feat: add partial clone argument in vcs import

vcstool/__init__.py

@@ -1,3 +1,3 @@
 from .clients import vcstool_clients  # noqa
 
-__version__ = '0.3.0'
+__version__ = '0.3.1'

vcstool/clients/git.py

@@ -313,6 +313,8 @@ def import_(self, command):
 
             # fetch updates for existing repo
             cmd_fetch = [GitClient._executable, 'fetch', remote]
+            if command.partial_clone:
+                cmd_fetch.append("--filter=blob:none")
             if command.shallow:
                 result_version_type, version_name = self._check_version_type(
                     command.url, checkout_version)
@@ -386,7 +388,10 @@ def import_(self, command):
 
             if not command.shallow or version_type in (None, 'branch'):
                 cmd_clone = [GitClient._executable, 'clone', command.url, '.']
-                if version_type == 'branch':
+                if command.partial_clone:
+                    cmd_clone += ["--filter=blob:none", "--no-checkout"]
+                    checkout_version = command.version
+                elif version_type == 'branch':
                     cmd_clone += ['-b', version_name]
                     checkout_version = None
                 else:

vcstool/commands/import_.py

@@ -34,6 +34,7 @@ def __init__(
         self.skip_existing = args.skip_existing
         self.recursive = recursive
         self.shallow = shallow
+        self.partial_clone = args.partial_clone
 
 
 def get_parser():
@@ -60,6 +61,10 @@ def get_parser():
         '--skip-existing', action='store_true', default=False,
         help="Don't overwrite existing directories or change custom checkouts "
              'in repos using the same URL (but fetch repos with same URL)')
+    group.add_argument(
+        '--partial-clone', action='store_true', default=False,
+        help="Only clone the partial git first, then checkout to the target version"
+    )
 
     return parser