Remove support code for Python < 3.4

Reviewed-by: Zac Medico <zmedico@gentoo.org>
Closes: https://github.com/gentoo/portage/pull/576
Signed-off-by: Michał Górny <mgorny@gentoo.org>

13 files changed, 20 insertions, 163 deletions

diff --git a/lib/_emerge/AsynchronousLock.py b/lib/_emerge/AsynchronousLock.py
index aed1bcb15..d2a6773ff 100644
--- a/lib/_emerge/AsynchronousLock.py
+++ b/lib/_emerge/AsynchronousLock.py
@@ -1,4 +1,4 @@
-# Copyright 2010-2018 Gentoo Foundation
+# Copyright 2010-2020 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 import fcntl
@@ -192,16 +192,6 @@ class _LockProcess(AbstractPollTask):
 		fcntl.fcntl(in_pr, fcntl.F_SETFL,
 			fcntl.fcntl(in_pr, fcntl.F_GETFL) | os.O_NONBLOCK)
 
-		# FD_CLOEXEC is enabled by default in Python >=3.4.
-		if sys.hexversion < 0x3040000:
-			try:
-				fcntl.FD_CLOEXEC
-			except AttributeError:
-				pass
-			else:
-				fcntl.fcntl(in_pr, fcntl.F_SETFD,
-					fcntl.fcntl(in_pr, fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
-
 		self.scheduler.add_reader(in_pr, self._output_handler)
 		self._registered = True
 		self._proc = SpawnProcess(
diff --git a/lib/_emerge/EbuildMetadataPhase.py b/lib/_emerge/EbuildMetadataPhase.py
index efe71892c..d00f194c2 100644
--- a/lib/_emerge/EbuildMetadataPhase.py
+++ b/lib/_emerge/EbuildMetadataPhase.py
@@ -1,4 +1,4 @@
-# Copyright 1999-2018 Gentoo Foundation
+# Copyright 1999-2020 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 from _emerge.SubProcess import SubProcess
@@ -93,16 +93,6 @@ class EbuildMetadataPhase(SubProcess):
 		fcntl.fcntl(master_fd, fcntl.F_SETFL,
 			fcntl.fcntl(master_fd, fcntl.F_GETFL) | os.O_NONBLOCK)
 
-		# FD_CLOEXEC is enabled by default in Python >=3.4.
-		if sys.hexversion < 0x3040000:
-			try:
-				fcntl.FD_CLOEXEC
-			except AttributeError:
-				pass
-			else:
-				fcntl.fcntl(master_fd, fcntl.F_SETFD,
-					fcntl.fcntl(master_fd, fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
-
 		fd_pipes[slave_fd] = slave_fd
 		settings["PORTAGE_PIPE_FD"] = str(slave_fd)
 
diff --git a/lib/_emerge/FifoIpcDaemon.py b/lib/_emerge/FifoIpcDaemon.py
index 2ec69d1cb..ab1fdb572 100644
--- a/lib/_emerge/FifoIpcDaemon.py
+++ b/lib/_emerge/FifoIpcDaemon.py
@@ -1,14 +1,8 @@
-# Copyright 2010-2018 Gentoo Foundation
+# Copyright 2010-2020 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 import sys
 
-try:
-	import fcntl
-except ImportError:
-	#  http://bugs.jython.org/issue1074
-	fcntl = None
-
 from portage import os
 from _emerge.AbstractPollTask import AbstractPollTask
 from portage.cache.mappings import slot_dict_class
@@ -28,17 +22,6 @@ class FifoIpcDaemon(AbstractPollTask):
 		self._files.pipe_in = \
 			os.open(self.input_fifo, os.O_RDONLY|os.O_NONBLOCK)
 
-		# FD_CLOEXEC is enabled by default in Python >=3.4.
-		if sys.hexversion < 0x3040000 and fcntl is not None:
-			try:
-				fcntl.FD_CLOEXEC
-			except AttributeError:
-				pass
-			else:
-				fcntl.fcntl(self._files.pipe_in, fcntl.F_SETFD,
-					fcntl.fcntl(self._files.pipe_in,
-						fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
-
 		self.scheduler.add_reader(
 			self._files.pipe_in,
 			self._input_handler)
@@ -55,17 +38,6 @@ class FifoIpcDaemon(AbstractPollTask):
 		self._files.pipe_in = \
 			os.open(self.input_fifo, os.O_RDONLY|os.O_NONBLOCK)
 
