fix(logs): preserve log tails across short reads by qingminglong · Pull Request #105066 · openclaw/openclaw

qingminglong · 2026-07-12T06:20:36Z

What Problem This Solves

Fixes an issue where users reading OpenClaw logs through the CLI, Gateway logs method, or diagnostic support export could receive an incomplete log tail when the filesystem returns a short positional read for the bounded tail window.

Why This Change Was Made

The shared log-tail reader now fills the requested bounded read window before decoding and splitting lines, matching the existing gateway diagnostic tail-reader invariant. This stays local to log-tail read completeness and does not change cursor, reset, truncation, schema, CLI, or UI behavior.

User Impact

Log views and support bundles now preserve the recent log lines available within the configured byte budget even when the underlying file read completes in smaller chunks.

Evidence

Claim proved at current head 024c90fd60070ba0cf2ecef21c1b9d0e07c43c63: readConfiguredLogTail, Gateway logs.tail, and diagnostic support export preserve the complete tail while the underlying real log-file reads repeatedly return only four bytes.
Command/action proof: node --import tsx --input-type=module - wrote a real temporary JSONL log file, wrapped fs.promises.open only for that file to force four-byte positional reads, imported the current branch modules, called readConfiguredLogTail, called Gateway logsHandlers["logs.tail"], wrote a diagnostic support zip with writeDiagnosticSupportExport, and inspected logs/openclaw-sanitized.jsonl from the zip with jszip.

{
  "head": "024c90fd60070ba0cf2ecef21c1b9d0e07c43c63",
  "fileBytes": 254,
  "readStats": {
    "totalReads": 192,
    "shortReads": 189,
    "examples": [
      { "requested": 254, "actual": 4, "position": 0 },
      { "requested": 250, "actual": 4, "position": 4 },
      { "requested": 246, "actual": 4, "position": 8 }
    ]
  },
  "readConfiguredLogTail": {
    "lineCount": 4,
    "cursor": 254,
    "size": 254,
    "completeTail": true
  },
  "gatewayLogsTail": {
    "ok": true,
    "lineCount": 4,
    "cursor": 254,
    "size": 254,
    "completeTail": true
  },
  "diagnosticSupportExport": {
    "files": [
      "diagnostics.json",
      "logs/openclaw-sanitized.jsonl",
      "manifest.json",
      "summary.md"
    ],
    "sanitizedLogMessages": [
      { "omitted": "unparsed", "bytes": 11 },
      "proof-short-read-one",
      "proof-short-read-two",
      "proof-short-read-three"
    ],
    "completeTail": true
  }
}

Focused regression after merge refresh: node scripts/run-vitest.mjs src/logging/log-tail.test.ts passed with 1 file and 2 tests.
Diff hygiene after merge refresh: git diff --check upstream/main...HEAD passed.
PR diff after merge refresh remains limited to src/logging/log-tail.ts and src/logging/log-tail.test.ts.

AI-assisted: yes. I reviewed the shared reader, Gateway logs handler, diagnostic support export path, focused test, current-head proof, and diff hygiene before refreshing this PR.

clawsweeper · 2026-07-12T06:30:22Z

Codex review: needs maintainer review before merge. Reviewed July 12, 2026, 6:26 AM ET / 10:26 UTC.

Summary
The PR changes the shared log-tail reader to accumulate short positional reads and adds regression coverage using four-byte reads.

PR surface: Source +21, Tests +32. Total +53 across 2 files.

Reproducibility: yes. Current main performs one positional read, while the exact-head real-file proof forces repeated four-byte reads and demonstrates complete output from the shared reader, Gateway handler, and diagnostic export after the fix.

Review metrics: none identified.

Stored data model
Persistent data-model change detected: serialized state: src/logging/log-tail.test.ts. Confirm migration or upgrade compatibility proof before merge.

Merge readiness
Overall: 🦞 diamond lobster
Proof: 🦞 diamond lobster
Patch quality: 🦞 diamond lobster
Result: ready for maintainer review.

Overall follows the weaker of proof and patch quality, so missing proof can cap an otherwise strong patch.

Next step before merge

[P2] No repair lane is needed; the exact head is clean and ready for routine maintainer merge handling.

Security
Cleared: The diff only changes bounded local file reads and regression tests, with no dependency, permission, secret, workflow, package, or supply-chain surface change.

Review details

Best possible solution:

Merge the exact-head shared-reader loop and real-file regression test after routine maintainer review; no alternate implementation, migration, or repair branch is needed.

Do we have a high-confidence way to reproduce the issue?

Yes. Current main performs one positional read, while the exact-head real-file proof forces repeated four-byte reads and demonstrates complete output from the shared reader, Gateway handler, and diagnostic export after the fix.

