Fix: Login/Register unreachable from the main menu -- no button opened it

Reported directly by the user playtesting the exported exe: Play was
permanently disabled and there was no way to log in or register. Root
cause: main_menu.tscn wired Play and Quit, but nothing was ever
connected to _on_login_button_pressed()/_on_register_button_pressed() --
the AuthPanel, its form, and all its backend-calling logic were fully
correct, just completely unreachable. The script's own top comment even
said "(the existing Play/Quit buttons)" as if Play/Quit somehow doubled
as login triggers, which they never did -- a sign nobody ever actually
clicked through the running scene, only checked things at the API level.

Fix: added a real AuthButtonsRow (LoginButton, RegisterButton) wired to
the existing handlers, which now hide themselves once auth succeeds.
Also fixed grab_focus() targeting the AuthPanel (which can't accept
focus, just a background warning) to focus the username field instead.

Verified via two new smoke tests (smoke_test_main_menu_ui.gd,
smoke_test_main_menu_full_flow.gd) using a *real signal emission* on
the buttons, not a direct method call -- that distinction is exactly
what would have caught the original bug. Full click-through confirmed
against a real backend: open register form, fill it, submit, Play
actually becomes enabled, welcome message shows, auth buttons hide.

Also documents a real headless-testing gotcha found while verifying
this: a synthetic Button.pressed.emit() on an await-using handler
doesn't reliably get driven forward in --script/SceneTree mode the way
real GUI input dispatch does -- confirmed by comparing direct-call vs
emit() behavior side by side. Not a bug in the actual click-driven flow,
a test-harness quirk to route around (call the handler directly,
awaited, instead of emitting the signal).

Full checkpoint suite re-verified clean on this branch: migrations,
68/68 pytest, all 6 Godot smoke tests (including the 2 new ones, picked
up automatically by run_checkpoint_tests.py's glob).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/testing/test_inventory.md

@@ -48,7 +48,7 @@ these yet):
 
 ## Godot client — `scripts/smoke_test_*.gd`
 
-**4 smoke tests merged into `main`.** Each needs a live backend —
+**6 smoke tests merged into `main`.** Each needs a live backend —
 `AGP_API_BASE_URL` env var, falling back to the
 `application/agp/api_base_url` project setting (default
 `http://127.0.0.1:8000`) if unset.
@@ -59,6 +59,8 @@ these yet):
 | `smoke_test_auth.gd` | Tests the full auth flow via `ApiClient` autoload: register unique user (201), duplicate username (409), under-18 registration (400), correct login (200), wrong password (401), nonexistent user (401). |
 | `smoke_test_e2e.gd` | End-to-end flow: health check → register → login → worlds list. Verifies the full request chain with a fresh user, including token storage and `get_worlds()` with auth header. |
 | `smoke_test_world_list.gd` | Instantiates `world_list.tscn` as a real scene, adds to tree (catches `@onready` node-path bugs), waits for `_refresh_worlds()` to complete, confirms the screen reaches a real end state (world cards, empty-list message, or error label — not stuck loading). |
+| `smoke_test_main_menu_ui.gd` | Instantiates `main_menu.tscn`, confirms the auth panel starts hidden, and confirms a **real signal emission** on LoginButton/RegisterButton (not calling the handler method directly) actually opens it. This is the check that would have caught 2026-08-20's real bug: the auth panel and its logic were fully correct, but nothing in the scene was ever wired to open it, so Login/Register were completely unreachable from the UI. |
+| `smoke_test_main_menu_full_flow.gd` | Full click-through: open the register form, fill it exactly as a user would, submit, confirm Play actually becomes enabled, the welcome message shows, and the auth buttons hide themselves. Calls the submit handler directly (awaited) rather than via `auth_button.pressed.emit()` — see the note at the top of the file: a synthetic `.emit()` on an `await`-using handler doesn't get driven forward reliably in `--script`/SceneTree headless mode the way real GUI input event dispatch does, confirmed by comparing direct-call vs `.emit()` behavior. Not a bug in the actual click-driven flow, just a headless-test-harness quirk to route around when writing tests. |
 
 Run (once, to build the class cache): `godot --headless --path . --import`,
 then for each smoke test: `godot --headless --path . --script
@@ -66,14 +68,18 @@ res://scripts/smoke_test_<name>.gd` — **no `--quit`**, it kills these before
 their awaited HTTP calls finish.
 
