implement files cache mode control, fixes #911

You can now control the files cache mode using this option:

--files-cache={ctime,mtime,size,inode,rechunk,disabled}*

(only some combinations are supported)

Previously, only these modes were supported:
- mtime,size,inode (default of borg < 1.1.0rc4)
- mtime,size (by using --ignore-inode)
- disabled (by using --no-files-cache)

Now, you additionally get:
- ctime alternatively to mtime (more safe), e.g.:
  ctime,size,inode (this is the new default of borg >= 1.1.0rc4)
- rechunk (consider all files as changed, rechunk them)

Deprecated:
- --ignore-inodes (use modes without "inode")
- --no-files-cache (use "disabled" mode)

The tests needed some changes:
- previously, we use os.utime() to set a files mtime (atime) to specific
  values, but that does not work for ctime.
- now use time.sleep() to create the "latest file" that usually does
  not end up in the files cache (see FAQ)

docs/internals/data-structures.rst

@@ -738,7 +738,7 @@ b) with ``create --chunker-params 19,23,21,4095`` (default):
 
   mem_usage  =  0.31GiB
 
-.. note:: There is also the ``--no-files-cache`` option to switch off the files cache.
+.. note:: There is also the ``--files-cache=disabled`` option to disable the files cache.
    You'll save some memory, but it will need to read / chunk all the files as
    it can not skip unmodified files then.
 

src/borg/archive.py

@@ -1087,13 +1087,13 @@ class FilesystemObjectProcessors:
         self.add_item(item)
         return 'i'  # stdin
 
-    def process_file(self, path, st, cache, ignore_inode=False):
+    def process_file(self, path, st, cache, ignore_inode=False, files_cache_mode=DEFAULT_FILES_CACHE_MODE):
         with self.create_helper(path, st, None) as (item, status, hardlinked, hardlink_master):  # no status yet
             is_special_file = is_special(st.st_mode)
             if not hardlinked or hardlink_master:
                 if not is_special_file:
                     path_hash = self.key.id_hash(safe_encode(os.path.join(self.cwd, path)))
-                    ids = cache.file_known_and_unchanged(path_hash, st, ignore_inode)
+                    ids = cache.file_known_and_unchanged(path_hash, st, ignore_inode, files_cache_mode)
                 else:
                     # in --read-special mode, we may be called for special files.
                     # there should be no information in the cache about special files processed in
@@ -1126,7 +1126,7 @@ class FilesystemObjectProcessors:
                     if not is_special_file:
                         # we must not memorize special files, because the contents of e.g. a
                         # block or char device will change without its mtime/size/inode changing.
-                        cache.memorize_file(path_hash, st, [c.id for c in item.chunks])
+                        cache.memorize_file(path_hash, st, [c.id for c in item.chunks], files_cache_mode)
                     status = status or 'M'  # regular file, modified (if not 'A' already)
                 self.stats.nfiles += 1
             item.update(self.metadata_collector.stat_attrs(st, path))

