Fix broken main_menu.gd on main + land Play->Back session persistence

Two things, found together while investigating a stuck blocker task:

1. URGENT: main_menu.gd currently fails to parse at all on main
   ("Identifier '_dob_edit' not declared in the current scope"). PR #44
   (hide-all-fields-on-auth-success) and PR #45 (DOBEdit -> Over18Check
   checkbox) each merged cleanly on their own -- Gitea's merge reported
   mergeable:true for both -- but together they left a reference to the
   old _dob_edit var on a line neither PR's diff touched, so no conflict
   was ever flagged. Same failure mode in smoke_test_main_menu_full_flow.gd
   (dob_edit, would have failed to even parse in the checkpoint suite).
   Fixed both to reference _over_18_check / over_18_check.

2. Lands the Play -> Back session-persistence fix (PR #43, task
   28357bca192d) that was stuck behind review the whole time main didn't
   have it yet: signal auth_state_ready, _show_authenticated() /
   _reset_to_logged_out() helpers, and _ready() restoring the
   authenticated UI (not resetting it) when ApiClient already holds a
   valid token. Plus the real fix a review round caught on top of that
   (task 9186405a6373): _show_authenticated() was hiding AuthPanel while
   claiming the welcome label inside it was visible -- a no-op UI-wise,
   since WelcomeLabel.visible=true does nothing once its parent is
   hidden. AuthPanel now stays visible; the regression test
   (smoke_test_main_menu_back.gd, new) asserts is_visible_in_tree(), not
   just .visible, so this class of bug can't pass silently again.

Verified against a live backend: 61/61 pytest, 7/7 Godot smoke tests
(including the new smoke_test_main_menu_back.gd, 12/12).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01M6rUEynmv2QmweocAQYARN

docs/testing/test_inventory.md

@@ -8,11 +8,12 @@ to know what "run the tests" actually checked.
 Run everything below in one shot with `scripts/run_checkpoint_tests.py`.
 
 Last verified against `main`: 2026-08-20 — full PC1 checkpoint run,
-migrations + pytest + all 6 Godot smoke tests + both platform exports, all
+migrations + pytest + all 7 Godot smoke tests + both platform exports, all
-clean. Two real bugs found and fixed via real playtesting this same day
+clean. Real bugs found and fixed via real playtesting this same day (not
-(not caught by the checkpoint suite as it stood before today): the main
+caught by the checkpoint suite as it stood before today): the main menu
-menu had no way to actually open the login/register form, and the world
+had no way to actually open the login/register form, the world list's
-list's cards rendered at ~1px wide once real data existed. Both are now
+cards rendered at ~1px wide once real data existed, and navigating Play →
+Back logged the user out despite a still-valid session. All three are now
 covered by the smoke tests below so they can't silently regress.
 
 ## Backend — `backend/tests/` (pytest)
@@ -52,7 +53,7 @@ these yet):
 
 ## Godot client — `scripts/smoke_test_*.gd`
 
-**6 smoke tests merged into `main`.** Each needs a live backend —
+**7 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.
@@ -65,6 +66,7 @@ these yet):
 | `smoke_test_world_list.gd` | Registers a user, **seeds a real world via `POST /api/worlds/`** (without this, `run_checkpoint_tests.py`'s always-fresh DB means the populated-card render path never actually runs in CI, only the empty-list path would), instantiates `world_list.tscn` as a real scene, waits for `_refresh_worlds()` to complete, confirms it reached the populated (not empty) state, and asserts **each rendered card's real computed width is >= 200px**. That last check is the one that matters: 2026-08-20, a real bug shipped where every card existed in the tree with a non-zero child count and no crash, but rendered at 1.0px wide (`ScrollContainer`'s `size_flags_horizontal`/`vertical` used the raw integer `4` = `Control.SIZE_SHRINK_CENTER` instead of `3` = `SIZE_EXPAND_FILL`) — invisible on screen, and a child-count-only check would never have caught it. Confirmed by deliberately reintroducing the bug: card width check correctly fails at 25px. |
 | `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. |
+| `smoke_test_main_menu_back.gd` | Regression test for Play → Back logging the user out even with a valid token still held. Registers a user, loads `main_menu.tscn` (asserts it restores the authenticated state via a real `auth_state_ready` signal wait, not a frame-count guess), clicks Play → `world_list.tscn`, clicks Back → `main_menu.tscn`, and asserts the menu is still authenticated. Checks `WelcomeLabel.is_visible_in_tree()`, not just `.visible` — the label lives inside AuthPanel, so `.visible` alone is a false positive if the panel itself is hidden (a real bug briefly present: `_show_authenticated()` hid AuthPanel while claiming the welcome label was visible, which rendered nothing). |
 
