jif cc737efd65 Preserve the multi-agent version when forking at a turn cutoff (#43540) ...

## Why

A fork cutoff can remove the only `TurnContext` recording the source thread's selected multi-agent version. Forking before the first turn must preserve that version, including when the child is resumed before its first turn.

## What changed

Recover the version from the untrimmed source history or loaded parent, independently of permission overrides, and carry it into the fork's session metadata for `last_turn_id` and `before_turn_id` cutoffs.

## Testing

Add regression coverage for forks before the first turn across legacy and paginated history modes, with loaded and unloaded parents and explicit permission overrides. Verify that the child persists `MultiAgentVersion::V2` and still uses the `collaboration` tools after restarting and resuming.

GitOrigin-RevId: d7e30cf8bfdeb4f755fefab3d1d0884964d7c977

2026-09-07 18:17:39 +00:00

..

common

Gate experimental context by model capability at session startup (#43147)

2026-09-06 02:28:38 +00:00

suite

Preserve the multi-agent version when forking at a turn cutoff (#43540)

2026-09-07 18:17:39 +00:00

all.rs

[codex] Use expect in integration tests (#28441)

2026-06-15 21:53:47 -07:00