fix(web): sample both sides of DST when comparing zones

CodeRabbit caught this and it is right: comparing the wall clock at one
instant treats zones that merely coincide right now as the same one.
America/New_York and America/Lima hold the same offset all winter, so a
panel set to the wrong one of the two ticked the step in January and then
ran an hour off from March -- a silent false pass, which is the failure the
whole check exists to prevent. Same shape as the dateStyle problem in the
previous commit: a comparison coarser than it looks.

Three instants now, all of which must agree: now, and mid-January and
mid-July of the current year. Those sit either side of DST in both
hemispheres, so only zones that agree year-round match. Toronto still
matches New York, which is correct -- either renders the same times.

Two tests. A static one asserts the comparison samples more than the
current instant, since reverting to `[now]` looks like a simplification.
And a table pinning which pairs must count as the same zone: aliases and
same-rule zones equal, seasonal coincidences (New York/Lima,
Phoenix/Los_Angeles, Sydney/Guadalcanal) not. That table mirrors the
algorithm rather than executing the shipped JS -- there is no JS runtime
here and the repo has no JS test infra -- so it records the verdicts the
browser code has to reach, and the static guard keeps the two aligned.

Mutation-checked: reverting to a single instant fails the static guard.

Also documented what the city test compares. CodeRabbit read it as always
failing, on the grounds that the label differs between Tampa and Seattle.
It does, but timezone_step() returns the opening tag only, so the
comparison is over data-done and data-tz and the label is not in it. The
assertion is left as an equality over the whole tag, which is stronger than
checking the two attributes by name; the docstring now says so.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01STMbQE4YctTacQXfbYqKuW

