[PATCH v7 05/31] python/machine: Disable pylint warning for open() in _pre_launch

[John Snow]

Shift the open() call later so that the pylint pragma applies *only* to
that one open() call. Add a note that suggests why this is safe: the
resource is unconditionally cleaned up in _post_shutdown().

_post_shutdown is called after failed launches (see launch()), and
unconditionally after every call to shutdown(), and therefore also on
__exit__.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Message-id: 20210517184808.3562549-6-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
---
 python/qemu/machine.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/python/qemu/machine.py b/python/qemu/machine.py
index 04e005f3811..c66bc6a9c69 100644
--- a/python/qemu/machine.py
+++ b/python/qemu/machine.py
@@ -306,7 +306,6 @@ def _base_args(self) -> List[str]:
 
     def _pre_launch(self) -> None:
         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)
@@ -321,6 +320,11 @@ def _pre_launch(self) -> None:
                 nickname=self._name
             )
 
+        # NOTE: Make sure any opened resources are *definitely* freed in
+        # _post_shutdown()!
+        # pylint: disable=consider-using-with
+        self._qemu_log_file = open(self._qemu_log_path, 'wb')
+
     def _post_launch(self) -> None:
         if self._qmp_connection:
             self._qmp.accept()
-- 
2.31.1