Is this the best way to solve the issue?

Yes. Accumulating reads in the shared bounded reader is the narrowest owner-aligned fix, matches Node's EOF contract and existing repository helpers, and avoids duplicating behavior in each consumer.

AGENTS.md: found and applied where relevant.

Codex review notes: model internal, reasoning high; reviewed against 0350b87f069b.

Label changes

Label justifications:

P2: The PR fixes incomplete bounded log tails across CLI, Gateway, and support-export paths with limited blast radius and no outage or data-loss evidence.
rating: 🦞 diamond lobster: Overall readiness is 🦞 diamond lobster; proof is 🦞 diamond lobster and patch quality is 🦞 diamond lobster.
status: 👀 ready for maintainer look: ClawSweeper has no concrete contributor-facing blocker left for this PR. Sufficient (terminal): Exact-head terminal proof uses a real temporary JSONL file and repeated four-byte reads to show the complete improved result through the shared reader, Gateway logs method, and diagnostic support export.
proof: sufficient: Contributor real behavior proof is sufficient. Exact-head terminal proof uses a real temporary JSONL file and repeated four-byte reads to show the complete improved result through the shared reader, Gateway logs method, and diagnostic support export.

Evidence reviewed

PR surface:

Source +21, Tests +32. Total +53 across 2 files.

View PR surface stats

Area	Files	Added	Removed	Net
Source	1	24	3	+21
Tests	1	32	0	+32
Docs	0	0	0	0
Config	0	0	0	0
Generated	0	0	0	0
Other	0	0	0	0
Total	2	56	3	+53

What I checked:

Current-main defect path: Current main allocates the bounded tail buffer, performs one positional read, and decodes only that call's bytesRead, so a valid short read produces an incomplete tail. (src/logging/log-tail.ts:127, 0350b87f069b)
Proposed implementation: The branch advances the buffer offset and file position until the requested window is filled or a zero-byte read indicates EOF. (src/logging/log-tail.ts:29, 024c90fd6007)
Focused regression coverage: The test wraps a real file handle with four-byte positional reads, verifies that all log lines survive, restores mocks, and removes its temporary directory. (src/logging/log-tail.test.ts:61, 024c90fd6007)
Shared owner boundary: The Gateway handler delegates cursor, byte-limit, source-selection, and tail-reading semantics to readConfiguredLogTail, making the shared reader the correct repair boundary. (src/gateway/server-methods/logs.ts:26, 0350b87f069b)
Sibling implementation precedent: The diagnostic tail reader already uses the same fill-until-EOF positional-read pattern, and the session file-range helper independently follows that invariant. (src/daemon/diagnostics.ts:19, 0350b87f069b)
Node dependency contract: Node 24 documentation states that zero bytes read indicates EOF for an unmodified file, supporting the loop's stop condition rather than treating the first short read as completion. (024c90fd6007)

Likely related people:

steipete: Commit 306fe84 moved Gateway log-tail behavior into the shared helper, and later work documented the logging helper surface. (role: introduced shared log-tail owner boundary and recent area contributor; confidence: high; commits: 306fe841f54b, add135d2381f; files: src/logging/log-tail.ts, src/gateway/server-methods/logs.ts)
eleqtrizit: Commit 8512941 added configured log-tail redaction behavior and the adjacent test suite. (role: major log-tail behavior contributor; confidence: high; commits: 851294126b30; files: src/logging/log-tail.ts, src/logging/log-tail.test.ts)
ethanclaw: Commit 492e2a3 maintained rolling-log resolution across date boundaries in the same helper and CLI path. (role: recent log-tail maintenance contributor; confidence: medium; commits: 492e2a3060db; files: src/logging/log-tail.ts, src/commands/channels/logs.ts)

What the crustacean ranks mean

🦀 challenger crab: rare, exceptional readiness with strong proof, clean implementation, and convincing validation.
🦞 diamond lobster: very strong readiness with only minor maintainer review expected.
🐚 platinum hermit: good normal PR, likely mergeable with ordinary maintainer review.
🦐 gold shrimp: useful signal, but proof or patch confidence is still limited.
🦪 silver shellfish: thin signal; proof, validation, or implementation needs work.
🧂 unranked krab: not merge-ready because proof is missing/unusable or there are serious correctness or safety concerns.
🌊 off-meta tidepool: rating does not apply to this item.

Shiny media proof means a screenshot, video, or linked artifact directly shows the changed behavior. Runtime, network, CSP, and security claims still need visible diagnostics.

