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Update README.md

Update README.md #61

name: Check changed Nix files with nixf-tidy (experimental)
on:
pull_request_target:
types: [opened, synchronize, reopened, edited]
permissions:
contents: read
jobs:
nixos:
name: exp-nixf-tidy-check
runs-on: ubuntu-latest
if: "!contains(github.event.pull_request.title, '[skip treewide]')"
steps:
- uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
with:
# pull_request_target checks out the base branch by default
ref: refs/pull/${{ github.event.pull_request.number }}/merge
# Fetches the merge commit and its parents
fetch-depth: 2
- name: Checking out base branch
run: |
base=$(mktemp -d)
baseRev=$(git rev-parse HEAD^1)
git worktree add "$base" "$baseRev"
echo "baseRev=$baseRev" >> "$GITHUB_ENV"
echo "base=$base" >> "$GITHUB_ENV"
- name: Get Nixpkgs revision for nixf
run: |
# pin to a commit from nixpkgs-unstable to avoid e.g. building nixf
# from staging
# This should not be a URL, because it would allow PRs to run arbitrary code in CI!
rev=$(jq -r .rev ci/pinned-nixpkgs.json)
echo "url=https://github.com/NixOS/nixpkgs/archive/$rev.tar.gz" >> "$GITHUB_ENV"
- uses: cachix/install-nix-action@08dcb3a5e62fa31e2da3d490afc4176ef55ecd72 # v30
with:
# explicitly enable sandbox
extra_nix_config: sandbox = true
nix_path: nixpkgs=${{ env.url }}
- name: Install nixf and jq
# provided jq is incompatible with our expression
run: "nix-env -f '<nixpkgs>' -iAP nixf jq"
- name: Check that Nix files pass nixf-tidy
run: |
# Filtering error messages we don't like
nixf_wrapper(){
nixf-tidy --variable-lookup < "$1" | jq -r '
[
"sema-escaping-with"
]
as $ignored_errors|[.[]|select(.sname as $s|$ignored_errors|index($s)|not)]
'
}
failedFiles=()
# Don't report errors to file overview
# to avoid duplicates when editing title and description
if [[ "${{ github.event.action }}" == 'edited' ]] && [[ -z "${{ github.event.edited.changes.base }}" ]]; then
DONT_REPORT_ERROR=1
else
DONT_REPORT_ERROR=
fi
# TODO: Make this more parallel
# Loop through all Nix files touched by the PR
while readarray -d '' -n 2 entry && (( ${#entry[@]} != 0 )); do
type=${entry[0]}
file=${entry[1]}
case $type in
A*)
source=""
dest=$file
;;
M*)
source=$file
dest=$file
;;
C*|R*)
source=$file
read -r -d '' dest
;;
*)
echo "Ignoring file $file with type $type"
continue
esac
if [[ -n "$source" ]] && [[ "$(nixf_wrapper ${{ env.base }}/"$source")" != '[]' ]] 2>/dev/null; then
echo "Ignoring file $file because it doesn't pass nixf-tidy in the base commit"
echo # insert blank line
else
nixf_report="$(nixf_wrapper "$dest")"
if [[ "$nixf_report" != '[]' ]]; then
echo "$dest doesn't pass nixf-tidy. Reported by nixf-tidy:"
errors=$(echo "$nixf_report" | jq -r --arg dest "$dest" '
def getLCur: "line=" + (.line+1|tostring) + ",col=" + (.column|tostring);
def getRCur: "endLine=" + (.line+1|tostring) + ",endColumn=" + (.column|tostring);
def getRange: "file=\($dest)," + (.lCur|getLCur) + "," + (.rCur|getRCur);
def getBody: . as $top|(.range|getRange) + ",title="+ .sname + "::" +
(.message|sub("{}" ; ($top.args.[]|tostring)));
def getNote: "\n::notice " + (.|getBody);
def getMessage: "::error " + (.|getBody) + (if (.notes|length)>0 then
([.notes.[]|getNote]|add) else "" end);
.[]|getMessage
')
if [[ -z "$DONT_REPORT_ERROR" ]]; then
echo "$errors"
else
# just print in plain text
echo "${errors/::/}"
echo # add one empty line
fi
failedFiles+=("$dest")
fi
fi
done < <(git diff -z --name-status ${{ env.baseRev }} -- '*.nix')
if [[ -n "$DONT_REPORT_ERROR" ]]; then
echo "Edited the PR but didn't change the base branch, only the description/title."
echo "Not reporting errors again to avoid duplication."
echo # add one empty line
fi
if (( "${#failedFiles[@]}" > 0 )); then
echo "Some new/changed Nix files don't pass nixf-tidy."
echo "See ${{ github.event.pull_request.html_url }}/files for reported errors."
echo "If you believe this is a false positive, ping @Aleksanaa and @inclyc in this PR."
exit 1
fi