 **Known gaps:**
-- No smoke tests for the main menu scene (`main_menu.tscn`).
 - No smoke tests for chunk loading/streaming (`chunk.gd`, `chunk_scene.gd`).
 - No smoke tests for dynamic/static object nodes.
 - All smoke tests require a live backend; no offline/unit smoke tests exist.
-- `smoke_test_world_list.gd` is the only one that exercises a real `.tscn`
+- `smoke_test_world_list.gd` and `smoke_test_main_menu_*.gd` are the only
-  scene instantiation — others only test the `ApiClient` autoload.
+  ones that exercise a real `.tscn` scene instantiation — others only test
+  the `ApiClient` autoload directly.
 - `get_me()` (`GET /auth/me`) is implemented in `scripts/api_client.gd` but
   has no smoke coverage yet.
+- The Login path (as opposed to Register) through `main_menu.gd` isn't
+  separately smoke-tested — it shares the same `_on_auth_button_pressed()`/
+  `_on_auth_complete()` code path already exercised for Register, but that's
+  inference, not a direct check.
 
 ## Client export
 

scenes/main_menu.tscn

@@ -29,6 +29,21 @@ text = "AGP Game"
 horizontal_alignment = 1
 theme_override_font_sizes/font_size = 72
 
+[node name="AuthButtonsRow" type="HBoxContainer" parent="CenterContainer/VBoxContainer"]
+layout_mode = 1
+theme_override_constants/separation = 16
+alignment = 1
+
+[node name="LoginButton" type="Button" parent="CenterContainer/VBoxContainer/AuthButtonsRow"]
+layout_mode = 1
+text = "Login"
+size_flags_horizontal = 3
+
+[node name="RegisterButton" type="Button" parent="CenterContainer/VBoxContainer/AuthButtonsRow"]
+layout_mode = 1
+text = "Register"
+size_flags_horizontal = 3
+
 [node name="AuthPanel" type="PanelContainer" parent="CenterContainer/VBoxContainer"]
 layout_mode = 1
 visible = false
@@ -106,6 +121,8 @@ layout_mode = 1
 text = "Quit"
 size_flags_horizontal = 4
 
+[connection signal="pressed" from="CenterContainer/VBoxContainer/AuthButtonsRow/LoginButton" to="." method="_on_login_button_pressed"]
+[connection signal="pressed" from="CenterContainer/VBoxContainer/AuthButtonsRow/RegisterButton" to="." method="_on_register_button_pressed"]
 [connection signal="pressed" from="CenterContainer/VBoxContainer/PlayButton" to="." method="_on_play_button_pressed"]
 [connection signal="pressed" from="CenterContainer/VBoxContainer/QuitButton" to="." method="_on_quit_button_pressed"]
 [connection signal="toggled" from="CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/ModeToggle" to="." method="_on_mode_toggle_toggled"]

scripts/main_menu.gd

@@ -1,17 +1,20 @@
 extends Control
 ## Main menu with login/register UI wired to the backend auth API.
 ##
-## The AuthPanel is hidden by default. When the user clicks "Login" or "Register"
+## The AuthPanel is hidden by default. When the user clicks the LoginButton or
-## (the existing Play/Quit buttons), the auth panel slides in. The ModeToggle
+## RegisterButton (AuthButtonsRow, above the panel), the auth panel slides in.
-## switches between Login and Register modes, showing/hiding the email and DOB
+## The ModeToggle switches between Login and Register modes, showing/hiding
-## fields accordingly.
+## the email and DOB fields accordingly.
 ##
-## On successful auth the token is stored via ApiClient, the welcome label
+## On successful auth the token is stored via ApiClient, AuthButtonsRow hides,
-## shows the username, and the Play button becomes enabled.
+## the welcome label shows the username, and the Play button becomes enabled.
 
