badger/lmdb: fix tag sorting when they are small.

badger/helpers.go

@@ -3,7 +3,6 @@ package badger
 import (
 	"encoding/binary"
 	"encoding/hex"
-	"strings"
 
 	"github.com/fiatjaf/eventstore"
 	"github.com/nbd-wtf/go-nostr"
@@ -87,7 +86,7 @@ func getIndexKeysForEvent(evt *nostr.Event, idx []byte) [][]byte {
 	}
 
 	// ~ by tagvalue+date
-	slices.SortFunc(evt.Tags, func(a, b nostr.Tag) int { return strings.Compare(a[1], b[1]) })
+	slices.SortFunc(evt.Tags, eventstore.TagSorter)
 	for i, tag := range evt.Tags {
 		if len(tag) < 2 || len(tag[0]) != 1 || len(tag[1]) == 0 || len(tag[1]) > 100 {
 			// not indexable

helpers.go

@@ -1,6 +1,8 @@
 package eventstore
 
-import "github.com/nbd-wtf/go-nostr"
+import (
+	"github.com/nbd-wtf/go-nostr"
+)
 
 func isOlder(previous, next *nostr.Event) bool {
 	return previous.CreatedAt < next.CreatedAt ||

lmdb/helpers.go

@@ -3,7 +3,6 @@ package lmdb
 import (
 	"encoding/binary"
 	"encoding/hex"
-	"strings"
 
 	"github.com/PowerDNS/lmdb-go/lmdb"
 	"github.com/fiatjaf/eventstore"
@@ -79,7 +78,7 @@ func (b *LMDBBackend) getIndexKeysForEvent(evt *nostr.Event) []key {
 	}
 
 	// ~ by tagvalue+date
-	slices.SortFunc(evt.Tags, func(a, b nostr.Tag) int { return strings.Compare(a[1], b[1]) })
+	slices.SortFunc(evt.Tags, eventstore.TagSorter)
 	for i, tag := range evt.Tags {
 		if len(tag) < 2 || len(tag[0]) != 1 || len(tag[1]) == 0 || len(tag[1]) > 100 {
 			// not indexable

utils.go

@@ -4,6 +4,8 @@ import (
 	"encoding/hex"
 	"strconv"
 	"strings"
+
+	"github.com/nbd-wtf/go-nostr"
 )
 
 func GetAddrTagElements(tagValue string) (kind uint16, pkb []byte, d string) {
@@ -17,3 +19,16 @@ func GetAddrTagElements(tagValue string) (kind uint16, pkb []byte, d string) {
 	}
 	return 0, nil, ""
 }
+
+func TagSorter(a, b nostr.Tag) int {
+	if len(a) < 2 {
+		if len(b) < 2 {
+			return 0
+		}
+		return -1
+	}
+	if len(b) < 2 {
+		return 1
+	}
+	return strings.Compare(a[1], b[1])
+}