Engine: fix negative pagination bounds and _ts accumulation

Two correctness bugs surfaced by CR / Phase 0, both inherited from
the bundled PhabricatorElasticFulltextStorageEngine pattern:

1. executeSearch() did not validate that $offset / $limit were
   non-negative. PHP's (int) cast on a negative string yields a
   negative int, which would be passed unchecked to Elasticsearch.
   Add an explicit non-negative check before the existing upper-
   bound (offset + limit > 10000) check.

2. reindexAbstractDocument()'s relationship-data loop assigned the
   '_ts' field unconditionally instead of accumulating. For multi-
   valued relationships (multiple authorPHID, projectPHID, etc.
   entries on the same doc), only the last timestamp survived.
   Change to array-append, parallel to the PHID array.

Both fixes diverge from the bundled engine; bundled retains the
faithful-but-broken behavior. Worth fixing in this extension since
we control the wire format.

🤖 Generated by [robots](https://vyos.io)

1 files changed, 10 insertions, 1 deletions

diff --git a/src/engine/VyOSElasticModernFulltextStorageEngine.php b/src/engine/VyOSElasticModernFulltextStorageEngine.php
index 5c3d9a2..ef4a14d 100644
--- a/src/engine/VyOSElasticModernFulltextStorageEngine.php
+++ b/src/engine/VyOSElasticModernFulltextStorageEngine.php
@@ -227,7 +227,11 @@ class VyOSElasticModernFulltextStorageEngine
         $spec[$field_name][] = $related_phid;
       }
       if ($time !== null) {
-        $spec[$field_name.'_ts'] = $time;
+        if (!isset($spec[$field_name.'_ts'])) {
+          $spec[$field_name.'_ts'] = array($time);
+        } else {
+          $spec[$field_name.'_ts'][] = $time;
+        }
       }
     }
 
@@ -420,6 +424,11 @@ class VyOSElasticModernFulltextStorageEngine
 
     $offset = (int)$query->getParameter('offset', 0);
     $limit  = (int)$query->getParameter('limit', 101);
+    if ($offset < 0 || $limit < 0) {
+      throw new Exception(pht(
+        'Query offset and limit must be non-negative. offset=%d limit=%d',
+        $offset, $limit));
+    }
     if ($offset + $limit > 10000) {
       throw new Exception(pht(
         'Query offset is too large. offset+limit=%s (max=%s)',