From: "ko1 (Koichi Sasada)" <redmine@...>
Date: 2013-01-07T15:01:29+09:00
Subject: [ruby-core:51289] [ruby-trunk - Bug #7668][Assigned] set_trace_func and TracePoint don't handle exception in finish frame


Issue #7668 has been reported by ko1 (Koichi Sasada).

----------------------------------------
Bug #7668: set_trace_func and TracePoint don't handle exception in finish frame 
https://bugs.ruby-lang.org/issues/7668

Author: ko1 (Koichi Sasada)
Status: Assigned
Priority: Urgent
Assignee: ko1 (Koichi Sasada)
Category: core
Target version: 2.0.0
ruby -v: ruby 2.0.0dev (2013-01-07 trunk 38719) [i686-linux]



The following code should trap exception correctly (should output ":ok"):

####
def m
  a = 1
  b = 2
  c = 3
  raise
end

trace = TracePoint.new{|tp|
  p tp
  raise # if tp.event == :c_return # if tp.event == :b_return
}

begin
  trace.enable{
    m
  }
rescue => e
  p :ok
end
####

But it outputs same event hook infinite:

#<TracePoint:b_call@/home/ko1/src/ruby/trunk/test.rb:15>
#<TracePoint:b_return@/home/ko1/src/ruby/trunk/test.rb:15>
#<TracePoint:c_return `enable'@/home/ko1/src/ruby/trunk/test.rb:15>
#<TracePoint:c_return `enable'@/home/ko1/src/ruby/trunk/test.rb:15>
#<TracePoint:c_return `enable'@/home/ko1/src/ruby/trunk/test.rb:15>
...

It is a bug.

This patch solve this issue:

Index: vm_trace.c
===================================================================
--- vm_trace.c	(revision 38718)
+++ vm_trace.c	(working copy)
@@ -316,7 +316,12 @@ rb_threadptr_exec_event_hooks_orig(rb_tr
 	th->vm->trace_running--;
 
 	if (state) {
-	    if (pop_p) th->cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(th->cfp);
+	    if (pop_p) {
+		if (VM_FRAME_TYPE_FINISH_P(th->cfp)) {
+		    th->tag = th->tag->prev;
+		}
+		th->cfp = RUBY_VM_PREVIOUS_CONTROL_FRAME(th->cfp);
+	    }
 	    TH_JUMP_TAG(th, state);
 	}
 	th->state = outer_state;


Output:
#<TracePoint:b_call@../trunk/test.rb:15>
#<TracePoint:b_return@../trunk/test.rb:15>
:ok




-- 
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