plugins/elements/junction.py: Add 'cache-junction-elements' option

The 'cache-junction-elements' configuration option for junction's
is a boolean which enables elements from within the junction to
interact with the parent project's remote(s).

A test has been added to enforce this behaviour and the
BST_FORMAT_VERSION has been bumped.

1 files changed, 46 insertions, 0 deletions

diff --git a/tests/artifactcache/junctions.py b/tests/artifactcache/junctions.py
index c93d79c4b..bfddcedac 100644
--- a/tests/artifactcache/junctions.py
+++ b/tests/artifactcache/junctions.py
@@ -87,3 +87,49 @@ def test_push_pull(cli, tmpdir, datafiles):
         assert state == 'cached'
         state = cli.get_element_state(base_project, 'base-element.bst')
         assert state == 'cached'
+
+
+@pytest.mark.datafiles(DATA_DIR)
+def test_caching_junction_elements(cli, tmpdir, datafiles):
+    project = os.path.join(str(datafiles), 'parent')
+    base_project = os.path.join(str(project), 'base')
+
+    # Load the junction element
+    junction_element = os.path.join(project, 'base.bst')
+    junction_data = _yaml.roundtrip_load(junction_element)
+
+    # Add the "cache-junction-elements" boolean to the junction Element
+    junction_data['config'] = {"cache-junction-elements": True}
+    _yaml.roundtrip_dump(junction_data, junction_element)
+
+    with create_artifact_share(os.path.join(str(tmpdir), 'artifactshare-parent')) as share,\
+        create_artifact_share(os.path.join(str(tmpdir), 'artifactshare-base')) as base_share:
+
+        # First build it without the artifact cache configured
+        result = cli.run(project=project, args=['build', 'target.bst'])
+        assert result.exit_code == 0
+
+        # Assert that we are now cached locally
+        state = cli.get_element_state(project, 'target.bst')
+        assert state == 'cached'
+        state = cli.get_element_state(base_project, 'base-element.bst')
+        assert state == 'cached'
+
+        project_set_artifacts(project, share.repo)
+        project_set_artifacts(base_project, base_share.repo)
+
+        # Now try bst artifact push
+        result = cli.run(project=project, args=['artifact', 'push', '--deps', 'all', 'target.bst'])
+        assert result.exit_code == 0
+
+        # And finally assert that the artifacts are in the right shares
+        #
+        # The parent project's cache should *also* contain elements from the junction
+        assert_shared(cli, share, project, 'target.bst', project_name='parent')
+        assert_shared(cli, share, project, 'app.bst', project_name='parent')
+        assert_shared(cli, share, base_project, 'base-element.bst', project_name='base')
+
+        # The junction project's cache should only contain elements in the junction project
+        assert_not_shared(cli, base_share, project, 'target.bst', project_name='parent')
+        assert_not_shared(cli, base_share, project, 'app.bst', project_name='parent')
+        assert_shared(cli, base_share, base_project, 'base-element.bst', project_name='base')