test(shared): add unit tests for surrogate-safe UTF-16 string slicing helpers by dwc1997 · Pull Request #97805 · openclaw/openclaw

dwc1997 · 2026-06-29T14:11:31Z

What Problem This Solves

The utf16-slice.ts module provides surrogate-safe UTF-16 string slicing helpers. However, this module lacked unit tests to verify the UTF-16 string slicing behavior, which could lead to regressions when the function is modified.

Why This Change Was Made

Add unit tests for sliceUtf16Safe and truncateUtf16Safe functions to verify UTF-16 string slicing behavior. This improves test coverage and prevents regressions.

Focused tests cover ASCII slicing, negative indices, out-of-bounds handling, surrogate pair preservation, and emoji handling.

User Impact

UTF-16 string slicing now has comprehensive test coverage, reducing the risk of regressions when the function is modified.

Evidence

Reproducibility: not applicable. This PR adds direct coverage for existing helper behavior rather than reporting a user-visible runtime bug. Source inspection confirms the helper behavior the tests target.

Direct behavior probe:

$ node --import tsx -e "import('./src/shared/utf16-slice.js').then(({ sliceUtf16Safe, truncateUtf16Safe }) => console.log(JSON.stringify([{ desc: 'sliceUtf16Safe slices ASCII string', input: 'hello world', start: 0, end: 5, result: sliceUtf16Safe('hello world', 0, 5), expected: 'hello' }, { desc: 'sliceUtf16Safe handles negative start', input: 'hello world', start: -5, result: sliceUtf16Safe('hello world', -5), expected: 'world' }, { desc: 'truncateUtf16Safe returns input when shorter than limit', input: 'hello', maxLen: 10, result: truncateUtf16Safe('hello', 10), expected: 'hello' }, { desc: 'truncateUtf16Safe truncates when longer than limit', input: 'hello world', maxLen: 5, result: truncateUtf16Safe('hello world', 5), expected: 'hello' }], null, 2)))"
[
  {
    "desc": "sliceUtf16Safe slices ASCII string",
    "input": "hello world",
    "start": 0,
    "end": 5,
    "result": "hello",
    "expected": "hello"
  },
  {
    "desc": "sliceUtf16Safe handles negative start",
    "input": "hello world",
    "start": -5,
    "result": "world",
    "expected": "world"
  },
  {
    "desc": "truncateUtf16Safe returns input when shorter than limit",
    "input": "hello",
    "maxLen": 10,
    "result": "hello",
    "expected": "hello"
  },
  {
    "desc": "truncateUtf16Safe truncates when longer than limit",
    "input": "hello world",
    "maxLen": 5,
    "result": "hello",
    "expected": "hello"
  }
]

Targeted test:

$ node scripts/run-vitest.mjs run src/shared/utf16-slice.test.ts

 RUN  v4.1.8 /home/0668001110/ZTEProject/openclaw-worktrees/pr-94335

 Test Files  1 passed (1)
      Tests  18 passed (18)
   Start at  22:06:58
   Duration  346ms (transform 62ms, setup 0ms, import 83ms, tests 8ms)

[test] passed 1 Vitest shard in 9.64s

Formatting:

$ npx oxfmt --check src/shared/utf16-slice.ts src/shared/utf16-slice.test.ts
Checking formatting...

All matched files use the correct format.
Finished in 65ms on 2 files using 8 threads.

Whitespace:

$ git diff --check

AI-assisted

Prepared with Codex. I reviewed the change, understand the touched code path, and kept the PR focused on the bug described above.

… helpers Add unit tests for sliceUtf16Safe and truncateUtf16Safe functions in src/shared/utf16-slice.ts to verify UTF-16 string slicing behavior. Tests cover: - sliceUtf16Safe slices ASCII string normally - sliceUtf16Safe handles negative start/end - sliceUtf16Safe handles start/end beyond length - sliceUtf16Safe swaps start and end when start > end - sliceUtf16Safe preserves emoji with surrogate pairs - sliceUtf16Safe avoids splitting surrogate pair at start/end - truncateUtf16Safe returns input when shorter than limit - truncateUtf16Safe truncates when longer than limit - truncateUtf16Safe handles zero/negative limit - truncateUtf16Safe floors decimal limit - truncateUtf16Safe preserves emoji with surrogate pairs - truncateUtf16Safe avoids splitting surrogate pair

clawsweeper · 2026-06-29T14:13:44Z

Codex review: needs maintainer review before merge. Reviewed June 29, 2026, 11:03 AM ET / 15:03 UTC.

