open-standards/scripts/pr-touches-paths-selftest.sh

#!/usr/bin/env bash
# Self-test for pr-touches-paths.py, run by the workflow-hygiene job.
#
# A gate that decides whether tests run is itself load-bearing: a wrong `false`
# silently skips a whole workflow. These cases pin both directions and, most
# importantly, that every way of failing fails OPEN.
set -euo pipefail
cd "$(dirname "$0")/.."
G=scripts/pr-touches-paths.py
tmp=$(mktemp -d); trap 'rm -rf "$tmp"' EXIT
fail=0
check() { # name expected actual
  if [ "$2" = "$3" ]; then printf '  ok    %s\n' "$1"
  else printf '  FAIL  %s: expected %s, got %s\n' "$1" "$2" "$3"; fail=1; fi
}

# A throwaway repo, so the diffs are real git diffs and not a mock.
repo="$tmp/r"; mkdir -p "$repo/wai/wai-pack" "$repo/jcp"
git -C "$repo" init -q
git -C "$repo" config user.email t@e; git -C "$repo" config user.name t
echo x > "$repo/jcp/SPEC.md"; echo y > "$repo/wai/wai-pack/lib.rs"
git -C "$repo" add -A; git -C "$repo" commit -qm base
BASE=$(git -C "$repo" rev-parse HEAD)
echo changed > "$repo/jcp/SPEC.md"
git -C "$repo" add -A; git -C "$repo" commit -qm jcp-only
JCP=$(git -C "$repo" rev-parse HEAD)
echo changed > "$repo/wai/wai-pack/lib.rs"
git -C "$repo" add -A; git -C "$repo" commit -qm wai-too
WAI=$(git -C "$repo" rev-parse HEAD)

wf="$tmp/w.yml"
cat > "$wf" <<'Y'
on:
  pull_request:
    paths:
      - 'wai/wai-pack/**'
Y

run() { ( cd "$repo" && python3 "$OLDPWD/$G" "$1" "$2" "$3" ); }
check "a jcp-only diff does not touch a wai filter" false "$(run "$wf" "$BASE" "$JCP")"
check "a diff that touches the filter runs"          true  "$(run "$wf" "$BASE" "$WAI")"

# Every failure mode must fail OPEN.
check "a missing workflow file"      true "$(run "$tmp/nope.yml" "$BASE" "$JCP")"
check "a workflow with no filter"    true "$(printf 'on:\n  pull_request:\n' > "$tmp/nofilter.yml"; run "$tmp/nofilter.yml" "$BASE" "$JCP")"
check "an empty base sha"            true "$(run "$wf" "" "$JCP")"
check "a sha git cannot resolve"     true "$(run "$wf" "$BASE" deadbeefdeadbeefdeadbeefdeadbeefdeadbeef)"
check "too few arguments"            true "$( cd "$repo" && python3 "$OLDPWD/$G" "$wf" )"
check "an empty diff"                true "$(run "$wf" "$JCP" "$JCP")"

# `**` spans separators; `*` does not.
cat > "$tmp/star.yml" <<'Y'
on:
  pull_request:
    paths:
      - 'jcp/*.md'
Y
# Only the NESTED file changes, so `jcp/*.md` must not match it. (A top-level
# .md in the same commit would match legitimately and prove nothing — which is
# how this case failed the first time it was written.)
mkdir -p "$repo/jcp/sub"; echo z > "$repo/jcp/sub/x.md"
git -C "$repo" add -A >/dev/null; git -C "$repo" commit -qm sub >/dev/null
SUB=$(git -C "$repo" rev-parse HEAD)
check "a single star does not span a separator" false "$(run "$tmp/star.yml" "$WAI" "$SUB")"
# And it does match a file at that level, so the glob is not simply never matching.
echo z > "$repo/jcp/top.md"
git -C "$repo" add -A >/dev/null; git -C "$repo" commit -qm top >/dev/null
check "a single star matches at its own level" true "$(run "$tmp/star.yml" "$SUB" "$(git -C "$repo" rev-parse HEAD)")"