src/borg/archiver.py

@@ -45,7 +45,7 @@ from .crypto.keymanager import KeyManager
 from .helpers import EXIT_SUCCESS, EXIT_WARNING, EXIT_ERROR
 from .helpers import Error, NoManifestError, set_ec
 from .helpers import positive_int_validator, location_validator, archivename_validator, ChunkerParams
-from .helpers import PrefixSpec, SortBySpec
+from .helpers import PrefixSpec, SortBySpec, FilesCacheMode
 from .helpers import BaseFormatter, ItemFormatter, ArchiveFormatter
 from .helpers import format_timedelta, format_file_size, parse_file_size, format_archive
 from .helpers import safe_encode, remove_surrogates, bin_to_hex, prepare_dump_dict
@@ -346,7 +346,7 @@ class Archiver:
             compression = '--compression=none'
             # measure create perf (without files cache to always have it chunking)
             t_start = time.monotonic()
-            rc = self.do_create(self.parse_args(['create', compression, '--no-files-cache', archive + '1', path]))
+            rc = self.do_create(self.parse_args(['create', compression, '--files-cache=disabled', archive + '1', path]))
             t_end = time.monotonic()
             dt_create = t_end - t_start
             assert rc == 0
@@ -485,6 +485,7 @@ class Archiver:
         self.output_filter = args.output_filter
         self.output_list = args.output_list
         self.ignore_inode = args.ignore_inode
+        self.files_cache_mode = args.files_cache_mode
         dry_run = args.dry_run
         t0 = datetime.utcnow()
         t0_monotonic = time.monotonic()
@@ -548,7 +549,7 @@ class Archiver:
                     return
             if stat.S_ISREG(st.st_mode):
                 if not dry_run:
-                    status = fso.process_file(path, st, cache, self.ignore_inode)
+                    status = fso.process_file(path, st, cache, self.ignore_inode, self.files_cache_mode)
             elif stat.S_ISDIR(st.st_mode):
                 if recurse:
                     tag_paths = dir_is_tagged(path, exclude_caches, exclude_if_present)
@@ -1960,14 +1961,17 @@ class Archiver:
 
     def preprocess_args(self, args):
         deprecations = [
-            # ('--old', '--new', 'Warning: "--old" has been deprecated. Use "--new" instead.'),
+            # ('--old', '--new' or None, 'Warning: "--old" has been deprecated. Use "--new" instead.'),
             ('--list-format', '--format', 'Warning: "--list-format" has been deprecated. Use "--format" instead.'),
             ('--keep-tag-files', '--keep-exclude-tags', 'Warning: "--keep-tag-files" has been deprecated. Use "--keep-exclude-tags" instead.'),
+            ('--ignore-inode', None, 'Warning: "--ignore-inode" has been deprecated. Use "--files-cache=ctime,size" or "...=mtime,size" instead.'),
+            ('--no-files-cache', None, 'Warning: "--no-files-cache" has been deprecated. Use "--files-cache=disabled" instead.'),
         ]
         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)
+                    if new_name is not None:
+                        args[i] = arg.replace(old_name, new_name)
                     print(warning, file=sys.stderr)
         return args
 
@@ -2595,13 +2599,39 @@ class Archiver:
         {now}, {utcnow}, {fqdn}, {hostname}, {user} and some others.
 
         Backup speed is increased by not reprocessing files that are already part of
-        existing archives and weren't modified. Normally, detecting file modifications
-        will take inode information into consideration. This is problematic for files
-        located on sshfs and similar network file systems which do not provide stable
-        inode numbers, such files will always be considered modified. The
-        ``--ignore-inode`` flag can be used to prevent this and improve performance.
-        This flag will reduce reliability of change detection however, with files
-        considered unmodified as long as their size and modification time are unchanged.
+        existing archives and weren't modified. The detection of unmodified files is
+        done by comparing multiple file metadata values with previous values kept in
+        the files cache.
+
+        This comparison can operate in different modes as given by ``--files-cache``:
+
+        - ctime,size,inode (default)
+        - mtime,size,inode (default behaviour of borg versions older than 1.1.0rc4)
+        - ctime,size (ignore the inode number)
+        - mtime,size (ignore the inode number)
+        - rechunk,ctime (all files are considered modified - rechunk, cache ctime)
+        - rechunk,mtime (all files are considered modified - rechunk, cache mtime)
+        - disabled (disable the files cache, all files considered modified - rechunk)
+
+        inode number: better safety, but often unstable on network filesystems
+
+        Normally, detecting file modifications will take inode information into
+        consideration to improve the reliability of file change detection.
+        This is problematic for files located on sshfs and similar network file
+        systems which do not provide stable inode numbers, such files will always
+        be considered modified. You can use modes without `inode` in this case to
+        improve performance, but reliability of change detection might be reduced.
+
+        ctime vs. mtime: safety vs. speed
+
+        - ctime is a rather safe way to detect changes to a file (metadata and contents)
+          as it can not be set from userspace. But, a metadata-only change will already
+          update the ctime, so there might be some unnecessary chunking/hashing even
+          without content changes. Some filesystems do not support ctime (change time).
+        - mtime usually works and only updates if file contents were changed. But mtime
+          can be arbitrarily set from userspace, e.g. to set mtime back to the same value
+          it had before a content change happened. This can be used maliciously as well as
+          well-meant, but in both cases mtime based cache modes can be problematic.
 
