Files
msd-core/gsd-core/references/execute-mvp-tdd.md
Tom Boucher 8249ebcf6e fix(#3770): require intentional RED evidence before GREEN (#4279)
* test(3770): add failing tests for intentional RED evidence gate

RED: classifyRedEvidence / buildRedEvidenceRecord / check tdd-red-evidence do
not exist yet; every row fails on require. Per #3770 only an intentional
target-test failure may authorize GREEN; zero-test discovery, fixture crashes,
unrelated failures, and unexpected green are INVALID_RED.

* fix(3770): require intentional RED evidence before GREEN

Only an intentional failure of the TARGET test (distinctly named, TAP-reported
assertion failure) classifies as RED_EVIDENCE_OK and authorizes GREEN. Zero-test
discovery, fixture/load crashes (file-named failures), nonzero exits without a
failing test, unrelated failures, unexpected greens, and malformed/missing
records are INVALID_RED and block GREEN.

- src/tdd-red-evidence.cts: pure classifier + persisted record builder (reuses
  the prohibition-enforcement TAP primitives; fail-closed, never throws)
- check tdd-red-evidence <record.json>: validates the persisted record
  (command, exit code, failing test, expected, actual)
- gsd-executor.md / references/tdd.md / references/execute-mvp-tdd.md: RED now
  requires the evidence record + gate verdict, not a nonzero exit or a RED: tag

* chore(3770): regenerate inventory manifest for tdd-red-evidence.cjs

* fix(3770): fit executor fail-fast under size cap, fix unrelated-failure fixture, ignore generated lib

- gsd-executor.md: compress the #3770 fail-fast rule to one line (49149 B <
  49152 cap; line-count parity keeps the #2751 PROSE_ALLOWLIST line 816 valid)
- tests: the row-6 fixture used String.replace (first-occurrence), so the
  `not ok` line still named the target test and the classifier was right to
  accept it; replaceAll makes the failure genuinely unrelated
- eslint.config.mjs: ignore tsc-generated bin/lib/tdd-red-evidence.cjs
  (lint the src/*.cts source, per ADR-457 migration rule)

Emitted-Drift-Ack-Growth: gsd-executor.md — the #3770 fail-fast rule now requires intentional RED evidence (check tdd-red-evidence) before GREEN; +172 bytes, kept under the LARGE cap and on one line

