Commit yarn 4 in the tree and install with --immutable (closes #149)

Follows sneak's ruling at
#149 (comment). This
repository now carries yarn 4.18.1 under .yarn/releases. The
distribution's yarn only starts that file, and that file does the work.
yarn.lock is converted once, and script/bootstrap installs with
--immutable instead of stopping on yarn's major version. Node is the
distribution's newest Node package: nodejs-current on Alpine and
nodejs_latest on nix. Every Dockerfile stage that needs yarn also copies
.yarnrc.yml and .yarn/releases/. The policies and both checklists say
so, with the steps for converting and for a new repository.

Model: opus-5-5

README.md

@@ -172,8 +172,7 @@ share, and evolve prompts across projects.
 The repository is a collection of Markdown files organized in the `prompts/`
 subdirectory. Each file contains one or more related prompts or policy
 documents. There is no build step or runtime component; the prompts are consumed
-by copying them into other projects or referencing them directly. `examples/`
+by copying them into other projects or referencing them directly.
-holds the example `Dockerfile` files that `prompts/REPO_POLICIES.md` links to.
 
 ## Template Repos
 

TODO.md

@@ -21,23 +21,6 @@ fmt-check, and commit.
 
 # Completed Steps
 
-- 2026-11-09: Compacted `prompts/REPO_POLICIES.md` from 1,165 lines and 8,556
-  words to 982 lines and 7,281 words
-  (https://git.eeqj.de/sneak/prompts/issues/158). Every rule keeps its meaning.
-  The rules now sit under headings, the pinning rule first. Each rule that was
-  stated in several places is stated once. The Makefile copies of the Go and
-  Python test commands are gone, because the `Dockerfile` examples carry the
-  same commands. Both checklists name the `.golangci.yml` section.
-- 2026-11-07: Go code is now formatted with `gofmt` and then `golines -m 77`
-  (https://git.eeqj.de/sneak/prompts/issues/160). `prompts/REPO_POLICIES.md`
-  says how `script/fmt`, `script/fmt-check` and `script/bootstrap` do it and
-  pins `golines`. The Go style guide and both checklists say the same. `lll`
-  stays at 88, since `golines` leaves long strings and comments as they are.
-- 2026-11-06: The pinning rule in `prompts/REPO_POLICIES.md` now opens with its
-  scope: what we download and install ourselves in scripts and Dockerfiles
-  (https://git.eeqj.de/sneak/prompts/issues/154). Distribution packages are
-  outside the rule, and updating and upgrading them is allowed. Both checklists
-  say the same.
 - 2026-11-04: Each repository now commits yarn 4 and installs with
   `yarn install --immutable` (https://git.eeqj.de/sneak/prompts/issues/149), on
   sneak's ruling at

examples/go-lint-system-libraries.Dockerfile

@@ -1,8 +0,0 @@
-FROM golangci/golangci-lint@sha256:... AS lint
-RUN apt-get update \
-    && apt-get install -y --no-install-recommends libvips-dev \
-    && rm -rf /var/lib/apt/lists/*
-WORKDIR /src
-COPY go.mod go.sum ./
-RUN go mod download
-ARG CACHEBUST

