ceremony/lib/forge-forgejo.sh

#!/usr/bin/env bash
# lib/forge-forgejo.sh — the Forgejo backend: /api/v1 over curl + jq
# (issue #188, term 1). Sourced by lib/forge.sh when forge_detect says
# forgejo; never sourced directly, and never at the same time as the github
# backend — they define the same verbs on purpose.
#
# curl+jq rather than a CLI because that is what the runner has. The image
# this instance runs jobs in (ghcr.io/catthehacker/ubuntu:act-22.04, probe
# task 278) carries curl, jq and node, and has neither `gh` nor `stoke`.

# forgejo_api_base — the /api/v1 root, from the runner's own environment.
# GITHUB_API_URL already IS the /api/v1 root on a Forgejo runner (measured:
# https://forgejo.heavyduty.builders/api/v1). CEREMONY_FORGE_API overrides
# it for tests and for anyone driving this outside Actions.
forgejo_api_base() {
  local base="${CEREMONY_FORGE_API:-${GITHUB_API_URL:-}}"
  if [ -z "$base" ]; then
    echo "forgejo_api_base: no GITHUB_API_URL or CEREMONY_FORGE_API — cannot reach the forge (#188)" >&2
    return 1
  fi
  printf '%s\n' "${base%/}"
}

# forgejo_page_url <endpoint> <page> — pure, so the page-size contract is
# testable without a network. Returns the endpoint with this backend's OWN
# paging parameters applied.
#
# THE TRAP THIS EXISTS TO REMOVE, measured 2026-08-02 against
# heavy-duty/rig (137 issues and PRs) and heavy-duty/ceremony on GitHub:
#
#   ?per_page=100   GitHub: 100 items      Forgejo: 30 items  (IGNORED)
#   ?limit=100      GitHub:  30 items      Forgejo: 50 items  (capped)
#
# Each forge silently ignores the other's page-size parameter, answers
# HTTP 200 with valid JSON, and says nothing. Every call site in this repo
# was written GitHub-shaped, so a verbatim port would have swept 30 of
# rig's 137 and printed "reconciled." — acceptance criterion 2 failing
# green, and the same "degraded read that does not report it degraded"
# failure class this whole issue exists to kill.
#
# So NO CALL SITE NAMES A PAGE SIZE. The backend owns it. Fixing the
# boundary once beats fixing nine call sites and trusting the tenth — the
# same argument that chose shape C over B, one level down.
#
# 50 is not a preference: Forgejo caps a page at MAX_RESPONSE_ITEMS (50 on
# this instance) whatever you ask for, so asking for more cannot help and
# pagination is mandatory rather than an optimisation.
forgejo_page_url() {
  local endpoint="${1:?forgejo_page_url: endpoint required}" page="${2:?forgejo_page_url: page required}"
  # Strip any page-size parameter a caller left behind, in either dialect,
  # rather than trusting that none did: this function is the one place that
  # decides paging, and a stray per_page= would be exactly the silent
  # truncation above.
  local clean="$endpoint"
  clean="$(printf '%s' "$clean" | sed -E 's/([?&])(per_page|limit|page)=[0-9]+/\1/g; s/[?&]+$//; s/([?&])&+/\1/g')"
  case "$clean" in
    *\?) printf '%slimit=50&page=%s\n' "$clean" "$page" ;;
    *\?*) printf '%s&limit=50&page=%s\n' "$clean" "$page" ;;
    *) printf '%s?limit=50&page=%s\n' "$clean" "$page" ;;
  esac
}

# forge_api [--paginate] <endpoint> [--jq <expr>]
#
# --paginate walks page= until a short page, then PROVES the walk was
# complete by comparing what it collected against the server's declared
# x-total-count. @kimi-reviewer-andresmgsl's hardening (#4699): a MISSING
# header is a loud refusal, not a pass. Header exposure is a server setting
# (access-control-expose-headers), and an instance that withholds it would
# make the completeness check compare null to a number — the guard itself
# degrading silently, which is the failure class re-entering through the
# door built to stop it.
forge_api() {
  local paginate=false endpoint="" jqexpr="" have_jq=false
  while [ $# -gt 0 ]; do
    case "$1" in
      --paginate) paginate=true ;;
      --jq) jqexpr="$2"; have_jq=true; shift ;;
      -*) ;;
      *) [ -n "$endpoint" ] || endpoint="$1" ;;
    esac
    shift
  done
  [ -n "$endpoint" ] || { echo "forge_api: endpoint required" >&2; return 1; }