* chore(3770): add changeset

* chore(3770): backfill PR number in changeset

---------

Co-authored-by: sim <sim@local>
2026-09-04 16:44:38 -04:00

82 lines
5.3 KiB
Markdown

# Execute-Phase — TDD Gate (Runtime Enforcement)
> Loaded by `execute-phase` workflow and `gsd-executor` agent when `TDD_MODE=true` for the phase (#4011 — the gate no longer requires MVP mode; MVP may imply TDD, but TDD never requires MVP). Defines the runtime gate that blocks behavior-adding tasks until a failing-test commit exists.
## When this gate fires
- `TDD_MODE` is `true` (resolved from `--tdd` flag → `workflow.tdd_mode` config). MVP mode is NOT required (#4011).
- The current task being executed has `tdd="true"` in its `<task>` frontmatter (set by the planner per Phase 1).
- The task's `<behavior>` block lists at least one expected behavior.
If any of these is false, the gate is inactive — execution proceeds normally.
## What the gate checks
For each task gated by TDD, the executor MUST verify (before running the implementation step):
1. **A failing-test commit exists.** Search git log on the current branch for a commit matching `test({phase}-{plan})` whose subject mentions the same plan as the current task. The commit must touch a test file (`*.test.*`, `*.spec.*`, `tests/**`).
2. **The test was actually red — INTENTIONALLY (#3770).** A nonzero exit is not RED by itself: syntax errors, zero-test discovery, fixture crashes, parser errors, and unrelated assertions are INVALID_RED. The executor must persist the RED evidence record (command, exit code, failing test, expected result from `<behavior>`, actual result) and verify it:
```bash
gsd_run check tdd-red-evidence <record.json> --raw
```
- `RED_EVIDENCE_OK` (reason `target_test_failed`): the TARGET test named by the plan failed on a real assertion — the ONLY verdict that authorizes GREEN.
- `INVALID_RED` (reasons `unexpected_green`, `zero_tests_discovered`, `nonzero_exit_without_test_failure`, `fixture_or_load_failure`, `no_target_test_failure`, `invalid_record`, `unreadable_record`): the gate trips — halt, fix the RED phase (test identity, fixture, discovery), and re-verify before any implementation step. A `RED:` prefix or `(RED)` tag in the commit message is NOT sufficient evidence on its own.
3. **No implementation commit yet.** No `feat({phase}-{plan})` commit may exist for the same plan ID before the failing-test commit.
If any check fails, the gate trips. For check 2, an INVALID_RED verdict (`check tdd-red-evidence`) trips the gate — the executor MUST halt and block the implementation step.
## What "behavior-adding task" means
A task is behavior-adding when:
- Its frontmatter has `tdd="true"` AND
- Its `<behavior>` block names at least one user-visible outcome (not a config-only or doc-only task) AND
- Its `<files>` list includes at least one source file (not exclusively docs/tests/config files such as `*.md`, `*.json`, `*.test.*`, `*.spec.*`, `*.yml`, `*.yaml`, `*.toml`, `*.ini`, `.env*`)
Pure documentation, configuration, or test-only tasks are skipped by this gate even when both modes are active.
## What happens when the gate trips
The executor MUST:
1. Halt before running the task's implementation step.
2. Emit a structured halt report:
```
### TDD GATE TRIPPED — Plan {plan_id}, Task {task_id}
Reason: {missing_red_commit | red_commit_not_failing | feat_before_test | invalid_red}
Behavior expected to be tested:
- {first behavior bullet}
Required next step:
1. Write a failing test for the behavior above.
2. Commit it as: test({phase}-{plan}): {short description}
3. Re-run /gsd execute-phase
```
3. Exit the current execution wave cleanly. Do NOT roll back any prior commits in the same wave.
4. Update `STATE.md` with `last_gate_trip: {plan_id}/{task_id}` so the user can resume after writing the test.
## Escalation: end-of-phase TDD review under TDD
The existing end-of-phase TDD review (in `workflows/execute-phase.md`'s `tdd_review_checkpoint` step) is normally **advisory** — it surfaces gate violations but does not block phase completion.
Under TDD mode, escalate this to **blocking**:
- If any TDD plan is missing a RED or GREEN commit, the executor MUST refuse to mark the phase complete.
- The user is shown the same review table, but the verdict line reads:
> "Phase blocked: {N} TDD plan(s) violate the RED→GREEN gate sequence under TDD. Resolve and re-run /gsd execute-phase, or override with `/gsd execute-phase {phase} --force-mvp-gate` to ship anyway."
The `--force-mvp-gate` flag is documented but not introduced by this plan — it is the escape hatch the spec mentions; if the user later builds it, the workflow already references the contract.
## What this gate does NOT do
- It does not enforce REFACTOR commits. REFACTOR remains optional (per `gsd-core/references/tdd.md`).
- It does not check test quality (the test could be trivially weak). That's the planner's job. It DOES check that the RED failure was intentional — the target test failing an assertion (#3770).
- It does not run tests. The executor only inspects git log + file system. Running tests is the implementation step's job.
- It does not gate config-only or doc-only tasks (see "behavior-adding task" definition).
## Compatibility with existing TDD discipline
This gate is additive to `gsd-core/references/tdd.md`. Tasks not under TDD mode continue to use the existing advisory TDD discipline (RED/GREEN/REFACTOR commits with end-of-phase review checkpoint). Only the runtime gate and the blocking escalation are new.