define error codes at module scope rather than at class scope

lib/spack/spack/cmd/license.py

@@ -90,11 +90,12 @@ def list_files(args):
         print(os.path.join(spack.paths.spack_root, relpath))
 
 
-class LicenseError(object):
-    OLD_LICENSE = 1
-    SPDX_MISMATCH = 2
-    GENERAL_MISMATCH = 3
+# Error codes for license verification. All values are chosen such that
+# bool(value) evaluates to True
+OLD_LICENSE, SPDX_MISMATCH, GENERAL_MISMATCH = range(1, 4)
+
 
+class LicenseError(object):
     def __init__(self):
         self.error_counts = defaultdict(int)
 
@@ -106,9 +107,9 @@ def has_errors(self):
 
     def error_messages(self):
         total = sum(self.error_counts.values())
-        missing = self.error_counts[LicenseError.GENERAL_MISMATCH]
-        spdx_mismatch = self.error_counts[LicenseError.SPDX_MISMATCH]
-        old_license = self.error_counts[LicenseError.OLD_LICENSE]
+        missing = self.error_counts[GENERAL_MISMATCH]
+        spdx_mismatch = self.error_counts[SPDX_MISMATCH]
+        old_license = self.error_counts[OLD_LICENSE]
         return (
             '%d improperly licensed files' % (total),
             'files with wrong SPDX-License-Identifier:   %d' % spdx_mismatch,
@@ -146,7 +147,7 @@ def _check_license(lines, path):
     def old_license(line, path):
         if re.search('This program is free software', line):
             print('{0}: has old LGPL license header'.format(path))
-            return LicenseError.OLD_LICENSE
+            return OLD_LICENSE
 
     # If the SPDX identifier is present, then there is a mismatch (since it
     # did not match the above regex)
@@ -156,7 +157,7 @@ def wrong_spdx_identifier(line, path):
             print('{0}: SPDX license identifier mismatch'
                   '(expecting {1}, found {2})'
                   .format(path, apache2_mit_spdx, m.group(1)))
-            return LicenseError.SPDX_MISMATCH
+            return SPDX_MISMATCH
 
     checks = [old_license, wrong_spdx_identifier]
 
@@ -167,7 +168,7 @@ def wrong_spdx_identifier(line, path):
                 return error
 
     print('{0}: the license does not match the expected format'.format(path))
-    return LicenseError.GENERAL_MISMATCH
+    return GENERAL_MISMATCH
 
 
 def verify(args):