[Tcl-bugs] [ tcl-Bugs-3072640 ] trace execution + yield fails ASSERT

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Bugs item #3072640, was opened at 2010-09-21 10:08
Message generated for change (Comment added) made by msofer
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https://sourceforge.net/tracker/?func=detail&atid=110894&aid=3072640&group_id=10894

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Category: 60. NRE and coroutines
Group: development: 8.6b1.1
Status: Open
Resolution: None
>Priority: 9
Private: No
Submitted By: Twylite (twylite)
Assigned to: miguel sofer (msofer)
Summary: trace execution + yield fails ASSERT

Initial Comment:
Adding an execution (enterstep) trace to a proc that yields causes an ASSERT to fail, crashing the interp.

Environment: 
- x86 32 bit
- Windows XP SP3 with latest patches
- Tcl 8.6b1.2 (from CVS 2010/08/30), also appears in Tcl 8.6b1.1)

Symptom:
- Assertion failed (MS Visual C++ Runtime Library error popup)
- Source of failure: tclExecute.c:2882 		NRE_ASSERT(BP == corPtr->eePtr->bottomPtr);

Code to reproduce:
--
  proc generate {n} {
    for {set i 0} {$i < $n} {incr i} {
      yield $i
    }
  }
  proc t {args} { puts "Trace: $args" }
  trace add execution ::generate enterstep ::t
  coroutine coro generate 5
--

Further information:
- Putting the [yield] into the trace handler ::t rather than the proc being traced results in the error "cannot yield: C stack busy", but doesn't lead to a crash.


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>Comment By: miguel sofer (msofer)
Date: 2010-09-22 14:35

Message:
Issue seemed fixed by today's commit, which fixed a different bug
discovered by Patch #3072080. BUT: new test execute-10.3 still bombs (it
doesn't with the patch)

----------------------------------------------------------------------

Comment By: miguel sofer (msofer)
Date: 2010-09-22 08:17

Message:
Patch #3072080 fixes this issue (which seems hard to hunt down in the
current NRE implementation); resolution pending the decision on adopting
that patch.

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=110894&aid=3072640&group_id=10894