From: Eric Wong <normalperson@...>
Date: 2018-11-02T21:14:53+00:00
Subject: [ruby-core:89685] Re: [Ruby trunk Feature#15277] at_exec

ruby-core@marc-andre.ca wrote:
> https://bugs.ruby-lang.org/issues/15277

Would this work for subprocesses? (system, spawn, ``, popen, ...)
(if so, it would defeat vfork optimization we do under Linux)

> There's currently no easy way to have code executed before a subsequent call
> to `exec`. One has to monkey-patch the builtin method.
> 
> Use case: we roll our own in `DeepCover`. Some test suites will call `exec`,
> and we need to store our counters before that happens.

As described above, Ruby already has a mechanism for hooking
existing method calls.  I tend to avoid monkey patching because
it leads to surprising behavior.  However, `at_exec` would have
the SAME surprises as monkey-patching.

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