[Sugar-devel] [PATCH v3 sugar-datastore 1/2] find(): fix sort order in ambiguous cases

[Sascha Silbe]

When several entries have the same timestamp, the exact ordering when sorting
by timestamp was undefined previously. That's good enough for most clients, but
a test suite needs repeatable results. We make sure the ordering is stable by
sorting by the automatically-assigned, strictly increasing Xapian document id
in the matching direction.

Signed-off-by: Sascha Silbe <silbe at activitycentral.com>
---
v2->v3: Better handling of unsupported order_by values, as pointed out
	by Simon

 src/carquinyol/indexstore.py |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/carquinyol/indexstore.py b/src/carquinyol/indexstore.py
index dc721e7..7e7bfb5 100644
--- a/src/carquinyol/indexstore.py
+++ b/src/carquinyol/indexstore.py
@@ -301,8 +301,10 @@ class IndexStore(object):
 
         if order_by == '+timestamp':
             enquire.set_sort_by_value(_VALUE_TIMESTAMP, True)
+            enquire.set_docid_order(False)
         elif order_by == '-timestamp':
             enquire.set_sort_by_value(_VALUE_TIMESTAMP, False)
+            enquire.set_docid_order(True)
         elif order_by == '+title':
             enquire.set_sort_by_value(_VALUE_TITLE, True)
         elif order_by == '-title':
@@ -316,7 +318,10 @@ class IndexStore(object):
         elif order_by == '-creation_time':
             enquire.set_sort_by_value(_VALUE_CREATION_TIME, False)
         else:
-            logging.warning('Unsupported property for sorting: %s', order_by)
+            logging.warning('Sorting by property %r is not supported, falling'
+                            ' back to default (+timestamp)', order_by)
+            enquire.set_sort_by_value(_VALUE_TIMESTAMP, True)
+            enquire.set_docid_order(False)
 
         query_result = enquire.get_mset(offset, limit, check_at_least)
         total_count = query_result.get_matches_estimated()
-- 
1.7.9.5