# A comment or a blank line inside a list does not end it, and a trailing comment is not
# part of a glob. (Lists with a comment used to be read only up to it, so a pull request
# touching a path after the comment was answered `false` and its tests skipped.)
cat > "$tmp/commented.yml" <<'Y'
on:
  pull_request:
    paths:
      - 'jcp/nothing-here/**'
      # a comment between entries

      - 'wai/wai-pack/**'   # and one after an entry
Y
check "a path listed after a comment and a blank line" true "$(run "$tmp/commented.yml" "$BASE" "$WAI")"
check "and the list still says false for a diff outside it" false "$(run "$tmp/commented.yml" "$BASE" "$JCP")"

# --paths-from and --wide: the files of a directory bring their own paths, and the wide glob
# the forge filters on stands for them alone. A step's file (`# paths:` in its header) names
# one extension text; a change to it runs the workflow, and a change to an extension text no
# file names does not, though the forge's wide glob matches both.
mkdir -p "$repo/wai/extensions" "$repo/steps"
echo a > "$repo/wai/extensions/owned.md"; echo b > "$repo/wai/extensions/other.md"
printf '# step: one\n# order: 10\n# paths: wai/extensions/owned.md\n#\n# prose: not a header\necho ok\n' > "$repo/steps/one.sh"
printf '# step: two\n# paths: wai/extensions/second/**\necho ok\n# paths: wai/extensions/other.md\n' > "$repo/steps/two.sh"
git -C "$repo" add -A >/dev/null; git -C "$repo" commit -qm steps >/dev/null
S0=$(git -C "$repo" rev-parse HEAD)
echo changed > "$repo/wai/extensions/owned.md"; git -C "$repo" commit -qam owned >/dev/null; OWN=$(git -C "$repo" rev-parse HEAD)
echo changed > "$repo/wai/extensions/other.md"; git -C "$repo" commit -qam other >/dev/null; OTH=$(git -C "$repo" rev-parse HEAD)
mkdir -p "$repo/wai/extensions/second"; echo c > "$repo/wai/extensions/second/x.md"
git -C "$repo" add -A >/dev/null; git -C "$repo" commit -qm second >/dev/null; SEC=$(git -C "$repo" rev-parse HEAD)
cat > "$tmp/wide.yml" <<'Y'
on:
  pull_request:
    paths:
      - 'wai/wai-pack/**'
      - 'wai/extensions/**'
Y
wide() { ( cd "$repo" && python3 "$OLDPWD/$G" "$tmp/wide.yml" "$1" "$2" --paths-from steps --wide 'wai/extensions/**' ); }
check "a path a step's file names runs the workflow"                 true  "$(wide "$S0" "$OWN")"
check "an extension text no file names does not, under the wide glob" false "$(wide "$OWN" "$OTH")"
check "a glob a file names matches below it"                           true  "$(wide "$OTH" "$SEC")"
check "the workflow's own globs still count"                           true  "$(wide "$BASE" "$WAI")"
check "without the flags the wide glob matches everything under it"    true  "$( cd "$repo" && python3 "$OLDPWD/$G" "$tmp/wide.yml" "$OWN" "$OTH" )"
check "a header line after the header is not read"                     false "$(printf '# step: two\necho ok\n# paths: wai/extensions/other.md\n' > "$repo/steps/two.sh"; wide "$OWN" "$OTH")"
# Every way of misreading them fails OPEN.
check "a --paths-from directory that does not exist"  true "$( cd "$repo" && python3 "$OLDPWD/$G" "$tmp/wide.yml" "$OWN" "$OTH" --paths-from nowhere --wide 'wai/extensions/**' )"
check "a --wide glob the workflow does not list"      true "$( cd "$repo" && python3 "$OLDPWD/$G" "$tmp/wide.yml" "$OWN" "$OTH" --paths-from steps --wide 'wai/nothing/**' )"
check "a --wide glob with no --paths-from"            true "$( cd "$repo" && python3 "$OLDPWD/$G" "$tmp/wide.yml" "$OWN" "$OTH" --wide 'wai/extensions/**' )"
check "an argument the script does not read"          true "$( cd "$repo" && python3 "$OLDPWD/$G" "$tmp/wide.yml" "$OWN" "$OTH" --what x )"

[ "$fail" = 0 ] && echo "pr-touches-paths self-test: all cases pass" || { echo "pr-touches-paths self-test FAILED"; exit 1; }