Context engines may mutate the message list they receive, and the
context-engine plugin guide says that mutation only becomes visible if
the pass commits. Callers that pass their own commit fence (gateway
session hygiene) or set compression.context_timeout_seconds to 0 hand
the live list to the engine without the facade's deep snapshot.
compress_context restored the pre-compression snapshot on the
no-progress and superseded refusals, but the compressor-abort,
empty-transcript and would-grow refusals returned the live list as the
engine left it. An engine that cleared its input and returned [] made
compress_context return an empty transcript while warning that the
conversation continues unchanged.
Restore the snapshot in compress_context whenever _candidate_rejected
refuses a candidate or the commit refuses a grown one, so every refusal
returns the original transcript. The no-progress and superseded
branches no longer restore on their own because the caller now does it
for every refusal. Warnings, telemetry and the commit path are
unchanged.
Signed-off-by: mnajafian-nv <mnajafian@nvidia.com>
(cherry picked from commit d14fc7c96031d15f85acb00d433bcfdd39804554)
2e4e024ec2