Merge pull request #2134 from textshell/feature/mandatory-features

Add minimal version of in repository mandatory feature flags.

borg/archive.py

@@ -870,7 +870,7 @@ class ArchiveChecker:
             self.manifest = self.rebuild_manifest()
         else:
             try:
-                self.manifest, _ = Manifest.load(repository, key=self.key)
+                self.manifest, _ = Manifest.load(repository, (Manifest.Operation.CHECK,), key=self.key)
             except IntegrityError as exc:
                 logger.error('Repository manifest is corrupted: %s', exc)
                 self.error_found = True

borg/archiver.py

@@ -56,7 +56,8 @@ def argument(args, str_or_bool):
     return str_or_bool
 
 
-def with_repository(fake=False, invert_fake=False, create=False, lock=True, exclusive=False, manifest=True, cache=False):
+def with_repository(fake=False, invert_fake=False, create=False, lock=True,
+                    exclusive=False, manifest=True, cache=False, compatibility=None):
     """
     Method decorator for subcommand-handling methods: do_XYZ(self, args, repository, …)
 
@@ -67,7 +68,20 @@ def with_repository(fake=False, invert_fake=False, create=False, lock=True, excl
     :param exclusive: (str or bool) lock repository exclusively (for writing)
     :param manifest: load manifest and key, pass them as keyword arguments
     :param cache: open cache, pass it as keyword argument (implies manifest)
+    :param compatibility: mandatory if not create and (manifest or cache), specifies mandatory feature categories to check
     """
+
+    if not create and (manifest or cache):
+        if compatibility is None:
+            raise AssertionError("with_repository decorator used without compatibility argument")
+        if type(compatibility) is not tuple:
+            raise AssertionError("with_repository decorator compatibility argument must be of type tuple")
+    else:
+        if compatibility is not None:
+            raise AssertionError("with_repository called with compatibility argument but would not check" + repr(compatibility))
+        if create:
+            compatibility = Manifest.NO_OPERATION_CHECK
+
     def decorator(method):
         @functools.wraps(method)
         def wrapper(self, args, **kwargs):
@@ -84,7 +98,7 @@ def with_repository(fake=False, invert_fake=False, create=False, lock=True, excl
                                         append_only=append_only)
             with repository:
                 if manifest or cache:
-                    kwargs['manifest'], kwargs['key'] = Manifest.load(repository)
+                    kwargs['manifest'], kwargs['key'] = Manifest.load(repository, compatibility)
                 if cache:
                     with Cache(repository, kwargs['key'], kwargs['manifest'],
                                do_files=getattr(args, 'cache_files', False), lock_wait=self.lock_wait) as cache_:
@@ -176,7 +190,7 @@ class Archiver:
             return EXIT_WARNING
         return EXIT_SUCCESS
 
-    @with_repository()
+    @with_repository(compatibility=(Manifest.Operation.CHECK,))
     def do_change_passphrase(self, args, repository, manifest, key):
         """Change repository key file passphrase"""
         if not hasattr(key, 'change_passphrase'):
@@ -241,7 +255,7 @@ class Archiver:
         logger.info('Key updated')
         return EXIT_SUCCESS
 
-    @with_repository(fake='dry_run', exclusive=True)
+    @with_repository(fake='dry_run', exclusive=True, compatibility=(Manifest.Operation.WRITE,))
     def do_create(self, args, repository, manifest=None, key=None):
         """Create new archive"""
         matcher = PatternMatcher(fallback=True)
@@ -424,7 +438,7 @@ class Archiver:
                 return matcher.match(item[b'path'])
         return item_filter
 
-    @with_repository()
+    @with_repository(compatibility=(Manifest.Operation.READ,))
     @with_archive
     def do_extract(self, args, repository, manifest, key, archive):
         """Extract archive contents"""
@@ -490,7 +504,7 @@ class Archiver:
                 self.print_warning("Include pattern '%s' never matched.", pattern)
         return self.exit_code
 