 Run (once, to build the class cache): `godot --headless --path . --import`,
 then for each smoke test: `godot --headless --path . --script

scripts/main_menu.gd

@@ -10,6 +10,20 @@ extends Control
 ## On successful auth the token is stored via ApiClient, AuthButtonsRow hides,
 ## the welcome label shows the username, and the Play button becomes enabled.
 ## The auth form fields are hidden, leaving only the welcome message visible.
+##
+## When returning from another scene (e.g. world_list), _ready() checks whether
+## ApiClient already holds a valid token. If so, it restores the authenticated
+## UI state (Play enabled, welcome message visible) instead of forcing the user
+## back to the login form.
+
+
+## Emitted once _ready()'s session check (has_token() + the awaited
+## get_me() call) has actually resolved, whichever way -- lets a test (or
+## anything else) know the UI state is trustworthy now, rather than
+## guessing from a frame count or from UI properties that are ambiguous
+## mid-await (e.g. AuthButtonsRow.visible is true both before the check
+## resolves AND in a genuine logged-out end state).
+signal auth_state_ready
 
 # ─── UI references ────────────────────────────────────────────────────────────
 
@@ -51,7 +65,51 @@ func _ready() -> void:
 	_play_button = $CenterContainer/VBoxContainer/PlayButton
 	_quit_button = $CenterContainer/VBoxContainer/QuitButton
 
-	# Initial state.
+	# Default to Play being gated. When a token exists, the async session
+	# check below may take several frames (a real get_me() round-trip);
+	# keeping the button disabled until validation succeeds prevents a fast
+	# click from navigating to world_list with an expired/invalid token.
+	_play_button.disabled = true
+
+	# Check whether a valid session already exists (e.g. user logged in,
+	# navigated to world_list, then clicked Back). If so, restore the
+	# authenticated UI state instead of forcing the login form again.
+	if ApiClient.has_token():
+		var me_result: Dictionary = await ApiClient.get_me()
+		if me_result.ok and me_result.data is Dictionary:
+			var username: String = str((me_result.data as Dictionary).get("username", ""))
+			if username != "":
+				_show_authenticated(username)
+				auth_state_ready.emit()
+				return
+
+	# Token missing or invalid — fall through to logged-out state.
+	_reset_to_logged_out()
+	auth_state_ready.emit()
+
+
+## Restore the UI to the authenticated state (Play enabled, welcome message
+## visible, auth buttons hidden). AuthPanel itself stays visible -- the
+## welcome label lives inside it, so hiding the panel hides the label too
+## even when the label's own `visible` is true (real bug, 2026-08-20: a
+## review caught the panel being hidden here while the label claimed to be
+## visible, which is a no-op UI-wise since Control.visible doesn't override
+## an ancestor's hidden state).
+func _show_authenticated(username: String) -> void:
+	_auth_panel.visible = true
+	_status_label.visible = false
+	_welcome_label.text = "Welcome, %s!" % username
+	_welcome_label.visible = true
+	_email_edit.visible = false
+	_over_18_check.visible = false
+	_play_button.disabled = false
+	_auth_buttons_row.visible = false
+	print("Restored authenticated session for: ", username)
+
+
+## Reset the UI to the logged-out state (Play disabled, auth panel hidden,
+## login/register buttons visible).
+func _reset_to_logged_out() -> void:
 	_auth_panel.visible = false
 	_status_label.visible = false
 	_welcome_label.visible = false
@@ -166,7 +224,7 @@ func _on_auth_complete(result: Dictionary) -> void:
 		_username_edit.visible = false
 		_password_edit.visible = false
 		_email_edit.visible = false
-		_dob_edit.visible = false
+		_over_18_check.visible = false
 		_auth_button.visible = false
 		_auth_mode_label.visible = false
 		_status_label.visible = false

