[PATCH v3 09/16] python/machine.py: Don't modify state in _base_args()

[John Snow]

Don't append to the _remove_files list during _base_args; instead do so
during _launch. Rework _base_args as a @property to help facilitate
this impression.

This has the additional benefit of making the type of _console_address
easier to analyze statically.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 python/qemu/machine.py | 16 ++++++++++------
 python/qemu/qtest.py   | 11 ++++++++---
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/python/qemu/machine.py b/python/qemu/machine.py
index aae78e3bc87..92528a44097 100644
--- a/python/qemu/machine.py
+++ b/python/qemu/machine.py
@@ -26,6 +26,7 @@
 import socket
 import tempfile
 from typing import (
+    List,
     Optional,
     Type,
 )
@@ -123,7 +124,9 @@ def __init__(self, binary, args=None, wrapper=None, 
name=None,
         self._console_index = 0
         self._console_set = False
         self._console_device_type = None
-        self._console_address = None
+        self._console_address = os.path.join(
+            self._sock_dir, f"{self._name}-console.sock"
+        )
         self._console_socket = None
         self._remove_files = []
         self._killed = False
@@ -239,7 +242,8 @@ def _load_io_log(self):
             with open(self._qemu_log_path, "r") as iolog:
                 self._iolog = iolog.read()
 
-    def _base_args(self):
+    @property
+    def _base_args(self) -> List[str]:
         args = ['-display', 'none', '-vga', 'none']
 
         if self._qmp_set:
@@ -257,9 +261,6 @@ def _base_args(self):
         for _ in range(self._console_index):
             args.extend(['-serial', 'null'])
         if self._console_set:
-            self._console_address = os.path.join(self._sock_dir,
-                                                 self._name + "-console.sock")
-            self._remove_files.append(self._console_address)
             chardev = ('socket,id=console,path=%s,server,nowait' %
                        self._console_address)
             args.extend(['-chardev', chardev])
@@ -275,6 +276,9 @@ def _pre_launch(self):
         self._qemu_log_path = os.path.join(self._temp_dir, self._name + ".log")
         self._qemu_log_file = open(self._qemu_log_path, 'wb')
 
+        if self._console_set:
+            self._remove_files.append(self._console_address)
+
         if self._qmp_set:
             if self._remove_monitor_sockfile:
                 assert isinstance(self._monitor_address, str)
@@ -349,7 +353,7 @@ def _launch(self):
         devnull = open(os.path.devnull, 'rb')
         self._pre_launch()
         self._qemu_full_args = (self._wrapper + [self._binary] +
-                                self._base_args() + self._args)
+                                self._base_args + self._args)
         LOG.debug('VM launch command: %r', ' '.join(self._qemu_full_args))
         self._popen = subprocess.Popen(self._qemu_full_args,
                                        stdin=devnull,
diff --git a/python/qemu/qtest.py b/python/qemu/qtest.py
index 888c8bd2f60..05c63a1d583 100644
--- a/python/qemu/qtest.py
+++ b/python/qemu/qtest.py
@@ -19,7 +19,11 @@
 
 import socket
 import os
-from typing import Optional, TextIO
+from typing import (
+    List,
+    Optional,
+    TextIO,
+)
 
 from .machine import QEMUMachine
 
@@ -111,8 +115,9 @@ def __init__(self, binary, args=None, name=None, 
test_dir="/var/tmp",
         self._qtest = None
         self._qtest_path = os.path.join(sock_dir, name + "-qtest.sock")
 
-    def _base_args(self):
-        args = super()._base_args()
+    @property
+    def _base_args(self) -> List[str]:
+        args = super()._base_args
         args.extend(['-qtest', 'unix:path=' + self._qtest_path,
                      '-accel', 'qtest'])
         return args
-- 
2.21.3