test/test_onboarding_checklist.py

@@ -0,0 +1,241 @@
+"""
+Getting Started checklist: what the server decides, and what it must not.
+
+The timezone step used to tick server-side when the saved timezone differed
+from the shipped default, OR-ed with the saved city. That made the step
+unsatisfiable for anyone genuinely in the default zone (the card nagged
+forever), and let a saved city tick it off while the timezone was still wrong.
+The step is now verified in the browser against its own zone, so the server's
+only job is to hand over the configured value and stay out of the decision.
+
+These tests pin that contract: the panel-size step still reflects config, the
+timezone step never pre-ticks, it carries the configured zone, and the city
+has no influence on it.
+"""
+
+import copy
+import re
+import sys
+from pathlib import Path
+from unittest.mock import MagicMock
+
+import pytest
+from flask import Flask
+
+PROJECT_ROOT = Path(__file__).parent.parent
+sys.path.insert(0, str(PROJECT_ROOT))
+
+BASE_CONFIG = {
+    "timezone": "America/New_York",
+    "location": {"city": "Tampa", "state": "Florida", "country": "US"},
+    "display": {
+        "hardware": {"rows": 32, "cols": 64, "chain_length": 2, "parallel": 1},
+        "runtime": {},
+        "double_sided": {"enabled": False},
+        "vegas_scroll": {"plugin_order": [], "excluded_plugins": []},
+        "plugin_rotation_order": [],
+    },
+    "plugin_system": {},
+    "schedule": {},
+    "dim_schedule": {},
+    "sync": {},
+}
+
+
+def render(config):
+    """Render the overview partial against one config, as app.py would."""
+    base = PROJECT_ROOT / "web_interface"
+    app = Flask(
+        __name__,
+        template_folder=str(base / "templates"),
+        static_folder=str(base / "static"),
+    )
+    app.config["TESTING"] = True
+
+    from web_interface.blueprints import pages_v3 as pv
+
+    # pages_v3 is a module-level singleton shared across the test process;
+    # restore whatever the previous test left on it.
+    original_cm = getattr(pv.pages_v3, "config_manager", None)
+    original_pm = getattr(pv.pages_v3, "plugin_manager", None)
+
+    mock_cm = MagicMock()
+    mock_cm.load_config.return_value = config
+    mock_cm.get_raw_file_content.return_value = config
+    pv.pages_v3.config_manager = mock_cm
+
+    mock_pm = MagicMock()
+    mock_pm.plugins = {}
+    mock_pm.get_all_plugin_info.return_value = []
+    mock_pm.get_plugin_display_modes.side_effect = lambda pid: []
+    pv.pages_v3.plugin_manager = mock_pm
+
+    app.register_blueprint(pv.pages_v3, url_prefix="")
+    try:
+        resp = app.test_client().get("/partials/overview")
+        assert resp.status_code == 200, resp.status_code
+        return resp.get_data(as_text=True)
+    finally:
+        pv.pages_v3.config_manager = original_cm
+        pv.pages_v3.plugin_manager = original_pm
+
+
+def timezone_step(body):
+    """The checklist <button> for the timezone step."""
+    match = re.search(r"<button[^>]*data-check=\"timezone\"[^>]*>", body)
+    assert match, "timezone step not found in the rendered checklist"
+    return match.group(0)
+
+
+def config_with(**overrides):
+    config = copy.deepcopy(BASE_CONFIG)
+    for key, value in overrides.items():
+        config[key] = value
+    return config
+
+
+@pytest.mark.parametrize(
+    "timezone",
+    ["America/New_York", "America/Los_Angeles", "Europe/Madrid", "Asia/Kolkata"],
+)
+def test_timezone_step_never_pre_ticks_server_side(timezone):
+    """The browser owns this decision; the server must not pre-empt it.
+
+    The default zone is in the list deliberately: that is the case the old
+    default-comparison could never tick.
+    """
+    step = timezone_step(render(config_with(timezone=timezone)))
+    assert 'data-done="0"' in step, step
+
+
+@pytest.mark.parametrize(
+    "timezone",
+    ["America/New_York", "Europe/Madrid", "Pacific/Auckland"],
+)
+def test_timezone_step_carries_the_configured_zone(timezone):
+    """JS compares data-tz against the browser, so it has to be the real value."""
+    assert f'data-tz="{timezone}"' in timezone_step(render(config_with(timezone=timezone)))
+
+
+def test_city_does_not_influence_the_timezone_step():
+    """The coupling this change removes: city said nothing about the timezone,
+    and OR-ing it let a saved city tick the step off with the zone still wrong.
+
+    timezone_step() returns the opening tag only, so this compares the state
+    the step is in -- data-done and data-tz -- and not the label, which does
+    still show the configured city as context and so differs between the two.
+    """
+    tampa = timezone_step(render(config_with(
+        location={"city": "Tampa", "state": "Florida", "country": "US"})))
+    seattle = timezone_step(render(config_with(
+        location={"city": "Seattle", "state": "Washington", "country": "US"})))
+    assert tampa == seattle
+
+
+def test_missing_timezone_leaves_the_step_open():
+    """Nothing saved means nothing to verify: the step stays unticked and the
+    JS bails on the empty value rather than comparing against ''."""
+    step = timezone_step(render(config_with(timezone="")))
+    assert 'data-tz=""' in step
+    assert 'data-done="0"' in step
+
+
+def test_zone_comparison_asks_for_the_time_of_day():
+    """Guard on the Intl options, which look like a stylistic choice.
+
+    dateStyle/timeStyle are late additions (Firefox shipped them in 91). An
+    implementation that does not know them ignores them and formats the date
+    alone -- which compares New York, Chicago and Madrid as equal and ticks
+    the step for a timezone that is plainly wrong. Explicit numeric fields
+    have been in Intl since ECMA-402 v1.
+    """
+    template = (PROJECT_ROOT / "web_interface" / "templates" / "v3"
+                / "partials" / "overview.html").read_text()
+    body = template[template.index("function sameZone"):]
+    body = body[:body.index("}())")]
+    # The comment above the options names dateStyle/timeStyle to explain why
+    # they are not used, so match on code only.
+    body = "\n".join(line for line in body.splitlines()
+                     if not line.lstrip().startswith("//"))
+    assert "dateStyle" not in body and "timeStyle" not in body, (
+        "zone comparison must not depend on dateStyle/timeStyle")
+    for field in ("hour:", "minute:", "year:", "month:", "day:"):
+        assert field in body, f"zone comparison dropped {field!r}"
+
+
+def test_zone_comparison_samples_both_sides_of_dst():
+    """One instant is not enough, and the shortfall is invisible for months.
+
+    America/New_York and America/Lima hold the same offset all winter, so a
+    check against now alone ticks the step in January for a panel that runs an
+    hour off from March. The comparison has to sample instants either side of
+    DST -- mid-January and mid-July, which covers both hemispheres.
+    """
+    template = (PROJECT_ROOT / "web_interface" / "templates" / "v3"
+                / "partials" / "overview.html").read_text()
+    body = template[template.index("function sameZone"):]
+    body = body[:body.index("}())")]
+    code = "\n".join(line for line in body.splitlines()
+                     if not line.lstrip().startswith("//"))
+    assert "Date.UTC" in code, (
+        "zone comparison samples only the current instant, so zones that "
+        "coincide seasonally would read as equal")
+    assert code.count("Date.UTC") >= 2, "expected an instant either side of DST"
+
+
+def _stamp(zone, instant):
+    """The JS comparison's algorithm, for pinning what it must decide.
+
+    There is no JS runtime here (and the repo has no JS test infra), so this
+    mirrors sameZone rather than executing it: same instants, same wall-clock
+    equality. It records the verdicts the shipped code has to reach.
+    """
+    from zoneinfo import ZoneInfo
+    return instant.astimezone(ZoneInfo(zone)).strftime("%m/%d/%Y %H:%M")
+
+
+@pytest.mark.parametrize(
+    "left,right,equivalent",
+    [
+        # Aliases: one zone under two names.
+        ("Asia/Calcutta", "Asia/Kolkata", True),
+        ("Europe/Kiev", "Europe/Kyiv", True),
+        # Same rules year-round: either renders the same times, so a panel set
+        # to one and browsed from the other is correctly configured.
+        ("America/New_York", "America/Toronto", True),
+        # Coincide in winter only -- the case a single-instant check gets wrong.
+        ("America/New_York", "America/Lima", False),
+        ("America/Phoenix", "America/Los_Angeles", False),
+        ("Australia/Sydney", "Pacific/Guadalcanal", False),
+        # Plainly different.
+        ("America/New_York", "America/Chicago", False),
+        ("America/New_York", "Europe/Madrid", False),
+    ],
+)
+def test_which_zone_pairs_must_count_as_the_same(left, right, equivalent):
+    from datetime import datetime
+    from zoneinfo import ZoneInfo
+
+    year = 2026
+    instants = [datetime(year, 1, 15, 12, tzinfo=ZoneInfo("UTC")),
+                datetime(year, 7, 15, 12, tzinfo=ZoneInfo("UTC"))]
+    matched = all(_stamp(left, at) == _stamp(right, at) for at in instants)
+    assert matched is equivalent, (
+        f"{left} vs {right}: sampling both seasons gave {matched}")
+
+
+@pytest.mark.parametrize(
+    "hardware,expected",
+    [
+        ({"rows": 32, "cols": 64, "chain_length": 2, "parallel": 1}, "1"),
+        ({"rows": 0, "cols": 0, "chain_length": 0, "parallel": 1}, "0"),
+    ],
+)
+def test_panel_size_step_still_reflects_config(hardware, expected):
+    """Regression guard: the hardware step is still decided server-side."""
+    config = config_with()
+    config["display"]["hardware"] = hardware
+    body = render(config)
+    match = re.search(r"<button[^>]*data-tab=\"display\"[^>]*>", body)
+    assert match, "panel-size step not found"
+    assert f'data-done="{expected}"' in match.group(0), match.group(0)