         The mount points of filesystems or filesystem snapshots should be the same for every
         creation of a new archive to ensure fast operation. This is because the file cache that
@@ -2692,7 +2722,7 @@ class Archiver:
         subparser.add_argument('--json', action='store_true',
                                help='output stats as JSON. Implies ``--stats``.')
         subparser.add_argument('--no-cache-sync', dest='no_cache_sync', action='store_true',
-                               help='experimental: do not synchronize the cache. Implies ``--no-files-cache``.')
+                               help='experimental: do not synchronize the cache. Implies not using the files cache.')
 
         define_exclusion_group(subparser, tag_files=True)
 
@@ -2707,6 +2737,9 @@ class Archiver:
                               help='do not store ctime into archive')
         fs_group.add_argument('--ignore-inode', dest='ignore_inode', action='store_true',
                               help='ignore inode data in the file metadata cache used to detect unchanged files.')
+        fs_group.add_argument('--files-cache', metavar='MODE', dest='files_cache_mode',
+                              type=FilesCacheMode, default=DEFAULT_FILES_CACHE_MODE_UI,
+                              help='operate files cache in MODE. default: %s' % DEFAULT_FILES_CACHE_MODE_UI)
         fs_group.add_argument('--read-special', dest='read_special', action='store_true',
                               help='open and read block and char device files as well as FIFOs as if they were '
                                    'regular files. Also follows symlinks pointing to these kinds of files.')

src/borg/cache.py

@@ -12,7 +12,7 @@ from .logger import create_logger
 
 logger = create_logger()
 
-from .constants import CACHE_README
+from .constants import CACHE_README, DEFAULT_FILES_CACHE_MODE
 from .hashindex import ChunkIndex, ChunkIndexEntry, CacheSynchronizer
 from .helpers import Location
 from .helpers import Error
@@ -34,7 +34,8 @@ from .platform import SaveFile
 from .remote import cache_if_remote
 from .repository import LIST_SCAN_LIMIT
 
-FileCacheEntry = namedtuple('FileCacheEntry', 'age inode size mtime chunk_ids')
+# note: cmtime might me either a ctime or a mtime timestamp
+FileCacheEntry = namedtuple('FileCacheEntry', 'age inode size cmtime chunk_ids')
 
 
 class SecurityManager:
@@ -492,7 +493,7 @@ class LocalCache(CacheStatsMixin):
 
     def _read_files(self):
         self.files = {}
-        self._newest_mtime = None
+        self._newest_cmtime = None
         logger.debug('Reading files cache ...')
 
         with IntegrityCheckedFile(path=os.path.join(self.path, 'files'), write=False,
@@ -538,18 +539,18 @@ class LocalCache(CacheStatsMixin):
         self.security_manager.save(self.manifest, self.key)
         pi = ProgressIndicatorMessage(msgid='cache.commit')
         if self.files is not None:
-            if self._newest_mtime is None:
+            if self._newest_cmtime is None:
                 # was never set because no files were modified/added
-                self._newest_mtime = 2 ** 63 - 1  # nanoseconds, good until y2262
+                self._newest_cmtime = 2 ** 63 - 1  # nanoseconds, good until y2262
             ttl = int(os.environ.get('BORG_FILES_CACHE_TTL', 20))
             pi.output('Saving files cache')
             with IntegrityCheckedFile(path=os.path.join(self.path, 'files'), write=True) as fd:
                 for path_hash, item in self.files.items():
-                    # Only keep files seen in this backup that are older than newest mtime seen in this backup -
-                    # this is to avoid issues with filesystem snapshots and mtime granularity.
+                    # Only keep files seen in this backup that are older than newest cmtime seen in this backup -
+                    # this is to avoid issues with filesystem snapshots and cmtime granularity.
                     # Also keep files from older backups that have not reached BORG_FILES_CACHE_TTL yet.
                     entry = FileCacheEntry(*msgpack.unpackb(item))
-                    if entry.age == 0 and bigint_to_int(entry.mtime) < self._newest_mtime or \
+                    if entry.age == 0 and bigint_to_int(entry.cmtime) < self._newest_cmtime or \
                        entry.age > 0 and entry.age < ttl:
                         msgpack.pack((path_hash, entry), fd)
             self.cache_config.integrity['files'] = fd.integrity_data
@@ -902,37 +903,47 @@ class LocalCache(CacheStatsMixin):
         else:
             stats.update(-size, -csize, False)
 
