1 = OpenTestDexFiles("Main");
+  std::vector<const DexFile*> dex1_raw = MakeNonOwningPointerVector(dex1);
+  result = context->CheckForDuplicateDexFiles(dex1_raw);
+  ASSERT_EQ(1u, result.size());
+  ASSERT_EQ(dex1_raw[0], result[0]);
+}
+
 }  // namespace art