-		# FD_CLOEXEC is enabled by default in Python >=3.4.
-		if sys.hexversion < 0x3040000 and fcntl is not None:
-			try:
-				fcntl.FD_CLOEXEC
-			except AttributeError:
-				pass
-			else:
-				fcntl.fcntl(self._files.pipe_in, fcntl.F_SETFD,
-					fcntl.fcntl(self._files.pipe_in,
-						fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
-
 		self.scheduler.add_reader(
 			self._files.pipe_in,
 			self._input_handler)
diff --git a/lib/_emerge/PipeReader.py b/lib/_emerge/PipeReader.py
index 1aa5ee3bf..90a31679e 100644
--- a/lib/_emerge/PipeReader.py
+++ b/lib/_emerge/PipeReader.py
@@ -1,4 +1,4 @@
-# Copyright 1999-2018 Gentoo Foundation
+# Copyright 1999-2020 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 import fcntl
@@ -27,16 +27,6 @@ class PipeReader(AbstractPollTask):
 			fcntl.fcntl(fd, fcntl.F_SETFL,
 				fcntl.fcntl(fd, fcntl.F_GETFL) | os.O_NONBLOCK)
 
-			# FD_CLOEXEC is enabled by default in Python >=3.4.
-			if sys.hexversion < 0x3040000:
-				try:
-					fcntl.FD_CLOEXEC
-				except AttributeError:
-					pass
-				else:
-					fcntl.fcntl(fd, fcntl.F_SETFD,
-						fcntl.fcntl(fd, fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
-
 			if self._use_array:
 				self.scheduler.add_reader(fd, self._array_output_handler, f)
 			else:
diff --git a/lib/_emerge/SpawnProcess.py b/lib/_emerge/SpawnProcess.py
index 60239a65a..91f5ed1a8 100644
--- a/lib/_emerge/SpawnProcess.py
+++ b/lib/_emerge/SpawnProcess.py
@@ -1,12 +1,6 @@
 # Copyright 2008-2020 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
-try:
-	import fcntl
-except ImportError:
-	# http://bugs.jython.org/issue1074
-	fcntl = None
-
 import errno
 import logging
 import signal
@@ -129,16 +123,6 @@ class SpawnProcess(SubProcess):
 		stdout_fd = None
 		if can_log and not self.background:
 			stdout_fd = os.dup(fd_pipes_orig[1])
-			# FD_CLOEXEC is enabled by default in Python >=3.4.
-			if sys.hexversion < 0x3040000 and fcntl is not None:
-				try:
-					fcntl.FD_CLOEXEC
-				except AttributeError:
-					pass
-				else:
-					fcntl.fcntl(stdout_fd, fcntl.F_SETFD,
-						fcntl.fcntl(stdout_fd,
-						fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
 
 		build_logger = BuildLogger(env=self.env,
 			log_path=log_file_path,
diff --git a/lib/portage/dbapi/_MergeProcess.py b/lib/portage/dbapi/_MergeProcess.py
index 236d1a255..274ef586f 100644
--- a/lib/portage/dbapi/_MergeProcess.py
+++ b/lib/portage/dbapi/_MergeProcess.py
@@ -112,16 +112,6 @@ class MergeProcess(ForkProcess):
 		fcntl.fcntl(elog_reader_fd, fcntl.F_SETFL,
 			fcntl.fcntl(elog_reader_fd, fcntl.F_GETFL) | os.O_NONBLOCK)
 
-		# FD_CLOEXEC is enabled by default in Python >=3.4.
-		if sys.hexversion < 0x3040000:
-			try:
-				fcntl.FD_CLOEXEC
-			except AttributeError:
-				pass
-			else:
-				fcntl.fcntl(elog_reader_fd, fcntl.F_SETFD,
-					fcntl.fcntl(elog_reader_fd, fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
-
 		blockers = None
 		if self.blockers is not None:
 			# Query blockers in the main process, since closing
diff --git a/lib/portage/locks.py b/lib/portage/locks.py
index 5c7a3f266..9df0089e6 100644
--- a/lib/portage/locks.py
+++ b/lib/portage/locks.py
@@ -330,17 +330,6 @@ def _lockfile_iteration(mypath, wantnewlockfile=False, unlinkfile=False,
 				return None
 
 	if myfd != HARDLINK_FD:
-
-		# FD_CLOEXEC is enabled by default in Python >=3.4.
-		if sys.hexversion < 0x3040000:
-			try:
-				fcntl.FD_CLOEXEC
-			except AttributeError:
-				pass
-			else:
-				fcntl.fcntl(myfd, fcntl.F_SETFD,
-					fcntl.fcntl(myfd, fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
-
 		_lock_manager(myfd, os.fstat(myfd) if fstat_result is None else fstat_result, mypath)
 