-    @with_repository(exclusive=True, cache=True)
+    @with_repository(exclusive=True, cache=True, compatibility=(Manifest.Operation.CHECK,))
     @with_archive
     def do_rename(self, args, repository, manifest, key, cache, archive):
         """Rename an existing archive"""
@@ -506,7 +520,7 @@ class Archiver:
         """Delete an existing repository or archive"""
         if args.location.archive:
             archive_name = args.location.archive
-            manifest, key = Manifest.load(repository)
+            manifest, key = Manifest.load(repository, (Manifest.Operation.DELETE,))
 
             if args.forced == 2:
                 try:
@@ -537,7 +551,7 @@ class Archiver:
             if not args.cache_only:
                 msg = []
                 try:
-                    manifest, key = Manifest.load(repository)
+                    manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
                 except NoManifestError:
                     msg.append("You requested to completely DELETE the repository *including* all archives it may contain.")
                     msg.append("This repository seems to have no manifest, so we can't tell anything about its contents.")
@@ -573,7 +587,7 @@ class Archiver:
 
         return self._do_mount(args)
 
-    @with_repository()
+    @with_repository(compatibility=(Manifest.Operation.READ,))
     def _do_mount(self, args, repository, manifest, key):
         from .fuse import FuseOperations
 
@@ -595,7 +609,7 @@ class Archiver:
         """un-mount the FUSE filesystem"""
         return umount(args.mountpoint)
 
-    @with_repository()
+    @with_repository(compatibility=(Manifest.Operation.READ,))
     def do_list(self, args, repository, manifest, key):
         """List archive or repository contents"""
         if args.location.archive:
@@ -681,7 +695,7 @@ class Archiver:
                     print(format_archive(archive_info))
         return self.exit_code
 
-    @with_repository(cache=True)
+    @with_repository(cache=True, compatibility=(Manifest.Operation.READ,))
     @with_archive
     def do_info(self, args, repository, manifest, key, archive, cache):
         """Show archive details such as disk space used"""
@@ -699,7 +713,7 @@ class Archiver:
         print(str(cache))
         return self.exit_code
 
-    @with_repository(exclusive=True)
+    @with_repository(exclusive=True, compatibility=(Manifest.Operation.DELETE,))
     def do_prune(self, args, repository, manifest, key):
         """Prune repository archives according to specified rules"""
         if not any((args.hourly, args.daily,
@@ -759,7 +773,7 @@ class Archiver:
     def do_upgrade(self, args, repository, manifest=None, key=None):
         """upgrade a repository from a previous version"""
         if args.tam:
-            manifest, key = Manifest.load(repository, force_tam_not_required=args.force)
+            manifest, key = Manifest.load(repository, (Manifest.Operation.CHECK,), force_tam_not_required=args.force)
 
             if not hasattr(key, 'change_passphrase'):
                 print('This repository is not encrypted, cannot enable TAM.')
@@ -784,7 +798,7 @@ class Archiver:
                 open(tam_file, 'w').close()
                 print('Updated security database')
         elif args.disable_tam:
-            manifest, key = Manifest.load(repository, force_tam_not_required=True)
+            manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK, force_tam_not_required=True)
             if tam_required(repository):
                 os.unlink(tam_required_file(repository))
             if key.tam_required:
@@ -817,7 +831,7 @@ class Archiver:
         print(sysinfo())
         return EXIT_SUCCESS
 
-    @with_repository()
+    @with_repository(compatibility=Manifest.NO_OPERATION_CHECK)
     def do_debug_dump_archive_items(self, args, repository, manifest, key):
         """dump (decrypted, decompressed) archive items metadata (not: data)"""
         archive = Archive(repository, key, manifest, args.location.archive)
@@ -830,7 +844,7 @@ class Archiver:
         print('Done.')
         return EXIT_SUCCESS
 
-    @with_repository()
+    @with_repository(compatibility=Manifest.NO_OPERATION_CHECK)
     def do_debug_dump_repo_objs(self, args, repository, manifest, key):
         """dump (decrypted, decompressed) repo objects"""
         marker = None
@@ -904,7 +918,7 @@ class Archiver:
         print('Done.')
         return EXIT_SUCCESS
 