examples/go.Dockerfile

@@ -1,85 +0,0 @@
-# In every stage ARG CACHEBUST comes right after the steps that install
-# system packages and download Go's modules, or right after FROM in a
-# stage with neither, and every step that lints, tests or compiles
-# comes after it. script/ passes a new value on every build, which
-# reruns every RUN step after it. Docker keeps the layers above it
-# until the base image, their own lines or go.mod and go.sum change.
-# The steps that compile mount Go's build cache, and golangci-lint run
-# also mounts golangci-lint's; both survive from build to build.
-
-# Lint phase
-# golangci/golangci-lint:v2.x.x, YYYY-MM-DD
-FROM golangci/golangci-lint@sha256:... AS lint
-WORKDIR /src
-COPY go.mod go.sum ./
-RUN go mod download
-ARG CACHEBUST
-COPY . .
-RUN --mount=type=cache,target=/root/.cache/go-build \
-    --mount=type=cache,target=/root/.cache/golangci-lint \
-    golangci-lint run --config .golangci.yml ./...
-
-# Test phase. -race needs cgo and so a C compiler, which the Debian Go
-# image ships and the alpine one does not. -count=1 because the mounted
-# cache also holds test results, which go test would otherwise replay.
-# A first run that timed out gets no rerun, because a rerun would only
-# wait for the same hang.
-# golang:1.x, YYYY-MM-DD
-FROM golang@sha256:... AS test
-WORKDIR /src
-COPY go.mod go.sum ./
-RUN go mod download
-ARG CACHEBUST
-COPY . .
-RUN --mount=type=cache,target=/root/.cache/go-build \
-    status=0; \
-    output=$(go test -count=1 -timeout 90s -race -cover ./... 2>&1) || status=$?; \
-    printf '%s\n' "$output"; \
-    test "$status" -eq 0 && exit 0; \
-    case "$output" in \
-        *"panic: test timed out"*|*"*** Test killed"*) exit 1 ;; \
-    esac; \
-    echo "--- Rerunning with -v for details ---"; \
-    go test -count=1 -timeout 90s -race -v ./...; \
-    exit 1
-
-# Build stage. Nothing is wanted from either phase above; the copies
-# are what make BuildKit build them first, so nothing after them can
-# run unless lint and test passed.
-# golang:1.x-alpine, YYYY-MM-DD
-FROM golang@sha256:... AS builder
-# git comes from the base image's own distribution package index, which
-# is trusted, so it needs no version and no hash.
-RUN apk add --no-cache git
-WORKDIR /src
-COPY go.mod go.sum ./
-RUN go mod download
-ARG CACHEBUST
-COPY --from=lint /src/go.sum /dev/null
-COPY --from=test /src/go.sum /dev/null
-# A tar-stream context keeps the sender's file owners, which git refuses.
-RUN git config --system --add safe.directory /src
-COPY . .
-
-# The VERSION build arg when one is given, otherwise
-# `git describe --tags --always` on the .git in the build context. With
-# .git present, a version that is still empty, dev or unknown fails the
-# build: git is missing or could not read the checkout.
-ARG VERSION
-RUN --mount=type=cache,target=/root/.cache/go-build \
-    VERSION="${VERSION:-$(git describe --tags --always)}"; \
-    if [ -e .git ]; then \
-        case "$VERSION" in ""|dev|unknown) \
-            echo "version is '$VERSION' although .git is present" >&2; \
-            exit 1 ;; \
-        esac; \
-    fi; \
-    CGO_ENABLED=0 go build -trimpath \
-        -ldflags="-s -w -X main.Version=${VERSION}" \
-        -o /app ./cmd/app/
-
-# Runtime stage, and the last one
-FROM alpine@sha256:...
-ARG CACHEBUST
-COPY --from=builder /app /usr/local/bin/app
-ENTRYPOINT ["app"]

examples/python-test-phase.Dockerfile

@@ -1,24 +0,0 @@
-# Test phase. Both pytest runs share one 90-second timeout, so a hang
-# uses it once and gets no rerun.
-# debian:trixie-slim, YYYY-MM-DD
-FROM debian@sha256:... AS test
-# Python, pip and venv come from the distribution, which is trusted, so
-# they need no version and no hash. make and git are base tools that
-# script/bootstrap installs when they are missing. Installed here, they
-# stay in their own layer when script/ changes.
-RUN apt-get update \
-    && apt-get install -y --no-install-recommends ca-certificates make git \
-        python3 python3-venv \
-    && rm -rf /var/lib/apt/lists/*
-# script/bootstrap installs pipenv in a virtual environment at
-# $HOME/.pipenv, and the tests below run that pipenv.
-ENV PATH=/root/.pipenv/bin:$PATH
-WORKDIR /app
-COPY script/ script/
-COPY Pipfile Pipfile.lock ./
-RUN script/bootstrap
-ARG CACHEBUST
-COPY . .
-RUN timeout 90 sh -c 'pipenv run pytest || { \
-        echo "--- Rerunning with -v for details ---"; \
-        pipenv run pytest -v; exit 1; }'

prompts/CODE_STYLEGUIDE_GO.md

@@ -1,16 +1,13 @@
 ---
 title: Code Styleguide — Go
-last_modified: 2026-11-07
+last_modified: 2026-10-18
 ---
 
-1.  Format Go code with `gofmt` and then `golines -m 77`, through `make fmt`.
+1.  Try to hard wrap long lines at 77 characters or less.
-    Don't commit anything `make fmt` would change. The only exception is when
-    committing things that aren't yet syntactically valid, which should only
-    happen pre-v0.0.1 or on a non-`main` branch.
 
-1.  Hard wrap long lines at 77 characters or less. `golines` does this for code.
+1.  Don't commit anything that hasn't been `go fmt`'d. The only exception is
-    Wrap comments and long string literals by hand, since `golines` leaves them
+    when committing things that aren't yet syntactically valid, which should
-    as they are.
+    only happen pre-v0.0.1 or on a non-`main` branch.
 