scripts/smoke_test_main_menu_back.gd

@@ -0,0 +1,153 @@
+extends SceneTree
+## Regression test for the Play -> Back navigation bug.
+##
+## The reported bug: after logging in and clicking Play, the user lands on
+## world_list.tscn; clicking Back returns to main_menu.tscn, but the menu
+## reset to a fully logged-out state (Play disabled, login form showing)
+## even though ApiClient still held a valid token. main_menu.gd's _ready()
+## used to unconditionally reset the UI on every scene load.
+##
+## This test drives the real navigation flow (change_scene_to_file) against
+## a live backend:
+##   1. Register a unique user so ApiClient holds a valid token.
+##   2. Load main_menu.tscn and assert it restores the authenticated state.
+##   3. Click Play -> world_list.tscn.
+##   4. Click Back -> main_menu.tscn.
+##   5. Assert the menu is STILL authenticated (Play enabled, welcome label
+##      actually visible in the tree, login/register buttons hidden).
+##
+## Run with:
+##     godot --headless --path . --script res://scripts/smoke_test_main_menu_back.gd
+##
+## Requires the backend to be running (default base URL
+## `application/agp/api_base_url` -> http://127.0.0.1:8000).
+
+const USERNAME := "backnav_%d"
+const EMAIL := "backnav_%d@test.example.com"
+const PASSWORD := "BackNav123!"
+
+var passed := 0
+var failed := 0
+
+
+func _initialize() -> void:
+	_run()
+
+
+func _run() -> void:
+	await process_frame
+
+	var api := root.get_node("ApiClient")
+	if api == null:
+		printerr("FAIL: ApiClient autoload not found")
+		quit(1)
+		return
+
+	# 1. Establish a real, valid session exactly the way a user would.
+	randomize()
+	var unique_id: int = int(Time.get_unix_time_from_system() * 1000) + randi() % 100000
+	var username := USERNAME % unique_id
+	var email := EMAIL % unique_id
+	print("\n=== Setup: register ", username, " ===")
+	var register_result: Dictionary = await api.register(username, email, PASSWORD, true)
+	if not _check("register succeeds", register_result.ok):
+		print("  detail: ", register_result.detail)
+		_finish()
+		return
+	_check("ApiClient stores token after register", api.has_token())
+
+	# 2. First visit to the main menu: should already show the authenticated
+	#    state (no login form, Play enabled).
+	change_scene_to_file("res://scenes/main_menu.tscn")
+	# change_scene_to_file defers the actual swap -- a couple frames is
+	# plenty for the scene object itself to exist (unlike the real
+	# get_me() network round-trip afterward, which is what auth_state_ready
+	# actually waits for below).
+	for i in 5:
+		await process_frame
+		if current_scene is Control:
+			break
+
+	var menu: Control = current_scene
+	if menu == null or not menu is Control:
+		printerr("FAIL: main_menu.tscn did not become current_scene")
+		_finish()
+		return
+	await menu.auth_state_ready
+	_check("first main menu visit restores authenticated state", _is_authenticated(menu))
+
+	# 3. Play -> world_list.tscn (real button press).
+	var play_button: Button = menu.get_node("CenterContainer/VBoxContainer/PlayButton")
+	play_button.pressed.emit()
+	await _wait_for_scene_change(menu)
+
+	var world_list_scene := current_scene
+	if world_list_scene == null or world_list_scene == menu:
+		printerr("FAIL: world_list.tscn did not become current_scene after Play")
+		_finish()
+		return
+
+	# 4. Back -> main_menu.tscn (real button press).