-    @with_repository(manifest=False, exclusive=True, cache=True)
+    @with_repository(manifest=False, exclusive=True, cache=True, compatibility=Manifest.NO_OPERATION_CHECK)
     def do_debug_refcount_obj(self, args, repository, manifest, key, cache):
         """display refcounts for the objects with the given IDs"""
         for hex_id in args.ids:

borg/cache.py

@@ -9,8 +9,8 @@ import shutil
 from .key import PlaintextKey
 from .logger import create_logger
 logger = create_logger()
-from .helpers import Error, get_cache_dir, decode_dict, int_to_bigint, \
+from .helpers import Error, Manifest, get_cache_dir, decode_dict, int_to_bigint, \
-    bigint_to_int, format_file_size, yes, bin_to_hex, Location, safe_ns
+    bigint_to_int, format_file_size, yes, bin_to_hex, Location, safe_ns, parse_stringified_list
 from .locking import Lock
 from .hashindex import ChunkIndex
 
@@ -84,6 +84,11 @@ class Cache:
                 self.begin_txn()
                 self.commit()
 
+            if not self.check_cache_compatibility():
+                self.wipe_cache()
+
+            self.update_compatibility()
+
             if sync and self.manifest.id != self.manifest_id:
                 # If repository is older than the cache something fishy is going on
                 if self.timestamp and self.timestamp > manifest.timestamp:
@@ -94,6 +99,7 @@ class Cache:
                 # Make sure an encrypted repository has not been swapped for an unencrypted repository
                 if self.key_type is not None and self.key_type != str(key.TYPE):
                     raise self.EncryptionMethodMismatch()
+
                 self.sync()
                 self.commit()
         except:
@@ -175,6 +181,8 @@ Chunk index:    {0.total_unique_chunks:20d} {0.total_chunks:20d}"""
         self.timestamp = self.config.get('cache', 'timestamp', fallback=None)
         self.key_type = self.config.get('cache', 'key_type', fallback=None)
         self.previous_location = self.config.get('cache', 'previous_location', fallback=None)
+        self.ignored_features = set(parse_stringified_list(self.config.get('cache', 'ignored_features', fallback='')))
+        self.mandatory_features = set(parse_stringified_list(self.config.get('cache', 'mandatory_features', fallback='')))
         self.chunks = ChunkIndex.read(os.path.join(self.path, 'chunks').encode('utf-8'))
         self.files = None
 
@@ -240,6 +248,8 @@ Chunk index:    {0.total_unique_chunks:20d} {0.total_chunks:20d}"""
         self.config.set('cache', 'timestamp', self.manifest.timestamp)
         self.config.set('cache', 'key_type', str(self.key.TYPE))
         self.config.set('cache', 'previous_location', self.repository._location.canonical_path())
+        self.config.set('cache', 'ignored_features', ','.join(self.ignored_features))
+        self.config.set('cache', 'mandatory_features', ','.join(self.mandatory_features))
         with open(os.path.join(self.path, 'config'), 'w') as fd:
             self.config.write(fd)
         self.chunks.write(os.path.join(self.path, 'chunks').encode('utf-8'))
@@ -390,6 +400,43 @@ Chunk index:    {0.total_unique_chunks:20d} {0.total_chunks:20d}"""
             self.do_cache = os.path.isdir(archive_path)
             self.chunks = create_master_idx(self.chunks)
 