  local base token
  base="$(forgejo_api_base)" || return 1
  token="${GH_TOKEN:-${GITHUB_TOKEN:-${FORGEJO_TOKEN:-}}}"

  local hdr body
  hdr="$(mktemp)"; body="$(mktemp)"
  # shellcheck disable=SC2064 # the paths are fixed at trap time on purpose
  trap "rm -f '$hdr' '$body'" RETURN

  if [ "$paginate" = false ]; then
    if ! curl -sS -D "$hdr" -o "$body" \
      -H "Authorization: token $token" -H 'Accept: application/json' \
      "$base/$endpoint"; then
      echo "forge_api: request failed: $endpoint" >&2
      return 1
    fi
    forgejo_http_ok "$hdr" "$endpoint" || return 1
    if [ "$have_jq" = true ]; then jq -r "$jqexpr" <"$body"; else cat "$body"; fi
    return 0
  fi

  # Paginated: accumulate into ONE array and apply --jq once at the end.
  # gh --paginate applies --jq per page and concatenates; for the `.[] | …`
  # shapes every call site here uses, the two are identical, and merging
  # first is what makes the completeness assert possible at all.
  local page=1 total="" got=0 n all="[]" pagejson
  while :; do
    if ! curl -sS -D "$hdr" -o "$body" \
      -H "Authorization: token $token" -H 'Accept: application/json' \
      "$base/$(forgejo_page_url "$endpoint" "$page")"; then
      echo "forge_api: request failed: $endpoint (page $page)" >&2
      return 1
    fi
    forgejo_http_ok "$hdr" "$endpoint" || return 1

    # Re-read on EVERY page, not once (#4712). A board that changes size
    # under the walk was invisible: page 1 declaring 4 and page 2 declaring
    # 9 stopped at 4 believing itself whole. A moving total means the read
    # cannot have been atomic, so it is refused rather than reconciled.
    local page_total
    page_total="$(forgejo_total_count "$hdr")" || return 1
    if [ -z "$total" ]; then
      total="$page_total"
    elif [ "$page_total" != "$total" ]; then
      cat >&2 <<EOF
forge_api: the declared total for '$endpoint' changed between pages — $total then $page_total (#188).
  The collection moved under the walk, so no page set can be proven whole.
  Refusing rather than reconciling a board that is already out of date.
EOF
      return 1
    fi

    pagejson="$(cat "$body")"
    # A 200 whose body is not a collection counted as zero items (#4712),
    # so an error object or a scalar arriving where a list belongs read as
    # a complete EMPTY collection whenever the declared total was 0.
    if [ "$(jq -r 'type' <<<"$pagejson" 2>/dev/null)" != array ]; then
      cat >&2 <<EOF
forge_api: '$endpoint' did not return a collection (#188).
  Expected a JSON array; got: $(head -c 200 <<<"$pagejson")
  Refusing: a body this shim cannot count must not be counted as empty.
EOF
      return 1
    fi
    n="$(jq 'length' <<<"$pagejson")"
    [ "$n" -gt 0 ] || break
    all="$(jq -s '.[0] + .[1]' <<<"$all"$'\n'"$pagejson")"
    got=$((got + n))
    [ "$got" -lt "$total" ] || break
    page=$((page + 1))
  done

  # The assert. A short read here is the silent-truncation bug arriving by
  # another route, so it is fatal rather than a warning.
  if [ "$got" -ne "$total" ]; then
    cat >&2 <<EOF
forge_api: incomplete gather for '$endpoint' — collected $got of $total declared (#188).
  Refusing rather than reconciling a partial board: a sweep over part of the
  queue that reports success is the failure this shim exists to prevent.
EOF
    return 1
  fi

  if [ "$have_jq" = true ]; then jq -r "$jqexpr" <<<"$all"; else printf '%s\n' "$all"; fi
}