+	var back_button: Button = world_list_scene.get_node("VBoxContainer/HeaderHBox/BackButton")
+	back_button.pressed.emit()
+	await _wait_for_scene_change(world_list_scene)
+
+	menu = current_scene
+	if menu == null or not menu is Control:
+		printerr("FAIL: main_menu.tscn did not become current_scene after Back")
+		_finish()
+		return
+
+	# The new main_menu instance's own _ready() is *also* awaiting a real
+	# get_me() call -- _wait_for_scene_change only confirms the scene
+	# object exists, not that its authenticated-state fields have been
+	# set yet. Wait for the real signal, not a guess.
+	await menu.auth_state_ready
+
+	# 5. THE regression assertion: still logged in after returning.
+	_check("main menu stays authenticated after Play -> Back", _is_authenticated(menu))
+
+	_finish()
+
+
+func _is_authenticated(menu: Control) -> bool:
+	var play_button: Button = menu.get_node("CenterContainer/VBoxContainer/PlayButton")
+	var welcome_label: Label = menu.get_node("CenterContainer/VBoxContainer/AuthPanel/MarginContainer/AuthVBox/WelcomeLabel")
+	var auth_buttons_row: HBoxContainer = menu.get_node("CenterContainer/VBoxContainer/AuthButtonsRow")
+	var auth_panel: PanelContainer = menu.get_node("CenterContainer/VBoxContainer/AuthPanel")
+
+	_check("Play enabled", not play_button.disabled)
+	# WelcomeLabel lives inside AuthPanel, so `.visible` alone is a
+	# false-positive: the label can have visible=true while its parent is
+	# hidden and it renders as nothing. `is_visible_in_tree()` is the
+	# check that proves the user can actually see the welcome message.
+	_check("Welcome label visible in tree", welcome_label.is_visible_in_tree())
+	_check("Auth buttons row hidden", not auth_buttons_row.visible)
+	_check("Auth panel visible (it contains the welcome label)", auth_panel.visible)
+
+	return (not play_button.disabled) \
+		and welcome_label.is_visible_in_tree() \
+		and not auth_buttons_row.visible \
+		and auth_panel.visible
+
+
+func _wait_for_scene_change(previous_scene: Node) -> void:
+	for i in 20:
+		await process_frame
+		if current_scene != previous_scene and current_scene != null:
+			return
+
+
+func _check(description: String, condition: bool) -> bool:
+	if condition:
+		print("  PASS: ", description)
+		passed += 1
+	else:
+		printerr("  FAIL: ", description)
+		failed += 1
+	return condition
+
+
+func _finish() -> void:
+	print("\n=== SMOKE RESULT: %d/%d passed ===" % [passed, passed + failed])
+	quit(0 if failed == 0 else 1)

scripts/smoke_test_main_menu_full_flow.gd

@@ -60,7 +60,7 @@ func _run() -> void:
 	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("Welcome label visible in tree", welcome_label.is_visible_in_tree())
 	_check("Auth buttons row hid itself after success", not auth_buttons_row.visible)
 
 	# Verify the auth form fields are hidden after successful auth,
@@ -68,7 +68,7 @@ func _run() -> void:
 	_check("Username edit hidden after auth", not username_edit.visible)
 	_check("Password edit hidden after auth", not password_edit.visible)
 	_check("Email edit hidden after auth", not email_edit.visible)
-	_check("DOB edit hidden after auth", not dob_edit.visible)
+	_check("Over18 checkbox hidden after auth", not over_18_check.visible)
 	_check("Auth button hidden after auth", not auth_button.visible)
 	_check("Auth mode label hidden after auth", not auth_mode_label.visible)
 	_check("Welcome label contains username", welcome_label.text.begins_with("Welcome, mainmenu_e2e_"))