[inspector] V8DebuggerAgent cleanup

src/debug/debug.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/debug/debug.h"
 
 #include <memory>
 
 #include "src/api.h"
 #include "src/arguments.h"
@@ skipping 982 matching lines @@
 
   // Get the debug info (create it if it does not exist).
   auto summary = FrameSummary::GetTop(frame).AsJavaScript();
   Handle<JSFunction> function(summary.function());
   Handle<SharedFunctionInfo> shared(function->shared());
   if (!EnsureDebugInfo(shared)) return;
   Handle<DebugInfo> debug_info(shared->GetDebugInfo());
 
   BreakLocation location = BreakLocation::FromFrame(debug_info, js_frame);
 
+  // It is used at least in two cases:
+  // - step-next at return position from first callback in microtask will break
+  // in next callback,
+  // - step-next at return position when caller frame is blackboxed will break
+  // in next not blackboxed function called by caller frame if any.
+  // TODO(kozyatinskiy): remove it.
+  if (step_action == StepNext && location.IsReturn()) {
+    thread_local_.last_step_action_ = StepIn;
+    UpdateHookOnFunctionCall();
+  }
+
   // Any step at a return is a step-out.
   if (location.IsReturn()) step_action = StepOut;
   // A step-next at a tail call is a step-out.
   if (location.IsTailCall() && step_action == StepNext) step_action = StepOut;
   // A step-next in blackboxed function is a step-out.
   if (step_action == StepNext && IsBlackboxed(shared)) step_action = StepOut;
 
   thread_local_.last_statement_position_ =
       summary.abstract_code()->SourceStatementPosition(summary.code_offset());
   int current_frame_count = CurrentFrameCount();
@@ skipping 746 matching lines @@
   if (uncaught) {
     // Uncaught exceptions are reported by either flags.
     if (!(break_on_uncaught_exception_ || break_on_exception_)) return;
   } else {
     // Caught exceptions are reported is activated.
     if (!break_on_exception_) return;
   }
 
   {
     JavaScriptFrameIterator it(isolate_);
-    // Check whether the top frame is blackboxed or the break location is muted.
-    if (!it.done() && (IsMutedAtCurrentLocation(it.frame()) ||
-                       IsExceptionBlackboxed(uncaught))) {
+    // Check whether the top frame is blackboxed or the break location is muted
+    // or current JS stack trace is empty.
+    if (it.done() || IsMutedAtCurrentLocation(it.frame()) ||
+        IsExceptionBlackboxed(uncaught)) {
       return;
     }
   }
 
   DebugScope debug_scope(this);
   if (debug_scope.failed()) return;
 
   if (debug_delegate_) {
     HandleScope scope(isolate_);
 
@@ skipping 614 matching lines @@
   return v8::Utils::ToLocal(callback_data_);
 }
 
 
 v8::Isolate* EventDetailsImpl::GetIsolate() const {
   return reinterpret_cast<v8::Isolate*>(exec_state_->GetIsolate());
 }
 
 }  // namespace internal
 }  // namespace v8