checkpatch: Normalize exit code for Windows

Using python `sys.exit(-1)` on Windows produces mixed results.
Let's take the following results from different shells:
CMD
>python -c "import sys; sys.exit(-1)" & echo %errorlevel%
1
MSYS
$ python -c "import sys; sys.exit(-1)" && echo $?
0
WSL
$ python -c "import sys; sys.exit(-1)"; echo $?
255

this results in the following tests to fail:
checkpatch

 10: checkpatch - sign-offs                          FAILED (checkpatch.at:32)
 11: checkpatch - parenthesized constructs           FAILED (checkpatch.at:32)
 12: checkpatch - parenthesized constructs - for     FAILED (checkpatch.at:32)
 13: checkpatch - comments                           FAILED (checkpatch.at:32)

because of:
 ./checkpatch.at:32: exit code was 0, expected 255

This patch introduces a positive constant for the default exit code (1)
similar to other OVS utilities.

Signed-off-by: Alin Gabriel Serdean <[email protected]>
Acked-by: Ben Pfaff <[email protected]>
Acked-by: Aaron Conole <[email protected]>

tests/checkpatch.at

@@ -30,7 +30,7 @@ try_checkpatch__() {
         :
     elif test -s expout; then
         AT_CHECK([$2 $top_srcdir/utilities/checkpatch.py -q test.patch],
-                 [255], [stdout])
+                 [1], [stdout])
         AT_CHECK([sed '/^Lines checked:/,$d' stdout], [0], [expout])
     else
         AT_CHECK([$2 $top_srcdir/utilities/checkpatch.py -q test.patch])

utilities/checkpatch.py

@@ -24,6 +24,7 @@
 RETURN_CHECK_INITIAL_STATE = 0
 RETURN_CHECK_STATE_WITH_RETURN = 1
 RETURN_CHECK_AWAITING_BRACE = 2
+EXIT_FAILURE = 1
 __errors = 0
 __warnings = 0
 empty_return_check_state = 0
@@ -842,7 +843,7 @@ def ovs_checkpatch_parse(text, filename, author=None, committer=None):
 
     run_file_checks(text)
     if __errors or __warnings:
-        return -1
+        return EXIT_FAILURE
     return 0
 
 
@@ -868,10 +869,10 @@ def usage():
           % sys.argv[0])
 
 
-def ovs_checkpatch_print_result(result):
+def ovs_checkpatch_print_result():
     global quiet, __warnings, __errors, total_line
 
-    if result < 0:
+    if __errors or __warnings:
         print("Lines checked: %d, Warnings: %d, Errors: %d\n" %
               (total_line, __warnings, __errors))
     elif not quiet:
@@ -891,7 +892,7 @@ def ovs_checkpatch_file(filename):
     result = ovs_checkpatch_parse(part.get_payload(decode=False), filename,
                                   mail.get('Author', mail['From']),
                                   mail['Commit'])
-    ovs_checkpatch_print_result(result)
+    ovs_checkpatch_print_result()
     return result
 
 
@@ -925,7 +926,7 @@ def partition(pred, iterable):
                                        "quiet"])
     except:
         print("Unknown option encountered. Please rerun with -h for help.")
-        sys.exit(-1)
+        sys.exit(EXIT_FAILURE)
 
     for o, a in optlist:
         if o in ("-h", "--help"):
@@ -951,7 +952,7 @@ def partition(pred, iterable):
             quiet = True
         else:
             print("Unknown option '%s'" % o)
-            sys.exit(-1)
+            sys.exit(EXIT_FAILURE)
 
     if sys.stdout.isatty():
         colors = True
@@ -977,17 +978,17 @@ def partition(pred, iterable):
             if not quiet:
                 print('== Checking %s ("%s") ==' % (revision[0:12], name))
             result = ovs_checkpatch_parse(patch, revision)
-            ovs_checkpatch_print_result(result)
+            ovs_checkpatch_print_result()
             if result:
-                status = -1
+                status = EXIT_FAILURE
         sys.exit(status)
 
     if not args:
         if sys.stdin.isatty():
             usage()
-            sys.exit(-1)
+            sys.exit(EXIT_FAILURE)
         result = ovs_checkpatch_parse(sys.stdin.read(), '-')
-        ovs_checkpatch_print_result(result)
+        ovs_checkpatch_print_result()
         sys.exit(result)
 
     status = 0
@@ -996,5 +997,5 @@ def partition(pred, iterable):
             print('== Checking "%s" ==' % filename)
         result = ovs_checkpatch_file(filename)
         if result:
-            status = -1
+            status = EXIT_FAILURE
     sys.exit(status)