Fix action state handling bug (#25395)

* Rejig action state handling

* Fix entity arg

* Fix deserialization

Content.IntegrationTests/Tests/Actions/ActionPvsDetachTest.cs

@@ -0,0 +1,59 @@
+using System.Linq;
+using Content.Shared.Actions;
+using Content.Shared.Eye;
+using Robust.Server.GameObjects;
+using Robust.Shared.GameObjects;
+
+namespace Content.IntegrationTests.Tests.Actions;
+
+[TestFixture]
+public sealed class ActionPvsDetachTest
+{
+    [Test]
+    public async Task TestActionDetach()
+    {
+        await using var pair = await PoolManager.GetServerClient(new PoolSettings { Connected = true });
+        var (server, client) = pair;
+        var sys = server.System<SharedActionsSystem>();
+        var cSys = client.System<SharedActionsSystem>();
+
+        // Spawn mob that has some actions
+        EntityUid ent = default;
+        var map = await pair.CreateTestMap();
+        await server.WaitPost(() => ent = server.EntMan.SpawnAtPosition("MobHuman", map.GridCoords));
+        await pair.RunTicksSync(5);
+        var cEnt = pair.ToClientUid(ent);
+
+        // Verify that both the client & server agree on the number of actions
+        var initActions = sys.GetActions(ent).Count();
+        Assert.That(initActions, Is.GreaterThan(0));
+        Assert.That(initActions, Is.EqualTo(cSys.GetActions(cEnt).Count()));
+
+        // PVS-detach action entities
+        // We do this by just giving them the ghost layer
+        var visSys = server.System<VisibilitySystem>();
+        var enumerator = server.Transform(ent).ChildEnumerator;
+        while (enumerator.MoveNext(out var child))
+        {
+            visSys.AddLayer(child, (int) VisibilityFlags.Ghost);
+        }
+        await pair.RunTicksSync(5);
+
+        // Client's actions have left been detached / are out of view, but action comp state has not changed
+        Assert.That(sys.GetActions(ent).Count(), Is.EqualTo(initActions));
+        Assert.That(cSys.GetActions(cEnt).Count(), Is.EqualTo(initActions));
+
+        // Re-enter PVS view
+        enumerator = server.Transform(ent).ChildEnumerator;
+        while (enumerator.MoveNext(out var child))
+        {
+            visSys.RemoveLayer(child, (int) VisibilityFlags.Ghost);
+        }
+        await pair.RunTicksSync(5);
+        Assert.That(sys.GetActions(ent).Count(), Is.EqualTo(initActions));
+        Assert.That(cSys.GetActions(cEnt).Count(), Is.EqualTo(initActions));
+
+        await server.WaitPost(() => server.EntMan.DeleteEntity(map.MapUid));
+        await pair.CleanReturnAsync();
+    }
+}