Tom Boucher fa41bfec5c enhance(#3942): the emitted-drift ack is PR-lifetime data — move it to a commit trailer (#3954)
* test(#3942): failing-first suite for the emitted-drift ack commit trailer

Binds 37 input classes from the phase test matrix to the behavior ADR-3942
specifies, before any of it exists. Stubs return benign empty values rather
than throwing, deliberately: several rows assert that something DOES throw
(cap overflow, uncomputable commit range), and a throwing stub would turn
those green for the wrong reason and destroy the red.

The two rows that carry the design's load:

- merge-base semantics. The range is $(git merge-base base HEAD)..HEAD, not
  base..HEAD, because changedPaths comes from `git diff base...HEAD` (three
  dot). Two-dot would let the ack set and the change set disagree about which
  commits are this PR's. The fixture forks a topic branch, puts a trailer on
  each side, and asserts only the topic-side trailer is in range.

- fail-closed on an uncomputable range. With fragments a depth-1 checkout
  passes VACUOUSLY, every fragment reading as brand-new. With trailers the
  range cannot be computed at all, and returning an empty set would silently
  disarm the gate, so it must throw. The fixture builds a genuine shallow
  clone rather than simulating one.

Also covers the self-inflicted case: this change's own documentation quotes
the trailer syntax, so an example landing at the end of a commit message would
arm a live acknowledgment keyed on the literal placeholder text. Keys carrying
angle brackets or whitespace are rejected.

Authored per the phase artifacts 40-design.md and 50-test-matrix.md.
Not yet run on the remote runner — this commit exists to be tested.

Refs #3942

* chore(#3942): move the emitted-drift ack to a commit trailer

Implements ADR-3942, superseding ADR-2719 section 3 and its #2789 amendment.
Sections 1, 2 and 4-7 are retained: the conservation law is unchanged, only the
storage of its escape hatch moved off the working tree.

An acknowledgment explains one PR's ripple, and the moment that PR merges the
ripple is in the base, so it can never clear anything again. It was stored in
permanent shared state anyway, and every consequence of that mismatch had to be
built and then maintained. The chain is #2789 -> #2914 -> #3078 -> #3842 ->
#3823 -> #3875, each fix generating the next defect, ending in a scheduled
sweeper whose own first PR could not merge itself.

Added
  parseAckTrailers + renderAckTrailer (pure) and readAckTrailers (IO shell),
  reading Emitted-Drift-Ack-Hash: / Emitted-Drift-Ack-Growth: trailers over
  the merge-base range. tests/emitted-ack-trailer.test.cjs, 37 cases, written
  failing-first and confirmed red before any of this existed.

Changed
  diffEmitted takes two structurally distinct key-space maps instead of one
  shared paths map. That closes a latent defect: the spaces were separated by
  convention only, so a growth key satisfied a hash lookup by naming
  coincidence. staleAcks now reports which space a key was declared in.
  REMEDIATION teaches the trailer, per space, with its example rendered through
  renderAckTrailer so the taught grammar cannot drift from what the parser
  accepts.

Removed
  the sweep workflow, the guard-no-ack-on-next job, the standalone linter and
  its lint:ci entry, the fragment directory and its three spent fragments, the
  legacy single-file union, and the baseAck/spentAcks mechanism -- spentness is
  now structural, not computed.

Two range properties carry the design and are pinned by tests rather than
asserted: the range is merge-base scoped, matching git diff base...HEAD, so an
already-merged trailer is out of range by construction; and an uncomputable
range throws instead of reading as zero acknowledgments, which is the inverse
of the fragment guard's vacuous pass.

Three deliberate observable changes, each disclosed in the changeset: the
unread runtime field is gone, the legacy file is no longer read, and cross-space
excusal no longer works.

Ten open PRs carry fragments and will meet a modify/delete conflict. Measured
before landing and accepted deliberately; the one-line migration is in the PR
body.

Verified: lint:ci exit 0. Remote runner to follow on this exact sha.

Refs #3942

* fix(#3942): silent trailer collapse, lost coverage, and an unbounded cap

Six findings from the orthogonal review round, all fixed in place.

BLOCKER -- two trailers of the same name on one commit collapsed silently.
readAckTrailers built `separator=1d` where git needs `separator=%x1d`: the
`separator=` value inside a %(trailers:...) placeholder is itself a
pretty-format string, so the bare hex was emitted as two literal characters
and the split on \x1d never matched. Two same-name trailers therefore joined
into one value with errors empty -- the first reason absorbing the second
entry's key. Silent truncation, the exact class MAX_ACK_TRAILERS throws to
prevent. Confirmed with od -c against real git output before and after.

The failing-first matrix did not catch it because its "both spaces coexist"
row uses Hash plus Growth -- different trailer NAMES -- so the value separator
was never exercised. Two regression tests now cover same-name trailers
directly.

Coverage recovered: normalizeAckReason and INVISIBLE stayed on the live path
via parseAckTrailers but lost every test when the old suite was pruned. Back
under test against the current surface -- all six invisible codepoints
individually, whitespace collapse, trim, CRLF, and two seeded fast-check
properties. Dropping any single codepoint now fails.

