Popen.communicate()是否隐式调用Popen.wait()？

Question

在Python3文档中，它在https://docs.python.org/3/library/subprocess.html#subprocess.Popen.communicate下面声明

等待进程终止。

这是否意味着Popen.communicate()也调用了Popen.wait()，这样我就可以通过在p2.returncode之前不写p2.wait()来走捷径了：

  p0 = subprocess.Popen(["/usr/bin/svn", "info"], stdout=subprocess.PIPE)
  p1 = subprocess.Popen(["/bin/grep", "Revision:"], stdin=p0.stdout, stdout=subprocess.PIPE)
  p2 = subprocess.Popen(["/bin/sed", r"s/Revision: //g"], stdin=p1.stdout, stdout=subprocess.PIPE,universal_newlines=True)
  stdout, stderr = p2.communicate()# implicitly calls p2.wait() to wait for exit code?
  info_struct.exitcode = p2.returncode

而不是

  p0 = subprocess.Popen(["/usr/bin/svn", "info"], stdout=subprocess.PIPE)
  p1 = subprocess.Popen(["/bin/grep", "Revision:"], stdin=p0.stdout, stdout=subprocess.PIPE)
  p2 = subprocess.Popen(["/bin/sed", r"s/Revision: //g"], stdin=p1.stdout, stdout=subprocess.PIPE,universal_newlines=True)
  stdout, stderr = p2.communicate()# implicitly calls p2.wait() to wait for exit code?
  p2.wait()# explicit wait for exit code call
  info_struct.exitcode = p2.returncode

Answer 1

是的，确实如此。请参阅源代码 (Python3.6.1版本链接)：

sts = self.wait(timeout=self._remaining_time(endtime))

您不必亲自调用p2.wait()，该进程已在此点结束。