[#1794] Fixes URI query handling for hashtags extraction in search.

lib/pleroma/web/mastodon_api/controllers/search_controller.ex

@@ -124,6 +124,7 @@ defp resource_search(:v1, "hashtags", query, _options) do
   defp prepare_tags(query, add_joined_tag \\ true) do
     tags =
       query
+      |> preprocess_uri_query()
       |> String.split(~r/[^#\w]+/u, trim: true)
       |> Enum.uniq_by(&String.downcase/1)
 
@@ -147,6 +148,19 @@ defp prepare_tags(query, add_joined_tag \\ true) do
     end
   end
 
+  # If `query` is a URI, returns last component of its path, otherwise returns `query`
+  defp preprocess_uri_query(query) do
+    if query =~ ~r/https?:\/\// do
+      query
+      |> URI.parse()
+      |> Map.get(:path)
+      |> String.split("/")
+      |> Enum.at(-1)
+    else
+      query
+    end
+  end
+
   defp joined_tag(tags) do
     tags
     |> Enum.map(fn tag -> String.capitalize(tag) end)

test/web/mastodon_api/controllers/search_controller_test.exs

@@ -111,6 +111,15 @@ test "constructs hashtags from search query", %{conn: conn} do
                %{"name" => "prone", "url" => "#{Web.base_url()}/tag/prone"},
                %{"name" => "AccidentProne", "url" => "#{Web.base_url()}/tag/AccidentProne"}
              ]
+
+      results =
+        conn
+        |> get("/api/v2/search?#{URI.encode_query(%{q: "https://shpposter.club/users/shpuld"})}")
+        |> json_response_and_validate_schema(200)
+
+      assert results["hashtags"] == [
+               %{"name" => "shpuld", "url" => "#{Web.base_url()}/tag/shpuld"}
+             ]
     end
 
     test "excludes a blocked users from search results", %{conn: conn} do