fetch: trust remote checksums

dvc/config.py

@@ -198,6 +198,7 @@ class Config(object):  # pylint: disable=too-many-instance-attributes
     SECTION_REMOTE_ASK_PASSWORD = "ask_password"
     SECTION_REMOTE_GSS_AUTH = "gss_auth"
     SECTION_REMOTE_NO_TRAVERSE = "no_traverse"
+    SECTION_REMOTE_VERIFY = "verify"
     SECTION_REMOTE_SCHEMA = {
         Required(SECTION_REMOTE_URL): str,
         SECTION_AWS_REGION: str,
@@ -232,6 +233,7 @@ class Config(object):  # pylint: disable=too-many-instance-attributes
         SECTION_GDRIVE_USER_CREDENTIALS_FILE: str,
         PRIVATE_CWD: str,
         SECTION_REMOTE_NO_TRAVERSE: Bool,
+        SECTION_REMOTE_VERIFY: Bool,
     }
 
     SECTION_STATE = "state"

dvc/data_cloud.py

@@ -73,13 +73,25 @@ def pull(self, cache, jobs=None, remote=None, show_checksums=False):
             show_checksums (bool): show checksums instead of file names in
                 information messages.
         """
-        return self.repo.cache.local.pull(
-            cache,
-            jobs=jobs,
-            remote=self.get_remote(remote, "pull"),
-            show_checksums=show_checksums,
+        remote = self.get_remote(remote, "pull")
+        downloaded_items_num = self.repo.cache.local.pull(
+            cache, jobs=jobs, remote=remote, show_checksums=show_checksums
         )
 
+        if not remote.verify:
+            self._save_pulled_checksums(cache)
+
+        return downloaded_items_num
+
+    def _save_pulled_checksums(self, cache):
+        for checksum in cache["local"].keys():
+            cache_file = self.repo.cache.local.checksum_to_path_info(checksum)
+            if self.repo.cache.local.exists(cache_file):
+                # We can safely save here, as existing corrupted files will be
+                # removed upon status, while files corrupted during download
+                # will not be moved from tmp_file (see `RemoteBASE.download()`)
+                self.repo.state.save(cache_file, checksum)
+
     def status(self, cache, jobs=None, remote=None, show_checksums=False):
         """Check status of data items in a cloud-agnostic way.
 

dvc/remote/base.py

@@ -80,6 +80,7 @@ class RemoteBASE(object):
     CHECKSUM_JOBS = max(1, min(4, cpu_count() // 2))
     DEFAULT_CACHE_TYPES = ["copy"]
     DEFAULT_NO_TRAVERSE = True
+    DEFAULT_VERIFY = False
 
     state = StateNoop()
 
@@ -93,6 +94,9 @@ def __init__(self, repo, config):
         self.no_traverse = config.get(
             Config.SECTION_REMOTE_NO_TRAVERSE, self.DEFAULT_NO_TRAVERSE
         )
+        self.verify = config.get(
+            Config.SECTION_REMOTE_VERIFY, self.DEFAULT_VERIFY
+        )
         self._dir_info = {}
 
         types = config.get(Config.SECTION_CACHE_TYPE, None)

dvc/remote/gdrive.py

@@ -63,6 +63,7 @@ class RemoteGDrive(RemoteBASE):
     path_cls = CloudURLInfo
     REQUIRES = {"pydrive2": "pydrive2"}
     DEFAULT_NO_TRAVERSE = False
+    DEFAULT_VERIFY = True
 
     GDRIVE_USER_CREDENTIALS_DATA = "GDRIVE_USER_CREDENTIALS_DATA"
     DEFAULT_USER_CREDENTIALS_FILE = "gdrive-user-credentials.json"

tests/func/test_data_cloud.py

@@ -9,10 +9,11 @@
 from mock import patch
 
 from dvc.cache import NamedCache
+from dvc.compat import fspath
 from dvc.config import Config
 from dvc.data_cloud import DataCloud
 from dvc.main import main
-from dvc.remote import RemoteAZURE
+from dvc.remote import RemoteAZURE, RemoteConfig
 from dvc.remote import RemoteGDrive
 from dvc.remote import RemoteGS
 from dvc.remote import RemoteHDFS
@@ -653,3 +654,37 @@ def test(self):
         assert self.message_header in self._caplog.text
         assert self.message_foo_part in self._caplog.text
         assert self.message_bar_part in self._caplog.text
+
+
+def test_verify_checksums(tmp_dir, scm, dvc, mocker, tmp_path_factory):
+    tmp_dir.dvc_gen({"file": "file1 content"}, commit="add file")
+    tmp_dir.dvc_gen({"dir": {"subfile": "file2 content"}}, commit="add dir")
+
+    RemoteConfig(dvc.config).add(
+        "local_remote",
+        fspath(tmp_path_factory.mktemp("local_remote")),
+        default=True,
+    )
+    dvc.push()
+
+    # remove artifacts and cache to trigger fetching
+    os.remove("file")
+    shutil.rmtree("dir")
+    shutil.rmtree(dvc.cache.local.cache_dir)
+
+    checksum_spy = mocker.spy(dvc.cache.local, "get_file_checksum")
+
+    dvc.pull()
+    assert checksum_spy.call_count == 0
+
+    # Removing cache will invalidate existing state entries
+    shutil.rmtree(dvc.cache.local.cache_dir)
+
+    dvc.config.set(
+        Config.SECTION_REMOTE_FMT.format("local_remote"),
+        Config.SECTION_REMOTE_VERIFY,
+        "True",
+    )
+
+    dvc.pull()
+    assert checksum_spy.call_count == 3