ceremony/lib/facts.sh

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#!/usr/bin/env bash
# lib/facts.sh — the merge door's fact gathering (issue #9).
#
# lib/decide.sh (issue #8) is pure: it consumes four facts and renders the
# 5-state verdict. This script is the impure half that establishes those
# facts. It runs inside the consumer's checkout (the working directory),
# talks to git and gh, and prints the facts in $GITHUB_OUTPUT form:
#
# ver=… base_ver=… released=(yes|no|empty) labeled=(yes|no|empty)
#
# stdout carries exclusively those lines — the release workflow appends the
# whole stream to $GITHUB_OUTPUT — so every diagnostic goes to stderr.
#
# Env in:
# VERSION_SOURCE file | package-json (the workflow's one input)
# MERGE_SHA the pushed head (github.sha)
# EVENT_BEFORE github.event.before — may be empty or all-zeros
# GITHUB_REPOSITORY for the two API facts
# GH_TOKEN for gh (unused when no API state is consulted)
#
# The API calls run only in the states that consult them (decide tolerates
# empty facts — issue #8): RELEASED only for a bare unchanged version,
# LABELED only for a bare transition. A -dev tree — every ordinary merge —
# decides on the two versions alone and never touches the API.
set -euo pipefail
# shellcheck source=lib/version.sh
. "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)/version.sh"
: "${VERSION_SOURCE:?facts: VERSION_SOURCE is required}"
: "${MERGE_SHA:?facts: MERGE_SHA is required}"
case "$VERSION_SOURCE" in
file) src=VERSION ;;
package-json) src=package.json ;;
*)
echo "facts: unknown VERSION_SOURCE '$VERSION_SOURCE' — expected file or package-json" >&2
exit 1
;;
esac
ver="$(version_read "$VERSION_SOURCE")"
# event.before is all-zeros on a branch-create push, and absent outside push
# events; the pushed head's first parent is main the instant before, either
# way (#1 constraint 10; cast's `*[!0]*` test — "contains a non-zero char").
base_sha="${EVENT_BEFORE:-}"
case "$base_sha" in
*[!0]*) ;;
*) base_sha="$(git rev-parse "$MERGE_SHA^1")" ;;
esac
# Belt-and-braces (cast's precedent): the workflow's fetch-depth: 2 resolves
# the first parent, but event.before can predate it when pushes raced. If
# the fetch still cannot produce it, the git show below is the loud failure.
git cat-file -e "$base_sha" 2>/dev/null \
|| git fetch --depth=1 origin "$base_sha" >&2 \
|| true
base_dir="$(mktemp -d)"
trap 'rm -rf "$base_dir"' EXIT
if git show "$base_sha:$src" >"$base_dir/$src" 2>/dev/null; then
base_ver="$(version_read "$VERSION_SOURCE" "$base_dir")"
else
# The base tree has no version source at all: the merge that ADDS the
# version machinery (a consumer's adoption PR, a greenfield repo's first
# caller). "(none)" is not a version, so decide sees a changed version
# and the table still governs: a -dev head is work (row 2, the guided
# bootstrap path), a bare head still demands the merged release label
# (rows 56). Nothing releases silently either way.
base_ver="(none)"
fi
released=""
labeled=""
if ! version_is_dev "$ver"; then
if [ "$base_ver" = "$ver" ]; then
# Any gh failure reads as "not released" — the sources' semantics; the
# verdict this feeds (row 4) is a refusal, and the ceremony path
# re-checks existence in the nothing-exists assert before creating
# anything.
if gh release view "$ver" -R "$GITHUB_REPOSITORY" --json name >/dev/null 2>&1; then
released=yes
else
released=no
fi
else
# The sources' exact jq: merged PRs only, `release` among the label
# names. Read via the API because a push event carries no PR payload —
# and the PR itself lives on a fork (the trigger comment in the
# workflow). A failed API call reads as "no label", which row 5
# refuses: fail-closed.
if gh api "repos/$GITHUB_REPOSITORY/commits/$MERGE_SHA/pulls" \
-q '[.[] | select(.merged_at != null) | .labels[].name] | index("release") != null' \
| grep -qx true; then
labeled=yes
else
labeled=no
fi
fi
fi
echo "facts: ver='$ver' base_ver='$base_ver' released='$released' labeled='$labeled'" >&2
printf 'ver=%s\n' "$ver"
printf 'base_ver=%s\n' "$base_ver"
printf 'released=%s\n' "$released"
printf 'labeled=%s\n' "$labeled"