# .gitea/workflows/gate.yml — the ENFORCED PR merge gate (Phase 6, WS-GITOSS).
#
# This is the LIVE gate wired to the in-cluster Gitea Actions runner (ns gitea-actions,
# Docker executor + DinD). It invokes the AGGREGATE merge gate — `./ci/gate.sh`, which is
# exactly what `make -C ci gate` runs, so CI and the devcontainer gate the same way
# (R-TEST-02): the runner just installs the pinned tools from ci/versions.env first (and see
# below for why the script, not `make`, is invoked here). It runs every stage in order —
# spec-immutability, lint, Kyverno L0, render==golden, L1 offline render — and then applies the
# R-TEST-03 decision, printing
# "MERGE GATE: PASS" (0) / "BLOCKED" (1) / "UNDETERMINED" (3) / "NOT APPLICABLE" (0). It is the
# single required status check on `main` (see branch protection). A non-zero exit fails the job,
# so a BLOCKED gate blocks the merge.
#
# WHY THIS STEP DECLARES GATE_STRICT_SKIPS AND TOLERATES EXIT 3 (2026-09-13). A SKIPPED stage is
# never green, and since 2026-09-13 gate.sh refuses to print PASS when one did not run (it used to
# print "— not green" and then "MERGE GATE: PASS", exit 0 — fail-open in the gate itself). Two
# kinds of non-run must be told apart HERE, in the caller, because only the caller knows which
# environment it is:
#   * a pinned tool missing or a seam unwired ON THIS RUNNER is a DEFECT — the toolchain is
#     installed for us two steps up. GATE_STRICT_SKIPS=true DECLARES that (no env sniffing, no
#     "does this look like CI?" heuristic) and makes those skips exit 1: untolerated, job fails.
#   * spec-immutability CANNOT be verified here at all: the spec repo is a separate repo and is
#     not checked out into this runner (SPEC_REPO_SLUG unwired; blueprint in merge-gate.yaml). It
#     is the ONLY skip that can still reach exit 3 under strict skips, which is what makes
#     `|| [ "$?" -eq 3 ]` a narrow, reviewed tolerance rather than a blanket one. The log still
#     says UNDETERMINED and names R-TEST-06 as unverified. Wire the spec checkout (or set
#     REQUIRE_SPEC_VERIFICATION=true) and this tolerance should be deleted.
# Called DIRECTLY, not through `make`: GNU make reports any recipe failure as its own exit 2, so
# `make -C ci gate || [ "$?" -eq 3 ]` would see 2 and fail the job. Same reason the
# spec-immutability pre-step below calls the script directly.
#
# The cluster-gated L2/L3 conformance stage SKIPS honestly here (exit 3, surfaced not faked
# — HARD RULE 4) because this runner declares no cluster: nothing here sets CLUSTER_AVAILABLE,
# so gate.sh reports the touched requirements UNVERIFIED — and NAMES that declared gap in its
# PASS headline — without blocking Phase-0/6 static work. L2/L3 run as an IN-CLUSTER Chainsaw Job (its own scoped SA; CI holds
# no broad kubeconfig) driven by the separate `conformance` job below.
#
# NOTE (R-TEST-06 / gate-semantics): spec-immutability is ALSO surfaced as its own explicit
# early step (below) so its result is a distinct, tolerant status in the Gitea UI; gate.sh
# re-runs it as its first stage, which is the authoritative one. The gate step below is the
# same script the laptop runs; the extra pre-step is a read-only git-diff check and is
# purely additive. The full pipeline blueprint (spec-checkout, per-layer jobs, decision job)
# is retained dormant in merge-gate.yaml.
---
name: gate

# TRIGGERS — deliberately only `pull_request` into main, plus `push` to main itself.
#
# There is NO per-branch push trigger. There used to be a prefix list (feature/** fix/**
# docs/** chore/**) for "fast feedback on the branch", and it was a net negative here:
#
#   * `act_runner` runs at capacity 1. A branch push and its PR fire the SAME gate over the
#     SAME tree, and the redundant run SERIALISES AHEAD of the PR run — doubling the wall
#     clock on the one result that actually gates the merge. That cost real time during the
#     2026-09-29 plex claim, where the loop is racing a short-lived token.
#   * The list silently did not match this repo's own convention. Branches here are `feat/**`,
#     which was absent, so the "fast feedback" never fired for the most common prefix anyway —
#     a mismatch nobody noticed for a month because its only symptom was a MISSING run.
#     Any hand-maintained prefix list has that failure mode; deleting it removes the class.
#   * It is redundant. CLAUDE.md already requires `./ci/gate.sh` in the pinned toolbox before
#     you push (74s locally), and the PR gate re-runs it authoritatively. A third run of the
#     same checks buys nothing.
#
# `push: [main]` is KEPT: post-merge main must still be verified, and it is the only run for
# which no PR context exists.
on:
  pull_request:
    branches: [main]
  push:
    branches:
      - main

concurrency:
  group: gate-${{ github.ref }}
  cancel-in-progress: true

jobs:
  # Single required status check: the static merge gate.
  gate:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0        # full history so ci/touched-requirements.sh can diff vs main

