python: remove more instances of sys.version_info

We guarantee 3.5+ everywhere; remove more dead checks. In general, try
to avoid using version checks and instead prefer to attempt behavior
when possible.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200514035230.25756-1-jsnow@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

scripts/analyze-migration.py

@@ -25,11 +25,6 @@
 import sys
 
 
-MIN_PYTHON = (3, 2)
-if sys.version_info < MIN_PYTHON:
-    sys.exit("Python %s.%s or later is required.\n" % MIN_PYTHON)
-
-
 def mkdir_p(path):
     try:
         os.makedirs(path)

scripts/decodetree.py

@@ -75,13 +75,6 @@ def output(*args):
         output_fd.write(a)
 
 
-if sys.version_info >= (3, 4):
-    re_fullmatch = re.fullmatch
-else:
-    def re_fullmatch(pat, str):
-        return re.match('^' + pat + '$', str)
-
-
 def output_autogen():
     output('/* This file is autogenerated by scripts/decodetree.py.  */\n\n')
 
@@ -428,18 +421,18 @@ def parse_field(lineno, name, toks):
     width = 0
     func = None
     for t in toks:
-        if re_fullmatch('!function=' + re_ident, t):
+        if re.fullmatch('!function=' + re_ident, t):
             if func:
                 error(lineno, 'duplicate function')
             func = t.split('=')
             func = func[1]
             continue
 
-        if re_fullmatch('[0-9]+:s[0-9]+', t):
+        if re.fullmatch('[0-9]+:s[0-9]+', t):
             # Signed field extract
             subtoks = t.split(':s')
             sign = True
-        elif re_fullmatch('[0-9]+:[0-9]+', t):
+        elif re.fullmatch('[0-9]+:[0-9]+', t):
             # Unsigned field extract
             subtoks = t.split(':')
             sign = False
@@ -488,11 +481,11 @@ def parse_arguments(lineno, name, toks):
     flds = []
     extern = False
     for t in toks:
-        if re_fullmatch('!extern', t):
+        if re.fullmatch('!extern', t):
             extern = True
             anyextern = True
             continue
-        if not re_fullmatch(re_ident, t):
+        if not re.fullmatch(re_ident, t):
             error(lineno, 'invalid argument set token "{0}"'.format(t))
         if t in flds:
             error(lineno, 'duplicate argument "{0}"'.format(t))
@@ -621,13 +614,13 @@ def parse_generic(lineno, is_format, name, toks):
             continue
 
         # 'Foo=%Bar' imports a field with a different name.
-        if re_fullmatch(re_ident + '=%' + re_ident, t):
+        if re.fullmatch(re_ident + '=%' + re_ident, t):
             (fname, iname) = t.split('=%')
             flds = add_field_byname(lineno, flds, fname, iname)
             continue
 
         # 'Foo=number' sets an argument field to a constant value
-        if re_fullmatch(re_ident + '=[+-]?[0-9]+', t):
+        if re.fullmatch(re_ident + '=[+-]?[0-9]+', t):
             (fname, value) = t.split('=')
             value = int(value)
             flds = add_field(lineno, flds, fname, ConstField(value))
@@ -635,7 +628,7 @@ def parse_generic(lineno, is_format, name, toks):
 
         # Pattern of 0s, 1s, dots and dashes indicate required zeros,
         # required ones, or dont-cares.
-        if re_fullmatch('[01.-]+', t):
+        if re.fullmatch('[01.-]+', t):
             shift = len(t)
             fms = t.replace('0', '1')
             fms = fms.replace('.', '0')
@@ -652,7 +645,7 @@ def parse_generic(lineno, is_format, name, toks):
             fixedmask = (fixedmask << shift) | fms
             undefmask = (undefmask << shift) | ubm
         # Otherwise, fieldname:fieldwidth
-        elif re_fullmatch(re_ident + ':s?[0-9]+', t):
+        elif re.fullmatch(re_ident + ':s?[0-9]+', t):
             (fname, flen) = t.split(':')
             sign = False
             if flen[0] == 's':

scripts/qmp/qmp-shell

@@ -77,9 +77,6 @@ import re
 sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'python'))
 from qemu import qmp
 
-if sys.version_info[0] == 2:
-    input = raw_input
-
 class QMPCompleter(list):
     def complete(self, text, state):
         for cmd in self:

tests/docker/docker.py

@@ -258,12 +258,13 @@ def _kill_instances(self, *args, **kwargs):
         return self._do_kill_instances(True)
 
     def _output(self, cmd, **kwargs):
-        if sys.version_info[1] >= 6:
+        try:
             return subprocess.check_output(self._command + cmd,
                                            stderr=subprocess.STDOUT,
                                            encoding='utf-8',
                                            **kwargs)
-        else:
+        except TypeError:
+            # 'encoding' argument was added in 3.6+
             return subprocess.check_output(self._command + cmd,
                                            stderr=subprocess.STDOUT,
                                            **kwargs).decode('utf-8')

tests/qemu-iotests/nbd-fault-injector.py

@@ -47,10 +47,7 @@
 import socket
 import struct
 import collections
-if sys.version_info.major >= 3:
-    import configparser
-else:
-    import ConfigParser as configparser
+import configparser
 
 FAKE_DISK_SIZE = 8 * 1024 * 1024 * 1024 # 8 GB