Summary
The branch adds a colocated Vitest test file for sliceUtf16Safe and truncateUtf16Safe, covering normal slicing, index normalization, limits, and surrogate-boundary behavior.

PR surface: Tests +88. Total +88 across 1 file.

Reproducibility: not applicable. This PR adds regression tests for an existing helper rather than reporting a runtime bug. The expected helper contract is visible in src/shared/utf16-slice.ts.

Review metrics: none identified.

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

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

Rank-up moves:

none.

Next step before merge

No ClawSweeper repair lane is needed; the remaining action is normal maintainer review and CI gating for the open PR.

Security
Cleared: The diff adds only a colocated Vitest test file and introduces no dependency, workflow, script, package, secret, or runtime execution surface.

Review details

Best possible solution:

Land the focused helper test coverage after ordinary maintainer and CI review, while keeping the production helper behavior unchanged.

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

Not applicable; this PR adds regression tests for an existing helper rather than reporting a runtime bug. The expected helper contract is visible in src/shared/utf16-slice.ts.

Is this the best way to solve the issue?

Yes; a colocated Vitest file is the narrowest maintainable layer for direct helper coverage, and current main does not already have equivalent shared-helper tests.

AGENTS.md: found and applied where relevant.

Codex review notes: model internal, reasoning high; reviewed against 86b9b88f4066.

Label changes

Label changes:

add rating: 🐚 platinum hermit: Overall readiness is 🐚 platinum hermit; proof is 🦞 diamond lobster and patch quality is 🐚 platinum hermit.
add status: 👀 ready for maintainer look: ClawSweeper has no concrete contributor-facing blocker left for this PR. Sufficient (terminal): The PR body includes terminal output for a direct helper behavior probe and the targeted Vitest run for the added test file after the assertion fix.
remove rating: 🦐 gold shrimp: Current PR rating is rating: 🐚 platinum hermit, so this older rating label is no longer current.
remove status: ⏳ waiting on author: Current PR status label is status: 👀 ready for maintainer look.

Label justifications:

P3: This is a low-risk test coverage cleanup for an existing shared helper with no production behavior, config, migration, or user-facing surface change.
rating: 🐚 platinum hermit: Overall readiness is 🐚 platinum hermit; proof is 🦞 diamond lobster and patch quality is 🐚 platinum hermit.
status: 👀 ready for maintainer look: ClawSweeper has no concrete contributor-facing blocker left for this PR. Sufficient (terminal): The PR body includes terminal output for a direct helper behavior probe and the targeted Vitest run for the added test file after the assertion fix.
proof: sufficient: Contributor real behavior proof is sufficient. The PR body includes terminal output for a direct helper behavior probe and the targeted Vitest run for the added test file after the assertion fix.

Evidence reviewed

PR surface:

Tests +88. Total +88 across 1 file.

View PR surface stats

Area	Files	Added	Net
Source	0	0	0
Tests	1	88	+88
Docs	0	0	0
Config	0	0	0
Generated	0	0	0
Other	0	0	0
Total	1	88	+88

What I checked:

Root policy read: Read the full root AGENTS.md and found no scoped AGENTS.md for src/shared; the root PR review rules were applied to read beyond the diff and check callers, current behavior, proof, and history. (AGENTS.md:1, 86b9b88f4066)
PR diff: The PR adds only src/shared/utf16-slice.test.ts; the follow-up commit replaces the previously vacuous boundary checks with exact outputs for the main slice/truncate surrogate-boundary cases. (src/shared/utf16-slice.test.ts:38, 143cdba51e62)
Current helper contract: Current main defines sliceUtf16Safe and truncateUtf16Safe as dependency-free helpers that avoid returning dangling surrogate halves at slice or truncation edges. (src/shared/utf16-slice.ts:15, 86b9b88f4066)
Shared surface and callers: The helper is re-exported through src/utils.ts and used by shared formatting, agents, gateway, cron, plugin SDK, and multiple plugin surfaces, so focused regression coverage is useful and not a duplicate of a single caller test. (src/utils.ts:75, 86b9b88f4066)
Adjacent test pattern: Existing adjacent shared-format tests assert exact truncated outputs and no dangling surrogates; the PR's revised exact boundary assertions now follow the important part of that pattern for the core helper. (src/shared/subagents-format.test.ts:43, 86b9b88f4066)
Current main lacks this test: Current main contains src/shared/utf16-slice.ts but no existing src/shared/utf16-slice.test.ts, so the central test coverage is not already implemented on main. (src/shared/utf16-slice.ts:1, 86b9b88f4066)