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Review history (3 earlier review cycles)

reviewed 2026-07-12T06:28:46.898Z sha 0ca736b :: needs real behavior proof before merge. :: none
reviewed 2026-07-12T08:24:41.422Z sha 0ca736b :: needs real behavior proof before merge. :: none
reviewed 2026-07-12T10:18:02.311Z sha 024c90f :: needs maintainer review before merge. :: none

qingminglong · 2026-07-12T07:56:11Z

@clawsweeper re-review

clawsweeper · 2026-07-12T07:56:14Z

🦞🧹
ClawSweeper re-review requested.

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Action: item re-review queued (workflow sweep.yml, event repository_dispatch).
Result: the existing ClawSweeper review comment will be edited in place when the review finishes.

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State: Complete
Detail: The targeted re-review published an exact durable review comment and queued an executing target-wide serialized router scan.
Run: https://github.com/openclaw/clawsweeper/actions/runs/29188555220
Updated: 2026-07-12T10:13:48.096Z

qingminglong · 2026-07-12T09:58:55Z

@clawsweeper re-review

…short-reads

qingminglong · 2026-07-12T10:14:01Z

@clawsweeper re-review

clawsweeper · 2026-07-12T10:14:04Z

🦞🧹
ClawSweeper re-review requested.

I asked ClawSweeper to review this item again.
Action: item re-review queued (workflow sweep.yml, event repository_dispatch).
Result: the existing ClawSweeper review comment will be edited in place when the review finishes.

Re-review progress:

State: Complete
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Run: https://github.com/openclaw/clawsweeper/actions/runs/29188943056
Updated: 2026-07-12T10:27:59.825Z

steipete · 2026-07-14T21:47:36Z

Land-ready maintainer proof for exact head 7ffaa0b594e4ed80728aaf44767deb65a55c878a.

Improved the fix at the logging owner boundary: one complete positional-read helper now serves both configured log tails and channels logs, with forced short-read regressions for both callers.
Migrated the new test temp directories to the repo auto-cleanup tracker.
Exact-head Testbox: focused logging/channel tests passed 10/10 (run 29370281379).
pnpm check:changed passed for the four-file surface; format, core/test types, lint, architecture, dependency, and temp-dir checks passed.
Fresh exact-head autoreview: no actionable findings (0.98 confidence).
Exact-head hosted CI passed (CI 29370191262); Workflow Sanity, CodeQL, Critical Quality, and Opengrep also passed.

Known proof gaps: none for this bounded reliability fix.

steipete · 2026-07-14T21:47:57Z

Merged via squash.

Prepared head SHA: 7ffaa0b594e4ed80728aaf44767deb65a55c878a
Landed commit: c94da0df6f38fcbc26b6562e98119809d29654a3

* fix(logs): preserve log tails across short reads * test(logging): track log-tail temp files --------- Co-authored-by: Peter Steinberger <[email protected]> Co-authored-by: Peter Steinberger <[email protected]>

fix(logs): preserve log tails across short reads

0ca736b

openclaw-barnacle Bot added the size: S label Jul 12, 2026

Merge remote-tracking branch 'upstream/main' into codex/fix-log-tail-…

024c90f

…short-reads

clawsweeper Bot removed rating: 🦪 silver shellfish Thin PR readiness signal; proof, validation, or implementation needs work. status: 📣 needs proof The PR needs real behavior proof before ClawSweeper can clear the contributor ask. labels Jul 12, 2026

steipete self-assigned this Jul 14, 2026

steipete and others added 2 commits July 14, 2026 14:19

Merge branch 'main' into codex/fix-log-tail-short-reads

1565e8f

test(logging): track log-tail temp files

3c63a8c

openclaw-barnacle Bot added app: web-ui App: web-ui scripts Repository scripts commands Command implementations channel: qqbot extensions: qa-lab channel: reef Channel integration: reef size: XL and removed size: S labels Jul 14, 2026

Merge branch 'main' into codex/fix-log-tail-short-reads

7ffaa0b

openclaw-barnacle Bot removed the app: web-ui App: web-ui label Jul 14, 2026

openclaw-barnacle Bot added size: S and removed scripts Repository scripts channel: qqbot extensions: qa-lab channel: reef Channel integration: reef size: XL labels Jul 14, 2026

steipete merged commit c94da0d into openclaw:main Jul 14, 2026
115 of 119 checks passed

github-actions Bot mentioned this pull request Jul 14, 2026

📡 Upstream Digest — 2026-07-14 22:49 UTC curtismercier/openclaw-mods#1296

Open

This was referenced Jul 15, 2026

fix(agents): decode only read bytes in bounded CLI session tails #108072

Merged

fix(sessions): keep tail follow cursor aligned with bytes actually read #108127

Merged

fix(gateway): fill bounded transcript windows across short reads #108242

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