[clang-tools-extra] r350633 - [clangd] Fix a crash when reading an empty index file.

[Haojian Wu via cfe-commits]

Author: hokein
Date: Tue Jan  8 07:24:47 2019
New Revision: 350633

URL: http://llvm.org/viewvc/llvm-project?rev=350633&view=rev
Log:
[clangd] Fix a crash when reading an empty index file.

Summary:
Unfortunately, yaml::Input::setCurrentDocument() and yaml::Input::nextDocument() are
internal APIs, the way we use them may cause a nullptr accessing when
processing an empty YAML file.

Reviewers: ilya-biryukov

Subscribers: ioeric, MaskRay, jkorous, arphaman, kadircet, cfe-commits

Differential Revision: https://reviews.llvm.org/D56442

Modified:
    clang-tools-extra/trunk/clangd/index/YAMLSerialization.cpp
    clang-tools-extra/trunk/unittests/clangd/SerializationTests.cpp

Modified: clang-tools-extra/trunk/clangd/index/YAMLSerialization.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clangd/index/YAMLSerialization.cpp?rev=350633&r1=350632&r2=350633&view=diff
==============================================================================
--- clang-tools-extra/trunk/clangd/index/YAMLSerialization.cpp (original)
+++ clang-tools-extra/trunk/clangd/index/YAMLSerialization.cpp Tue Jan  8 07:24:47 2019
@@ -314,17 +314,20 @@ llvm::Expected<IndexFileIn> readYAML(llv
       Arena; // store the underlying data of Position::FileURI.
   llvm::UniqueStringSaver Strings(Arena);
   llvm::yaml::Input Yin(Data, &Strings);
-  do {
+  while (Yin.setCurrentDocument()) {
+    llvm::yaml::EmptyContext Ctx;
     VariantEntry Variant;
-    Yin >> Variant;
+    yamlize(Yin, Variant, true, Ctx);
     if (Yin.error())
       return llvm::errorCodeToError(Yin.error());
+
     if (Variant.Symbol)
       Symbols.insert(*Variant.Symbol);
     if (Variant.Refs)
       for (const auto &Ref : Variant.Refs->second)
         Refs.insert(Variant.Refs->first, Ref);
-  } while (Yin.nextDocument());
+    Yin.nextDocument();
+  }
 
   IndexFileIn Result;
   Result.Symbols.emplace(std::move(Symbols).build());

Modified: clang-tools-extra/trunk/unittests/clangd/SerializationTests.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/unittests/clangd/SerializationTests.cpp?rev=350633&r1=350632&r2=350633&view=diff
==============================================================================
--- clang-tools-extra/trunk/unittests/clangd/SerializationTests.cpp (original)
+++ clang-tools-extra/trunk/unittests/clangd/SerializationTests.cpp Tue Jan  8 07:24:47 2019
@@ -91,6 +91,10 @@ MATCHER_P2(IncludeHeaderWithRef, Include
   return (arg.IncludeHeader == IncludeHeader) && (arg.References == References);
 }
 
+TEST(SerializationTest, NoCrashOnEmptyYAML) {
+  EXPECT_TRUE(bool(readIndexFile("")));
+}
+
 TEST(SerializationTest, YAMLConversions) {
   auto In = readIndexFile(YAML);
   EXPECT_TRUE(bool(In)) << In.takeError();