-    def file_known_and_unchanged(self, path_hash, st, ignore_inode=False):
-        if not (self.do_files and stat.S_ISREG(st.st_mode)):
+    def file_known_and_unchanged(self, path_hash, st, ignore_inode=False, cache_mode=DEFAULT_FILES_CACHE_MODE):
+        if 'd' in cache_mode or not self.do_files or not stat.S_ISREG(st.st_mode):  # d(isabled)
             return None
         if self.files is None:
             self._read_files()
+        if 'r' in cache_mode:  # r(echunk)
+            return None
         entry = self.files.get(path_hash)
         if not entry:
             return None
         entry = FileCacheEntry(*msgpack.unpackb(entry))
-        if (entry.size == st.st_size and bigint_to_int(entry.mtime) == st.st_mtime_ns and
-                (ignore_inode or entry.inode == st.st_ino)):
-            # we ignored the inode number in the comparison above or it is still same.
-            # if it is still the same, replacing it in the tuple doesn't change it.
-            # if we ignored it, a reason for doing that is that files were moved to a new
-            # disk / new fs (so a one-time change of inode number is expected) and we wanted
-            # to avoid everything getting chunked again. to be able to re-enable the inode
-            # number comparison in a future backup run (and avoid chunking everything
-            # again at that time), we need to update the inode number in the cache with what
-            # we see in the filesystem.
-            self.files[path_hash] = msgpack.packb(entry._replace(inode=st.st_ino, age=0))
-            return entry.chunk_ids
-        else:
+        if 's' in cache_mode and entry.size != st.st_size:
             return None
-
-    def memorize_file(self, path_hash, st, ids):
-        if not (self.do_files and stat.S_ISREG(st.st_mode)):
+        if 'i' in cache_mode and not ignore_inode and entry.inode != st.st_ino:
+            return None
+        if 'c' in cache_mode and bigint_to_int(entry.cmtime) != st.st_ctime_ns:
+            return None
+        elif 'm' in cache_mode and bigint_to_int(entry.cmtime) != st.st_mtime_ns:
+            return None
+        # we ignored the inode number in the comparison above or it is still same.
+        # if it is still the same, replacing it in the tuple doesn't change it.
+        # if we ignored it, a reason for doing that is that files were moved to a new
+        # disk / new fs (so a one-time change of inode number is expected) and we wanted
+        # to avoid everything getting chunked again. to be able to re-enable the inode
+        # number comparison in a future backup run (and avoid chunking everything
+        # again at that time), we need to update the inode number in the cache with what
+        # we see in the filesystem.
+        self.files[path_hash] = msgpack.packb(entry._replace(inode=st.st_ino, age=0))
+        return entry.chunk_ids
+
+    def memorize_file(self, path_hash, st, ids, cache_mode=DEFAULT_FILES_CACHE_MODE):
+        # note: r(echunk) modes will update the files cache, d(isabled) mode won't
+        if 'd' in cache_mode or not self.do_files or not stat.S_ISREG(st.st_mode):
             return
-        mtime_ns = safe_ns(st.st_mtime_ns)
-        entry = FileCacheEntry(age=0, inode=st.st_ino, size=st.st_size, mtime=int_to_bigint(mtime_ns), chunk_ids=ids)
+        if 'c' in cache_mode:
+            cmtime_ns = safe_ns(st.st_ctime_ns)
+        elif 'm' in cache_mode:
+            cmtime_ns = safe_ns(st.st_mtime_ns)
+        entry = FileCacheEntry(age=0, inode=st.st_ino, size=st.st_size, cmtime=int_to_bigint(cmtime_ns), chunk_ids=ids)
         self.files[path_hash] = msgpack.packb(entry)
-        self._newest_mtime = max(self._newest_mtime or 0, mtime_ns)
+        self._newest_cmtime = max(self._newest_cmtime or 0, cmtime_ns)
 
