Fix SstFileWriter destructor

Summary:
If user did not call SstFileWriter::Finish() or called Finish() but it failed.
We need to abandon the builder, to avoid destructing it while it's open
Closes https://github.com/facebook/rocksdb/pull/1502

Differential Revision: D4171660

Pulled By: IslamAbdelRahman

fbshipit-source-id: ab6f434

db/external_sst_file_test.cc

@@ -1761,6 +1761,25 @@ TEST_F(ExternalSSTFileTest, CompactionDeadlock) {
   bg_block_put.join();
 }
 
+TEST_F(ExternalSSTFileTest, DirtyExit) {
+  Options options = CurrentOptions();
+  DestroyAndReopen(options);
+  std::string file_path = sst_files_dir_ + "/dirty_exit";
+  std::unique_ptr<SstFileWriter> sst_file_writer;
+
+  // Destruct SstFileWriter without calling Finish()
+  sst_file_writer.reset(
+      new SstFileWriter(EnvOptions(), options, options.comparator));
+  ASSERT_OK(sst_file_writer->Open(file_path));
+  sst_file_writer.reset();
+
+  // Destruct SstFileWriter with a failing Finish
+  sst_file_writer.reset(
+      new SstFileWriter(EnvOptions(), options, options.comparator));
+  ASSERT_OK(sst_file_writer->Open(file_path));
+  ASSERT_NOK(sst_file_writer->Finish());
+}
+
 #endif  // ROCKSDB_LITE
 
 }  // namespace rocksdb

table/sst_file_writer.cc

@@ -43,7 +43,15 @@ SstFileWriter::SstFileWriter(const EnvOptions& env_options,
                              const Comparator* user_comparator)
     : rep_(new Rep(env_options, options, user_comparator)) {}
 
-SstFileWriter::~SstFileWriter() { delete rep_; }
+SstFileWriter::~SstFileWriter() {
+  if (rep_->builder) {
+    // User did not call Finish() or Finish() failed, we need to
+    // abandon the builder.
+    rep_->builder->Abandon();
+  }
+
+  delete rep_;
+}
 
 Status SstFileWriter::Open(const std::string& file_path) {
   Rep* r = rep_;