[ruby-core:44388] Re: [ruby-trunk - Bug #6288] Change error message for thread block to be less misleading

Hello,

2012/4/16 rklemme (Robert Klemme) <[e-mail]>:
>> If so, you should write "sleep" simply. f not, your code is
>> actually "deadlocked", in a common sense.
>
> There is no deadlock because there are no two threads (or processes) accessing resources in a bad order.  am not aware of any deadlock which can be caused by a single thread only. f you find a definition of deadlock which needs only a single thread / action / process please let us know.
>
> "A deadlock is a situation wherein two or more competing actions are each waiting for the other to finish, and thus neither ever does."
> http://en.wikipedia.org/wiki/Deadlock

I see.

But, what do you think about the following?

  m = Mutex.new
  m.lock
  m.lock  #=> deadlock; recursive locking

The article of wikipedia also says:

"For non-recursive locks, a lock may be entered only once (where a
single thread entering twice without unlocking will cause a
deadlock..."

The definition of "deadlock" is difficult :-)

My informal definition of "deadlock" is, a situation where
all threads are waiting for an action of other threads.
For example, Thread.stop, Queue#pop, Mutex#lock, etc. may
wait for other threads.  If the only thread do so in a
single threaded program, *all* threads are indeed waiting,
which is a deadlock in my definition.


Anyway, regardless of the definition, I think your message
proposal is better than the current, so I'll change it.
Thanks!

-- 
Yusuke Endoh <[e-mail]>