Add --force / -f option to source-checkout command

buildstream/_frontend/cli.py

@@ -684,6 +684,8 @@ def checkout(app, element, location, force, deps, integrate, hardlinks, tar):
 #                  Source Checkout Command                      #
 ##################################################################
 @cli.command(name='source-checkout', short_help='Checkout sources for an element')
+@click.option('--force', '-f', default=False, is_flag=True,
+              help="Allow files to be overwritten")
 @click.option('--except', 'except_', multiple=True,
               type=click.Path(readable=False),
               help="Except certain dependencies")
@@ -699,12 +701,13 @@ def checkout(app, element, location, force, deps, integrate, hardlinks, tar):
                 type=click.Path(readable=False))
 @click.argument('location', type=click.Path())
 @click.pass_obj
-def source_checkout(app, element, location, deps, fetch_, except_, tar):
+def source_checkout(app, element, location, force, deps, fetch_, except_, tar):
     """Checkout sources of an element to the specified location
     """
     with app.initialized():
         app.stream.source_checkout(element,
                                    location=location,
+                                   force=force,
                                    deps=deps,
                                    fetch=fetch_,
                                    except_targets=except_,

buildstream/_stream.py

@@ -449,12 +449,13 @@ class Stream():
     #
     def source_checkout(self, target, *,
                         location=None,
+                        force=False,
                         deps='none',
                         fetch=False,
                         except_targets=(),
                         tar=False):
 
-        self._check_location_writable(location, tar=tar)
+        self._check_location_writable(location, force=force, tar=tar)
 
         elements, _ = self._load((target,), (),
                                  selection=deps,
@@ -468,7 +469,7 @@ class Stream():
 
         # Stage all sources determined by scope
         try:
-            self._source_checkout(elements, location, deps, fetch, tar)
+            self._source_checkout(elements, location, force, deps, fetch, tar)
         except BstError as e:
             raise StreamError("Error while writing sources"
                               ": '{}'".format(e), detail=e.detail, reason=e.reason) from e
@@ -1189,6 +1190,7 @@ class Stream():
     # Helper function for source_checkout()
     def _source_checkout(self, elements,
                          location=None,
+                         force=False,
                          deps='none',
                          fetch=False,
                          tar=False):
@@ -1204,7 +1206,7 @@ class Stream():
             if tar:
                 self._create_tarball(temp_source_dir.name, location)
             else:
-                self._move_directory(temp_source_dir.name, location)
+                self._move_directory(temp_source_dir.name, location, force)
         except OSError as e:
             raise StreamError("Failed to checkout sources to {}: {}"
                               .format(location, e)) from e
@@ -1212,10 +1214,9 @@ class Stream():
             with suppress(FileNotFoundError):
                 temp_source_dir.cleanup()
 
-
     # Move a directory src to dest. This will work across devices and
     # may optionaly overwrite existing files.
-    def _move_directory(self, src, dest):
+    def _move_directory(self, src, dest, force=False):
         def is_empty_dir(path):
             return os.path.isdir(dest) and not os.listdir(dest)
 
@@ -1225,7 +1226,7 @@ class Stream():
         except OSError:
             pass
 
-        if is_empty_dir(dest):
+        if force or is_empty_dir(dest):
             try:
                 utils.link_files(src, dest)
             except utils.UtilError as e:

tests/frontend/source_checkout.py

 import os
 import pytest
 import tarfile
+from pathlib import Path
 
 from tests.testutils import cli
 
@@ -47,6 +48,22 @@ def test_source_checkout(datafiles, tmpdir_factory, cli, with_workspace):
     assert os.path.exists(os.path.join(checkout, 'checkout-deps', 'etc', 'buildstream', 'config'))
 
 
+@pytest.mark.datafiles(DATA_DIR)
+@pytest.mark.parametrize('force_flag', ['--force', '-f'])
+def test_source_checkout_force(datafiles, cli, force_flag):
+    project = os.path.join(datafiles.dirname, datafiles.basename)
+    checkout = os.path.join(cli.directory, 'source-checkout')
+    target = 'checkout-deps.bst'
+
+    os.makedirs(os.path.join(checkout, 'some-thing'))
+    # Path(os.path.join(checkout, 'some-file')).touch()
+
+    result = cli.run(project=project, args=['source-checkout', force_flag, target, '--deps', 'none', checkout])
+    result.assert_success()
+
+    assert os.path.exists(os.path.join(checkout, 'checkout-deps', 'etc', 'buildstream', 'config'))
+
+
 @pytest.mark.datafiles(DATA_DIR)
 def test_source_checkout_tar(datafiles, cli):
     project = os.path.join(datafiles.dirname, datafiles.basename)