Merge pull request #374 from mbillow/claude/pr-303-code-review-6mghcs

Load a config entry offline from the last discovery snapshot

README.md

@@ -270,6 +270,12 @@ If reconnects become persistent (more than a handful per minute), something's ac
 
 Deregistering a device in SmartThings causes a reset of its network settings as soon as it accesses Samsung's servers, dropping it off Wi-Fi until it's re-onboarded through the SmartThings app. As such, consider keeping devices registered even if egress-blocked, to avoid them resetting upon brief internet access.
 
+### Restarting while an appliance is powered off
+
+If Home Assistant restarts while an appliance is unplugged or switched off at the wall, its device and entities still load — restored from the last successful discovery, showing `unavailable` until the appliance answers again. Automations and dashboards keep referring to entities that exist, and the integration retries in the background, so the device comes back on its own within a poll cycle of being powered on. Entities read `unavailable` rather than their last known values on purpose: the integration can't verify what a disconnected appliance is doing, and recorded history is kept by the recorder either way.
+
+This only applies to an appliance the integration has reached at least once. A brand-new device that has never answered has nothing to restore from, so setting it up still requires it to be reachable.
+
 ### Multi-subdevice ("2-in-1") air conditioner systems
 
 Some Samsung installs run more than one indoor subdevice off a single outdoor unit, all reachable over the *one* IP/DTLS session your config entry connects to (a floor-standing + wall-mounted 2-in-1 is a common shape). The integration discovers any sibling subdevices automatically, once, right after the first successful poll — there's nothing to configure. Each discovered subdevice gets its own HA device (linked to the main one via "via device") and its own `climate` card, so it lands in its own room in the dashboard instead of being invisible or mixed into the master's state.

custom_components/localthings/__init__.py

@@ -19,7 +19,7 @@ from homeassistant.helpers import entity_registry as er
 from homeassistant.helpers.typing import ConfigType
 
 from .const import CONF_DEVICE_TYPE, CONF_HOST, CONF_PORT, CONF_SERIAL, DOMAIN, PLATFORMS
-from .coordinator import LocalThingsCoordinator
+from .coordinator import LocalThingsCoordinator, snapshot_store
 from .registry.identity import resolve_serial
 from .services import async_setup_services
 
@@ -260,17 +260,30 @@ async def async_migrate_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
 async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     hass.data.setdefault(DOMAIN, {})
     coordinator = LocalThingsCoordinator(hass, entry)
+
+    # Before the first refresh, so the coordinator keeps rescheduling even
+    # when that refresh fails and leaves nothing subscribed: the base class
+    # only re-arms its timer while it has listeners, and an offline load can
+    # legitimately have zero live entities (every one of them disabled, say).
+    # Without this the entry loads once and never polls again (issue #295).
+    entry.async_on_unload(coordinator.async_add_listener(lambda: None))
+
     try:
         await coordinator.async_config_entry_first_refresh()
-    except Exception as err:
-        # `_poll_once` deliberately leaves the session up on a TimeoutError
-        # (see its docstring), so a refresh failing that way leaves a live,
-        # bound UDP socket nothing would ever close. HA retries setup with a
-        # new coordinator, and the source port is fixed by design
-        # (`_local_source_port`), so an abandoned socket would squat the
-        # exact port the next attempt binds.
-        await coordinator.async_close()
-        raise ConfigEntryNotReady(f"Cannot connect to device: {err}") from err
+    except ConfigEntryNotReady:
+        # An entry that has polled successfully before comes up on its last
+        # known entity set and keeps retrying on the normal poll interval,
+        # rather than sitting in setup-retry with a device that reads as
+        # broken and entities that exist only as registry rows (issue #295).
+        #
+        # An entry that has never reached the device has no snapshot, so
+        # there is nothing to show and no device metadata to name it with --
+        # that case still fails, which is also what keeps the door open for
+        # setup flows that need to interact with the device (issue #168).
+        if not await coordinator.async_rehydrate():
+            await coordinator.async_close()
+            raise
+
     hass.data[DOMAIN][entry.entry_id] = coordinator
 
     # Send the DTLS close_notify on Core shutdown, not just on unload (issue
@@ -327,6 +340,16 @@ async def async_remove_config_entry_device(
     return not (device.identifiers & live)
 
 
+async def async_remove_entry(hass: HomeAssistant, entry: ConfigEntry) -> None:
+    """Delete the discovery snapshot this entry accumulated (issue #295).
+
+    Nothing else would: the store is keyed on entry_id, so re-adding the same
+    appliance mints a new one and the old file would linger in .storage
+    forever.
+    """
+    await snapshot_store(hass, entry).async_remove()
+
+
 async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     unloaded = await hass.config_entries.async_unload_platforms(entry, PLATFORMS)
     if unloaded:

custom_components/localthings/coordinator.py

@@ -9,6 +9,7 @@ import logging
 import threading
 import time
 import zlib
+from dataclasses import asdict
 from datetime import timedelta
 from typing import Any, cast
 
@@ -18,6 +19,7 @@ from homeassistant.core import HomeAssistant, callback
 from homeassistant.exceptions import HomeAssistantError, ServiceValidationError
 from homeassistant.helpers import issue_registry as ir
 from homeassistant.helpers.device_registry import DeviceInfo
+from homeassistant.helpers.storage import Store
 from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
 from smartthings_local.ocf.state_cache import StateCache
 from smartthings_local.protocol.dtls_session import DtlsCoapSession
@@ -47,7 +49,7 @@ from .const import (
 from .learned import LEARNABLE, LearnedModes, persist
 from .observe import GRACE_PERIOD_S, MODE_OBSERVE, MODE_POLL, ObserveManager
 from .registry import CAPABILITIES
-from .registry.adapter import flatten
+from .registry.adapter import _key, flatten
 from .registry.batch import parse_device0_batch
 from .registry.by_type import resolve as resolve_registry
 from .registry.capabilities.common import (
@@ -83,6 +85,20 @@ _LOGGER = logging.getLogger(__name__)
 
