ensure thread.history_mode is immutable#30261
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| self.observe_items_with_update(items, ThreadMetadataPatch::default()) | ||
| let mut update = self.observe_items_with_update(items, ThreadMetadataPatch::default())?; | ||
| // Later SessionMeta lines do not redefine the canonical history_mode. | ||
| update.history_mode = Some(canonical_history_mode_from_rollout_items(items)); |
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seems possibly slightly inefficient to re-scan the items to rederive the old history mode, vs just omitting history mode from the ThreadMetadataPatch? But minor
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actually, much cleaner to omit it from ThreadMetadataPatch entirely. updated
wiltzius-openai
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Jun 26, 2026
wiltzius-openai
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this avoid the metadata sync rewriting the value; do we also need to forbid it in the app server APIs that can mutate metadata (or was it never exposed)?
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yeah, we only allow |
anp-oai
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Jun 26, 2026
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Description
This PR makes
thread.history_modeimmutable after the thread's canonical firstSessionMetahas been written. Later same-threadSessionMetalines are compatibility metadata writes, not a new thread definition.Without this, an older binary could append a
SessionMetathat omitshistory_mode; when a newer binary replays it, serde defaults that missing field tolegacyand SQLite could downgrade a paginated thread.Why
history_modeis the persisted thread storage contract. Paginated-thread fail-closed behavior and SQLite memory filtering depend on it staying aligned with canonical rollout metadata, especially when multiple Codex binary versions can touch the same local rollout.What changed
history_modefrom laterSessionMetaitems.history_modefromThreadMetadataPatch, so mutable metadata sync and app-server metadata updates cannot rewrite it.history_modefrom the rollout's canonical firstSessionMetainstead of from a mutable patch.history_modeinstead of metadata patches.CreateThreadParamsinitializer with the newhistory_modefield; Bazel CI caught this after the parent history-mode PR landed.Validation
just fmtjust test -p codex-thread-storejust test -p codex-state session_meta_does_not_set_model_or_reasoning_effort