fix: prevent GTK double-populate crash and KeyError in entity/callback cleanup

[Copilot]

Users experience a gtk_list_tile_split assertion SIGABRT when navigating back to a page with configured HA buttons. A previous fix only guarded the "not connected" path; the crash still fires when on_ready() is called twice in the same GTK idle cycle while connected (double page-load observed in logs).

GTK double-populate crash (base_core.py)

_load_domains / _load_entities used get_item_amount() / get_item_at() to determine whether repopulation was needed. Because GTK processes model writes lazily, both rapid calls see stale widget state, each triggers populate(), and GTK's internal list-tile state is corrupted.

Fix: replace GTK model reads with Python-level caches (_last_loaded_domains, _last_loaded_entities). The cache is written synchronously on the first call, so a second rapid call skips populate() entirely.

# before – reads from GTK model (can return stale data in same idle cycle)
if domains != self._get_current_domains():
    self.domain_combo.populate(domains, domain, trigger_callback=False)

# after – compares against Python cache, always consistent
old_domains = self._last_loaded_domains
self._last_loaded_domains = list(domains)
if domains != old_domains:
    self.domain_combo.populate(domains, domain, trigger_callback=False)

_last_loaded_entities is also reset to None inside on_change_domain when the domain actually changes, ensuring the entity combo is always repopulated for the new domain.

KeyError crashes in cleanup (home_assistant_backend.py)

• remove_tracked_entity: direct self._entities[domain] access raises KeyError when a domain disappears after a reconnect/reload. set.remove() raises KeyError when the callback was never registered. Fixed with .get() chaining + early return on None + discard().
• remove_action_ready_callback: set.remove() raises KeyError under the same race conditions. Fixed with discard().

Tests

New cases cover: unknown domain in remove_tracked_entity, unregistered callback in both remove methods, entity cache reset on domain change, and the double-populate prevention for both domain and entity combos.

[Copilot]

Pull request overview

This pull request hardens the Home Assistant action UI against a GTK crash caused by rapid double-population of combo models, and makes backend cleanup methods resilient to race conditions that previously raised KeyError.

Changes:

• Replace GTK model state reads in BaseCore._load_domains() / _load_entities() with Python-level “last loaded” caches to prevent double populate() calls in the same GTK idle cycle.
• Make backend deregistration paths idempotent by using .get(...) lookups and set.discard() in remove_tracked_entity() and remove_action_ready_callback().
• Add/adjust unit tests covering unknown domain cleanup, missing callback removal, entity cache reset on domain change, and double-populate prevention.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
actions/cores/base_core/base_core.py	Adds _last_loaded_domains/_last_loaded_entities caches, resets entity cache on domain change, and prevents redundant populate() calls.
backend/home_assistant_backend.py	Avoids KeyError during callback/entity cleanup by switching to discard() and safe .get() chaining with early returns.
test/backend/test_backend_remove_tracked_entity.py	Adds coverage for removing tracked entities when the domain is missing or the callback wasn’t registered.
test/backend/test_backend_remove_action_ready_callback.py	Adds coverage for removing a callback that was never registered.
test/actions/cores/base_core/test_base_core_on_change_domain.py	Verifies that changing the domain resets the entity cache so entities will repopulate.
test/actions/cores/base_core/test_base_core_load_entities.py	Updates tests to rely on the new cache behavior; adds a “no double populate on repeated call” case.
test/actions/cores/base_core/test_base_core_load_domains.py	Updates tests to rely on the new cache behavior; adds a “no double populate on repeated call” case.

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