 _SEED_PATH = ["device", "0"]
 
+# Discovery snapshot (issue #295): exactly what the last successful first
+# cycle fed _run_discovery, so a restart can register the same entities
+# while the appliance is unreachable. Kept in .storage rather than on the
+# config entry -- it's device state, not configuration, and runs to tens of
+# kilobytes.
+_SNAPSHOT_VERSION = 1
+
+
+def snapshot_store(hass: HomeAssistant, entry: ConfigEntry) -> Store[dict[str, Any]]:
+    """This entry's discovery-snapshot store. A free function so
+    `async_remove_entry` can delete the file without standing up a whole
+    coordinator to reach it."""
+    return Store(hass, _SNAPSHOT_VERSION, f"{DOMAIN}.{entry.entry_id}.discovery")
+
 
 class _NoOpDescriptor:
     """No-op: StateCache requires an on_observation hook; this integration
@@ -248,6 +264,11 @@ class LocalThingsCoordinator(DataUpdateCoordinator[dict[str, Any]]):
         self._identity: DeviceIdentity | None = None
         self._discovered = False
         self.bound = []
+        self._snapshot_store = snapshot_store(hass, entry)
+        # Both set only when this entry loaded from a snapshot instead of a
+        # live poll -- see async_rehydrate.
+        self._rehydrate_resources: dict[str, dict] | None = None
+        self._rehydrated_keys: frozenset[tuple[str, str]] | None = None
         # Sibling indoor subdevices on this connection (issue #177); set
         # once at first discovery, narrowed to the ones with live state (see
         # subdevices.discover_partitioned). Never includes MAIN itself.
@@ -405,6 +426,35 @@ class LocalThingsCoordinator(DataUpdateCoordinator[dict[str, Any]]):
         self._canonical_cache[view_key] = view
         return view
 
+    @property
+    def rehydrated(self) -> bool:
+        """True while this entry's entities came from a snapshot rather than
+        a live poll (issue #295)."""
+        return self._rehydrate_resources is not None
+
+    @property
+    def discovery_resources(self) -> dict[str, dict]:
+        """What entity._is_included should judge an entity's existence
+        against: the rehydration snapshot on an offline load, the live cache
+        otherwise.
+
+        Deliberately separate from `last_resources`, which stays empty until
+        the device answers -- that emptiness is what keeps a rehydrated
+        entity `unavailable` instead of rendering a snapshot's stale value.
+        Only read while platforms are being forwarded; nothing consults it
+        once the entities exist.
+        """
+        if self._rehydrate_resources is None:
+            return self.last_resources
+        return self._rehydrate_resources
+
+    def discovery_canonical(self, subdevice: Subdevice) -> dict[str, dict]:
+        """`discovery_resources` in `subdevice`'s canonical view -- the
+        exists_fn counterpart to canonical_resources."""
+        if self._rehydrate_resources is None:
+            return self.canonical_resources(subdevice)
+        return canonical_view(subdevice, self._rehydrate_resources, self.subdevices)
+
     # ------------------------------------------------------------------
     # Learned modes (issue #327)
     # ------------------------------------------------------------------
@@ -999,7 +1049,148 @@ class LocalThingsCoordinator(DataUpdateCoordinator[dict[str, Any]]):
             self._entry, data={**self._entry.data, **identity}
         )
 