MAX_ACK_TRAILERS counted raw trailers before de-duplication, so one trailer
carried forward across rebased commits counted once per commit and could throw
on a legitimate branch. Now counts distinct entries; 100 identical repeats
dedupe to one.

diffEmitted validated baseline, current and changedPaths but not the new
ackHash/ackGrowth, so a bad shape raised an unhandled TypeError instead of an
error verdict -- the same defect shape this file documents for #2778.

Docs: CONTRIBUTING and TESTING-SUITES were rewritten only in their first
sections; the later passages still taught fragments, git rm and the deleted
guard, contradicting the new text directly above them. Finished.

Also extends lint-removed-but-needed to exempt docs/adr and docs/research.
That gate fails on any docs mention of a file deleted in the same diff, which
makes it impossible to document a deletion in the PR performing it -- an ADR's
whole job is naming what it retired. Exemption is narrow and comes with a test
proving the gate still fires for a live consumer elsewhere under docs/. A
guard that cannot fail is worse than no guard. Maintainer-approved.

CONTEXT.md names the retired machinery by role rather than by filename: its
generated projection lands in docs/, which that gate does scan.

Adds docs/how-to/acknowledge-emitted-drift.md. The required docs set is
Reference and Explanation, so the task quadrant can be empty with every gate
green -- and this change has a real multi-step journey, including the fragment
migration ten open PRs now need.

lint:ci exit 0.

Refs #3942

* docs(#3942): correct the duplicate-trailer rule in CONTRIBUTING

Both axes of the code review independently flagged the same passage, without
seeing each other's output.

It claimed two declarations of the same key are always "a hard, loudly-reported
error, not a silent last-wins". That is only half true, and the missing half is
the one contributors hit: identical declarations -- same key, same reason --
dedupe silently, because a trailer legitimately survives a rebase and reappears
on every rebased commit. Failing there would red a branch for doing nothing
wrong, which is exactly why the dedup exists.

Only a same-key/different-reason pair errors, and that one is a genuine
ambiguity about which explanation holds.

As written, the paragraph told a contributor that a rebase-carried trailer
breaks the gate -- the opposite of the behavior. CONTEXT.md's parallel entry
already stated it correctly; this brings CONTRIBUTING into line.

Doc-only, root-level markdown.

Refs #3942

* chore(#3942): backfill changeset PR number to 3954

---------

Co-authored-by: sim <sim@local>
2026-08-27 17:28:39 -04:00

GSD Core

Git. Ship. Done.

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A light-weight meta-prompting, context engineering, and spec-driven development system for Claude Code, OpenCode, Antigravity CLI, Kimi CLI, Kilo, Codex, Copilot, Cursor, Windsurf, and more.

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What is GSD Core

GSD Core is a context-engineering and spec-driven development framework that drives AI coding agents (Claude Code, Codex, Antigravity CLI, Kimi CLI, Copilot, Cursor, and more) through a disciplined phase loop. It solves context rot — the quality degradation that accumulates as an AI fills its context window — by running all heavy research, planning, and execution work in fresh-context subagents while keeping your main session lean.


How it works

Each milestone repeats the same five-step loop, one phase at a time:

  1. Discuss — capture implementation decisions before anything is planned
  2. Plan — research, decompose, and verify the plan fits a fresh context window
  3. Execute — run plans in parallel waves; each executor starts with a clean 200k-token context
  4. Verify — walk through what was built; diagnose and fix before declaring done
  5. Ship — create the PR, archive the phase, repeat for the next one

Quickstart

npx @opengsd/gsd-core@latest

The installer prompts for your runtime (Claude Code, OpenCode, Antigravity CLI, Kimi CLI, Kilo, Codex, Copilot, Cursor, Windsurf, and more) and whether to install globally or locally. The installer is required for cross-runtime compatibility — do not copy files from agents/ or commands/ directly.

On another runtime or without Node.js? See Install on your runtime.

Once installed, start a new project or onboard an existing repo:

/gsd-new-project   # greenfield project
/gsd-onboard       # existing codebase

New here? Follow Your first project for a guided walkthrough from install to first shipped phase, or Onboarding an existing codebase for brownfield setup.


Documentation

What's new in 1.7.0 → docs/whats-new-1.7.0.md

Tutorials — learning by doing:

How-to guides — task-focused recipes:

Reference — authoritative facts:

Explanation — concepts and design decisions:

Full index: docs/README.md. Other languages: 日本語 · 한국어 · Português · 简体中文.


Why it works

Most AI-coding setups fail at scale because context bloat silently degrades output quality, there is no shared memory between sessions, and nothing verifies that code actually works. GSD Core solves all three: heavy work runs in fresh subagents, structured artifacts like STATE.md and CONTEXT.md survive session boundaries, and the verify step walks through what was built and generates fix plans before a phase is declared done. See docs/explanation/context-engineering.md for the full reasoning.

Troubleshooting? See docs/how-to/recover-and-troubleshoot.md.


Community

Project Platform
gsd-opencode Original OpenCode port
Discord Community support

Star History

Star History Chart

License

MIT License. See LICENSE for details.


Claude Code is powerful. GSD Core makes it reliable.

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