      - name: Install pinned CI toolchain (ci/versions.env)
        run: |
          ./.gitea/workflows/scripts/install-tools.sh l0
          ./.gitea/workflows/scripts/install-tools.sh l1

      # R-TEST-06: the spec is read-only to agents. An EXPLICIT early surfacing of the
      # spec-immutability check, so its result is a distinct, tolerant status line in the
      # Gitea UI before the (longer) aggregate gate log. The spec repo is NOT checked out
      # into CI here (separate repo; SPEC_REPO_SLUG not wired into this runner), so the guard
      # honestly SKIPS (exit 3) rather than faking green; a real drift/edit of a co-located
      # spec exits 1 and fails. Tolerated: exit 3 only. Call the script DIRECTLY, not via
      # `make spec-immutability`: GNU make masks a recipe's exit code as its own 2, so
      # `make spec-immutability || [ $? -eq 3 ]` would see 2 and fail. The AUTHORITATIVE
      # spec-immutability run is the FIRST stage of `make -C ci gate` below (gate.sh calls
      # the script directly, so it sees exit 3 → SKIP, not a mask); this pre-step is a cheap,
      # read-only git-diff duplicate that only adds early UI signal.
      - name: Spec immutability (R-TEST-06, skips if spec repo absent)
        run: ./ci/spec-immutability.sh || [ "$?" -eq 3 ]

      # Aggregate merge gate: the same script a human runs in the devcontainer via
      # `make -C ci gate`. Runs spec-immutability, lint, Kyverno L0, render==golden and L1
      # render, then the R-TEST-03 decision. Exits non-zero on a BLOCKED gate, which fails this
      # job. The cluster-gated L2/L3 stage SKIPS here (no CLUSTER_AVAILABLE) — surfaced as
      # UNVERIFIED and NAMED in the PASS headline, never faked green. GATE_STRICT_SKIPS + the
      # tolerated exit 3 are explained in the file header; the tolerance covers exactly one
      # thing, the unverifiable spec repo, and nothing else can produce a 3 here.
      - name: Merge gate — ci/gate.sh (what `make -C ci gate` runs)
        env:
          GATE_STRICT_SKIPS: "true"
        run: ./ci/gate.sh || [ "$?" -eq 3 ]

      # NOTE: no actions/upload-artifact step. Gitea Actions rejects upload-artifact@v4
      # ("not supported on GHES" — Gitea does not implement the artifact-v2 backend), which
      # would fail the job even on a green gate. JUnit + coverage are written under
      # conformance/_artifacts/ in the job workspace; wire artifact upload later via the
      # Gitea-compatible @v3 action or Gitea's own artifact backend if retention is wanted.

  # ───────────────────────────────────────────────────────────────────────────
  # PLACEHOLDER — NOT WIRED (deferred; concrete plan written, awaiting operator decision).
  # L2/L3 conformance (Chainsaw behavioural + fault-injection) needs a LIVE cluster and is
  # gated behind vars.CLUSTER_AVAILABLE + a narrow secrets.CONFORMANCE_TRIGGER_KUBECONFIG.
  # The intended model: an in-cluster Chainsaw Job (conformance/incluster/) under its OWN
  # scoped ServiceAccount — CI holds NO broad kubeconfig, only a trigger credential. The
  # blocker is a real privilege-escalation design question (a `create jobs` credential can
  # create a Job running as the privileged runner SA), plus a runner image + repo-clone +
  # results-collection that don't exist yet. Full analysis + step sequence:
  #   docs/plans/l2-l3-conformance-ci-wiring.md
  # The blueprint job shape is retained dormant in merge-gate.yaml.
  # Kept `if: false` so it never runs (shows skipped, never fakes green — HARD RULE 4).
  # ───────────────────────────────────────────────────────────────────────────
  conformance:
    runs-on: ubuntu-latest
    needs: [gate]
    if: false
    steps:
      - name: Placeholder
        run: |
          echo "L2/L3 conformance not wired — see gate.yml header + WS-GITOSS report." >&2
          exit 1