-    def _run_discovery(self, resources: dict[str, dict]) -> None:
+    # ------------------------------------------------------------------
+    # Discovery snapshot (issue #295)
+    # ------------------------------------------------------------------
+
+    def _bound_keys(self) -> frozenset[tuple[str, str]]:
+        """This entity set's identity: one (subdevice, state key) pair per
+        bound entity. `_key` is the unique_id suffix, so two discoveries that
+        agree here would register byte-identical entities."""
+        return frozenset((b.subdevice.key, _key(b)) for b in self.bound)
+
+    async def _async_save_snapshot(
+        self, resources: dict[str, dict], candidates: list[Subdevice]
+    ) -> None:
+        """Record what this first cycle handed `_run_discovery`, so the next
+        restart can replay it while the appliance is unreachable.
+
+        `candidates` is the pre-narrowing subdevice list (issue #177):
+        `discover_partitioned` takes candidates and returns the live ones, so
+        replaying against the narrowed list would rediscover nothing for a
+        composite appliance's siblings.
+
+        Written now rather than through `async_delay_save`, because a pending
+        delayed write outlives whatever queued it: it lands after
+        `async_remove_entry` has deleted the file and recreates it orphaned,
+        and a reload scheduled by `_reconcile_rehydrated` would read the
+        pre-reload snapshot back off disk. This runs once per entry load, so
+        the immediate write costs nothing worth deferring.
+        """
+        ident = self._identity
+        try:
+            await self._snapshot_store.async_save(
+                {
+                    "resources": dict(resources),
+                    "subdevice_candidates": [asdict(su) for su in candidates],
+                    "identity": asdict(ident) if ident is not None else None,
+                }
+            )
+        except Exception as e:
+            # Never fail a poll over the snapshot -- a board reporting
+            # something the JSON encoder rejects would otherwise break
+            # polling outright. Worst case this entry can't load offline,
+            # which is where it was before any of this existed.
+            self._log.warning("could not write discovery snapshot: %s", e)
+
+    async def async_rehydrate(self) -> bool:
+        """Register the last known entity set without reaching the device.
+
+        Replays the stored snapshot through `_run_discovery`, which is what
+        makes this faithful: same code path, same registry resolution, so an
+        offline load produces the entity set the device last actually
+        reported rather than a guess reconstructed from a parallel format.
+
+        Returns False when there's nothing stored (an entry that has never
+        polled successfully) or the replay produced nothing usable -- the
+        caller raises ConfigEntryNotReady in that case, exactly as before.
+        """
+        try:
+            stored = await self._snapshot_store.async_load()
+        except Exception as e:  # corrupt or unreadable store
+            self._log.warning("could not read discovery snapshot: %s", e)
+            return False
+        if not stored or not stored.get("resources"):
+            return False
+
+        resources = stored["resources"]
+        try:
+            ident = stored.get("identity")
+            if ident is not None:
+                self._identity = DeviceIdentity(
+                    manufacturer=ident.get("manufacturer") or "",
+                    model=ident.get("model") or "",
+                    name=ident.get("name") or "",
+                    serial=ident.get("serial"),
+                    device_types=tuple(ident.get("device_types") or ()),
+                    raw=ident.get("raw") or {},
+                )
+            # JSON gives lists back where Subdevice declares tuples, and it's
+            # a frozen (hashable) dataclass used as a dict key in flatten().
+            self.subdevices = [
+                Subdevice(
+                    kind=su["kind"],
+                    key=su["key"],
+                    seed_path=tuple(su.get("seed_path") or ()),
+                    flat_hrefs=tuple(su.get("flat_hrefs") or ()),
+                )
+                for su in stored.get("subdevice_candidates") or ()
+            ]
+            self._run_discovery(resources, from_snapshot=True)
+        except Exception as e:
+            # A snapshot written by an older release can outlive both the
+            # stored shape and the registry it was discovered against. This
+            # has to catch the rebuild as well as the replay: an exception
+            # escaping here reaches async_setup_entry, which only handles
+            # ConfigEntryNotReady, so the entry would land in SETUP_ERROR --
+            # never retried, and with its session left open.
+            self._log.warning("discovery snapshot could not be replayed: %s", e, exc_info=True)
+            self.bound = []
+            self.subdevices = []
+            return False
+
+        # _run_discovery sets _discovered; put it back. The snapshot only
+        # supplied an entity set to register -- the first live poll must
+        # still enumerate subdevices and rediscover for real.
+        self._discovered = False
+        self._rehydrate_resources = resources
+        self._rehydrated_keys = self._bound_keys()
+        if not self.bound:
+            return False
+        self._log.info(
+            "device unreachable; restored %d entities from the last discovery "
+            "snapshot and will keep retrying every %ds",
+            len(self.bound),
+            SUMMARY_INTERVAL_S,
+        )
+        return True
+
+    @callback
+    def _reconcile_rehydrated(self) -> None:
+        """Reload the entry when a live discovery disagrees with the snapshot
+        this load registered from.
+
+        Platforms enumerate `bound` exactly once, at forward time, so a
+        firmware update, a newly-answering sibling subdevice or a different
+        appliance at the same IP can't be picked up in place -- the entry has
+        to come back up against the live set.
+        """
+        if self._rehydrated_keys is None:
+            return
+        stale = self._rehydrated_keys
+        self._rehydrated_keys = None
+        live = self._bound_keys()
+        if live == stale:
+            return
+        self._log.info(
+            "live discovery differs from the snapshot this entry loaded from "
+            "(%d entities gone, %d new); reloading",
+            len(stale - live),
+            len(live - stale),
+        )
+        self.hass.config_entries.async_schedule_reload(self._entry.entry_id)
+
+    def _run_discovery(self, resources: dict[str, dict], from_snapshot: bool = False) -> None:
         # Diagnostics only -- names the firmware generation (e.g. '7.0 Air
         # conditioner' is Tizen Lite); doesn't route, since every device
         # that reports it is already typed by modelNum.
@@ -1115,7 +1306,13 @@ class LocalThingsCoordinator(DataUpdateCoordinator[dict[str, Any]]):
             model=model,
         )
         self._persist_identity(serial, model, mfr, device_type_name)
-        self._update_coverage_gap_issue(device_type_name is None, unbound, name)
+        if not from_snapshot:
+            # A coverage gap is a claim about what the device reports, so only
+            # a live poll gets to make it. Replaying a snapshot would restate
+            # last run's conclusion while pointing the user at a diagnostics
+            # download that is empty until the appliance answers, and any
+            # drift in the device name between the two would churn the issue.
+            self._update_coverage_gap_issue(device_type_name is None, unbound, name)
 
         self._hot_hrefs = sorted(hot)
         self._warm_hrefs = sorted(warm)
@@ -1422,7 +1619,13 @@ class LocalThingsCoordinator(DataUpdateCoordinator[dict[str, Any]]):
             # StateCache has no eviction, so the only way to keep them out
             # is to not put them in. Safe to reorder: _run_discovery reads
             # the passed dict, never the cache.
+            candidates = list(self.subdevices)
             self._run_discovery(resources)
+            # Banked before the reconcile below, so a reload it schedules
+            # comes up against this discovery rather than the one that is
+            # being replaced.
+            await self._async_save_snapshot(resources, candidates)
+            self._reconcile_rehydrated()
             resources = self._live_subdevice_resources(resources)
         sweep_mismatch = False
         if self._observe.mode == MODE_OBSERVE:

