[PATCH v3 01/16] python: Update for pylint 2.10

[John Snow]

A few new annoyances. Of note is the new warning for an unspecified
encoding when opening a text file, which actually does indicate a
potentially real problem; see
https://www.python.org/dev/peps/pep-0597/#motivation

Use LC_CTYPE to determine an encoding to use for interpreting QEMU's
terminal output. Note that Python states: "language code and encoding
may be None if their values cannot be determined" -- use a platform
default as a backup.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 python/qemu/machine/machine.py | 9 ++++++++-
 python/setup.cfg               | 1 +
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/python/qemu/machine/machine.py b/python/qemu/machine/machine.py
index a7081b1845..51b6e79a13 100644
--- a/python/qemu/machine/machine.py
+++ b/python/qemu/machine/machine.py
@@ -19,6 +19,7 @@
 
 import errno
 from itertools import chain
+import locale
 import logging
 import os
 import shutil
@@ -290,8 +291,14 @@ def get_pid(self) -> Optional[int]:
         return self._subp.pid
 
     def _load_io_log(self) -> None:
+        # Assume that the output encoding of QEMU's terminal output
+        # is defined by our locale. If indeterminate, use a platform default.
+        _, encoding = locale.getlocale()
+        if encoding is None:
+            encoding = locale.getpreferredencoding(do_setlocale=False)
         if self._qemu_log_path is not None:
-            with open(self._qemu_log_path, "r") as iolog:
+            with open(self._qemu_log_path, "r",
+                      encoding=encoding) as iolog:
                 self._iolog = iolog.read()
 
     @property
diff --git a/python/setup.cfg b/python/setup.cfg
index 83909c1c97..0f0cab098f 100644
--- a/python/setup.cfg
+++ b/python/setup.cfg
@@ -104,6 +104,7 @@ good-names=i,
 [pylint.similarities]
 # Ignore imports when computing similarities.
 ignore-imports=yes
+ignore-signatures=yes
 
 # Minimum lines number of a similarity.
 # TODO: Remove after we opt in to Pylint 2.8.3. See commit msg.
-- 
2.31.1