[Bug] Inspector Cordis-tree growth crashes Desktop Host: source state exceeds source-frame byte limit

[damokelis]

Observed behavior

With the optional Inspector profile enabled, growing the live Cordis tree can terminate the Desktop Host with an uncaught exception:

Error: inspector: source state exceeds the source-frame byte limit
  at InspectorSourceBuffer.setState
  at HostBridgePublisher.setState
  at HostInspectorSource.setState
  at publish

Observed on Windows x64 and reproduced on macOS arm64 with Desktop 0.2.1-alpha.1, Electron 44.0.0, Node 24.18.1. No private conversation data or original filesystem paths are included here.

The macOS reproduction used the installed Desktop application, enabled Inspector and incrementally registered disposable no-op runtime plugins via Inspector CDP. The Host exited with code 1 and generated the same error stack. The last queried tree was not necessarily the crashing snapshot, so no exact trigger size is claimed.

Expected behavior

Cordis tree growth should be truncated within the complete retained-record byte budget without terminating the observed Host.

Suspected implementation mismatch

Host and Client pass maxFrameBytes - 4096 to the Cordis collector as a payload-only budget. InspectorSourceBuffer.stateFits() checks the serialized array of records containing monotonicMs, topic, and payload, plus 4096 bytes. A snapshot can satisfy the former budget while violating the latter.

A deterministic test creates a bounded Cordis tree and chooses a frame limit equal to its snapshot payload length +4096. Publication with the existing implementation throws the exact exception above. Reserving the record envelope before tree collection makes the test pass.

Related production behavior

Local node and team publishing succeeded with a smaller tree. Thus this is not a claim that every node/team publication crashes; mutation under a sufficiently large tree is the relevant condition.

[damokelis]

Fix branch is now available: https://github.com/damokelis/deepseek-harness/tree/fix/inspector-retained-state-budget
Commit: damokelis@7a28f53

The new deterministic regression fails with the original budget and passes with the fix. Added asynchronous growth/disposal coverage and real Loader+Worker growth under a small frame limit; truncated trees remain queryable. Changed publisher scoped coverage is100%; focused tests, Oxlint and required documentation/type checks passed (one initial test typing error was corrected).

Attempted to open a PR: REST pulls endpoint returned404, and GraphQL CreatePullRequest returned FORBIDDEN for this contributor despite successful fork push. Maintainers: is external PR submission restricted? Please review the linked fix and advise the supported contribution path, or cherry-pick if appropriate. No installed Desktop update or deployment is claimed.

[suyunxing]

Additional reproduction on Windows 11 — and confirmation the throw still ships in every published version

Environment — Windows 11 26H2, DeepSeek Harness Desktop, profile install @deepseek-ai/dsh-experimental-inspector@0.2.1-rc.3 (commit 39a0ada5).

Symptom — the desktop shell reports "应用无法启动或已意外停止" ("app failed to start or stopped unexpectedly"). crash-*-host.log records:

dsh: fatal uncaught exception: Error: inspector: source state exceeds the source-frame byte limit
    at InspectorSourceBuffer.setState (…/lib/index.js:996:10)
    at HostBridgePublisher.setState (…/lib/index.js:1109:16)
    at HostInspectorSource.setState (…/lib/index.js:836:18)
    at …/lib/index.js:2322:13
    at publish (…/lib/index.js:2294:3)

followed by dsh desktop host exited with 1. Two consecutive days produced byte-identical stacks.

Mechanism — the Cordis-tree collector trims against spec.maxSourceFrameBytes - 4096 (lib/index.js:2404), but setState re-measures the same snapshot with the record wrapper and array brackets added:

// lib/index.js:1082
stateFits() {
  return jsonByteLength([...this.state.values()]) + SOURCE_FRAME_OVERHEAD_BYTES <= this.options.maxFrameBytes;
}

The two budgets therefore differ by tens to hundreds of bytes. Once the plugin tree approaches the 128 KiB default, the collector's trim "succeeds" while setState still throws — and that call sits inside queueMicrotask(publishCordisTree) (:2294) with no catch, so it becomes an uncaught exception that takes the host down. This also explains the "only started happening these last few days" onset: it tracks plugin count, not any particular plugin.

Not fixed in any published version — I unpacked the npm tarballs of 0.2.1-rc.4, 0.2.1-rc.5 and 0.2.2-alpha.2: all three still contain the same throw new Error("inspector: source state exceeds the source-frame byte limit") in setState. Current dist-tags: latest=0.1.6-alpha.1, next=0.2.1-rc.5, alpha=0.2.2-alpha.2.

Local mitigation that works (in case it helps whoever lands the fix): raise maxSourceFrameBytes via a profile patch (e.g. 524288), make setState evict stale topics / clear and enqueue instead of throwing, and give the collector a real margin instead of the bare 4096.

Happy to test a build if one appears.