restore some print statements

the heuristics i used are the following:

 1. if we are prompting the use, use print on stderr (input() may
    produce some stuff on stdout, but it's outside the scope of this
    patch). we do not want those prompts to end up on the standard
    output in case we are piping stuff around

 2. if the command is primarily producing output for the user on the
    console (`list`, `info`, `help`), we simply print on the default
    file descriptor.

 3. everywhere else, we use the logging module with varying levels of
    verbosity, as appropriate.

borg/archiver.py

@@ -162,15 +162,15 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
             if args.stats:
                 t = datetime.now()
                 diff = t - t0
-                logger.warning('-' * 78)
-                logger.warning('Archive name: %s' % args.archive.archive)
-                logger.warning('Archive fingerprint: %s' % hexlify(archive.id).decode('ascii'))
-                logger.warning('Start time: %s' % t0.strftime('%c'))
-                logger.warning('End time: %s' % t.strftime('%c'))
-                logger.warning('Duration: %s' % format_timedelta(diff))
-                logger.warning('Number of files: %d' % archive.stats.nfiles)
-                logger.warning(archive.stats.print_('This archive:', cache))
-                logger.warning('-' * 78)
+                print('-' * 78)
+                print('Archive name: %s' % args.archive.archive)
+                print('Archive fingerprint: %s' % hexlify(archive.id).decode('ascii'))
+                print('Start time: %s' % t0.strftime('%c'))
+                print('End time: %s' % t.strftime('%c'))
+                print('Duration: %s' % format_timedelta(diff))
+                print('Number of files: %d' % archive.stats.nfiles)
+                print(archive.stats.print_('This archive:', cache))
+                print('-' * 78)
         return self.exit_code
 
     def _process(self, archive, cache, excludes, exclude_caches, skip_inodes, path, restrict_dev,
@@ -317,11 +317,12 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
             if args.stats:
                 logger.warning(stats.print_('Deleted data:', cache))
         else:
-            logger.warning("You requested to completely DELETE the repository *including* all archives it contains:")
+            print("You requested to completely DELETE the repository *including* all archives it contains:", file=sys.stderr)
             for archive_info in manifest.list_archive_infos(sort_by='ts'):
-                logger.warning(format_archive(archive_info))
+                print(format_archive(archive_info), file=sys.stderr)
             if not os.environ.get('BORG_CHECK_I_KNOW_WHAT_I_AM_DOING'):
-                print("""Type "YES" if you understand this and want to continue.""")
+                print("""Type "YES" if you understand this and want to continue.""", file=sys.stderr)
+                # XXX: prompt may end up on stdout, but we'll assume that input() does the right thing
                 if input('Do you want to continue? ') != 'YES':
                     self.exit_code = 1
                     return self.exit_code
@@ -365,7 +366,7 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
             archive = Archive(repository, key, manifest, args.src.archive)
             if args.short:
                 for item in archive.iter_items():
-                    print(remove_surrogates(item[b'path']), file=sys.stderr)
+                    print(remove_surrogates(item[b'path']))
             else:
                 tmap = {1: 'p', 2: 'c', 4: 'd', 6: 'b', 0o10: '-', 0o12: 'l', 0o14: 's'}
                 for item in archive.iter_items():
@@ -393,11 +394,10 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
                     print('%s%s %-6s %-6s %8d %s %s%s' % (
                         type, mode, item[b'user'] or item[b'uid'],
                         item[b'group'] or item[b'gid'], size, format_time(mtime),
-                        remove_surrogates(item[b'path']), extra),
-                          file=sys.stderr)
+                        remove_surrogates(item[b'path']), extra))
         else:
             for archive_info in manifest.list_archive_infos(sort_by='ts'):
-                print(format_archive(archive_info), file=sys.stderr)
+                print(format_archive(archive_info))
         return self.exit_code
 
     def do_info(self, args):
@@ -407,14 +407,14 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
         cache = Cache(repository, key, manifest, do_files=args.cache_files)
         archive = Archive(repository, key, manifest, args.archive.archive, cache=cache)
         stats = archive.calc_stats(cache)
-        logger.warning('Name:', archive.name)
-        logger.warning('Fingerprint: %s' % hexlify(archive.id).decode('ascii'))
-        logger.warning('Hostname:', archive.metadata[b'hostname'])
-        logger.warning('Username:', archive.metadata[b'username'])
-        logger.warning('Time: %s' % to_localtime(archive.ts).strftime('%c'))
-        logger.warning('Command line:', remove_surrogates(' '.join(archive.metadata[b'cmdline'])))
-        logger.warning('Number of files: %d' % stats.nfiles)
-        logger.warning(stats.print_('This archive:', cache))
+        print('Name:', archive.name)
+        print('Fingerprint: %s' % hexlify(archive.id).decode('ascii'))
+        print('Hostname:', archive.metadata[b'hostname'])
+        print('Username:', archive.metadata[b'username'])
+        print('Time: %s' % to_localtime(archive.ts).strftime('%c'))
+        print('Command line:', remove_surrogates(' '.join(archive.metadata[b'cmdline'])))
+        print('Number of files: %d' % stats.nfiles)
+        print(stats.print_('This archive:', cache))
         return self.exit_code
 
     def do_prune(self, args):
@@ -496,10 +496,10 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
         if not args.topic:
             parser.print_help()
         elif args.topic in self.helptext:
-            print(self.helptext[args.topic], file=sys.stderr)
+            print(self.helptext[args.topic])
         elif args.topic in commands:
             if args.epilog_only:
-                print(commands[args.topic].epilog, file=sys.stderr)
+                print(commands[args.topic].epilog)
             elif args.usage_only:
                 commands[args.topic].epilog = None
                 commands[args.topic].print_help()
@@ -531,13 +531,13 @@ Type "Yes I am sure" if you understand this and want to continue.\n""")
             ('--yearly', '--keep-yearly', 'Warning: "--yearly" has been deprecated. Use "--keep-yearly" instead.')
         ]
         if args and args[0] == 'verify':
-            print('Warning: "borg verify" has been deprecated. Use "borg extract --dry-run" instead.', file=sys.stderr)
+            print('Warning: "borg verify" has been deprecated. Use "borg extract --dry-run" instead.')
             args = ['extract', '--dry-run'] + args[1:]
         for i, arg in enumerate(args[:]):
             for old_name, new_name, warning in deprecations:
                 if arg.startswith(old_name):
                     args[i] = arg.replace(old_name, new_name)
-                    print(warning, file=sys.stderr)
+                    print(warning)
         return args
 
     def run(self, args=None):

borg/cache.py

@@ -74,9 +74,9 @@ class Cache:
         self.close()
 
     def _confirm(self, message, env_var_override=None):
-        logger.warning(message)
+        print(message, file=sys.stderr)
         if env_var_override and os.environ.get(env_var_override):
-            logger.warning("Yes (From {})".format(env_var_override))
+            print("Yes (From {})".format(env_var_override), file=sys.stderr)
             return True
         if not sys.stdin.isatty():
             return False

borg/key.py

@@ -196,9 +196,9 @@ class Passphrase(str):
                     logger.info('Remember your passphrase. Your data will be inaccessible without it.')
                     return passphrase
                 else:
-                    logger.warning('Passphrases do not match')
+                    print('Passphrases do not match', file=sys.stderr)
             else:
-                logger.warning('Passphrase must not be blank')
+                print('Passphrase must not be blank', file=sys.stderr)
 
     def __repr__(self):
         return '<Passphrase "***hidden***">'