+    def check_cache_compatibility(self):
+        my_features = Manifest.SUPPORTED_REPO_FEATURES
+        if self.ignored_features & my_features:
+            # The cache might not contain references of chunks that need a feature that is mandatory for some operation
+            # and which this version supports. To avoid corruption while executing that operation force rebuild.
+            return False
+        if not self.mandatory_features <= my_features:
+            # The cache was build with consideration to at least one feature that this version does not understand.
+            # This client might misinterpret the cache. Thus force a rebuild.
+            return False
+        return True
+
+    def wipe_cache(self):
+        logger.warning("Discarding incompatible cache and forcing a cache rebuild")
+        archive_path = os.path.join(self.path, 'chunks.archive.d')
+        if os.path.isdir(archive_path):
+            shutil.rmtree(os.path.join(self.path, 'chunks.archive.d'))
+            os.makedirs(os.path.join(self.path, 'chunks.archive.d'))
+        self.chunks = ChunkIndex()
+        with open(os.path.join(self.path, 'files'), 'wb'):
+            pass  # empty file
+        self.manifest_id = ''
+        self.config.set('cache', 'manifest', '')
+
+        self.ignored_features = set()
+        self.mandatory_features = set()
+
+    def update_compatibility(self):
+        operation_to_features_map = self.manifest.get_all_mandatory_features()
+        my_features = Manifest.SUPPORTED_REPO_FEATURES
+        repo_features = set()
+        for operation, features in operation_to_features_map.items():
+            repo_features.update(features)
+
+        self.ignored_features.update(repo_features - my_features)
+        self.mandatory_features.update(repo_features & my_features)
+
     def add_chunk(self, id, data, stats):
         if not self.txn_active:
             self.begin_txn()

borg/helpers.py

@@ -2,6 +2,7 @@ import argparse
 from binascii import hexlify
 from collections import namedtuple
 import contextlib
+import enum
 from functools import wraps
 import grp
 import os
@@ -110,6 +111,10 @@ class PlaceholderError(Error):
     """Formatting Error: "{}".format({}): {}({})"""
 
 
+class MandatoryFeatureUnsupported(Error):
+    """Unsupported repository feature(s) {}. A newer version of borg is required to access this repository."""
+
+
 def check_extension_modules():
     from . import platform, compress
     if hashindex.API_VERSION != '1.0_01':
@@ -126,6 +131,34 @@ def check_extension_modules():
 
 class Manifest:
 
+    @enum.unique
+    class Operation(enum.Enum):
+        # The comments here only roughly describe the scope of each feature. In the end, additions need to be
+        # based on potential problems older clients could produce when accessing newer repositories and the
+        # tradeofs of locking version out or still allowing access. As all older versions and their exact
+        # behaviours are known when introducing new features sometimes this might not match the general descriptions
+        # below.
+
+        # The READ operation describes which features are needed to safely list and extract the archives in the
+        # repository.
+        READ = 'read'
+        # The CHECK operation is for all operations that need either to understand every detail
+        # of the repository (for consistency checks and repairs) or are seldom used functions that just
+        # should use the most restrictive feature set because more fine grained compatibility tracking is
+        # not needed.
+        CHECK = 'check'
+        # The WRITE operation is for adding archives. Features here ensure that older clients don't add archives
+        # in an old format, or is used to lock out clients that for other reasons can no longer safely add new
+        # archives.
+        WRITE = 'write'
+        # The DELETE operation is for all operations (like archive deletion) that need a 100% correct reference
+        # count and the need to be able to find all (directly and indirectly) referenced chunks of a given archive.
+        DELETE = 'delete'
+
+    NO_OPERATION_CHECK = tuple()
+
+    SUPPORTED_REPO_FEATURES = frozenset([])
+
     MANIFEST_ID = b'\0' * 32
 
     def __init__(self, key, repository, item_keys=None):
@@ -139,7 +172,7 @@ class Manifest:
         self.timestamp = None
 
     @classmethod
-    def load(cls, repository, key=None, force_tam_not_required=False):
+    def load(cls, repository, operations, key=None, force_tam_not_required=False):
         from .key import key_factory, tam_required_file, tam_required
         from .repository import Repository
         from .archive import ITEM_KEYS
@@ -153,7 +186,7 @@ class Manifest:
         data = key.decrypt(None, cdata)
         m, manifest.tam_verified = key.unpack_and_verify_manifest(data, force_tam_not_required=force_tam_not_required)
         manifest.id = key.id_hash(data)
-        if not m.get(b'version') == 1:
+        if m.get(b'version') not in (1, 2):
             raise ValueError('Invalid manifest version')
         manifest.archives = dict((k.decode('utf-8'), v) for k, v in m[b'archives'].items())
         manifest.timestamp = m.get(b'timestamp')
@@ -173,8 +206,34 @@ class Manifest:
             if not manifest_required and security_required:
                 logger.debug('Manifest is TAM verified and says TAM is *not* required, updating security database...')
                 os.unlink(tam_required_file(repository))
+        manifest.check_repository_compatibility(operations)
         return manifest, key
 
