Module: Homebrew::VernierForkGuard Private

Extended by:
T::Sig
Defined in:
prof/vernier_fork_guard.rb

This module is part of a private API. This module may only be used in the Homebrew/brew repository. Third parties should avoid using this module if possible, as it may be removed or changed without warning.

Class Method Summary collapse

Methods included from T::Sig

sig

Class Method Details

.stop_running_collector ⇒ void

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

This method returns an undefined value.



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# File 'prof/vernier_fork_guard.rb', line 46

def self.stop_running_collector
  return unless Object.const_defined?(:Vernier)

  autorun = T.let(Object.const_get(:Vernier).const_get(:Autorun), T.untyped)
  return unless autorun.running?

  autorun.stop
end

.without_running_collector(&block) ⇒ Object

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Raises:

  • (ArgumentError) 


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# File 'prof/vernier_fork_guard.rb', line 15

def self.without_running_collector(&block)
  raise ArgumentError, "block required" unless block

  return yield unless Object.const_defined?(:Vernier)

  # `Vernier::Autorun` is created by `-r vernier/autorun`; Sorbet's RBI for
  # the gem does not expose it, so keep this lookup dynamic.
  autorun = T.let(Object.const_get(:Vernier).const_get(:Autorun), T.untyped)
  return yield unless autorun.running?

  # Vernier registers internal thread hooks and owns native mutexes while the
  # collector is running. Forking with that state active can leave the child
  # process stuck before it reaches exec.
  #
  # Stopping here loses samples taken during fork setup, but that is a better
  # tradeoff than hanging the profiled command. The common process helpers use
  # spawn while `HOMEBREW_SPAWN_SYSTEM` is set, so this remains a fallback.
  autorun.collector.stop
  autorun.collector = nil
  pid = nil
  begin
    pid = yield
  ensure
    # Restart only in the parent. In the child, `yield` returns nil and exec
    # should happen immediately through the original fork path.
    autorun.start if pid && !autorun.running?
  end
  pid
end