web_interface/templates/v3/partials/overview.html

@@ -63,13 +63,13 @@
 
 <!-- Getting Started checklist: non-gating, dismissible (localStorage), items
      auto-check from existing config/endpoints — no new persisted state.
-     Known heuristic limits (acceptable, disclosed): values left at legitimate
-     defaults (e.g. a user actually in Tampa) read as "not done". -->
+     The timezone step is verified against the browser's own zone rather than
+     compared to the shipped default; see the data-check="timezone" block below
+     for why. -->
 {% set _hw = main_config.display.hardware if main_config and main_config.display else {} %}
 {% set _hw_done = (_hw.rows or 0) > 0 and (_hw.cols or 0) > 0 and (_hw.chain_length or 0) > 0 %}
 {% set _loc = main_config.location if main_config and main_config.location else {} %}
-{% set _loc_done = (main_config.timezone and main_config.timezone != 'America/New_York')
-                   or (_loc.city and _loc.city != 'Tampa') %}
+{% set _tz = (main_config.timezone if main_config else '') or '' %}
 <div id="getting-started-card" class="bg-blue-50 border border-blue-200 rounded-lg p-4 mb-4" style="display:none" role="region" aria-label="Getting started checklist">
     <div class="flex items-start justify-between">
         <div class="flex-1">
@@ -78,8 +78,8 @@
             <ul class="space-y-1 text-sm" id="getting-started-items">
                 <li><button type="button" class="gs-item text-left w-full" data-done="{{ '1' if _hw_done else '0' }}" data-tab="display">
                     <i class="far fa-square mr-2"></i>Set your panel size (Display tab)</button></li>
-                <li><button type="button" class="gs-item text-left w-full" data-done="{{ '1' if _loc_done else '0' }}" data-tab="general">
-                    <i class="far fa-square mr-2"></i>Set your timezone and location (General tab)</button></li>
+                <li><button type="button" class="gs-item text-left w-full" data-done="0" data-check="timezone" data-tz="{{ _tz }}" data-tab="general">
+                    <i class="far fa-square mr-2"></i>Set your timezone{% if _tz %} — currently {{ _tz }}{% if _loc.city %}, {{ _loc.city }}{% endif %}{% endif %} (General tab)<span data-gs-tz-note class="text-xs"></span></button></li>
                 <li><button type="button" class="gs-item text-left w-full" data-done="0" data-check="installed" data-tab="plugins">
                     <i class="far fa-square mr-2"></i>Install a plugin from the Plugin Store</button></li>
                 <li><button type="button" class="gs-item text-left w-full" data-done="0" data-check="enabled" data-tab="plugins">
@@ -165,6 +165,91 @@
     });
     maybeAutoHide();
 
