config/debian/dak.conf

@@ -307,7 +307,7 @@ External-Signature-Requests {
     "experimental";
     "unstable";
     "testing-proposed-updates";
-    "stable";
+    "proposed-updates";
     "buster-backports";
     "stretch-backports-sloppy";
     "stretch-backports";

daklib/archive.py

@@ -165,7 +165,8 @@ class ArchiveTransaction(object):
                     .filter(Suite.suite_id == source_suites.c.id)
             source = source_query.first()
             if source is None:
-                raise ArchiveException('{0}: trying to install to {1}, but could not find source'.format(binary.hashed_file.filename, suite.suite_name))
+                raise ArchiveException('{0}: trying to install to {1}, but could not find source ({2} {3})'.
+                    format(binary.hashed_file.filename, suite.suite_name, source_name, source_version))
             self.copy_source(source, suite, source.poolfile.component)
 
         db_file = self._install_file(directory, binary.hashed_file, suite.archive, component, source_name)