 1.  Even if you are planning to deal with only positive integers, use
     `int`/`int64` types instead of `uint`/`uint64` types. This is for

prompts/EXISTING_REPO_CHECKLIST.md

@@ -1,6 +1,6 @@
 ---
 title: Existing Repo Checklist
-last_modified: 2026-11-09
+last_modified: 2026-11-04
 ---
 
 Use this checklist when beginning work in a repo that may not yet conform to our
@@ -71,8 +71,8 @@ with your task.
       also mounts golangci-lint's
       (`--mount=type=cache,target=/root/.cache/golangci-lint`), and no step
       mounts anything else; both `go test` runs carry `-count=1`; a first run
-      that timed out gets no rerun, as in `examples/go.Dockerfile` in the
+      that timed out gets no rerun, as in the canonical Go `Dockerfile` in
-      `prompts` repo
+      `REPO_POLICIES.md`
 - [ ] Python: a `test` phase that installs its packages from `Pipfile.lock` does
       it above `ARG CACHEBUST`, with `COPY script/ script/`,
       `COPY Pipfile Pipfile.lock ./` and `RUN script/bootstrap`. When
@@ -92,8 +92,8 @@ with your task.
     installs no Python, because a step above it already did. `Pipfile` names no
     `python_version`, because `--deploy` stops when the distribution's Python
     differs from it. The tests run after `ARG CACHEBUST`, and every other stage
-    installs its Python packages after it, as in
+    installs its Python packages after it, as in the Python `test` phase example
-    `examples/python-test-phase.Dockerfile` in the `prompts` repo
+    in `REPO_POLICIES.md`
 
 - [ ] The gate phases invoke their tools directly, never through `make lint` or
       `script/test` — those are themselves a `docker build` and would recurse
@@ -163,7 +163,7 @@ with your task.
     - [ ] Go: `go.mod`, `go.sum`, `.golangci.yml` (fetch from
           `https://git.eeqj.de/sneak/prompts/raw/branch/main/.golangci.yml` and,
           in the same commit, set the lint phase digest to the one named in the
-          `.golangci.yml` section of `REPO_POLICIES.md`)
+          `.golangci.yml` paragraph of `REPO_POLICIES.md`)
     - [ ] JS: `package.json`, `yarn.lock`, `.yarnrc.yml`, `.yarn/releases/`,
           `.gitattributes`, `.prettierrc`, `.prettierignore` (fetch the last two
           from `https://git.eeqj.de/sneak/prompts/raw/branch/main/.prettierrc`
@@ -259,27 +259,22 @@ with your task.
 
 # Formatting
 
-- [ ] Platform-standard formatter is configured (`black`, `prettier`, and for Go
+- [ ] Platform-standard formatter is configured (`black`, `prettier`, `go fmt`)
-      `gofmt` then `golines -m 77`)
+- [ ] Default formatter config, only exception: four-space indents (except Go)
-- [ ] Default formatter config, except four-space indents (not Go),
-      `proseWrap: always` for Markdown, and the Go 77-column limit
-- [ ] Go: `script/bootstrap` installs `golines` with `go install` pinned to a
-      commit hash; `script/fmt-check` fails when `gofmt` or `golines -m 77`
-      would change a file
 - [ ] All files pass `make fmt-check`
 
 # Git Hygiene
 
 - [ ] Pre-commit hook is installed (`make hooks`)
 - [ ] No secrets in the repo (`.env`, keys, credentials)
-- [ ] No mutable references (tags, `@latest`) to what the repo downloads and
+- [ ] No mutable references in Dockerfiles or scripts (tags, `@latest`) — all
-      installs itself in scripts and Dockerfiles — all pinned by cryptographic
+      pinned by cryptographic hash with version/date comment. The one exception
-      hash with version/date comment. Distribution packages are outside this
+      is a package from the distribution's own package index, which needs no
-      rule. They need no version and no hash, and updating and upgrading them is
+      version and no hash. Pulling that index is also allowed. In a
-      fine too. In a `Dockerfile`, the distribution is the pinned base image's.
+      `Dockerfile`, the distribution is the pinned base image's. On a host, it
-      On a host, it is the host's, and the host's package manager stands for it,
+      is the host's, and the host's package manager stands for it, nix and brew
-      nix and brew included. A package source that a `Dockerfile` adds itself is
+      included. A package source that a `Dockerfile` adds itself does not get
-      not the distribution's own, so its packages are pinned
+      this exception
 - [ ] node, yarn, npm, python, pip and venv come from the distribution wherever
       possible, never from nvm, pyenv, corepack or `npm install -g yarn`. If the
       distribution's version is too old, use a newer distribution. node means

prompts/NEW_REPO_CHECKLIST.md

@@ -1,6 +1,6 @@
 ---
 title: New Repo Checklist
-last_modified: 2026-11-09
+last_modified: 2026-11-04
 ---
 