+    // Timezone: verified against the browser's own zone.
+    //
+    // This step used to tick when the saved timezone differed from the value
+    // config.template.json ships (America/New_York), with the saved city
+    // OR-ed in. Two things were wrong with that. "Differs from the default"
+    // answers "did somebody edit this?", but what the checklist needs to know
+    // is whether the value is RIGHT — so anyone who genuinely lives in the
+    // default zone could never satisfy it and the card nagged forever. And
+    // the city has no bearing on whether the timezone is set: because the two
+    // were OR-ed, saving a city ticked the step off with the timezone still
+    // wrong, which is the direction that actually breaks displays (event
+    // times render in the wrong zone).
+    //
+    // The browser already knows its zone, so compare against that: no new
+    // persisted state, no network, and it catches the reverse case too — a
+    // panel still set to the old zone after a move now stays unticked, where
+    // the old test ticked it the moment the value stopped being the default.
+    function sameZone(a, b) {
+        if (a === b) return true;
+        // Compare the wall-clock time each zone yields, not the identifiers:
+        // aliases (Asia/Calcutta vs Asia/Kolkata, Europe/Kiev vs Europe/Kyiv)
+        // name one zone and must not read as a mismatch.
+        //
+        // Sampled at three instants, all of which have to agree. Checking only
+        // now is not enough: America/New_York and America/Lima hold the same
+        // offset all winter, so a panel set to the wrong one of those would
+        // tick in January and then run an hour off from March. Mid-January and
+        // mid-July sit either side of DST in both hemispheres, so only zones
+        // that agree year-round match -- while Toronto still matches New York,
+        // which is right, since either renders the same times.
+        try {
+            var now = new Date();
+            var year = now.getUTCFullYear();
+            var instants = [now,
+                            new Date(Date.UTC(year, 0, 15, 12)),
+                            new Date(Date.UTC(year, 6, 15, 12))];
+            var stamp = function (tz, at) {
+                // Explicit numeric fields rather than dateStyle/timeStyle:
+                // those are late additions to Intl (Firefox shipped them in
+                // 91), and an implementation that does not know them ignores
+                // them and formats the date alone. That would compare
+                // New York, Chicago and Madrid as equal and tick the step for
+                // a timezone that is plainly wrong -- the exact failure this
+                // check exists to catch. These options have been in Intl
+                // since ECMA-402 v1.
+                return new Intl.DateTimeFormat('en-US', {
+                    timeZone: tz, year: 'numeric', month: '2-digit',
+                    day: '2-digit', hour: '2-digit', minute: '2-digit',
+                    hour12: false
+                }).format(at);
+            };
+            for (var i = 0; i < instants.length; i++) {
+                if (stamp(a, instants[i]) !== stamp(b, instants[i])) {
+                    return false;
+                }
+            }
+            return true;
+        } catch (e) {
+            // An unparseable zone in the config is worth surfacing, not hiding.
+            return false;
+        }
+    }
+
+    (function () {
+        var tzBtn = card.querySelector('[data-check="timezone"]');
+        if (!tzBtn) return;
+        var configured = tzBtn.dataset.tz || '';
+        if (!configured) return;          // nothing saved yet: leave it open
+        var local = '';
+        try {
+            local = (Intl.DateTimeFormat().resolvedOptions().timeZone) || '';
+        } catch (e) {
+            return;                        // no Intl: leave it to the manual tick
+        }
+        if (!local) return;
+        if (sameZone(configured, local)) {
+            markDone(tzBtn);
+            return;
+        }
+        // Unticked on its own says "wrong" without saying why; name the zone
+        // the browser is in so the step is actionable.
+        var note = tzBtn.querySelector('[data-gs-tz-note]');
+        if (note) note.textContent = ' — this browser is in ' + local;
+    }());
+
     // Plugin-derived states from the existing installed-plugins endpoint.
     fetch('/api/v3/plugins/installed')
         .then(function (r) { return r.json(); })