givemejob: Stop synthesising host information when it's missing

Any lorry in the database should have been either:

1. Generated based on a 'trove' or 'gitlab' section, with
   'from_host' set to the Upstream Host name.
2. Read from a lorry referred to in a 'lorries' section, with
   'from_host' set to an empty string.

So this error case indicates a dangling reference in the database.
The current schema does not use foreign keys so this could happen,
but it's reasonable to just give up and return empty metadata.

1 files changed, 3 insertions, 10 deletions

diff --git a/lorrycontroller/givemejob.py b/lorrycontroller/givemejob.py
index 1a0fe35..8f4a2a8 100644
--- a/lorrycontroller/givemejob.py
+++ b/lorrycontroller/givemejob.py
@@ -76,16 +76,9 @@ class GiveMeJob(lorrycontroller.LorryControllerRoute):
         try:
             host_info = statedb.get_host_info(lorry_info['from_host'])
         except lorrycontroller.HostNotFoundError:
-            # XXX We don't know whether upstream is Trove.  It should be
-            # possible to set host type for single repositories.
-            host_info = {
-                'host':        lorry_info['from_host'],
-                'protocol':    'ssh',
-                'username':    None,
-                'password':    None,
-                'type':        'trove',
-                'type_params': {},
-            }
+            # XXX Shouldn't happen, but currently the database schema
+            # does not prevent it
+            return {}
 
         metadata = lorrycontroller.get_upstream_host(host_info) \
                                   .get_repo_metadata(lorry_info['from_path'])