custom_components/localthings/entity.py

@@ -35,12 +35,16 @@ def _is_included(bound: BoundEntity, coordinator: LocalThingsCoordinator) -> boo
     `bound`'s own subdevice's canonical view instead of the raw snapshot,
     same rule as everywhere else a whole-resources-dict scan happens --
     this is a free function, so it can't use self._resources.
+
+    Reads `discovery_resources`, not `last_resources`: on an offline load
+    (issue #295) the live cache is still empty, and judging existence
+    against it would filter every rehydrated entity away.
     """
-    rep = coordinator.last_resources.get(bound.href)
+    rep = coordinator.discovery_resources.get(bound.href)
     if rep is None:
         return False
     if bound.desc.exists_fn is not None:
-        return bound.desc.exists_fn(rep, coordinator.canonical_resources(bound.subdevice))
+        return bound.desc.exists_fn(rep, coordinator.discovery_canonical(bound.subdevice))
     if bound.desc.field:
         if not rep or is_stub_rep(rep):
             return True

docs/investigations/offline-setup.md

@@ -0,0 +1,187 @@
+# Loading a config entry while the appliance is offline
+
+Issue #295 asks for faster recovery when a powered-off appliance comes back,
+instead of waiting out HA's `ConfigEntryNotReady` backoff. PR #303 tried to
+get there by catching the first-refresh failure in `async_setup_entry` and
+loading the entry anyway.
+
+That doesn't work here, and the reason is worth writing down: this
+integration has no static entity list. Every entity comes from discovery,
+and discovery only happens inside a successful poll.
+
+(The issue's "up to 15 minutes" is out of date, incidentally. Current HA
+retries on `2 ** min(tries, 4) * 5` seconds — capped at 80s, not 900. The
+backoff was never the worst part; a device card reading "Retrying setup" with
+no entities behind it is.)
+
+## What PR #303 produces today
+
+Measured on the PR's branch — set up with `_poll_once` raising, then advance
+the clock four summary intervals:
+
+| | |
+| --- | --- |
+| entry state | `LOADED` |
+| `coordinator.bound` | 0 |
+| entities in the state machine | 0 |
+| registry entries | 1 (the disabled connection-mode sensor) |
+| coordinator listeners | 0 |
+| `_unsub_refresh` | `None` |
+| poll attempts over the next 4 intervals | **0** |
+
+The entry loads and then never polls again. `DataUpdateCoordinator._async_refresh`
+reschedules only `if not auth_failed and self._listeners and not
+self.hass.is_stopping`; with no bound entities the only unconditional entity
+is `LocalThingsConnectionModeSensor`, which is
+`entity_registry_enabled_default = False` and so never added and never
+subscribes. Nothing reloads the entry either. The device comes back online to
+an entry that is permanently empty until a manual reload — strictly worse
+than the backoff it replaces, which did recover on its own within 15 minutes.
+
+## Why entities can't just be created offline
+
+Four independent gates, all of which need live device data:
+
+1. `bound` is only ever assigned in `_run_discovery` (`coordinator.py:1081`),
+   which runs on a poll's `resources` dict.
+2. All ten platforms enumerate `coordinator.bound` exactly once, at forward
+   time (`sensor.py:34` and siblings). Nothing adds entities later — the
+   invariant is already documented at `coordinator.py:1283-1286`.
+3. `_is_included` (`entity.py:39`) returns False whenever `last_resources`
+   has no rep for the href. Even a fully reconstructed `bound` filters to
+   nothing while `StateCache` is empty.
+4. `LocalThingsEntity` is a bare `CoordinatorEntity` with no `available`
+   override, no `RestoreEntity`, and no `Store` anywhere in the component. An
+   entity that did exist offline would be `unavailable` with no state.
+
+The issue cites ESPHome, Shelly, LIFX and WLED as precedent for setup that
+never fails. Those integrations can do it because each one has a *persisted
+device description* to build entities from — ESPHome keeps its entity list in
+`.storage`, Shelly caches device info. The pattern is portable; the mechanism
+underneath it is the part PR #303 is missing.
+
+## How the implemented version works
+
+Three pieces, plus a gating rule.
+
+### 1. A persisted discovery snapshot
+
+After each successful first cycle, `_save_snapshot` banks exactly the
+`resources` dict that cycle handed `_run_discovery`, along with the
+pre-narrowing subdevice candidate list and the `DeviceIdentity` read from
+`/oic/*`.
+
+Storing the poll input rather than a rendered entity list is the decision
+that keeps this honest. `BoundEntity` holds live
+`Capability`/`SamsungEntityDescription` objects and isn't serializable, so
+the alternative was a parallel format plus a re-resolution path — a second
+implementation of discovery that could drift from the real one. Replaying the
+input through `_run_discovery` means the same code, the same registry
+resolution, and no second source of truth.
+
+Three things ride along because `_run_discovery` reads them off `self`
+rather than out of `resources`, and getting them wrong would silently resolve
+a *different* registry offline than online — which reconciliation below would
+then see as a real change and reload on every restart:
+
+- `_identity.device_types` routes `resolve_registry`.
+- `self.subdevices` is the candidate list `discover_partitioned` narrows;
+  replaying against the already-narrowed list finds no siblings at all.
+- `_identity.manufacturer`/`model` feed `device_info`.
+
+It lives in `.storage` (`Store`, keyed on entry_id) rather than on the config
+entry: it's device state, not configuration, and runs to tens of kilobytes.
+`async_remove_entry` deletes it with the entry.
+
+The write is awaited, not `async_delay_save`d. A deferred write outlives
+whatever queued it: it lands after `async_remove_entry` has deleted the file
+and recreates it orphaned, and a reload scheduled by the reconcile below
+would read the pre-reload snapshot back off disk. It runs once per entry
+load, so there's nothing worth deferring. A write that fails is logged and
+swallowed — a board reporting something the JSON encoder rejects must not
+break polling.
+
+### 2. Reconcile on reconnect
+
+The snapshot is a claim about a device we haven't talked to yet. When the
+first live poll lands, `_reconcile_rehydrated` compares the live entity set
+against the rehydrated one — as `(subdevice key, _key(bound))` pairs, which
+is the unique_id identity — and calls `async_schedule_reload` if they differ.
+
+Gate 2 above is why this has to be a reload rather than an in-place fixup.
+It's what makes the feature safe against a firmware update, a sibling
+subdevice that starts answering, or a different appliance at the same IP.
+
+### 3. Keep polling with no listeners
+
+`async_setup_entry` holds one listener for the entry's lifetime:
+
+```python
+entry.async_on_unload(coordinator.async_add_listener(lambda: None))
+```
+
+Registered *before* the first refresh, so scheduling survives a refresh that
+fails. This alone fixes the measured "never polls again" bug, and covers a
+rehydrated set whose entities are all registry-disabled. Removing the last
+listener unschedules the timer, and HA runs `async_on_unload` callbacks when
+setup raises, so the setup-retry path doesn't leak a polling coordinator.
+
+### Gating rule: only load offline when there's a snapshot
+
+An entry that has never successfully polled has nothing to restore and keeps
+raising `ConfigEntryNotReady`. This is what answers the objection in the PR
+thread — with a snapshot we *do* have metadata to build a device from, and
+without one HA's backoff is still the right behavior. It also leaves room for
+the #168-style flows that need to interact with the device during setup: a
+device that never completed setup still blocks.
+
+It also means `async_remove_config_entry_device` is no longer reachable with
+an empty `coordinator.subdevices`, so an offline load can't offer to delete a
+real-but-unreachable subdevice.
+
+### The coverage-gap Repair stays live-only
+
+`_run_discovery(..., from_snapshot=True)` skips `_update_coverage_gap_issue`.
+The Repair points the user at a diagnostics download, which is empty until
+the appliance answers, and a device name that drifts between the snapshot and
+the live poll would churn the issue for no reason.
+
+Not a de-duplication measure — HA already handles that. `async_create_issue`
+is keyed on `(domain, issue_id)`, `dataclasses.replace` in
+`async_get_or_create` leaves `dismissed_version` alone, and the registry
+reloads non-persistent issues with their dismissal intact, so one row per
+entry survives restarts and an "Ignore" sticks.
+
+## What this still won't do
+
+Entities will be present and `unavailable` — not showing their last values.
+Gate 4 means last-known values require either `RestoreEntity` per platform or
+persisting `StateCache`, and both mean asserting state the integration cannot
+verify: a washer unplugged for a week would read "Running". HA's convention
+is that unreachable means unavailable, and the recorder keeps the history
+either way, so long-term statistics and history graphs are unaffected by this
+choice.
+
+Worth being explicit about, because it is the gap between what PR #303
+promises in the thread ("load their previously recorded states") and what any
+correct version can deliver.
+
+## Rejected: zeroconf
+
+The issue's other suggestion — wire zeroconf so the device's own boot
+announcement triggers a retry, which is the genuinely idiomatic HA answer —
+is a non-starter as things stand: there is no `zeroconf` or `dhcp` key in
+`manifest.json` and the config flow is user-driven only, so HA has no
+discovery signal for this integration to hang a retry on. It would first need
+a confirmed mDNS service on the appliance. Worth revisiting if one turns up;
+it would make recovery near-instant instead of within one poll interval.
+
+## Rejected: the cheap version
+
+Keeping `ConfigEntryNotReady` and adding a probe that calls
+`async_schedule_reload` on first success would have fixed the recovery *time*
+in about twenty lines, with no persistence and no reconcile. It was rejected
+because it leaves the device reading as broken for as long as the appliance
+is off, which is the half of issue #295 that actually bites — an appliance
+switched off at the wall is offline for days, not seconds, and a whole
+integration that looks failed for that entire window is the complaint.

