fix(ci): the invisible-character gate never matched anything - #34
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MEASURED 2026-08-27: this gate's pattern 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
characters, U+00C2 then U+00A0, which is never present.
grep -P '\xc2\xa0' -> miss
grep -P '\x{a0}' -> MATCH
Only \x00 worked, being single-byte in both readings.
FIXED: codepoint escapes; C0 control characters \x01-\x08,\x0B,\x0C,\x0E-\x1F
added (TAB/LF/CR excluded); and grep -a, without which 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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📝 WalkthroughSummary by CodeRabbit
WalkthroughThe workflow updates invisible-character detection to use Unicode code-point escapes, adds C0 controls and the word joiner, and scans binary files with ChangesInvisible-character gate
Estimated code review effort: 2 (Simple) | ~10 minutes Merge Risk: ⚪ Minimal · up to This PR corrects the workflow’s invisible-character matching and expands detection coverage; no actionable merge-blocking risk remains beyond normal checks and review. Poem
🚥 Pre-merge checks | ✅ 4 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (4 passed)
Full details: Linked Issues checkExplanation The changes satisfy the codepoint escape, C0 control, and grep -a requirements for the inline CI gate. The linked issue also requires a separate leading-BOM check and alignment with the compiled linter, but this PR shows no such changes. Full details: Docstring CoverageExplanation 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.)
✨ Finishing Touches 💡 1🛠️ Fix failing CI checks 💡
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Up to standards ✅🟢 Issues
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Pull Request Overview
The PR fixes the invisible-character gate in the CI pipeline, which was previously ineffective. By transitioning to Unicode codepoint escapes and utilizing the -a flag for binary/NUL byte handling, the detection logic now correctly identifies NBSP, C0 control codes, and other hidden characters. Codacy analysis indicates the changes are up to standards.
While the logic improvements are sound, there is a notable gap in automated verification; no dummy files containing these characters were added to ensure the gate remains functional in the future. Additionally, an optimization is recommended for the find command to reduce process overhead during scans.
About this PR
- The PR description mentions manual verification, but the repository lacks automated test fixtures (e.g., sample files containing invisible characters) to verify this CI gate. Adding such fixtures would prevent future regressions where the gate might become silent again.
Test suggestions
- Detect NBSP (U+00A0) in a source file
- Detect C0 control characters (e.g., Backspace \x08) in a source file
- Detect NUL bytes (\x00) and ensure the file is not skipped by grep
- Detect Zero-Width Joiners (U+200D)
Prompt proposal for missing tests
Consider implementing these tests if applicable:
1. Detect NBSP (U+00A0) in a source file
2. Detect C0 control characters (e.g., Backspace \x08) in a source file
3. Detect NUL bytes (\x00) and ensure the file is not skipped by grep
4. Detect Zero-Width Joiners (U+200D)
TIP Improve review quality by adding custom instructions
TIP How was this review? Give us feedback
| -o -name '*.idr' -o -name '*.zig' -o -name '*.v' -o -name '*.jl' \ | ||
| -o -name '*.gleam' -o -name '*.hs' -o -name '*.ml' -o -name '*.sh' \) \ | ||
| -exec grep -Prl "$PATTERNS" {} \; > /tmp/empty-lint-results.txt 2>/dev/null | ||
| -exec grep -aPrl "$PATTERNS" {} \; > /tmp/empty-lint-results.txt 2>/dev/null |
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🟡 MEDIUM RISK
Suggestion: The -r flag is redundant here as find already provides the file paths. Using + instead of \; will significantly improve performance by batching many files into a single grep invocation.
| -exec grep -aPrl "$PATTERNS" {} \; > /tmp/empty-lint-results.txt 2>/dev/null | |
| -exec grep -aPl "$PATTERNS" {} + > /tmp/empty-lint-results.txt 2>/dev/null |
1 participant
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) whilegrep -Pmatches characters. Bytesc2 a0are one character U+00A0;\xc2\xa0asks for two, U+00C2 then U+00A0 — never present.Only
\x00worked, being single-byte in both readings. The gate ran, passed, and could not see what it exists to see.Fixed
\x01-\x08,\x0B,\x0C,\x0E-\x1Fadded (TAB/LF/CR excluded)grep -a— without it grep skips any NUL-bearing file as binaryThe 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.