Move sendAbort to the end of invariantViolation()

Summary: The commits moves the `sendAbort()` to the end of invarian violation logic and add the delay destructor  to the `invariantViolation` . This way the service handler can invoke customized send error implementation without being worrid about keeping the transaction around.

Reviewed By: hanidamlaj

Differential Revision: D69196385

fbshipit-source-id: 82c17e6a8ac610db228af0611f64f35a7c6274cc

Author: Yu-Ho Hsieh

third-party/proxygen/src/proxygen/lib/http/session/HTTPTransaction.cpp

@@ -640,14 +640,18 @@ bool HTTPTransaction::validateEgressStateTransition(
 }
 
 void HTTPTransaction::invariantViolation(HTTPException ex) {
+  DestructorGuard g(this);
   LOG(ERROR) << "invariantViolation msg=" << ex.what()
              << " aborted_=" << uint32_t(aborted_) << " " << *this;
-  sendAbort();
   if (handler_) {
     handler_->onInvariantViolation(ex);
   } else {
     LOG(FATAL) << "Invariant violation with no handler; ex=" << ex.what();
   }
+  // In http/1.1, this will send TCP reset and ungracefully terminate the
+  // connection. In h2, this will send stream reset but keep the connection
+  // open.
+  sendAbort(ErrorCode::NO_ERROR);
 }
 
 void HTTPTransaction::abortAndDeliverError(ErrorCode codecError,

third-party/proxygen/src/proxygen/lib/http/session/HTTPTransaction.h

@@ -257,6 +257,7 @@ class HTTPTransactionHandler : public TraceEventObserver {
    * invoked in cases that violate an internal invariant that is fatal to the
    * transaction but can be recoverable for the session or library.  One such
    * example is mis-use of the egress APIs (sendBody() before sendHeaders()).
+   *
    */
   virtual void onInvariantViolation(const HTTPException& error) noexcept {
     LOG(FATAL) << error.what();

third-party/proxygen/src/proxygen/lib/http/session/test/DownstreamTransactionTest.cpp

@@ -158,7 +158,6 @@ TEST_F(DownstreamTransactionTest, InvariantViolationHandler) {
   EXPECT_CALL(transport_, sendAbort(_, _));
   EXPECT_CALL(handler_, _detachTransaction());
   EXPECT_CALL(transport_, detach(&txn));
-
   txn.setHandler(&handler_);
   // Send body before headers -- oops;
   txn.sendBody(makeBuf(10));