tests/localthings/test_coordinator.py

@@ -71,7 +71,12 @@ async def test_summary_interval(hass: HomeAssistant, mock_entry, mock_coordinato
 
 
 async def test_update_failed_on_persistent_poll_error(hass: HomeAssistant, mock_entry) -> None:
-    """ConfigEntryNotReady raised when poll fails even after reconnect."""
+    """ConfigEntryNotReady raised when poll fails even after reconnect.
+
+    An entry with no stored discovery snapshot has never reached this device,
+    so there is nothing to load offline from (issue #295) -- it stays on HA's
+    backoff rather than loading empty.
+    """
 
     with (
         patch("custom_components.localthings.coordinator.LocalThingsCoordinator._connect_session"),
@@ -1824,10 +1829,11 @@ async def test_first_refresh_timeout_recovers_via_reconnect(
 async def test_first_refresh_persistent_timeout_fails_setup(
     hass: HomeAssistant, mock_entry
 ) -> None:
-    """When the reconnect times out too, the first refresh must fail so HA
-    retries on its backoff -- not load an entity-less entry. The session it
-    left open is closed on the way out (`_poll_once` keeps it up on a
-    `TimeoutError`, and the source port is fixed per device)."""
+    """With no snapshot to load from, a reconnect that times out too must
+    fail the first refresh so HA retries on its backoff -- not load an
+    entity-less entry. The session it left open is closed on the way out
+    (`_poll_once` keeps it up on a `TimeoutError`, and the source port is
+    fixed per device)."""
     with (
         patch("custom_components.localthings.coordinator.LocalThingsCoordinator._connect_session"),
         patch(

