fix(ci): the invisible-character gate never matched anything

[hyperpolymath]

Measured 2026-08-27: this gate caught 0 of 6 invisible-character test cases. It has never detected an NBSP, zero-width space, BOM, soft hyphen, bidi override or word joiner.

Root cause

The pattern used UTF-8 byte sequences (\xc2\xa0) while grep -P matches characters. Bytes c2 a0 are one character U+00A0; \xc2\xa0 asks for two, U+00C2 then U+00A0 — never present.

grep -P '\xc2\xa0'  ->  miss
grep -P '\x{a0}'    ->  MATCH

Only \x00 worked, being single-byte in both readings. The gate ran, passed, and could not see what it exists to see.

Fixed

• codepoint escapes in place of byte sequences
• C0 controls \x01-\x08,\x0B,\x0C,\x0E-\x1F added (TAB/LF/CR excluded)
• grep -a — without it grep skips any NUL-bearing file as binary

The C0 range matters: a stray backspace byte made a workflow unparseable in developer-ecosystem, so it never ran — and this linter called it clean.

Canonical fix: hyperpolymath/empty-linter#70. 1 file(s) here.

Verified: YAML re-parsed, and the corrected pattern was confirmed to catch a real NBSP before the change was kept.

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro Plus

Run ID: 1509d69a-8cf5-42d8-b2fe-d08b6054bbf6

📥 Commits

Reviewing files that changed from the base of the PR and between 9343e19 and 9c51c76.

📒 Files selected for processing (1)

• .github/workflows/dogfood-gate.yml

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

📜 Recent review details

🔇 Additional comments (2)

.github/workflows/dogfood-gate.yml (2)

145-145: LGTM!

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134-134: 🎯 Functional Correctness

No separate leading-BOM check is needed.

GNU grep 3.11 does not strip a UTF-8 BOM before -P matching. In a UTF-8 locale, \x{feff} matches the BOM as U+FEFF, so the existing pattern detects it.

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📝 Walkthrough

Summary by CodeRabbit

• Bug Fixes
  • Improved detection of invisible characters during automated validation.
  • Improved handling of text files containing non-standard or Unicode characters.

Walkthrough

The workflow updates invisible-character detection. It uses Unicode code-point escapes, adds ASCII control-character coverage, and runs grep in text mode.

Changes

Invisible-character gate

Layer / File(s)	Summary
Update invisible-character scanning .github/workflows/dogfood-gate.yml	The pattern uses Unicode code-point escapes and covers additional ASCII control characters. The grep command uses -a to treat files as text.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to 9c51c

This localized workflow change corrects invisible-character detection and adds handling for relevant control characters and binary files. No actionable merge-blocking risk remains after normal checks and review.

Poem

A rabbit checks the hidden signs,
Where quiet bytes cross workflow lines.
Code points glow in careful rows,
Text mode helps the scanner know.
The gate now spots what darkness throws.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Linked Issues check	⚠️ Warning	The workflow change addresses codepoint escapes, C0 control detection, and grep -a. The provided changes do not show the required separate leading-BOM check or alignment with the compiled linter and i…	Add the separate leading-BOM check and update the compiled linter and config with the same C0-control behaviour. Verify that the CI gate and compiled linter remain aligned, then document the verification results.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly states the main change: fixing the CI gate that failed to detect invisible characters.
Description check	✅ Passed	The description explains the root cause, the implemented changes, and the verification performed. It does not reproduce every template heading or checklist item, but it provides the required technical…
Out of Scope Changes check	✅ Passed	The changes are limited to the CI invisible-character gate and relate directly to issue #70. No unrelated code changes are shown.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…

Full details: Description check

Explanation

The description explains the root cause, the implemented changes, and the verification performed. It does not reproduce every template heading or checklist item, but it provides the required technical context.

Full details: Linked Issues check

Explanation

The workflow change addresses codepoint escapes, C0 control detection, and grep -a. The provided changes do not show the required separate leading-BOM check or alignment with the compiled linter and its configuration.

Full details: Docstring Coverage

Explanation

No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0 files. (1 skipped: 1 unsupported.)

• Fix all pre-merge checks with AI

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[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

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