[erlang-bugs] Trace bug?

[Robert Virding]

Can anyone tell me if this is a bug? If not how do I get around it in
simple way?

Robert



On 27 May 2014 17:45, Robert Virding <rvirding@REDACTED> wrote:

> We have discovered strange behaviour when tracing message sends. We turn
> on tracing message send for a process. In R16 and 17 it seems like there is
> no trace message when sending to a registered process name, while sending
> to a pid generates a trace message as it should. In R15 however you get a
> trace message both sending to a registered name and hen sending to a pid.
> Is this a bug or is it a new undocumented feature?
>
> As an example I include simple program in which worker sends a message to
> a registered server and the server replies by sending the worker pid. Here
> are outputs when running in 17:
>
> Erlang/OTP 17 [erts-6.0] [source-07b8f44] [64-bit] [smp:4:4]
> [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
>
> Eshell V6.0  (abort with ^G)
> 1> c(trace_procs).
> {ok,trace_procs}
> 2> trace_procs:start().
> trace_procs 7 Server: '<0.39.0>'
> trace_procs 10 Worker: '<0.40.0>'
> trace_procs 34 Message: '{trace,<0.39.0>,send,answer,<0.40.0>}'
> trace_procs 34 Message: '{trace,<0.39.0>,send,answer,<0.40.0>}'
> trace_procs 34 Message: '{trace,<0.39.0>,send,answer,<0.40.0>}'
> trace_procs 34 Message: '{trace,<0.39.0>,send,answer,<0.40.0>}'
> trace_procs 34 Message: '{trace,<0.39.0>,send,answer,<0.40.0>}'
>
> and in R15:
>
> Erlang R15B03 (erts-5.9.3.1) [source] [64-bit] [smp:4:4] [async-threads:0]
> [hipe] [kernel-poll:false]
>
> Eshell V5.9.3.1  (abort with ^G)
> 1> c(trace_procs).
> {ok,trace_procs}
> 2> trace_procs:start().
> trace_procs 7 Server: '<0.38.0>'
> trace_procs 10 Worker: '<0.39.0>'
> trace_procs 34 Message: '{trace,<0.39.0>,send,{request,<0.39.0>},server}'
> trace_procs 34 Message: '{trace,<0.38.0>,send,answer,<0.39.0>}'
> trace_procs 34 Message: '{trace,<0.39.0>,send,{request,<0.39.0>},server}'
> trace_procs 34 Message: '{trace,<0.38.0>,send,answer,<0.39.0>}'
> trace_procs 34 Message: '{trace,<0.39.0>,send,{request,<0.39.0>},server}'
> trace_procs 34 Message: '{trace,<0.38.0>,send,answer,<0.39.0>}'
> trace_procs 34 Message: '{trace,<0.39.0>,send,{request,<0.39.0>},server}'
>
> What gives?
>
> Robert
>
>
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