[PATCH] portage.getpid: call os.getpid() lazily

Call os.getpid() lazily, which eliminates getpid calls when possible
after os.fork() in the portage.process module.

Bug: https://bugs.gentoo.org/767913
Signed-off-by: Zac Medico <[email protected]>
---
 lib/portage/__init__.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/portage/__init__.py b/lib/portage/__init__.py
index 3c9f78497..24c9d8b89 100644
--- a/lib/portage/__init__.py
+++ b/lib/portage/__init__.py
@@ -375,7 +375,7 @@ _sync_mode = False
 class _ForkWatcher:
 	@staticmethod
 	def hook(_ForkWatcher):
-		_ForkWatcher.current_pid = _os.getpid()
+		_ForkWatcher.current_pid = None
 		# Force instantiation of a new event loop policy as a workaround
 		# for https://bugs.python.org/issue22087.
 		asyncio.set_event_loop_policy(None)
@@ -388,6 +388,8 @@ def getpid():
 	"""
 	Cached version of os.getpid(). ForkProcess updates the cache.
 	"""
+	if _ForkWatcher.current_pid is None:
+		_ForkWatcher.current_pid = _os.getpid()
 	return _ForkWatcher.current_pid
 
 def _get_stdin():
-- 
2.26.2