Unclear status of Debug::SetMessageHandler2 function

[Peter Rybin]

Hi Soren

I am looking at  Debug::SetMessageHandler2  function and I see some controversy about its status.

It uses HandleScope, that means it requires to be called from a regular V8 thread with locker. On the other hand  DebuggerAgent::Run  calls this function from its thread without acquiring any lockers. It starts to fail if you activate Lockers yourself, probably nobody has tried it yet.

I tried to remove HandleScope, thinking that this function should not touch any sensitive part of V8 at all and thus being available from any thread without lockers, but tests demonstrate the opposite:


11 Handle() /home/prybin/src-v8-3/src/handles-inl.h:42 0x080b5253   
10 v8::internal::CodeStub::GetCode() /home/prybin/src-v8-3/src/code-stubs.cc:114 0x081141ba   
9 BreakLocationIterator() /home/prybin/src-v8-3/src/debug.cc:76 0x08126ecf   
8 v8::internal::Debug::ClearAllBreakPoints() /home/prybin/src-v8-3/src/debug.cc:983 0x08126ff7   
7 v8::internal::Debugger::UnloadDebugger() /home/prybin/src-v8-3/src/debug.cc:1997 0x0812705b   
6 v8::internal::Debugger::ListenersChanged() /home/prybin/src-v8-3/src/debug.cc:2221 0x081271d6   
5 v8::internal::Debugger::SetMessageHandler() /home/prybin/src-v8-3/src/debug.cc:2198 0x081271ff   
4 v8::Debug::SetMessageHandler2() /home/prybin/src-v8-3/src/api.cc:3675 0x080f0b87   
3 TestDebuggerUnload() /home/prybin/src-v8-3/test/cctest/test-debug.cc:4528 0x080af892   

My sample appication "lineprocessor" depends on this, so I guess we need some fixing here.

Peter