_versions.py: Added new file just to hold basic symbolic versions

This is where we're going to store BST_CORE_ARTIFACT_VERSION
and BST_FORMAT_VERSION from now on.

This was a little bit weirdly defined before, and now we need to
at least have BST_FORMAT_VERSION available from the frontend/cli
without onerous imports (we need to import it there, but dont want
to slow down load time for bash completion runs).

1 files changed, 37 insertions, 0 deletions

diff --git a/buildstream/_versions.py b/buildstream/_versions.py
new file mode 100644
index 000000000..b08048c1f
--- /dev/null
+++ b/buildstream/_versions.py
@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+#
+#  Copyright (C) 2016 Codethink Limited
+#
+#  This program is free software; you can redistribute it and/or
+#  modify it under the terms of the GNU Lesser General Public
+#  License as published by the Free Software Foundation; either
+#  version 2 of the License, or (at your option) any later version.
+#
+#  This library is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
+#  Lesser General Public License for more details.
+#
+#  You should have received a copy of the GNU Lesser General Public
+#  License along with this library. If not, see <http://www.gnu.org/licenses/>.
+#
+#  Authors:
+#        Tristan Van Berkom <tristan.vanberkom@codethink.co.uk>
+
+
+# The base BuildStream format version
+#
+# This version is bumped whenever enhancements are made
+# to the `project.conf` format or the core element format.
+#
+BST_FORMAT_VERSION = 6
+
+
+# The base BuildStream artifact version
+#
+# The artifact version changes whenever the cache key
+# calculation algorithm changes in an incompatible way
+# or if buildstream was changed in a way which can cause
+# the same cache key to produce something that is no longer
+# the same.
+BST_CORE_ARTIFACT_VERSION = 1