 
 # ── UI references ────────────────────────────────────────────────────────────
 
+var _auth_buttons_row: HBoxContainer
+var _login_button: Button
+var _register_button: Button
 var _auth_panel: PanelContainer
 var _auth_mode_label: Label
 var _username_edit: LineEdit
@@ -33,6 +36,9 @@ var _is_authenticating: bool = false
 
 func _ready() -> void:
 	# Cache node references.
+	_auth_buttons_row = $CenterContainer/VBoxContainer/AuthButtonsRow
+	_login_button = $CenterContainer/VBoxContainer/AuthButtonsRow/LoginButton
+	_register_button = $CenterContainer/VBoxContainer/AuthButtonsRow/RegisterButton
 	_auth_panel = $CenterContainer/VBoxContainer/AuthPanel
 	_auth_mode_label = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthModeLabel
 	_username_edit = $CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/UsernameEdit
@@ -73,18 +79,19 @@ func _on_quit_button_pressed() -> void:
 # ── Auth panel toggle ────────────────────────────────────────────────────────
 
 func _on_login_button_pressed() -> void:
-	"""Show the auth panel (called from a future Login button on the main menu)."""
+	"""Show the auth panel, called from AuthButtonsRow/LoginButton."""
 	_auth_panel.visible = true
-	_auth_panel.grab_focus()
+	_username_edit.grab_focus()
 
 
 func _on_register_button_pressed() -> void:
-	"""Show the auth panel in register mode."""
+	"""Show the auth panel in register mode, called from AuthButtonsRow/RegisterButton."""
 	_auth_panel.visible = true
 	_is_register_mode = true
 	_mode_toggle.button_pressed = true
 	_update_auth_mode_ui()
 	_clear_status()
+	_username_edit.grab_focus()
 
 
 # ── Mode toggle (Login / Register) ───────────────────────────────────────────
@@ -166,11 +173,14 @@ func _on_auth_complete(result: Dictionary) -> void:
 	_is_authenticating = false
 
 	if result.ok:
-		# Success — show welcome, enable Play.
+		# Success — show welcome, enable Play, hide the now-redundant
+		# Login/Register entry points (the auth panel itself stays open,
+		# showing the welcome message in place of the form).
 		_welcome_label.text = "Welcome, %s!" % _username_edit.text.strip_edges()
 		_welcome_label.visible = true
 		_status_label.visible = false
 		_play_button.disabled = false
+		_auth_buttons_row.visible = false
 		print("Auth successful. Token stored.")
 	else:
 		# Failure — show backend error detail.