# forgejo_total_count <header-file> — the declared size of the collection.
# Absent is fatal (#4699): without it the completeness assert cannot run,
# and an assert that cannot run must not silently pass.
forgejo_total_count() {
  local hdr="$1" total
  total="$(tr -d '\r' <"$hdr" | awk 'tolower($1) == "x-total-count:" { print $2 }' | tail -n1)"
  if [ -z "$total" ]; then
    cat >&2 <<EOF
forge_api: this forge did not send x-total-count — cannot prove the gather is complete (#188).
  The header is exposed by a server setting (access-control-expose-headers).
  Refusing: an unprovable read must not be reported as a whole one.
EOF
    return 1
  fi
  # Validate before it reaches arithmetic (#4712). `X-Total-Count:
  # not-a-number` used to sail through and become the bound the walk was
  # compared against — a guard whose own input was never checked.
  case "$total" in
    '' | *[!0-9]*)
      cat >&2 <<EOF
forge_api: x-total-count is not a non-negative integer: '$total' (#188).
  Refusing: the completeness bound must be a number, or the assert that
  uses it proves nothing.
EOF
      return 1
      ;;
  esac
  printf '%s\n' "$total"
}

# forgejo_http_ok <header-file> <endpoint> — a non-2xx is named, not
# swallowed. gh exits non-zero on HTTP failure; curl does not without -f,
# and -f would throw away the body that says why.
forgejo_http_ok() {
  local hdr="$1" endpoint="$2" code
  code="$(tr -d '\r' <"$hdr" | awk '/^HTTP\// { c = $2 } END { print c }')"
  case "$code" in
    2*) return 0 ;;
    *)
      echo "forge_api: HTTP $code from '$endpoint'" >&2
      return 1
      ;;
  esac
}

# --- the verbs the reconcilers use, over /api/v1 --------------------------
# Three asymmetries with gh, all measured against this instance on
# 2026-08-02 using a scratch repo (never a live board):
#
#   1. Adding labels takes NAMES         POST /issues/{n}/labels {"labels":["x"]}  -> 200
#      Removing one takes a numeric ID   DELETE /issues/{n}/labels/x               -> 422
#                                        DELETE /issues/{n}/labels/149             -> 204
#      So a removal must resolve name -> id first. gh hides this; the shim
#      cannot.
#
#   2. Assignees are SET, not added and removed. PATCH /issues/{n} takes the
#      whole list ({"assignees":[]} clears it, 201), so --remove-assignee is
#      a read-modify-write rather than a delete.
#
#   3. There is no statusCheckRollup. The portable equivalent is the
#      combined commit status, GET /commits/{sha}/status, which returns
#      {state, statuses[]}.

# forgejo_label_ids — name<TAB>id for every label in the repo, read once per
# call site that needs it. Paginated through forge_api, so a repo with more
# than one page of labels cannot silently lose the tail (#188).
forgejo_label_ids() {
  forge_api --paginate "repos/$REPO/labels" --jq '.[] | "\(.name)\t\(.id)"'
}

# forge_issue_edit <n> [--add-label X]… [--remove-label X]… [--add-assignee U]… [--remove-assignee U]…
# gh's flag surface, translated. Accepts comma-separated values, as gh does.
forge_issue_edit() {
  local n="${1:?forge_issue_edit: number required}"
  shift
  local add_labels=() rm_labels=() add_assignees=() rm_assignees=() v
  while [ $# -gt 0 ]; do
    case "$1" in
      --add-label) IFS=, read -ra v <<<"$2"; add_labels+=("${v[@]}"); shift ;;
      --remove-label) IFS=, read -ra v <<<"$2"; rm_labels+=("${v[@]}"); shift ;;
      --add-assignee) IFS=, read -ra v <<<"$2"; add_assignees+=("${v[@]}"); shift ;;
      --remove-assignee) IFS=, read -ra v <<<"$2"; rm_assignees+=("${v[@]}"); shift ;;
      *) ;;
    esac
    shift
  done

  if [ "${#add_labels[@]}" -gt 0 ]; then
    local payload
    payload="$(printf '%s\n' "${add_labels[@]}" | jq -R . | jq -s '{labels: .}')"
    forgejo_write POST "repos/$REPO/issues/$n/labels" "$payload" >/dev/null || return 1
  fi

  if [ "${#rm_labels[@]}" -gt 0 ]; then
    local ids id name
    ids="$(forgejo_label_ids)" || return 1
    for name in "${rm_labels[@]}"; do
      id="$(awk -F '\t' -v want="$name" '$1 == want { print $2; exit }' <<<"$ids")"
      # A label the repo does not have is not an error: the reconcilers call
      # --remove-label unconditionally to converge state, and gh's own
      # behaviour there is a no-op.
      [ -n "$id" ] || continue
      forgejo_write DELETE "repos/$REPO/issues/$n/labels/$id" '' >/dev/null || return 1
    done
  fi