 
 class AdHocCache(CacheStatsMixin):
@@ -973,10 +984,10 @@ Chunk index:    {0.total_unique_chunks:20d}             unknown"""
     files = None
     do_files = False
 
-    def file_known_and_unchanged(self, path_hash, st, ignore_inode=False):
+    def file_known_and_unchanged(self, path_hash, st, ignore_inode=False, cache_mode=DEFAULT_FILES_CACHE_MODE):
         return None
 
-    def memorize_file(self, path_hash, st, ids):
+    def memorize_file(self, path_hash, st, ids, cache_mode=DEFAULT_FILES_CACHE_MODE):
         pass
 
     def add_chunk(self, id, chunk, stats, overwrite=False, wait=True):

src/borg/constants.py

@@ -60,6 +60,10 @@ CHUNKER_PARAMS = (CHUNK_MIN_EXP, CHUNK_MAX_EXP, HASH_MASK_BITS, HASH_WINDOW_SIZE
 # chunker params for the items metadata stream, finer granularity
 ITEMS_CHUNKER_PARAMS = (15, 19, 17, HASH_WINDOW_SIZE)
 
+# operating mode of the files cache (for fast skipping of unchanged files)
+DEFAULT_FILES_CACHE_MODE_UI = 'ctime,size,inode'
+DEFAULT_FILES_CACHE_MODE = 'cis'  # == CacheMode(DEFAULT_FILES_CACHE_MODE_UI)
+
 # return codes returned by borg command
 # when borg is killed by signal N, rc = 128 + N
 EXIT_SUCCESS = 0  # everything done, no problems

src/borg/helpers/parseformat.py

@@ -117,6 +117,22 @@ def ChunkerParams(s):
     return int(chunk_min), int(chunk_max), int(chunk_mask), int(window_size)
 
 
+def FilesCacheMode(s):
+    ENTRIES_MAP = dict(ctime='c', mtime='m', size='s', inode='i', rechunk='r', disabled='d')
+    VALID_MODES = ('cis', 'ims', 'cs', 'ms', 'cr', 'mr', 'd')  # letters in alpha order
+    entries = set(s.strip().split(','))
+    if not entries <= set(ENTRIES_MAP):
+        raise ValueError('cache mode must be a comma-separated list of: %s' % ','.join(sorted(ENTRIES_MAP)))
+    short_entries = {ENTRIES_MAP[entry] for entry in entries}
+    mode = ''.join(sorted(short_entries))
+    if mode not in VALID_MODES:
+        raise ValueError('cache mode short must be one of: %s' % ','.join(VALID_MODES))
+    return mode
+
+
+assert FilesCacheMode(DEFAULT_FILES_CACHE_MODE_UI) == DEFAULT_FILES_CACHE_MODE  # keep these 2 values in sync!
+
+
 def partial_format(format, mapping):
     """
     Apply format.format_map(mapping) while preserving unknown keys

src/borg/testsuite/archiver.py

@@ -318,8 +318,6 @@ class ArchiverTestCaseBase(BaseTestCase):
         """Create a minimal test case including all supported file types
         """
         # File
-        self.create_regular_file('empty', size=0)
-        os.utime('input/empty', (MAX_S, MAX_S))
         self.create_regular_file('file1', size=1024 * 80)
         self.create_regular_file('flagfile', size=1024)
         # Directory
@@ -370,6 +368,8 @@ class ArchiverTestCaseBase(BaseTestCase):
             if e.errno not in (errno.EINVAL, errno.ENOSYS):
                 raise
             have_root = False
+        time.sleep(1)  # "empty" must have newer timestamp than other files
+        self.create_regular_file('empty', size=0)
         return have_root
 