Likely related people:

llagy009: Current blame and git log -S tie the shared UTF-16 helper implementation to the merged Tlon boundary fix commit. (role: introduced behavior; confidence: high; commits: 6299b679c05f; files: src/shared/utf16-slice.ts, src/utils.ts, src/plugin-sdk/text-utility-runtime.ts)
vincentkoc: Live PR metadata shows this person merged the PR that introduced the shared helper now being tested. (role: merger signal; confidence: medium; commits: 6299b679c05f; files: src/shared/utf16-slice.ts)
zenglingbiao: Recent merged shared UTF-16 truncation work touched adjacent shared formatting and assistant-error paths that use this helper contract. (role: recent adjacent contributor; confidence: medium; files: src/shared/subagents-format.ts, src/shared/subagents-format.test.ts, src/shared/assistant-error-format.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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Replace vague 'result.length >= 0' assertions with exact expected output checks for surrogate pair boundary cases. The helper returns empty string when slicing at surrogate pair boundaries.

… helpers (openclaw#97805) * test(shared): add unit tests for surrogate-safe UTF-16 string slicing helpers Add unit tests for sliceUtf16Safe and truncateUtf16Safe functions in src/shared/utf16-slice.ts to verify UTF-16 string slicing behavior. Tests cover: - sliceUtf16Safe slices ASCII string normally - sliceUtf16Safe handles negative start/end - sliceUtf16Safe handles start/end beyond length - sliceUtf16Safe swaps start and end when start > end - sliceUtf16Safe preserves emoji with surrogate pairs - sliceUtf16Safe avoids splitting surrogate pair at start/end - truncateUtf16Safe returns input when shorter than limit - truncateUtf16Safe truncates when longer than limit - truncateUtf16Safe handles zero/negative limit - truncateUtf16Safe floors decimal limit - truncateUtf16Safe preserves emoji with surrogate pairs - truncateUtf16Safe avoids splitting surrogate pair * fix: replace tautological surrogate assertions with exact output checks Replace vague 'result.length >= 0' assertions with exact expected output checks for surrogate pair boundary cases. The helper returns empty string when slicing at surrogate pair boundaries.

openclaw-barnacle Bot added the size: S label Jun 29, 2026

fix: replace tautological surrogate assertions with exact output checks

143cdba

Replace vague 'result.length >= 0' assertions with exact expected output checks for surrogate pair boundary cases. The helper returns empty string when slicing at surrogate pair boundaries.

vincentkoc merged commit f92ec2d into openclaw:main Jun 29, 2026
112 of 116 checks passed

github-actions Bot mentioned this pull request Jun 29, 2026

📡 Upstream Digest — 2026-06-29 19:45 UTC curtismercier/openclaw-mods#1175

Open

This was referenced Jun 30, 2026

fix(qqbot): drop dangling surrogates in gateway onMessageSent TTS preview #98211

Closed

fix(ios): preserve single newlines as visible line breaks in chat #98222

Closed

clawsweeper Bot mentioned this pull request Jul 11, 2026

fix(browser): keep Chrome stderr hint tail UTF-16 safe #104603

Merged

OpenClawKobian99 mentioned this pull request Jul 14, 2026

[Bug]: memory-core dreaming narrative fails with "no low surrogate in string" API 400 — clampDiaryContextEntry truncates mid-surrogate-pair (fix on main, missing from v2026.7.1) #107815

Closed

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test(shared): add unit tests for surrogate-safe UTF-16 string slicing helpers#97805

test(shared): add unit tests for surrogate-safe UTF-16 string slicing helpers#97805
vincentkoc merged 2 commits into
openclaw:mainfrom
dwc1997:fix/utf16-slice-tests

dwc1997 commented Jun 29, 2026

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clawsweeper Bot commented Jun 29, 2026 •

edited

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dwc1997 commented Jun 29, 2026

What Problem This Solves

Why This Change Was Made

User Impact

Evidence

AI-assisted

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clawsweeper Bot commented Jun 29, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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clawsweeper Bot commented Jun 29, 2026 •

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