  if [ "${#add_assignees[@]}" -gt 0 ] || [ "${#rm_assignees[@]}" -gt 0 ]; then
    local current want payload
    current="$(forge_api "repos/$REPO/issues/$n" --jq '[.assignees[]?.login] | join("\n")')" || return 1
    want="$(
      {
        printf '%s\n' "$current"
        [ "${#add_assignees[@]}" -gt 0 ] && printf '%s\n' "${add_assignees[@]}"
      } | grep -v '^$' | sort -u
    )"
    if [ "${#rm_assignees[@]}" -gt 0 ]; then
      want="$(grep -vxF -f <(printf '%s\n' "${rm_assignees[@]}") <<<"$want" || true)"
    fi
    payload="$(printf '%s' "$want" | jq -R . | jq -s '{assignees: [.[] | select(. != "")]}')"
    forgejo_write PATCH "repos/$REPO/issues/$n" "$payload" >/dev/null || return 1
  fi
}

forge_issue_comment() {
  local n="${1:?forge_issue_comment: number required}" body="${2?forge_issue_comment: body required}"
  forgejo_write POST "repos/$REPO/issues/$n/comments" "$(jq -n --arg b "$body" '{body: $b}')" >/dev/null
}

forge_pr_list() {
  forge_api --paginate "repos/$REPO/pulls?state=open" --jq '.[].number'
}

# forge_pr_view <n> — the {mergeable, statusCheckRollup} shape the state
# machine reads, assembled from the two places Forgejo keeps it. The rollup
# is mapped into the node shape checks_state already parses, so the decision
# code is untouched.
forge_pr_view() {
  local n="${1:?forge_pr_view: number required}" pr sha status
  pr="$(forge_api "repos/$REPO/pulls/$n")" || return 1
  sha="$(jq -r '.head.sha // ""' <<<"$pr")"
  [ -n "$sha" ] || { echo "forge_pr_view: PR $n has no head sha" >&2; return 1; }
  status="$(forge_api "repos/$REPO/commits/$sha/status")" || return 1
  jq -n --argjson pr "$pr" --argjson st "$status" '
    {
      mergeable: (if $pr.mergeable == true then "MERGEABLE"
                  elif $pr.mergeable == false then "CONFLICTING"
                  else "UNKNOWN" end),
      statusCheckRollup: [
        $st.statuses[]? | {
          __typename: "StatusContext",
          context: .context,
          state: (.status | ascii_upcase)
        }
      ]
    }'
}

forge_label_list() { forge_api --paginate "repos/$REPO/labels" --jq '.[].name'; }

forge_label_create() {
  local name="${1:?}" color="${2:?}" desc="${3:-}"
  forgejo_write POST "repos/$REPO/labels" \
    "$(jq -n --arg n "$name" --arg c "$color" --arg d "$desc" '{name:$n,color:$c,description:$d}')" >/dev/null
}

forge_label_delete() {
  local name="${1:?}" ids id
  ids="$(forgejo_label_ids)" || return 1
  id="$(awk -F '\t' -v want="$name" '$1 == want { print $2; exit }' <<<"$ids")"
  [ -n "$id" ] || return 0
  forgejo_write DELETE "repos/$REPO/labels/$id" '' >/dev/null
}

# forgejo_write <method> <endpoint> <json-body> — every mutation goes through
# here so a non-2xx is named rather than swallowed, the same contract
# forgejo_http_ok gives reads.
forgejo_write() {
  local method="$1" endpoint="$2" payload="$3" base token hdr body rc
  base="$(forgejo_api_base)" || return 1
  token="${GH_TOKEN:-${GITHUB_TOKEN:-${FORGEJO_TOKEN:-}}}"
  hdr="$(mktemp)"; body="$(mktemp)"
  if [ -n "$payload" ]; then
    curl -sS -X "$method" -D "$hdr" -o "$body" \
      -H "Authorization: token $token" -H 'Content-Type: application/json' \
      -d "$payload" "$base/$endpoint"
  else
    curl -sS -X "$method" -D "$hdr" -o "$body" \
      -H "Authorization: token $token" "$base/$endpoint"
  fi
  rc=$?
  if [ "$rc" -ne 0 ]; then
    rm -f "$hdr" "$body"
    echo "forge: $method $endpoint failed to send" >&2
    return 1
  fi
  if ! forgejo_http_ok "$hdr" "$method $endpoint"; then
    head -c 300 "$body" >&2; echo >&2
    rm -f "$hdr" "$body"
    return 1
  fi
  cat "$body"
  rm -f "$hdr" "$body"
}