Use utf-8 encoding by default for all subprocess communication. (#10558)

This seems to mostly be a problem on windows. There is even a PEP
out to make this the default: https://www.python.org/dev/peps/pep-0597

Fixes: #10551

Author: sbc100

tools/shared.py

@@ -177,19 +177,20 @@ def run_process(cmd, check=True, input=None, *args, **kw):
 
   debug_text = '%sexecuted %s' % ('successfully ' if check else '', ' '.join(cmd))
 
-  if hasattr(subprocess, "run"):
-    ret = subprocess.run(cmd, check=check, input=input, *args, **kw)
-    logger.debug(debug_text)
-    return ret
+  if hasattr(subprocess, 'run'):
+    # Python 3.5 and above only
+    kw.setdefault('encoding', 'utf-8')
+    result = subprocess.run(cmd, check=check, input=input, *args, **kw)
+  else:
+    # Python 2 compatibility: Introduce Python 3 subprocess.run-like behavior
+    if input is not None:
+      kw['stdin'] = subprocess.PIPE
+    proc = Popen(cmd, *args, **kw)
+    stdout, stderr = proc.communicate(input)
+    result = Py2CompletedProcess(cmd, proc.returncode, stdout, stderr)
+    if check:
+      result.check_returncode()
 
-  # Python 2 compatibility: Introduce Python 3 subprocess.run-like behavior
-  if input is not None:
-    kw['stdin'] = subprocess.PIPE
-  proc = Popen(cmd, *args, **kw)
-  stdout, stderr = proc.communicate(input)
-  result = Py2CompletedProcess(cmd, proc.returncode, stdout, stderr)
-  if check:
-    result.check_returncode()
   logger.debug(debug_text)
   return result