Properly delete losing leaf revs

x/sqlite/delete.go

@@ -48,21 +48,23 @@ func (d *db) Delete(ctx context.Context, docID string, options driver.Options) (
 	}
 	defer tx.Rollback()
 
-	var curRev revision
+	var found bool
 	err = tx.QueryRowContext(ctx, fmt.Sprintf(`
-		SELECT rev, rev_id
-		FROM %q
-		WHERE id = $1
-		ORDER BY rev DESC, rev_id DESC
-		LIMIT 1
-	`, d.name), data.ID).Scan(&curRev.rev, &curRev.id)
+		SELECT child.id IS NULL
+		FROM %[2]q AS rev
+		LEFT JOIN %[2]q AS child ON rev.id = child.id AND rev.rev = child.parent_rev AND rev.rev_id = child.parent_rev_id
+		JOIN %[1]q AS doc ON rev.id = doc.id AND rev.rev = doc.rev AND rev.rev_id = doc.rev_id
+		WHERE rev.id = $1
+			AND rev.rev = $2
+			AND rev.rev_id = $3
+	`, d.name, d.name+"_revs"), data.ID, delRev.rev, delRev.id).Scan(&found)
 	switch {
 	case errors.Is(err, sql.ErrNoRows):
 		return "", &internal.Error{Status: http.StatusNotFound, Message: "not found"}
 	case err != nil:
 		return "", err
 	}
-	if curRev.String() != optRev {
+	if !found {
 		return "", &internal.Error{Status: http.StatusConflict, Message: "conflict"}
 	}
 	var r revision

x/sqlite/delete_test.go

@@ -120,7 +120,7 @@ func TestDBDelete(t *testing.T) {
 			wantErr:    "conflict",
 		},
 		{
-			name: "delete losing rev for conflict",
+			name: "delete losing rev for conflict should succeed",
 			setup: func(t *testing.T, db driver.DB) {
 				_, err := db.Put(context.Background(), "foo", map[string]string{
 					"cat":  "meow",
@@ -139,7 +139,7 @@ func TestDBDelete(t *testing.T) {
 			},
 			id:      "foo",
 			options: kivik.Rev("1-aaa"),
-			wantRev: "2-xxxxx",
+			wantRev: "2-df2a4fe30cde39c357c8d1105748d1b9",
 		},
 		{
 			name:       "invalid rev format",