+    def check_repository_compatibility(self, operations):
+        for operation in operations:
+            assert isinstance(operation, self.Operation)
+            feature_flags = self.config.get(b'feature_flags', None)
+            if feature_flags is None:
+                return
+            if operation.value.encode() not in feature_flags:
+                continue
+            requirements = feature_flags[operation.value.encode()]
+            if b'mandatory' in requirements:
+                unsupported = set(requirements[b'mandatory']) - self.SUPPORTED_REPO_FEATURES
+                if unsupported:
+                    raise MandatoryFeatureUnsupported([f.decode() for f in unsupported])
+
+    def get_all_mandatory_features(self):
+        result = {}
+        feature_flags = self.config.get(b'feature_flags', None)
+        if feature_flags is None:
+            return result
+
+        for operation, requirements in feature_flags.items():
+            if b'mandatory' in requirements:
+                result[operation.decode()] = set([feature.decode() for feature in requirements[b'mandatory']])
+        return result
+
     def write(self):
         if self.key.tam_required:
             self.config[b'tam_required'] = True
@@ -881,6 +940,11 @@ def bin_to_hex(binary):
     return hexlify(binary).decode('ascii')
 
 
+def parse_stringified_list(s):
+    l = re.split(" *, *", s)
+    return [item for item in l if item != '']
+
+
 class Location:
     """Object representing a repository / archive location
     """

borg/testsuite/archiver.py

@@ -25,7 +25,7 @@ from ..archiver import Archiver
 from ..cache import Cache
 from ..crypto import bytes_to_long, num_aes_blocks
 from ..helpers import Manifest, PatternMatcher, parse_pattern, EXIT_SUCCESS, EXIT_WARNING, EXIT_ERROR, bin_to_hex, \
-    get_security_dir, MAX_S
+    get_security_dir, MAX_S, MandatoryFeatureUnsupported, Location
 from ..key import RepoKey, KeyfileKey, Passphrase, TAMRequiredError
 from ..keymanager import RepoIdMismatch, NotABorgKeyFile
 from ..remote import RemoteRepository, PathNotAllowed
@@ -248,7 +248,7 @@ class ArchiverTestCaseBase(BaseTestCase):
     def open_archive(self, name):
         repository = Repository(self.repository_path, exclusive=True)
         with repository:
-            manifest, key = Manifest.load(repository)
+            manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
             archive = Archive(repository, key, manifest, name)
         return archive, repository
 
@@ -815,7 +815,7 @@ class ArchiverTestCase(ArchiverTestCaseBase):
         self.cmd('extract', '--dry-run', self.repository_location + '::test.4')
         # Make sure both archives have been renamed
         with Repository(self.repository_path) as repository:
-            manifest, key = Manifest.load(repository)
+            manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
         self.assert_equal(len(manifest.archives), 2)
         self.assert_in('test.3', manifest.archives)
         self.assert_in('test.4', manifest.archives)
@@ -853,7 +853,7 @@ class ArchiverTestCase(ArchiverTestCaseBase):
         self.cmd('init', '--encryption=none', self.repository_location)
         self.create_src_archive('test')
         with Repository(self.repository_path, exclusive=True) as repository:
-            manifest, key = Manifest.load(repository)
+            manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
             archive = Archive(repository, key, manifest, 'test')
             for item in archive.iter_items():
                 if 'chunks' in item:
@@ -870,7 +870,7 @@ class ArchiverTestCase(ArchiverTestCaseBase):
         self.cmd('init', '--encryption=none', self.repository_location)
         self.create_src_archive('test')
         with Repository(self.repository_path, exclusive=True) as repository:
-            manifest, key = Manifest.load(repository)
+            manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
             archive = Archive(repository, key, manifest, 'test')
             id = archive.metadata[b'items'][0]
             repository.put(id, b'corrupted items metadata stream chunk')
@@ -915,9 +915,111 @@ class ArchiverTestCase(ArchiverTestCaseBase):
         self.cmd('create', '--dry-run', self.repository_location + '::test', 'input')
         # Make sure no archive has been created
         with Repository(self.repository_path) as repository:
-            manifest, key = Manifest.load(repository)
+            manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
         self.assert_equal(len(manifest.archives), 0)
 