 	writemsg(str((lockfilename, myfd, unlinkfile)) + "\n", 1)
diff --git a/lib/portage/process.py b/lib/portage/process.py
index f550bcb30..6af668db4 100644
--- a/lib/portage/process.py
+++ b/lib/portage/process.py
@@ -223,7 +223,7 @@ def cleanup():
 def spawn(mycommand, env=None, opt_name=None, fd_pipes=None, returnpid=False,
           uid=None, gid=None, groups=None, umask=None, cwd=None, logfile=None,
           path_lookup=True, pre_exec=None,
-          close_fds=(sys.version_info < (3, 4)), unshare_net=False,
+          close_fds=False, unshare_net=False,
           unshare_ipc=False, unshare_mount=False, unshare_pid=False,
 	  cgroup=None):
 	"""
diff --git a/lib/portage/util/_async/PipeLogger.py b/lib/portage/util/_async/PipeLogger.py
index cc746bf52..aa240806d 100644
--- a/lib/portage/util/_async/PipeLogger.py
+++ b/lib/portage/util/_async/PipeLogger.py
@@ -54,16 +54,6 @@ class PipeLogger(AbstractPollTask):
 		fcntl.fcntl(fd, fcntl.F_SETFL,
 			fcntl.fcntl(fd, fcntl.F_GETFL) | os.O_NONBLOCK)
 
-		# FD_CLOEXEC is enabled by default in Python >=3.4.
-		if sys.hexversion < 0x3040000:
-			try:
-				fcntl.FD_CLOEXEC
-			except AttributeError:
-				pass
-			else:
-				fcntl.fcntl(fd, fcntl.F_SETFD,
-					fcntl.fcntl(fd, fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
-
 		self._io_loop_task = asyncio.ensure_future(self._io_loop(self.input_fd), loop=self.scheduler)
 		self._io_loop_task.add_done_callback(self._io_loop_done)
 		self._registered = True
diff --git a/lib/portage/util/_eventloop/EventLoop.py b/lib/portage/util/_eventloop/EventLoop.py
index a3bea97aa..f870190d9 100644
--- a/lib/portage/util/_eventloop/EventLoop.py
+++ b/lib/portage/util/_eventloop/EventLoop.py
@@ -168,18 +168,6 @@ class EventLoop(object):
 				# IOError: [Errno 38] Function not implemented
 				pass
 			else:
-
-				# FD_CLOEXEC is enabled by default in Python >=3.4.
-				if sys.hexversion < 0x3040000 and fcntl is not None:
-					try:
-						fcntl.FD_CLOEXEC
-					except AttributeError:
-						pass
-					else:
-						fcntl.fcntl(epoll_obj.fileno(), fcntl.F_SETFD,
-							fcntl.fcntl(epoll_obj.fileno(),
-								fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
-
 				self._poll_obj = _epoll_adapter(epoll_obj)
 				self.IO_ERR = select.EPOLLERR
 				self.IO_HUP = select.EPOLLHUP
@@ -432,17 +420,6 @@ class EventLoop(object):
 					fcntl.fcntl(self._sigchld_read,
 					fcntl.F_GETFL) | os.O_NONBLOCK)
 
-				# FD_CLOEXEC is enabled by default in Python >=3.4.
-				if sys.hexversion < 0x3040000:
-					try:
-						fcntl.FD_CLOEXEC
-					except AttributeError:
-						pass
-					else:
-						fcntl.fcntl(self._sigchld_read, fcntl.F_SETFD,
-							fcntl.fcntl(self._sigchld_read,
-							fcntl.F_GETFD) | fcntl.FD_CLOEXEC)
-
 			# The IO watch is dynamically registered and unregistered as
 			# needed, since we don't want to consider it as a valid source
 			# of events when there are no child listeners. It's important
diff --git a/lib/portage/util/_eventloop/global_event_loop.py b/lib/portage/util/_eventloop/global_event_loop.py
index 2f6371dc1..73b7db0d3 100644
--- a/lib/portage/util/_eventloop/global_event_loop.py
+++ b/lib/portage/util/_eventloop/global_event_loop.py
@@ -1,4 +1,4 @@
-# Copyright 2012 Gentoo Foundation
+# Copyright 2012-2020 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 import os
@@ -7,16 +7,11 @@ import sys
 from .EventLoop import EventLoop
 from portage.util._eventloop.asyncio_event_loop import AsyncioEventLoop
 
-_asyncio_enabled = sys.version_info >= (3, 4)
-_default_constructor = AsyncioEventLoop if _asyncio_enabled else EventLoop
-
-# If _default_constructor doesn't support multiprocessing,
-# then _multiprocessing_constructor is used in subprocesses.
-_multiprocessing_constructor = EventLoop
 
 _MAIN_PID = os.getpid()
 _instances = {}
 
+
 def global_event_loop():
 	"""
 	Get a global EventLoop (or compatible object) instance which
@@ -28,9 +23,11 @@ def global_event_loop():
 	if instance is not None:
 		return instance
 