scripts/smoke_test_main_menu_full_flow.gd

@@ -0,0 +1,76 @@
+extends SceneTree
+## Full click-through simulation of the real user flow: press Register,
+## fill the form exactly as a human would, submit, confirm Play actually
+## becomes clickable. This is the check that would have caught the
+## original bug (no way to even open the form) and would catch a repeat
+## of it.
+
+var passed := 0
+var failed := 0
+
+
+func _initialize() -> void:
+	_run()
+
+
+func _run() -> void:
+	await process_frame
+
+	var packed: PackedScene = load("res://scenes/main_menu.tscn")
+	var instance: Control = packed.instantiate()
+	root.add_child(instance)
+	await process_frame
+
+	var register_button: Button = instance.get_node("CenterContainer/VBoxContainer/AuthButtonsRow/RegisterButton")
+	var auth_buttons_row: HBoxContainer = instance.get_node("CenterContainer/VBoxContainer/AuthButtonsRow")
+	var username_edit: LineEdit = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/UsernameEdit")
+	var password_edit: LineEdit = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/PasswordEdit")
+	var email_edit: LineEdit = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/EmailEdit")
+	var dob_edit: LineEdit = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/DOBEdit")
+	var auth_button: Button = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/AuthButton")
+	var welcome_label: Label = instance.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/WelcomeLabel")
+	var play_button: Button = instance.get_node("CenterContainer/VBoxContainer/PlayButton")
+
+	_check("Play starts disabled", play_button.disabled)
+
+	# Click Register -- a real signal emission is fine here since
+	# _on_register_button_pressed() is synchronous (no await), same as a
+	# real click's GUI event dispatch would drive it.
+	register_button.pressed.emit()
+	await process_frame
+
+	_check("auth panel opened in register mode", instance.get_node("CenterContainer/VBoxContainer/AuthPanel").visible)
+
+	# Fill the form exactly as a user would type into it.
+	var unique_id := int(Time.get_unix_time_from_system() * 1000)
+	username_edit.text = "mainmenu_e2e_%d" % unique_id
+	password_edit.text = "TestPass123!"
+	email_edit.text = "mainmenu_e2e_%d@test.example.com" % unique_id
+	dob_edit.text = "2000-01-01"
+
+	# Call the submit handler directly (awaited) rather than via
+	# auth_button.pressed.emit() -- a synthetic .emit() in --script/
+	# SceneTree headless mode doesn't drive an await-using handler's
+	# coroutine forward the same way real GUI input event dispatch does
+	# (confirmed via a direct-call vs emit() comparison: the direct call
+	# always resolves, the synthetic emit sometimes doesn't advance past
+	# its own await point even after 50 real process_frame waits). This
+	# is a headless-mode test-harness limitation, not a bug in the actual
+	# click-driven flow.
+	await instance._on_auth_button_pressed()
+
+	_check("Play became enabled after real register submission", not play_button.disabled)
+	_check("Welcome label visible", welcome_label.visible)
+	_check("Auth buttons row hid itself after success", not auth_buttons_row.visible)
+
+	print("\n=== SMOKE RESULT: %d/%d passed ===" % [passed, passed + failed])
+	quit(0 if failed == 0 else 1)
+
+
+func _check(description: String, condition: bool) -> void:
+	if condition:
+		print("  PASS: ", description)
+		passed += 1
+	else:
+		printerr("  FAIL: ", description)
+		failed += 1

scripts/smoke_test_main_menu_ui.gd

@@ -0,0 +1,60 @@
+extends SceneTree
+## Verifies the main menu's Login/Register buttons actually open the auth
+## panel via a real signal emission (not calling the handler method
+## directly) -- that's the exact gap that shipped without ever being
+## caught: the AuthPanel and its logic were all correct, but nothing in
+## the scene was ever wired to open it.
+
+
+func _initialize() -> void:
+	_run()
+
+
+func _run() -> void:
+	await process_frame
+
+	var passed := 0
+	var failed := 0
+
+	var packed: PackedScene = load("res://scenes/main_menu.tscn")
+	var instance: Control = packed.instantiate()
+	root.add_child(instance)
+	await process_frame
+
+	var login_button: Button = instance.get_node("CenterContainer/VBoxContainer/AuthButtonsRow/LoginButton")
+	var register_button: Button = instance.get_node("CenterContainer/VBoxContainer/AuthButtonsRow/RegisterButton")
+	var auth_panel: PanelContainer = instance.get_node("CenterContainer/VBoxContainer/AuthPanel")
+
+	if _check("auth panel starts hidden", not auth_panel.visible):
+		passed += 1
+	else:
+		failed += 1
+
+	login_button.pressed.emit()
+	await process_frame
+
+	if _check("auth panel visible after a real LoginButton press signal", auth_panel.visible):
+		passed += 1
+	else:
+		failed += 1
+
+	# Reset and check RegisterButton independently too.
+	auth_panel.visible = false
+	register_button.pressed.emit()
+	await process_frame
+
+	if _check("auth panel visible after a real RegisterButton press signal", auth_panel.visible):
+		passed += 1
+	else:
+		failed += 1
+
+	print("\n=== SMOKE RESULT: %d/%d passed ===" % [passed, passed + failed])
+	quit(0 if failed == 0 else 1)
+
+
+func _check(description: String, condition: bool) -> bool:
+	if condition:
+		print("  PASS: ", description)
+	else:
+		printerr("  FAIL: ", description)
+	return condition