tests/localthings/test_offline_setup.py

@@ -0,0 +1,418 @@
+"""Loading a config entry while the appliance is unreachable (issue #295).
+
+The device's entity set only exists as the output of a live poll, so coming
+up offline means replaying the last successful discovery from a stored
+snapshot. These tests pin the four things that makes load-bearing: the
+snapshot gets written, it produces the same entity set offline, the
+coordinator keeps polling until the device answers, and a live discovery that
+disagrees with the snapshot reloads the entry rather than silently keeping a
+stale set.
+"""
+
+from __future__ import annotations
+
+from contextlib import contextmanager
+from datetime import timedelta
+from unittest.mock import patch
+
+import pytest
+from homeassistant.config_entries import ConfigEntryState
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers import issue_registry as ir
+from homeassistant.util import dt as dt_util
+from pytest_homeassistant_custom_component.common import async_fire_time_changed
+
+from custom_components.localthings.const import DOMAIN, SUMMARY_INTERVAL_S
+from custom_components.localthings.coordinator import LocalThingsCoordinator
+from custom_components.localthings.registry.identity import DeviceIdentity
+
+from .conftest import _load_fridge_resources as _load_fridge
+
+_COORD = "custom_components.localthings.coordinator.LocalThingsCoordinator"
+
+
+@contextmanager
+def _reachable(resources: dict, identity: DeviceIdentity | None = None):
+    """A device that answers, optionally with an /oic/* identity -- which
+    `_connect_session` is what normally reads, so a test that patches it out
+    otherwise leaves `_identity` None."""
+
+    def _connect(self) -> None:
+        self._identity = identity
+
+    with (
+        patch(f"{_COORD}._connect_session", _connect),
+        patch(f"{_COORD}._poll_once", return_value=resources),
+        patch(f"{_COORD}._close_session"),
+    ):
+        yield
+
+
+@contextmanager
+def _unreachable():
+    with (
+        patch(f"{_COORD}._connect_session"),
+        patch(f"{_COORD}._poll_once", side_effect=OSError("device offline")),
+        patch(f"{_COORD}._close_session"),
+    ):
+        yield
+
+
+def _store_key(entry) -> str:
+    return f"{DOMAIN}.{entry.entry_id}.discovery"
+
+
+async def _tick(hass: HomeAssistant) -> None:
+    """Advance past one summary interval so the coordinator polls again.
+
+    `wait_background_tasks` is load-bearing: DataUpdateCoordinator runs its
+    interval refresh as a background task, which a plain block_till_done
+    doesn't await -- the poll would still be in flight at the assertion.
+    """
+    async_fire_time_changed(hass, dt_util.utcnow() + timedelta(seconds=SUMMARY_INTERVAL_S + 1))
+    await hass.async_block_till_done(wait_background_tasks=True)
+
+
+async def _setup_online_then_unload(hass: HomeAssistant, entry, resources: dict) -> set[str]:
+    """Bring the entry up against a live device, bank the snapshot, and take
+    it back down. Returns the entity_ids that run produced."""
+    with _reachable(resources):
+        await hass.config_entries.async_setup(entry.entry_id)
+        await hass.async_block_till_done()
+        entity_ids = {s.entity_id for s in hass.states.async_all()}
+        await hass.config_entries.async_unload(entry.entry_id)
+        await hass.async_block_till_done()
+    return entity_ids
+
+
+# ---------------------------------------------------------------------------
+# Writing the snapshot
+# ---------------------------------------------------------------------------
+
+
+async def test_snapshot_written_after_first_discovery(
+    hass: HomeAssistant, mock_entry, mock_coordinator_session, hass_storage
+) -> None:
+    """A successful first cycle banks what it handed _run_discovery."""
+    await hass.config_entries.async_setup(mock_entry.entry_id)
+    await hass.async_block_till_done()
+
+    stored = hass_storage[_store_key(mock_entry)]["data"]
+    assert stored["resources"]
+    assert "/information/vs/0" in stored["resources"]
+    assert "subdevice_candidates" in stored
+
+
+async def test_snapshot_not_written_when_device_never_answers(
+    hass: HomeAssistant, mock_entry, hass_storage
+) -> None:
+    """Nothing to bank, so nothing is -- this is what keeps the no-snapshot
+    gate meaningful on a brand-new entry."""
+    with _unreachable():
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+        assert mock_entry.state is ConfigEntryState.SETUP_RETRY
+
+    assert _store_key(mock_entry) not in hass_storage
+
+
+async def test_snapshot_removed_when_entry_removed(
+    hass: HomeAssistant, mock_entry, mock_coordinator_session, hass_storage
+) -> None:
+    """The store is keyed on entry_id, so re-adding the appliance mints a new
+    one -- the old file has to go with the entry that wrote it.
+
+    The clock is run on afterwards because a deferred write would land here:
+    with `async_delay_save` the removal was undone a few seconds later by the
+    save the last poll had queued, leaving the file orphaned for good.
+    """
+    await hass.config_entries.async_setup(mock_entry.entry_id)
+    await hass.async_block_till_done()
+    assert _store_key(mock_entry) in hass_storage
+
+    await hass.config_entries.async_remove(mock_entry.entry_id)
+    await hass.async_block_till_done()
+    assert hass_storage.get(_store_key(mock_entry), {}).get("data") is None
+
+    async_fire_time_changed(hass, dt_util.utcnow() + timedelta(seconds=60))
+    await hass.async_block_till_done(wait_background_tasks=True)
+
+    assert hass_storage.get(_store_key(mock_entry), {}).get("data") is None
+
+
+# ---------------------------------------------------------------------------
+# Loading from it
+# ---------------------------------------------------------------------------
+
+
+async def test_offline_load_restores_the_same_entity_set(
+    hass: HomeAssistant, mock_entry, hass_storage
+) -> None:
+    """The whole point: a restart with the appliance powered off comes up on
+    the entity set the device last actually reported."""
+    resources = _load_fridge()
+    online_ids = await _setup_online_then_unload(hass, mock_entry, resources)
+    assert online_ids  # guard: the online run must actually produce entities
+
+    with _unreachable():
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert mock_entry.state is ConfigEntryState.LOADED
+    assert {s.entity_id for s in hass.states.async_all()} == online_ids
+
+
+async def test_offline_entities_are_unavailable_not_stale(hass: HomeAssistant, mock_entry) -> None:
+    """Restored entities must not render the snapshot's values -- the
+    appliance is unreachable, so `unavailable` is the honest state and the
+    live cache stays empty to enforce it."""
+    resources = _load_fridge()
+    await _setup_online_then_unload(hass, mock_entry, resources)
+
+    with _unreachable():
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    states = hass.states.async_all()
+    assert states
+    assert all(s.state == "unavailable" for s in states)
+
+    coordinator: LocalThingsCoordinator = hass.data[DOMAIN][mock_entry.entry_id]
+    assert coordinator.rehydrated
+    assert not coordinator.last_resources
+
+
+async def test_offline_load_without_snapshot_still_fails(hass: HomeAssistant, mock_entry) -> None:
+    """No snapshot means no device metadata to build anything from, so the
+    entry stays on HA's backoff rather than loading empty."""
+    with _unreachable():
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert mock_entry.state is ConfigEntryState.SETUP_RETRY
+    assert not hass.states.async_all()
+
+
+async def test_malformed_snapshot_falls_back_to_setup_retry(
+    hass: HomeAssistant, mock_entry, hass_storage
+) -> None:
+    """A stored row missing a field the current dataclass declares must fail
+    the same way an unreachable device does.
+
+    Anything escaping async_rehydrate reaches async_setup_entry, which only
