fix issue #2

single-element tags need to be handled

lib/gc_index_relay/nostr/pub_event.ex

@@ -59,8 +59,12 @@ defmodule GcIndexRelay.Nostr.PubEvent do
   defp to_tags(tags) when is_list(tags) do
     for t <- tags do
       [name | values] = t
-      # Single-element tags will cause a crash
-      [value | rest] = values
+
+      {value, rest} =
+        case values do
+          [] -> {nil, []}
+          [v | r] -> {v, r}
+        end
 
       %Tag{
         name: name,
@@ -93,6 +97,11 @@ defmodule GcIndexRelay.Nostr.PubEvent do
   end
 
   defp from_tags(tags) when is_list(tags) do
-    for t <- tags, do: [t.name, t.value | t.additional_values]
+    for t <- tags do
+      case t.value do
+        nil -> [t.name]
+        value -> [t.name, value | t.additional_values]
+      end
+    end
   end
 end

lib/gc_index_relay/nostr/tag.ex

@@ -13,6 +13,6 @@ defmodule GcIndexRelay.Nostr.Tag do
   def changeset(tag, attrs) do
     tag
     |> cast(attrs, [:name, :value, :additional_values])
-    |> validate_required([:name, :value])
+    |> validate_required([:name])
   end
 end

priv/repo/migrations/20260407062511_allow_null_tag_value.exs

@@ -0,0 +1,9 @@
+defmodule GcIndexRelay.Repo.Migrations.AllowNullTagValue do
+  use Ecto.Migration
+
+  def change do
+    alter table(:tags) do
+      modify :value, :string, null: true, from: {:string, null: false}
+    end
+  end
+end

test/gc_index_relay/nostr/pub_event_test.exs

@@ -127,6 +127,28 @@ defmodule GcIndexRelay.Nostr.PubEventTest do
       assert result.tags == tags
     end
 
+    test "preserves single-element tags (e.g. ['bot'])" do
+      tags = [["bot"]]
+
+      pub_event = valid_pub_event_fixture(tags: tags)
+
+      assert {:ok, result} = pub_event |> PubEvent.to_db() |> PubEvent.from_db()
+      assert result.tags == tags
+    end
+
+    test "preserves mixed single-element and multi-element tags" do
+      tags = [
+        ["bot"],
+        ["p", "def456"],
+        ["content-warning"]
+      ]
+
+      pub_event = valid_pub_event_fixture(tags: tags)
+
+      assert {:ok, result} = pub_event |> PubEvent.to_db() |> PubEvent.from_db()
+      assert result.tags == tags
+    end
+
     test "preserves event with empty content" do
       pub_event = valid_pub_event_fixture(content: "")