FENCE-2852: Make .swiftlint-baseline.json diffs readable via git clean filter#614
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SwiftLint writes the baseline as one minified line, so every change to it shows up as a single unreadable git diff line. SwiftLint only ever reads the file (via --baseline) with a JSON decoder, so formatting is irrelevant to it. Add a git clean filter that pretty-prints the baseline with `jq -S .` on stage, so git always stores and diffs a readable, sorted-key version regardless of how SwiftLint wrote the working copy. A regeneration that changes no violations now produces no diff at all. - .gitattributes: bind the baseline to a swiftlint-baseline filter - bootstrap.sh: install jq and configure the (non-required) clean filter - AGENTS.md: document the filter and the `make bootstrap` requirement - .swiftlint-baseline.json: one-time reformat (pretty, sorted keys) Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
stevepopovich
changed the title
alanjcharles14
approved these changes
Jun 4, 2026
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Problem
Every change to
.swiftlint-baseline.jsonshows up in git as one giant unreadable line, because SwiftLint serializes the baseline as minified single-line JSON. The file is only ever read (via--baselineinmake lint-swift,make lint-swift-fix, and CI), and SwiftLint parses it with a JSON decoder — so whitespace is irrelevant to SwiftLint and a pretty-printed file is accepted identically.A one-time reformat wouldn't survive the next
swiftlint --write-baselineregeneration, which would revert it to one line.Is this worth the merge?
Fix
Add a git clean filter that pretty-prints the baseline with
jq -S .(sorted keys → deterministic) whenever it's staged. Git always stores and diffs a readable version regardless of how SwiftLint wrote the working copy. As a bonus, a regeneration that changes no violations produces no diff at all (git runs both sides through the clean filter before comparing)..gitattributes— bind.swiftlint-baseline.jsonto aswiftlint-baselinefilterbootstrap.sh— installjqand configure the clean filter (clean-only, non-requiredso an unconfigured clone gracefully falls back to today's behavior)AGENTS.md(CLAUDE.mdsymlinks to it) — document the filter and themake bootstraprequirement.swiftlint-baseline.json— one-time reformat (pretty, sorted keys)Notes
make bootstraponce, just installsjqon the user's machine. Until then they fall back to the current one-line behavior — no errors.