+    handles ConfigEntryNotReady -- so the entry would land in SETUP_ERROR,
+    which HA never retries, with its DTLS session left open on the fixed
+    source port the next attempt binds.
+    """
+    key = _store_key(mock_entry)
+    hass_storage[key] = {
+        "version": 1,
+        "minor_version": 1,
+        "key": key,
+        "data": {
+            "resources": _load_fridge(),
+            "subdevice_candidates": [{"key": "1"}],  # no "kind"
+        },
+    }
+
+    with (
+        _unreachable(),
+        patch.object(LocalThingsCoordinator, "async_close", autospec=True) as close,
+    ):
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert mock_entry.state is ConfigEntryState.SETUP_RETRY
+    close.assert_awaited_once()
+
+
+async def test_corrupt_snapshot_falls_back_to_setup_retry(
+    hass: HomeAssistant, mock_entry, hass_storage
+) -> None:
+    """A snapshot whose resources no longer replay cleanly must not take the
+    entry down with it."""
+    key = _store_key(mock_entry)
+    hass_storage[key] = {
+        "version": 1,
+        "minor_version": 1,
+        "key": key,
+        "data": {"resources": {"/information/vs/0": "not-a-rep"}, "subdevice_candidates": []},
+    }
+
+    with _unreachable():
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert mock_entry.state is ConfigEntryState.SETUP_RETRY
+
+
+async def test_snapshot_restores_identity(hass: HomeAssistant, mock_entry) -> None:
+    """`/oic/d`'s device types route the registry, so an offline load that
+    lost them could resolve a different one than the live poll did -- which
+    would show up as a spurious reconcile reload every restart."""
+    resources = _load_fridge()
+    identity = DeviceIdentity(
+        manufacturer="Samsung",
+        model="TEST-MODEL",
+        name="Fridge",
+        serial=None,
+        device_types=("oic.d.refrigerator",),
+        raw={"/oic/p": {}, "/oic/d": {}, "/oic/res": []},
+    )
+    with _reachable(resources, identity):
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+        await hass.config_entries.async_unload(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    with _unreachable():
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    coordinator: LocalThingsCoordinator = hass.data[DOMAIN][mock_entry.entry_id]
+    assert coordinator._identity is not None
+    assert coordinator._identity.device_types == ("oic.d.refrigerator",)
+
+
+# ---------------------------------------------------------------------------
+# Recovery and reconciliation
+# ---------------------------------------------------------------------------
+
+
+async def test_offline_load_keeps_polling_and_recovers(hass: HomeAssistant, mock_entry) -> None:
+    """The failure the PR this replaces actually shipped: with zero live
+    listeners the base coordinator stops rescheduling, and the entry never
+    polls again. Entities must go available on the next interval once the
+    appliance answers."""
+    resources = _load_fridge()
+    await _setup_online_then_unload(hass, mock_entry, resources)
+
+    with _unreachable():
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    coordinator: LocalThingsCoordinator = hass.data[DOMAIN][mock_entry.entry_id]
+    assert coordinator._unsub_refresh is not None  # a poll is actually queued
+    assert not coordinator.last_update_success
+
+    with _reachable(resources):
+        await _tick(hass)
+
+    assert coordinator.last_update_success
+    assert any(s.state != "unavailable" for s in hass.states.async_all())
+
+
+async def test_reconcile_reloads_when_live_discovery_differs(
+    hass: HomeAssistant, mock_entry, hass_storage
+) -> None:
+    """Platforms enumerate `bound` once, so a live set that disagrees with the
+    snapshot can only be adopted by bringing the entry back up."""
+    resources = _load_fridge()
+
+    with _reachable(resources):
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+        coordinator: LocalThingsCoordinator = hass.data[DOMAIN][mock_entry.entry_id]
+        victim = coordinator.bound[0].href
+        await hass.config_entries.async_unload(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    with _unreachable():
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    reduced = {href: rep for href, rep in resources.items() if href != victim}
+    with (
+        _reachable(reduced),
+        patch.object(hass.config_entries, "async_schedule_reload") as reload,
+    ):
+        await _tick(hass)
+
+    reload.assert_called_once_with(mock_entry.entry_id)
+    # Banked before the reload is scheduled, so the entry that comes back up
+    # replays this discovery rather than the one it is replacing -- otherwise
+    # a device that goes quiet again mid-reload rehydrates the stale set and
+    # reconciles all over again.
+    assert victim not in hass_storage[_store_key(mock_entry)]["data"]["resources"]
+
+
+async def test_reconcile_is_quiet_when_live_discovery_agrees(
+    hass: HomeAssistant, mock_entry
+) -> None:
+    """The common case -- same appliance, same firmware -- must not reload,
+    or every offline restart would cost a second setup cycle."""
+    resources = _load_fridge()
+    await _setup_online_then_unload(hass, mock_entry, resources)
+
+    with _unreachable():
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    with (
+        _reachable(resources),
+        patch.object(hass.config_entries, "async_schedule_reload") as reload,
+    ):
+        await _tick(hass)
+
+    reload.assert_not_called()
+
+
+def test_coverage_gap_repair_is_live_only(hass: HomeAssistant, mock_entry) -> None:
+    """A coverage gap is a claim about what the device reports, so replaying
+    a snapshot must not raise the Repair -- it would restate last run's
+    conclusion while the diagnostics download it points at is still empty."""
+    gappy = {
+        "/information/vs/0": {
+            "x.com.samsung.da.modelNum": "TOTALLY_UNKNOWN_BOARD",
+            "x.com.samsung.da.serialNum": "TEST-SERIAL-0000",
+        },
+        "/nothing/maps/this/vs/0": {"someField": 1},
+    }
+    issue_id = f"device_gap_{mock_entry.entry_id}"
+    coordinator = LocalThingsCoordinator(hass, mock_entry)
+
+    coordinator._run_discovery(gappy, from_snapshot=True)
+    assert coordinator._unbound_hrefs  # the gap is real, it just stays quiet
+    assert ir.async_get(hass).async_get_issue(DOMAIN, issue_id) is None
+
+    coordinator._run_discovery(gappy)
+    assert ir.async_get(hass).async_get_issue(DOMAIN, issue_id) is not None
+
+
+async def test_live_load_never_reconciles(
+    hass: HomeAssistant, mock_entry, mock_coordinator_session
+) -> None:
+    """An entry that came up against a live device has nothing to reconcile
+    against; the reload path must stay out of the normal startup entirely."""
+    with patch.object(hass.config_entries, "async_schedule_reload") as reload:
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+
+    coordinator: LocalThingsCoordinator = hass.data[DOMAIN][mock_entry.entry_id]
+    assert not coordinator.rehydrated
+    reload.assert_not_called()
+
+
+@pytest.mark.parametrize("failures", [1, 3])
+async def test_offline_load_survives_repeated_poll_failures(
+    hass: HomeAssistant, mock_entry, failures: int
+) -> None:
+    """Recovery isn't one-shot: the entry keeps its entities and keeps
+    retrying across however many intervals the appliance stays dark."""
+    resources = _load_fridge()
+    online_ids = await _setup_online_then_unload(hass, mock_entry, resources)
+
+    with _unreachable():
+        await hass.config_entries.async_setup(mock_entry.entry_id)
+        await hass.async_block_till_done()
+        for _ in range(failures):
+            await _tick(hass)
+
+    assert mock_entry.state is ConfigEntryState.LOADED
+    assert {s.entity_id for s in hass.states.async_all()} == online_ids
+
+    with _reachable(resources):
+        await _tick(hass)
+
+    coordinator: LocalThingsCoordinator = hass.data[DOMAIN][mock_entry.entry_id]
+    assert coordinator.last_update_success

