Add Error to git and ostree sources configure

Raise a error at configure time if the track and ref properties are
not present in the sources.

This is to address https://gitlab.com/BuildStream/buildstream/issues/471
that documented unhelpful behaviour when tracking git sources. However
the issue was also identified in ostree.

2 files changed, 13 insertions, 0 deletions

diff --git a/buildstream/plugins/sources/git.py b/buildstream/plugins/sources/git.py
index 855e766d2..b3bc9cac7 100644
--- a/buildstream/plugins/sources/git.py
+++ b/buildstream/plugins/sources/git.py
@@ -309,6 +309,13 @@ class GitSource(Source):
         self.original_url = self.node_get_member(node, str, 'url')
         self.mirror = GitMirror(self, '', self.original_url, ref)
         self.tracking = self.node_get_member(node, str, 'track', None)
+
+        # At this point we now know if the source has a ref and/or a track.
+        # If it is missing both then we will be unable to track or build.
+        if self.mirror.ref is None and self.tracking is None:
+            raise SourceError("{}: Git sources require a ref and/or track".format(self),
+                              reason="missing-track-and-ref")
+
         self.checkout_submodules = self.node_get_member(node, bool, 'checkout-submodules', True)
         self.submodules = []
 
diff --git a/buildstream/plugins/sources/ostree.py b/buildstream/plugins/sources/ostree.py
index 6266731bf..526a91aa0 100644
--- a/buildstream/plugins/sources/ostree.py
+++ b/buildstream/plugins/sources/ostree.py
@@ -73,6 +73,12 @@ class OSTreeSource(Source):
         self.mirror = os.path.join(self.get_mirror_directory(),
                                    utils.url_directory_name(self.original_url))
 
+        # At this point we now know if the source has a ref and/or a track.
+        # If it is missing both then we will be unable to track or build.
+        if self.ref is None and self.tracking is None:
+            raise SourceError("{}: OSTree sources require a ref and/or track".format(self),
+                              reason="missing-track-and-ref")
+
         # (optional) Not all repos are signed. But if they are, get the gpg key
         self.gpg_key_path = None
         if self.node_get_member(node, str, 'gpg-key', None):