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docs(buglog): bug-1923 sim drops shared resource values from the recording snapshot

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Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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Rongsong Shen 2026-10-08 07:18:37 +00:00
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.wolf/buglog.json
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@ -17424,6 +17424,31 @@
"record": ".wolf/bugs/bug-1922.md",
"gitea_issue": 346,
"gitea_synced_status": "fixed"
},
{
"id": "bug-1923",
"status": "open",
"status_updated": "2026-10-08",
"status_note": "newly logged",
"component": "scheduler",
"severity": "wrong-result",
"timestamp": "2026-10-08T07:17:34Z",
"last_seen": "2026-10-08T07:17:34Z",
"occurrences": 1,
"error_message": "xce_scheduler --sim drops shared resource values from the snapshot (license shows value=(none))\n\n**Observed:** a shared (cluster-wide, `GLOBAL|SHARED|CONSUMABLE`) resource value that is present in a recording's `SnapshotEntry` is not loaded by `xce_scheduler --sim`. `info resource license`, after `step` or straight after load, shows:\n```\n[sim] resource license: desc= valtype=numeric ordtype=incr flags=GLOBAL,SHARED,CONSUMABLE interval=0\n[sim] value=(none)\n[sim] DISPATCH jobid=0-0-0-101\n[sim] PEND jobid=0-0-0-102\n[sim] PEND jobid=0-0-0-103\n[sim] PEND jobid=0-0-0-104\n```\nWhen the same value arrives as a `RESVALS_FULL` replay event, it loads (`value=2.00 used=2.00`), and jobs 102 and 103 dispatch.\n\n**Expected:** every shared resource value in the snapshot is loaded into `core->sharedInst`, so the simulator starts with the same shared pool the recorder had.\n\n**Impact:** wrong result in the simulator. A replay whose shared resource values were set before recording started, and never re-sent as a `RESVALS_FULL` event during the recording, simulates with no license pool. Jobs needing the resource pend instead of dispatching, so a sim replay diverges from what live did. Nothing is logged when the value is dropped.\n\n**Found by:** spec task scheduler-sim-decision-trace 1.1, while building the trace-off REPL baseline fixture (`src/scheduler/testsuite/test_repl_trace_baseline.c`). That fixture now sends the license value as a `RESVALS_FULL` event to work around this bug.\n\nTwo separate defects were found (see Reproduction, variants A and C):\n- **Read side, confirmed with gdb and a decoder:** `snapshot_load.c:129` skips the entry when `rv->host != NULL`. After the capnp round trip, a host that was written as NULL decodes as `\"\"`, so every shared resval in a snapshot is skipped and line 140's `zarray_put` is never reached. The `RESVALS_FULL` path (`core_events.c:1124-1147`) has no such host check.\n- **Write side, Suspected (from code reading, matches the decoder output):** `snapshot.c:431` loops `for (i = 0; i < core->sharedInst.count; i++)`, but `zarray_put_ex` (`src/lib/zarray.c:291-330`) counts filled slots, not the highest index plus one. A sparse `sharedInst` therefore drops values at higher indices: with the license at idx 2 and `count == 1`, the snapshot carries `resvals count=0`. The same pattern may affect per-worker resvals at `snapshot_wire.c:242` (`w->resvals.count`); not checked.",
"file": "src/scheduler/src/snapshot.c, src/scheduler/src/snapshot_load.c, src/scheduler/src/snapshot_wire.c",
"root_cause": "TODO: required for fixed/partial",
"fix": "TODO: required for fixed/partial\n\nVerification:\n- Test: TODO: name + file; RED before the fix, GREEN after\n- Suites: TODO: suite results and build profile\n- Live: TODO: soak/deploy run, or n/a and why",
"tags": [
"sim",
"snapshot",
"resvals",
"replay",
"persistence"
],
"related_bugs": [],
"fix_commits": [],
"record": ".wolf/bugs/bug-1923.md"
}
]
}