Follow-up to the salvage of #45035 + #48682. The two PRs touched different
functions (resolve_resume_session_id vs get_compression_tip) but #45035's
descendant walk followed ANY parent_session_id child, so a delegate/subagent
child could hijack the resume target. Apply the same _branched_from /
_delegate_from / source!='tool' exclusion the rest of hermes_state.py uses,
so the resume walk only follows genuine compression continuations.
Also updates the unrealistic delegation test fixture to carry the real
_delegate_from marker, and updates 3 list_sessions_rich test mocks for the
order_by_last_active kwarg #48682 added.
AUTHOR_MAP: map PINKIIILQWQ + ailang323 salvage authors.
After context compression, the parent session holds pre-compression messages
and a child (or deeper descendant) holds the continuation.
resolve_resume_session_id() short-circuited when the input session already
had messages (row is not None -> return session_id), causing REST API
endpoints, gateway resume, and CLI resume to serve stale parent messages.
Remove the early-return. Walk the full descendant chain, record the
deepest node that has messages (best), and return best if not None
else the original session_id (preserving the empty-chain fallback).
Callers (api_server.py, web_server.py, cli_agent_setup_mixin.py,
cli_commands_mixin.py) all use the resolved != input -> redirect pattern
and are transparent to this change.
The new compression-tip tests poke started_at/ended_at directly via
db._conn to force deterministic lineage ordering. _conn is typed
Optional[Connection], so ty flagged .execute/.commit as unresolved on
None. Bind a local and assert it's non-None first to narrow the union.
Auto-compression ends the live session and forks a continuation child
(linked via parent_session_id). A long-lived parent keeps its own flushed
message rows, so resolve_resume_session_id()'s empty-head walk never
redirected it — resuming the parent id reloaded the pre-compression
transcript and dropped every turn generated after compression, including
the assistant's response. On the desktop this is the recurring "I sent a
message, came back, and the reply isn't there" report on large sessions:
the chat's routed id is the pre-rotation id, and both the gateway
session.resume RPC and the REST /messages read anchored on it.
Fix the resolver at the chokepoint: resolve_resume_session_id() now
follows the compression-continuation chain forward via get_compression_tip()
before its existing empty-head descendant walk. get_compression_tip() only
follows children whose parent ended with end_reason='compression' (created
after the parent was ended), so delegation/branch children never hijack a
resume. This fixes every resume caller at once (REST /messages, CLI
--resume, gateway /resume).
session.resume in tui_gateway was the one resume path that never called the
resolver — it used the raw target id directly. Route it through
resolve_resume_session_id() too (non-lazy only; lazy watch windows must
stay on their exact child branch). Resolving up front also re-anchors the
live-session fast path so a still-live rotated session is reused by its new
key instead of rebuilding a duplicate agent on the stale parent.
Tests:
- resolve_resume_session_id follows the tip even when the parent retains
messages, and is not confused by a delegation child.
- session.resume binds the agent to the continuation tip and returns the
post-compression reply.
When context compression fires mid-session, run_agent's _compress_context
ends the current session, creates a new child session linked by
parent_session_id, and resets the SQLite flush cursor. New messages land
in the child; the parent row ends up with message_count = 0. A user who
runs 'hermes --resume <original_id>' sees a blank chat even though the
transcript exists — just under a descendant id.
PR #12920 already fixed the exit banner to print the live descendant id
at session end, but that didn't help users who resume by a session id
captured BEFORE the banner update (scripts, sessions list, old terminal
scrollback) or who type the parent id manually.
Fix: add SessionDB.resolve_resume_session_id() which walks the
parent→child chain forward and returns the first descendant with at
least one message row. Wire it into all three resume entry points:
- HermesCLI._preload_resumed_session() (early resume at run() time)
- HermesCLI._init_agent() (the classical resume path)
- /resume slash command
Semantics preserved when the chain has no descendants with messages,
when the requested session already has messages, or when the id is
unknown. A depth cap of 32 guards against malformed loops.
This does NOT concatenate the pre-compression parent transcript into
the child — the whole point of compression is to shrink that, so
replaying it would blow the cache budget we saved. We just jump to
the post-compression child. The summary already reflects what was
compressed away.
Tests: tests/hermes_state/test_resolve_resume_session_id.py covers
- the exact 6-session shape from the issue
- passthrough when session has messages / no descendants
- passthrough for nonexistent / empty / None input
- middle-of-chain redirects
- fork resolution (prefers most-recent child)
Closes#15000
