Close the root class of incident ORCH-114: a pytest/worktree process performed a
REAL write (PATCH issues state=<Done> + comment) against the PRODUCTION Plane
project, because test/staging processes inherit the live Plane token
(PLANE_HEADERS/PROJECT_ID are captured at import — a post-hoc env/token swap is a
no-op) and nothing forced them to write only to the sandbox. Symmetric to the
existing _no_telegram autouse floor.
- New pure never-raise leaf src/plane_write_guard.py (decide/audit_block/
audit_allow), wired into the 3 plane_sync write primitives (update_issue_state /
add_comment / _set_issue_state_direct) via _guard_allows_write, AT CALL TIME,
before any network step. Active ONLY in a test process (pytest in sys.modules /
PYTEST_CURRENT_TEST); live + staging runtimes (uvicorn) are a strict no-op.
- In a test process: default-deny. A write is allowed iff opt-in
(plane_test_write_enabled) AND target project in the sandbox allowlist
(plane_test_sandbox_projects, default = the one SANDBOX id). Prod is blocked even
with opt-in (allowlist sandbox-only); unresolved project -> block (fail-closed).
- Independent second layer: tests/conftest.py::_plane_sandbox_only autouse floor.
Intentionally NO prod-block kill-switch (anti back-door, NFR-6).
- Audit: block -> loud ERROR; sandbox-allow -> INFO.
- Bypass fixtures for the 3 (+1) pre-existing tests that assert on the mocked
write primitive's httpx call (header/URL/state logic), the guard is no Quality
Gate: STAGE_TRANSITIONS / QG_CHECKS / check_* / machine-verdict / DB schema
untouched.
- Tests: tests/test_orch117_plane_write_isolation.py (TC-01 mandatory ORCH-114
regression + TC-02..TC-14). Docs: CLAUDE.md, architecture/README.md,
operations/INFRA.md, .env.example, CHANGELOG.md.
Refs: ORCH-117
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