 
@@ -1591,9 +1591,8 @@ class ArchiverTestCase(ArchiverTestCaseBase):
         """test that various file status show expected results
 
         clearly incomplete: only tests for the weird "unchanged" status for now"""
-        now = time.time()
         self.create_regular_file('file1', size=1024 * 80)
-        os.utime('input/file1', (now - 5, now - 5))  # 5 seconds ago
+        time.sleep(1)  # file2 must have newer timestamps than file1
         self.create_regular_file('file2', size=1024 * 80)
         self.cmd('init', '--encryption=repokey', self.repository_location)
         output = self.cmd('create', '--list', self.repository_location + '::test', 'input')
@@ -1606,12 +1605,51 @@ class ArchiverTestCase(ArchiverTestCaseBase):
         # https://borgbackup.readthedocs.org/en/latest/faq.html#i-am-seeing-a-added-status-for-a-unchanged-file
         self.assert_in("A input/file2", output)
 
+    def test_file_status_cs_cache_mode(self):
+        """test that a changed file with faked "previous" mtime still gets backed up in ctime,size cache_mode"""
+        self.create_regular_file('file1', contents=b'123')
+        time.sleep(1)  # file2 must have newer timestamps than file1
+        self.create_regular_file('file2', size=10)
+        self.cmd('init', '--encryption=repokey', self.repository_location)
+        output = self.cmd('create', '--list', '--files-cache=ctime,size', self.repository_location + '::test1', 'input')
+        # modify file1, but cheat with the mtime (and atime) and also keep same size:
+        st = os.stat('input/file1')
+        self.create_regular_file('file1', contents=b'321')
+        os.utime('input/file1', ns=(st.st_atime_ns, st.st_mtime_ns))
+        # this mode uses ctime for change detection, so it should find file1 as modified
+        output = self.cmd('create', '--list', '--files-cache=ctime,size', self.repository_location + '::test2', 'input')
+        self.assert_in("A input/file1", output)
+
+    def test_file_status_ms_cache_mode(self):
+        """test that a chmod'ed file with no content changes does not get chunked again in mtime,size cache_mode"""
+        self.create_regular_file('file1', size=10)
+        time.sleep(1)  # file2 must have newer timestamps than file1
+        self.create_regular_file('file2', size=10)
+        self.cmd('init', '--encryption=repokey', self.repository_location)
+        output = self.cmd('create', '--list', '--files-cache=mtime,size', self.repository_location + '::test1', 'input')
+        # change mode of file1, no content change:
+        st = os.stat('input/file1')
+        os.chmod('input/file1', st.st_mode ^ stat.S_IRWXO)  # this triggers a ctime change, but mtime is unchanged
+        # this mode uses mtime for change detection, so it should find file1 as unmodified
+        output = self.cmd('create', '--list', '--files-cache=mtime,size', self.repository_location + '::test2', 'input')
+        self.assert_in("U input/file1", output)
+
+    def test_file_status_rc_cache_mode(self):
+        """test that files get rechunked unconditionally in rechunk,ctime cache mode"""
+        self.create_regular_file('file1', size=10)
+        time.sleep(1)  # file2 must have newer timestamps than file1
+        self.create_regular_file('file2', size=10)
+        self.cmd('init', '--encryption=repokey', self.repository_location)
+        output = self.cmd('create', '--list', '--files-cache=rechunk,ctime', self.repository_location + '::test1', 'input')
+        # no changes here, but this mode rechunks unconditionally
+        output = self.cmd('create', '--list', '--files-cache=rechunk,ctime', self.repository_location + '::test2', 'input')
+        self.assert_in("A input/file1", output)
+
     def test_file_status_excluded(self):
         """test that excluded paths are listed"""
 
