From 9ad2e84e8165767506c6ddb7dbc3b8278181ad3d Mon Sep 17 00:00:00 2001
From: Ivan Sokolov <ivan-p-sokolov@ya.ru>
Date: Tue, 22 Aug 2023 21:52:33 +0300
Subject: [PATCH] Fix explosion of empty lists in queries

---
 lib/yuri_template/query_expander.ex        | 3 +++
 test/yuri_template/query_expander_test.exs | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/lib/yuri_template/query_expander.ex b/lib/yuri_template/query_expander.ex
index c1f1efa..a7d451f 100644
--- a/lib/yuri_template/query_expander.ex
+++ b/lib/yuri_template/query_expander.ex
@@ -28,6 +28,9 @@ defmodule YuriTemplate.QueryExpander do
         value = if is_map(value), do: Enum.to_list(value), else: value
 
         case value do
+          [] ->
+            acc
+
           [{k1, v1} | kvs] ->
             Enum.reduce(
               kvs,
diff --git a/test/yuri_template/query_expander_test.exs b/test/yuri_template/query_expander_test.exs
index f2263a5..66436b5 100644
--- a/test/yuri_template/query_expander_test.exs
+++ b/test/yuri_template/query_expander_test.exs
@@ -21,4 +21,11 @@ defmodule YuriTemplate.QueryExpanderTest do
       {"{?keys,who}", "?keys=semi,%3B,dot,.,comma,%2C&who=fred"},
       {"{?list,half}", "?list=red,green,blue&half=50%25"}
     ]
+
+  test "empty keys explode" do
+    YuriTemplate.expand!(
+      "/category/{category_id}/{category_transliterate}/{page}{?specs*,per_page,sort,order}",
+      %{category_id: "1", category_transliterate: "x", page: "2", specs: []}
+    ) == "/category/1/x/2"
+  end
 end