-	constructor = _default_constructor
+	constructor = AsyncioEventLoop
+	# If the default constructor doesn't support multiprocessing,
+	# then multiprocessing constructor is used in subprocesses.
 	if not constructor.supports_multiprocessing and pid != _MAIN_PID:
-		constructor = _multiprocessing_constructor
+		constructor = EventLoop
 
 	# Use the _asyncio_wrapper attribute, so that unit tests can compare
 	# the reference to one retured from _wrap_loop(), since they should
diff --git a/lib/portage/util/futures/_asyncio/__init__.py b/lib/portage/util/futures/_asyncio/__init__.py
index f4b03891f..04034911d 100644
--- a/lib/portage/util/futures/_asyncio/__init__.py
+++ b/lib/portage/util/futures/_asyncio/__init__.py
@@ -41,7 +41,6 @@ portage.proxy.lazyimport.lazyimport(globals(),
 )
 from portage.util._eventloop.asyncio_event_loop import AsyncioEventLoop as _AsyncioEventLoop
 from portage.util._eventloop.global_event_loop import (
-	_asyncio_enabled,
 	global_event_loop as _global_event_loop,
 )
 from portage.util.futures.futures import (
@@ -111,11 +110,6 @@ def set_child_watcher(watcher):
     return get_event_loop_policy().set_child_watcher(watcher)
 
 
-# Python 3.4 and later implement PEP 446, which makes newly
-# created file descriptors non-inheritable by default.
-_close_fds_default = sys.version_info < (3, 4)
-
-
 def create_subprocess_exec(*args, **kwargs):
 	"""
 	Create a subprocess.
@@ -138,8 +132,10 @@ def create_subprocess_exec(*args, **kwargs):
 	@return: subset of asyncio.subprocess.Process interface
 	"""
 	loop = _wrap_loop(kwargs.pop('loop', None))
-	kwargs.setdefault('close_fds', _close_fds_default)
-	if _asyncio_enabled and isinstance(loop._asyncio_wrapper, _AsyncioEventLoop):
+	# Python 3.4 and later implement PEP 446, which makes newly
+	# created file descriptors non-inheritable by default.
+	kwargs.setdefault('close_fds', False)
+	if isinstance(loop._asyncio_wrapper, _AsyncioEventLoop):
 		# Use the real asyncio create_subprocess_exec (loop argument
 		# is deprecated since since Python 3.8).
 		return _real_asyncio.create_subprocess_exec(*args, **kwargs)
@@ -191,7 +187,7 @@ def ensure_future(coro_or_future, loop=None):
 	@return: an instance of Future
 	"""
 	loop = _wrap_loop(loop)
-	if _asyncio_enabled and isinstance(loop._asyncio_wrapper, _AsyncioEventLoop):
+	if isinstance(loop._asyncio_wrapper, _AsyncioEventLoop):
 		# Use the real asyncio loop and ensure_future.
 		return _real_asyncio.ensure_future(
 			coro_or_future, loop=loop._asyncio_wrapper._loop)
@@ -240,18 +236,12 @@ def _wrap_loop(loop=None):
 	@rtype: asyncio.AbstractEventLoop (or compatible)
 	@return: event loop
 	"""
-	return loop or _global_event_loop()
-
-
-if _asyncio_enabled:
 	# The default loop returned by _wrap_loop should be consistent
 	# with global_event_loop, in order to avoid accidental registration
 	# of callbacks with a loop that is not intended to run.
-
-	def _wrap_loop(loop=None):
-		loop = loop or _global_event_loop()
-		return (loop if hasattr(loop, '_asyncio_wrapper')
-			else _AsyncioEventLoop(loop=loop))
+	loop = loop or _global_event_loop()
+	return (loop if hasattr(loop, '_asyncio_wrapper')
+		else _AsyncioEventLoop(loop=loop))
 
 
 def _safe_loop():
diff --git a/lib/portage/util/futures/unix_events.py b/lib/portage/util/futures/unix_events.py
index 3381eaa7d..4adf021ce 100644
--- a/lib/portage/util/futures/unix_events.py
+++ b/lib/portage/util/futures/unix_events.py
@@ -32,7 +32,6 @@ import subprocess
 import sys
 
 from portage.util._eventloop.global_event_loop import (
-	_asyncio_enabled,
 	global_event_loop as _global_event_loop,
 )
 from portage.util.futures import (
@@ -701,5 +700,4 @@ class _AsyncioEventLoopPolicy(_PortageEventLoopPolicy):
 		return super(_AsyncioEventLoopPolicy, self).get_child_watcher()
 
 
-DefaultEventLoopPolicy = (_AsyncioEventLoopPolicy if _asyncio_enabled
-	else _PortageEventLoopPolicy)
+DefaultEventLoopPolicy = _AsyncioEventLoopPolicy