verify: clean up weird error/warning lists

Nested functions in Python are not able to assign to variables in the
outer scope without something like the list trick because assignments
refer to the inner scope. So, we formerly used a list to give an
object to assign into.

Now that error and warning are object members, the [0] hack is no
longer needed.

mercurial/verify.py

@@ -51,8 +51,8 b' class verifier(object):'
         self.repo = repo.unfiltered()
         self.ui = repo.ui
         self.badrevs = set()
-        self.errors = [0]
-        self.warnings = [0]
+        self.errors = 0
+        self.warnings = 0
         self.havecl = len(repo.changelog) > 0
         self.havemf = len(repo.manifest) > 0
         self.revlogv1 = repo.changelog.version != revlog.REVLOGV0
@@ -62,7 +62,7 b' class verifier(object):'
 
     def warn(self, msg):
         self.ui.warn(msg + "\n")
-        self.warnings[0] += 1
+        self.warnings += 1
 
     def err(self, linkrev, msg, filename=None):
         if linkrev is not None:
@@ -73,7 +73,7 b' class verifier(object):'
         if filename:
             msg = "%s@%s" % (filename, msg)
         self.ui.warn(" " + msg + "\n")
-        self.errors[0] += 1
+        self.errors += 1
 
     def exc(self, linkrev, msg, inst, filename=None):
         if not str(inst):
@@ -87,8 +87,6 b' class verifier(object):'
         filenodes = {}
         revisions = 0
         badrevs = self.badrevs
-        errors = self.errors
-        warnings = self.warnings
         ui = repo.ui
         cl = repo.changelog
         mf = repo.manifest
@@ -352,13 +350,13 b' class verifier(object):'
 
         ui.status(_("%d files, %d changesets, %d total revisions\n") %
                        (len(files), len(cl), revisions))
-        if warnings[0]:
-            ui.warn(_("%d warnings encountered!\n") % warnings[0])
+        if self.warnings:
+            ui.warn(_("%d warnings encountered!\n") % self.warnings)
         if self.fncachewarned:
             ui.warn(_('hint: run "hg debugrebuildfncache" to recover from '
                       'corrupt fncache\n'))
-        if errors[0]:
-            ui.warn(_("%d integrity errors encountered!\n") % errors[0])
+        if self.errors:
+            ui.warn(_("%d integrity errors encountered!\n") % self.errors)
             if badrevs:
                 ui.warn(_("(first damaged changeset appears to be %d)\n")
                         % min(badrevs))