don't ignore key when executing CONTAINS (#2924)

Fixes #2912

CHANGELOG_PENDING.md

@@ -21,3 +21,4 @@ Special thanks to external contributors on this release:
 ### IMPROVEMENTS:
 
 ### BUG FIXES:
+- [kv indexer] \#2912 don't ignore key when executing CONTAINS

state/txindex/kv/kv.go

@@ -332,18 +332,18 @@ func isRangeOperation(op query.Operator) bool {
 	}
 }
 
-func (txi *TxIndex) match(c query.Condition, startKey []byte) (hashes [][]byte) {
+func (txi *TxIndex) match(c query.Condition, startKeyBz []byte) (hashes [][]byte) {
 	if c.Op == query.OpEqual {
-		it := dbm.IteratePrefix(txi.store, startKey)
+		it := dbm.IteratePrefix(txi.store, startKeyBz)
 		defer it.Close()
 		for ; it.Valid(); it.Next() {
 			hashes = append(hashes, it.Value())
 		}
 	} else if c.Op == query.OpContains {
-		// XXX: doing full scan because startKey does not apply here
-		// For example, if startKey = "account.owner=an" and search query = "accoutn.owner CONSISTS an"
-		// we can't iterate with prefix "account.owner=an" because we might miss keys like "account.owner=Ulan"
-		it := txi.store.Iterator(nil, nil)
+		// XXX: startKey does not apply here.
+		// For example, if startKey = "account.owner/an/" and search query = "accoutn.owner CONTAINS an"
+		// we can't iterate with prefix "account.owner/an/" because we might miss keys like "account.owner/Ulan/"
+		it := dbm.IteratePrefix(txi.store, startKey(c.Tag))
 		defer it.Close()
 		for ; it.Valid(); it.Next() {
 			if !isTagKey(it.Key()) {

state/txindex/kv/kv_test.go

@@ -89,8 +89,10 @@ func TestTxSearch(t *testing.T) {
 		{"account.date >= TIME 2013-05-03T14:45:00Z", 0},
 		// search using CONTAINS
 		{"account.owner CONTAINS 'an'", 1},
-		// search using CONTAINS
+		// search for non existing value using CONTAINS
 		{"account.owner CONTAINS 'Vlad'", 0},
+		// search using the wrong tag (of numeric type) using CONTAINS
+		{"account.number CONTAINS 'Iv'", 0},
 	}
 
 	for _, tc := range testCases {