tests/test_airconditioner_ailp_fac_capabilities.py

@@ -36,6 +36,15 @@ class _FakeCoordinator:
     def canonical_resources(self, subdevice):
         return self.last_resources
 
+    # _is_included judges existence against the discovery view, which is the
+    # live cache for everything but an offline load (issue #295).
+    @property
+    def discovery_resources(self):
+        return self.last_resources
+
+    def discovery_canonical(self, subdevice):
+        return self.canonical_resources(subdevice)
+
 
 def _resources():
     return _load_device("airconditioner_ailp_fac")

tests/test_entity.py

@@ -29,6 +29,15 @@ class _FakeCoordinator:
         # subdevices (issue #177).
         return self.last_resources
 
+    # _is_included judges existence against the discovery view, which is the
+    # live cache for everything but an offline load (issue #295).
+    @property
+    def discovery_resources(self):
+        return self.last_resources
+
+    def discovery_canonical(self, subdevice):
+        return self.canonical_resources(subdevice)
+
 
 def _coord(last_resources) -> LocalThingsCoordinator:
     return cast(LocalThingsCoordinator, _FakeCoordinator(last_resources))

tests/test_unique_ids.py

@@ -34,6 +34,15 @@ class _FakeCoordinator:
 
         return canonical_view(subdevice, self.last_resources, self._subdevices)
 
+    # _is_included judges existence against the discovery view, which is the
+    # live cache for everything but an offline load (issue #295).
+    @property
+    def discovery_resources(self):
+        return self.last_resources
+
+    def discovery_canonical(self, subdevice):
+        return self.canonical_resources(subdevice)
+
 
 @pytest.mark.parametrize("name", _FIXTURE_NAMES)
 def test_key_is_unique_across_all_bound_entities(name):