 Use this checklist when creating a new repository from scratch. Follow the steps
@@ -138,8 +138,8 @@ Template files can be fetched from:
       also mounts golangci-lint's
       (`--mount=type=cache,target=/root/.cache/golangci-lint`), and no step
       mounts anything else; both `go test` runs carry `-count=1`; a first run
-      that timed out gets no rerun, as in `examples/go.Dockerfile` in the
+      that timed out gets no rerun, as in the canonical Go `Dockerfile` in
-      `prompts` repo
+      `REPO_POLICIES.md`
     - Python: a `test` phase that installs its packages from `Pipfile.lock` does
       it above `ARG CACHEBUST`, with `COPY script/ script/`,
       `COPY Pipfile Pipfile.lock ./` and `RUN script/bootstrap`. When
@@ -160,8 +160,8 @@ Template files can be fetched from:
         because a step above it already did. `Pipfile` names no
         `python_version`, because `--deploy` stops when the distribution's
         Python differs from it. The tests run after `ARG CACHEBUST`, and every
-        other stage installs its Python packages after it, as in
+        other stage installs its Python packages after it, as in the Python
-        `examples/python-test-phase.Dockerfile` in the `prompts` repo
+        `test` phase example in `REPO_POLICIES.md`
 
     - Server: the final stage builds and runs the application
     - Non-server: the final stage brings up the dev environment
@@ -178,7 +178,7 @@ Template files can be fetched from:
     - [ ] Go: `go mod init sneak.berlin/go/<name>`, `.golangci.yml` (fetch from
           `https://git.eeqj.de/sneak/prompts/raw/branch/main/.golangci.yml` and,
           in the same commit, set the lint phase digest to the one named in the
-          `.golangci.yml` section of `REPO_POLICIES.md`)
+          `.golangci.yml` paragraph of `REPO_POLICIES.md`)
     - [ ] JS, or any repository that runs prettier through yarn: make the first
           `yarn.lock` with the steps below. `script/bootstrap` installs no yarn
           until `yarn.lock` exists, so run them with any distribution's node and
@@ -233,11 +233,9 @@ are thin shims calling them. Model scripts:
       which writes no image. No lint verdict may come from a host invocation of
       the linter.
 - [ ] `script/fmt` / `make fmt` — formats code (writes; native, never in a
-      container). Go code gets `gofmt`, then `golines -m 77`.
+      container)
 - [ ] `script/fmt-check` / `make fmt-check` — checks formatting (read-only;
-      native). Fails when `gofmt` or `golines -m 77` would change a Go file.
+      native)
-- [ ] Go: `script/bootstrap` installs `golines` with `go install` pinned to a
-      commit hash
 - [ ] `script/check` / `make check` — runs `test`, `lint`, `fmt-check`; must not
       modify files
 - [ ] `script/projectname` — outputs the project name (used by `script/docker`
@@ -287,13 +285,12 @@ are thin shims calling them. Model scripts:
       final stage is missing its `COPY --from=` edge to the gate phases.
 - [ ] No secrets in repo, and none in the build context: enumerate a probe image
       rather than reading `.dockerignore`
-- [ ] No mutable references to what the repo downloads and installs itself in
+- [ ] No mutable image/package references. The one exception is a package from
-      scripts and Dockerfiles. Distribution packages are outside this rule. They
+      the distribution's own package index, which needs no version and no hash.
-      need no version and no hash, and updating and upgrading them is fine too.
+      Pulling that index is also allowed. In a `Dockerfile`, the distribution is
-      In a `Dockerfile`, the distribution is the pinned base image's. On a host,
+      the pinned base image's. On a host, it is the host's, and the host's
-      it is the host's, and the host's package manager stands for it, nix and
+      package manager stands for it, nix and brew included. A package source
-      brew included. A package source that a `Dockerfile` adds itself is not the
+      that a `Dockerfile` adds itself does not get this exception
-      distribution's own, so its packages are pinned
 - [ ] node, yarn, npm, python, pip and venv come from the distribution wherever
       possible, never from nvm, pyenv, corepack or `npm install -g yarn`. If the
       distribution's version is too old, use a newer distribution. node means