+    def add_unknown_feature(self, operation):
+        with Repository(self.repository_path, exclusive=True) as repository:
+            manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
+            manifest.config[b'feature_flags'] = {operation.value.encode(): {b'mandatory': [b'unknown-feature']}}
+            manifest.write()
+            repository.commit()
+
+    def cmd_raises_unknown_feature(self, args):
+        if self.FORK_DEFAULT:
+            self.cmd(*args, exit_code=EXIT_ERROR)
+        else:
+            with pytest.raises(MandatoryFeatureUnsupported) as excinfo:
+                self.cmd(*args)
+            assert excinfo.value.args == (['unknown-feature'],)
+
+    def test_unknown_feature_on_create(self):
+        print(self.cmd('init', self.repository_location))
+        self.add_unknown_feature(Manifest.Operation.WRITE)
+        self.cmd_raises_unknown_feature(['create', self.repository_location + '::test', 'input'])
+
+    def test_unknown_feature_on_change_passphrase(self):
+        print(self.cmd('init', self.repository_location))
+        self.add_unknown_feature(Manifest.Operation.CHECK)
+        self.cmd_raises_unknown_feature(['change-passphrase', self.repository_location])
+
+    def test_unknown_feature_on_read(self):
+        print(self.cmd('init', self.repository_location))
+        self.cmd('create', self.repository_location + '::test', 'input')
+        self.add_unknown_feature(Manifest.Operation.READ)
+        with changedir('output'):
+            self.cmd_raises_unknown_feature(['extract', self.repository_location + '::test'])
+
+        self.cmd_raises_unknown_feature(['list', self.repository_location])
+        self.cmd_raises_unknown_feature(['info', self.repository_location + '::test'])
+
+    def test_unknown_feature_on_rename(self):
+        print(self.cmd('init', self.repository_location))
+        self.cmd('create', self.repository_location + '::test', 'input')
+        self.add_unknown_feature(Manifest.Operation.CHECK)
+        self.cmd_raises_unknown_feature(['rename', self.repository_location + '::test', 'other'])
+
+    def test_unknown_feature_on_delete(self):
+        print(self.cmd('init', self.repository_location))
+        self.cmd('create', self.repository_location + '::test', 'input')
+        self.add_unknown_feature(Manifest.Operation.DELETE)
+        # delete of an archive raises
+        self.cmd_raises_unknown_feature(['delete', self.repository_location + '::test'])
+        self.cmd_raises_unknown_feature(['prune', '--keep-daily=3', self.repository_location])
+        # delete of the whole repository ignores features
+        self.cmd('delete', self.repository_location)
+
+    @unittest.skipUnless(has_llfuse, 'llfuse not installed')
+    def test_unknown_feature_on_mount(self):
+        self.cmd('init', self.repository_location)
+        self.cmd('create', self.repository_location + '::test', 'input')
+        self.add_unknown_feature(Manifest.Operation.READ)
+        mountpoint = os.path.join(self.tmpdir, 'mountpoint')
+        os.mkdir(mountpoint)
+        # XXX this might hang if it doesn't raise an error
+        self.cmd_raises_unknown_feature(['mount', self.repository_location + '::test', mountpoint])
+
+    @pytest.mark.allow_cache_wipe
+    def test_unknown_mandatory_feature_in_cache(self):
+        if self.prefix:
+            path_prefix = 'ssh://__testsuite__'
+        else:
+            path_prefix = ''
+
+        print(self.cmd('init', self.repository_location))
+
+        with Repository(self.repository_path, exclusive=True) as repository:
+            if path_prefix:
+                repository._location = Location(self.repository_location)
+            manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
+            with Cache(repository, key, manifest) as cache:
+                cache.begin_txn()
+                cache.mandatory_features = set(['unknown-feature'])
+                cache.commit()
+
+        if self.FORK_DEFAULT:
+            self.cmd('create', self.repository_location + '::test', 'input')
