scripts: clean up meson-buildoptions.py

Fix a few issues reported by flake8 and pylint, mostly parameter names
that shadow globals.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

scripts/meson-buildoptions.py

@@ -111,13 +111,13 @@ def help_line(left, opt, indent, long):
     right = f'{opt["description"]}'
     if long:
         value = get_help(opt)
-        if value != "auto" and value != "":
+        if value not in {"", "auto"}:
             right += f" [{value}]"
     if "choices" in opt and long:
         choices = "/".join(sorted(opt["choices"]))
         right += f" (choices: {choices})"
-    for x in wrap("  " + left, right, indent):
-        sh_print(x)
+    for line in wrap("  " + left, right, indent):
+        sh_print(line)
 
 
 # Return whether the option (a dictionary) can be used with
@@ -144,18 +144,18 @@ def require_arg(opt):
     return not ({"enabled", "disabled"}.intersection(opt["choices"]))
 
 
-def filter_options(json):
-    if ":" in json["name"]:
+def filter_options(opt):
+    if ":" in opt["name"]:
         return False
-    if json["section"] == "user":
-        return json["name"] not in SKIP_OPTIONS
+    if opt["section"] == "user":
+        return opt["name"] not in SKIP_OPTIONS
     else:
-        return json["name"] in BUILTIN_OPTIONS
+        return opt["name"] in BUILTIN_OPTIONS
 
 
-def load_options(json):
-    json = [x for x in json if filter_options(x)]
-    return sorted(json, key=lambda x: x["name"])
+def load_options(opts):
+    opts = [opt for opt in opts if filter_options(opt)]
+    return sorted(opts, key=lambda opt: opt["name"])
 
 
 def cli_option(opt):
@@ -223,7 +223,7 @@ def print_parse(options):
         key = cli_option(opt)
         name = opt["name"]
         if require_arg(opt):
-            if opt["type"] == "array" and not "choices" in opt:
+            if opt["type"] == "array" and "choices" not in opt:
                 print(f'    --{key}=*) quote_sh "-D{name}=$(meson_option_build_array $2)" ;;')
             else:
                 print(f'    --{key}=*) quote_sh "-D{name}=$2" ;;')
@@ -241,14 +241,19 @@ def print_parse(options):
     print("  esac")
     print("}")
 
-json_data = sys.stdin.read()
-try:
-    options = load_options(json.loads(json_data))
-except:
-    print("Failure in scripts/meson-buildoptions.py parsing stdin as json",
-          file=sys.stderr)
-    print(json_data, file=sys.stderr)
-    sys.exit(1)
-print("# This file is generated by meson-buildoptions.py, do not edit!")
-print_help(options)
-print_parse(options)
+
+def main():
+    json_data = sys.stdin.read()
+    try:
+        options = load_options(json.loads(json_data))
+    except:
+        print("Failure in scripts/meson-buildoptions.py parsing stdin as json",
+              file=sys.stderr)
+        print(json_data, file=sys.stderr)
+        sys.exit(1)
+    print("# This file is generated by meson-buildoptions.py, do not edit!")
+    print_help(options)
+    print_parse(options)
+
+
+sys.exit(main())