A session row persists the provider identity a chat actually used. When that
provider is later renamed or removed (e.g. a custom_providers:/providers:
entry deleted, or a provider renamed oldone->newone), Desktop/TUI resume
restores the stale name into agent init and dies with:
agent init failed: Unknown provider '<name>'
while the CLI resumes the same session fine with the configured default.
- runtime_provider: add is_routable_provider() (full resolution chain:
built-in -> providers: -> custom_providers: -> models.dev)
- _stored_session_runtime_overrides: heal a non-routable provider via
canonical_custom_identity (base_url -> model -> configured provider),
drop to the configured default when unrecoverable, and clear the stale
base_url after healing so a dead endpoint cannot override the registry URL
- _start_agent_build: gate deferred-resume overrides on provider routability;
when the stored provider is gone, prefer the model the user picked for THIS
session, else the configured default
- tests: is_routable_provider cases, heal/fallback round-trips, gate checks
Refs #75128
7b5a18817 migrated the sibling slug sites to custom_provider_slug, which
keeps a keyed providers: entry's config key as its durable identity. It
covered find_custom_provider_identity_by_model; canonical_custom_identity's
third recovery source - the configured-provider fallback - still built
f"custom:{normalized}" out of whatever string the caller happened to hold.
_get_named_custom_provider matches on either spelling, so a display name
that differs from its config key matches the entry and then heals to
custom:<display-name>. That is a second identity for one endpoint: the
endpoint- and model-based sources of the same function return
custom:<config-key>, and so does everything that persists or restores a
session's provider override. canonical_custom_identity exists precisely to
make a bare "custom" routable again, and tui_gateway calls it on the
session-persist, resume and recovery paths - so the divergence lands in
stored session identity.
Re-resolve through the endpoint the matched entry owns, reusing the
function's own URL-based canonicaliser rather than duplicating the match
logic. Legacy unkeyed custom_providers: entries keep their name identity,
and an unconfigured candidate still returns None.
lorzl