Issue #54465 established that a same-provider retry after a full-budget
timeout costs a second whole `timeout` window before the fallback chain is
reached, doubling the user-visible stall, and that compression must not pay
it because it sits on a critical path. The guard added for that is spelled
`task == "compression"`, so vision — which sits on the interactive path —
still retries.
The cost is the same and the stall is more visible: the turn holding the
image cannot answer, and because turns are serialised the following user
messages queue behind it. Two sequential full-budget timeouts on an
unhealthy vision provider is a long stall for something the fallback chain
could have served immediately.
Replaces the string comparison at both retry sites (sync `call_llm` and
`async_call_llm`) with `_TIMEOUT_NO_RETRY_TASKS = {"compression", "vision"}`,
so the two paths cannot drift again. Behaviour is unchanged for every other
task: fast blips (a streaming-close or a 5xx) still retry, and only
full-budget timeouts on those two tasks skip straight to fallback.
Tests: vision now falls straight through to fallback with the primary tried
exactly once, and a non-critical task still gets its one same-provider
retry, so the change stays scoped. Reverting the source change fails the
vision test and leaves the scoping test green.
Not the same as #51513, which fixes five separate defects in the vision
fallback chain (capability detection, sync/async client misuse, geo-block
and RemoteProtocolError classification, and chain iteration). This is about
what happens before that chain is reached.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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