collect¶
Assemble the per-request save payloads of one trace into its results.
Locally, the invoke blocks of one trace share their outer names: a container
bound above the invokes (rows = [None] * n; rows.save()) is ONE object
every invoke mutates. On the engine each invoke rides its own request into the
worker process with its own COPY, so the copies come back one per request,
each carrying only that request's writes. :func:merge_shared_saves
reproduces the shared-object semantics before results are pushed back into the
trace frame.
Merge same-name saves across a multi-invoke trace's requests, in place.
A name that was bound and saved ABOVE the invokes (mediator.presaved) is
one object locally, so its per-request copies merge element-wise — same-length lists slot-wise with None as the
unwritten marker (the common pattern: a pre-sized slot list each invoke
fills at its own index), dicts by key-union, everything else (and any
conflicting slot several requests wrote) keeping the later request's copy —
and the merged value is written into every mediator's scope so results push
identically whichever mediator they're read from.
A name each block saved for itself is NOT merged, however many requests shipped it: those are separate values, not copies of one, and merging them would keep only the last, leaving three prompts holding one prompt's activation. The caller returns those as a list instead.
Returns the merged shared values by name (the caller re-marks them saved: the merge builds new containers the save-gate hasn't seen).