+        else:
+            called = False
+            wipe_cache_safe = Cache.wipe_cache
+
+            def wipe_wrapper(*args):
+                nonlocal called
+                called = True
+                wipe_cache_safe(*args)
+
+            with patch.object(Cache, 'wipe_cache', wipe_wrapper):
+                self.cmd('create', self.repository_location + '::test', 'input')
+
+            assert called
+
+        with Repository(self.repository_path, exclusive=True) as repository:
+            if path_prefix:
+                repository._location = Location(self.repository_location)
+            manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
+            with Cache(repository, key, manifest) as cache:
+                assert cache.mandatory_features == set([])
+
     def test_progress(self):
         self.create_regular_file('file1', size=1024 * 80)
         self.cmd('init', self.repository_location)
@@ -1594,7 +1696,7 @@ class ArchiverCheckTestCase(ArchiverTestCaseBase):
         # This bug can still live on in Borg repositories (through borg upgrade).
         archive, repository = self.open_archive('archive1')
         with repository:
-            manifest, key = Manifest.load(repository)
+            manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
             with Cache(repository, key, manifest) as cache:
                 archive = Archive(repository, key, manifest, '0.13', cache=cache, create=True)
                 archive.items_buffer.add({
@@ -1611,7 +1713,7 @@ class ArchiverCheckTestCase(ArchiverTestCaseBase):
 class ManifestAuthenticationTest(ArchiverTestCaseBase):
     def spoof_manifest(self, repository):
         with repository:
-            _, key = Manifest.load(repository)
+            _, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
             repository.put(Manifest.MANIFEST_ID, key.encrypt(msgpack.packb({
                 'version': 1,
                 'archives': {},
@@ -1624,7 +1726,7 @@ class ManifestAuthenticationTest(ArchiverTestCaseBase):
         self.cmd('init', self.repository_location)
         repository = Repository(self.repository_path, exclusive=True)
         with repository:
-            manifest, key = Manifest.load(repository)
+            manifest, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
             repository.put(Manifest.MANIFEST_ID, key.encrypt(msgpack.packb({
                 'version': 1,
                 'archives': {},
@@ -1641,7 +1743,7 @@ class ManifestAuthenticationTest(ArchiverTestCaseBase):
         repository = Repository(self.repository_path, exclusive=True)
         with repository:
             shutil.rmtree(get_security_dir(bin_to_hex(repository.id)))
-            _, key = Manifest.load(repository)
+            _, key = Manifest.load(repository, Manifest.NO_OPERATION_CHECK)
             key.tam_required = False
             key.change_passphrase(key._passphrase)
 

conftest.py

@@ -4,6 +4,8 @@ import sys
 
 import pytest
 
+import borg.cache
+
 # needed to get pretty assertion failures in unit tests:
 if hasattr(pytest, 'register_assert_rewrite'):
     pytest.register_assert_rewrite('borg.testsuite')
@@ -35,3 +37,22 @@ def clean_env(tmpdir_factory, monkeypatch):
     keys = [key for key in os.environ if key.startswith('BORG_')]
     for key in keys:
         monkeypatch.delenv(key, raising=False)
+
+
+class DefaultPatches:
+    def __init__(self, request):
+        self.org_cache_wipe_cache = borg.cache.Cache.wipe_cache
+
+        def wipe_should_not_be_called(*a, **kw):
+            raise AssertionError("Cache wipe was triggered, if this is part of the test add @pytest.mark.allow_cache_wipe")
+        if 'allow_cache_wipe' not in request.keywords:
+            borg.cache.Cache.wipe_cache = wipe_should_not_be_called
+        request.addfinalizer(self.undo)
+
+    def undo(self):
+        borg.cache.Cache.wipe_cache = self.org_cache_wipe_cache
+
+
+@pytest.fixture(autouse=True)
+def default_patches(request):
+    return DefaultPatches(request)