-        now = time.time()
         self.create_regular_file('file1', size=1024 * 80)
-        os.utime('input/file1', (now - 5, now - 5))  # 5 seconds ago
+        time.sleep(1)  # file2 must have newer timestamps than file1
         self.create_regular_file('file2', size=1024 * 80)
         if has_lchflags:
             self.create_regular_file('file3', size=1024 * 80)
@@ -1647,9 +1685,8 @@ class ArchiverTestCase(ArchiverTestCaseBase):
         assert 'stats' in archive
 
     def test_create_topical(self):
-        now = time.time()
         self.create_regular_file('file1', size=1024 * 80)
-        os.utime('input/file1', (now-5, now-5))
+        time.sleep(1)  # file2 must have newer timestamps than file1
         self.create_regular_file('file2', size=1024 * 80)
         self.cmd('init', '--encryption=repokey', self.repository_location)
         # no listing by default
@@ -2363,7 +2400,7 @@ class ArchiverTestCase(ArchiverTestCaseBase):
             fd.write(b'b' * 280)
         self.cmd('init', '--encryption=repokey', self.repository_location)
         self.cmd('create', '--chunker-params', '7,9,8,128', self.repository_location + '::test1', 'input')
-        self.cmd('create', self.repository_location + '::test2', 'input', '--no-files-cache')
+        self.cmd('create', self.repository_location + '::test2', 'input', '--files-cache=disabled')
         list = self.cmd('list', self.repository_location + '::test1', 'input/large_file',
                         '--format', '{num_chunks} {unique_chunks}')
         num_chunks, unique_chunks = map(int, list.split(' '))
@@ -3513,7 +3550,6 @@ class TestCommonOptions:
         add_common_option('-p', '--progress', dest='progress', action='store_true', help='foo')
         add_common_option('--lock-wait', dest='lock_wait', type=int, metavar='N', default=1,
                           help='(default: %(default)d).')
-        add_common_option('--no-files-cache', dest='no_files_cache', action='store_false', help='foo')
 
     @pytest.fixture
     def basic_parser(self):
@@ -3555,7 +3591,6 @@ class TestCommonOptions:
 
     def test_simple(self, parse_vars_from_line):
         assert parse_vars_from_line('--error') == {
-            'no_files_cache': True,
             'append': [],
             'lock_wait': 1,
             'log_level': 'error',
@@ -3563,7 +3598,6 @@ class TestCommonOptions:
         }
 
         assert parse_vars_from_line('--error', 'subcommand', '--critical') == {
-            'no_files_cache': True,
             'append': [],
             'lock_wait': 1,
             'log_level': 'critical',
@@ -3576,7 +3610,6 @@ class TestCommonOptions:
             parse_vars_from_line('--append-only', 'subcommand')
 
         assert parse_vars_from_line('--append=foo', '--append', 'bar', 'subcommand', '--append', 'baz') == {
-            'no_files_cache': True,
             'append': ['foo', 'bar', 'baz'],
             'lock_wait': 1,
             'log_level': 'warning',
@@ -3589,7 +3622,6 @@ class TestCommonOptions:
     @pytest.mark.parametrize('flag,args_key,args_value', (
         ('-p', 'progress', True),
         ('--lock-wait=3', 'lock_wait', 3),
-        ('--no-files-cache', 'no_files_cache', False),
     ))
     def test_flag_position_independence(self, parse_vars_from_line, position, flag, args_key, args_value):
         line = []
@@ -3600,7 +3632,6 @@ class TestCommonOptions:
             line.append(flag)
 
         result = {
-            'no_files_cache': True,
             'append': [],
             'lock_wait': 1,
             'log_level': 'warning',