Bootstrap keeps yarn and node only at their pinned versions (closes #154)

script/bootstrap kept any yarn found on PATH, so YARN_VERSION applied
only where none was installed. It now keeps the yarn on PATH only when
yarn --version is exactly YARN_VERSION, and otherwise prepares that
version through corepack. The node on PATH is used only when it has the
pinned major version and is at least NODE_MIN_VERSION, as
REPO_POLICIES.md asks. After installing either, bootstrap looks the tool
up through PATH again, stops naming the path if it is not the pinned
one, and prints the version it uses, as it does for Go. script/fmt and
script/fmt-check use the same node test, and otherwise run prettier
under the pinned node in nvm.

Model: opus-5-5

README.md

@@ -41,11 +41,13 @@ The scripts cover both the frontend and the Go backend, so `make check` fails if
 either one is broken. We provide:
 
 - `script/bootstrap` — install all dependencies (the pinned node via nvm unless
-  one new enough for the frontend's dependencies is installed, yarn via
-  corepack, `yarn install --frozen-lockfile`, Go `GO_VERSION` unless the `go` on
-  `PATH` is exactly that version, and the Go modules), linking what it installs
-  itself into `~/.local/bin`, which has to be on `PATH`. It installs no Go
-  linter and not Docker: `make test` and `make lint` run in Docker
+  the `node` on `PATH` has the pinned major version and is new enough for the
+  frontend's dependencies, yarn `YARN_VERSION` via corepack unless the `yarn` on
+  `PATH` is exactly that version, `yarn install --frozen-lockfile`, Go
+  `GO_VERSION` unless the `go` on `PATH` is exactly that version, and the Go
+  modules), linking what it installs itself into `~/.local/bin`, which has to be
+  on `PATH`. It installs no Go linter and not Docker: `make test` and
+  `make lint` run in Docker
 - `script/setup` — make a fresh clone ready for development: bootstrap plus the
   git pre-commit hook
 - `script/dev` — run the Vite dev server, which proxies `/api` to a locally
@@ -66,7 +68,9 @@ either one is broken. We provide:
   eslint in its `frontend-lint` stage, and golangci-lint over the Go packages
 - `script/fmt` — format all files (writes): prettier over the JavaScript, CSS,
   HTML and Markdown, then gofmt over `cmd/` and `internal/`. It runs on the
-  host, as `script/fmt-check` does, with `~/.local/bin` put on `PATH`
+  host, as `script/fmt-check` does, with `~/.local/bin` put on `PATH`, and runs
+  prettier under the pinned node in nvm when the `node` on `PATH` is not one
+  `script/bootstrap` would use
 - `script/fmt-check` — check formatting (read-only): prettier, then gofmt
 - `script/check` — run test, lint, and fmt-check
 - `script/add-dependency` — add a frontend package, or move one to another

TODO.md

@@ -21,6 +21,17 @@ Run `make frontend-viewport-test` in CI as its own step; it is not part of
 
 # Completed Steps
 
+- 2026-10-19: `script/bootstrap` keeps the `yarn` on `PATH` only when
+  `yarn --version` is exactly `YARN_VERSION`, and otherwise prepares that
+  version through corepack, as it did when no yarn was installed
+  ([#154](https://git.eeqj.de/sneak/netwatch/issues/154)); any yarn used to be
+  kept. It uses the `node` on `PATH` only when that node has the major version
+  of `NODE_VERSION` as well as being at least `NODE_MIN_VERSION`, as
+  `REPO_POLICIES.md` asks; a node 24 was kept before. After installing node or
+  yarn it looks the tool up through `PATH` again and stops if that is not the
+  pinned one, as it does for Go, and it prints the node and yarn versions it
+  uses. `script/fmt` and `script/fmt-check` use the same node test, and
+  otherwise run prettier under the pinned node in nvm
 - 2026-10-19: `DEBUG` unset or empty leaves debug logging off, and any other
   value, `false` and `0` included, turns it on, as the code style guide says
   ([#159](https://git.eeqj.de/sneak/netwatch/issues/159)). No value of it stops

script/bootstrap

@@ -3,11 +3,13 @@
 # this repo. Idempotent: every install is guarded by a check so already
 # installed tools are skipped. Base tooling comes from nix, apt, brew,
 # or apk (detected in that order); assumes nothing is present. Node is
-# used directly if it is at least NODE_MIN_VERSION; otherwise it is
-# installed at a pinned version via nvm (installing nvm itself first,
-# from a hash-verified release archive, never curl | sh). Go, with its
-# gofmt, is used directly only if it is exactly GO_VERSION; otherwise
-# that release is installed from its hash-verified archive.
+# used directly only if it has the major version of NODE_VERSION and is
+# at least NODE_MIN_VERSION; otherwise NODE_VERSION is installed via nvm
+# (installing nvm itself first, from a hash-verified release archive,
+# never curl | sh). Yarn is used directly only if it is exactly
+# YARN_VERSION; otherwise that version is prepared through corepack.
+# Go, with its gofmt, is used directly only if it is exactly GO_VERSION;
+# otherwise that release is installed from its hash-verified archive.
 #
 # What this script installs outside the system package manager lives
 # under $HOME and is linked into ~/.local/bin, where make and the git
@@ -142,32 +144,65 @@ ensure_nvm() {
     rm -rf "$tmp"
 }
 
-# node_ok: the node on PATH is at least NODE_MIN_VERSION. node itself
-# compares the two: major, then minor, then patch.
+# node_ok: the node on PATH has the major version of NODE_VERSION and is
+# at least NODE_MIN_VERSION. Only the major is compared with the pin:
+# the Dockerfile's node stages start from a node 22 alpine image whose
+# exact version is not the pin, and nvm cannot install a prebuilt node
+# on alpine. node itself compares the versions: major, then minor, then
+# patch. A node that fails does not pass. script/bootstrap, script/fmt
+# and script/fmt-check carry this function unchanged.
 node_ok() {
-    if missing node; then return 1; fi
+    if ! command -v node >/dev/null 2>&1; then return 1; fi
     node -e '
         const have = process.versions.node.split(".").map(Number);
         const want = process.argv[1].split(".").map(Number);
+        const pinned = process.argv[2].split(".").map(Number);
+        if (have[0] !== pinned[0]) process.exit(1);
         for (let i = 0; i < 3; i++) {
             if (have[i] !== want[i]) process.exit(have[i] > want[i] ? 0 : 1);
         }
-    ' "$NODE_MIN_VERSION"
+    ' "$NODE_MIN_VERSION" "$NODE_VERSION"
 }
 
 # ensure_node: unless node_ok, install NODE_VERSION and link its node.
+# Afterwards node is looked up through PATH again and must pass node_ok.
 ensure_node() {
-    if node_ok; then return 0; fi
+    if node_ok; then
+        echo "bootstrap: using node $(node --version)"
+        return 0
+    fi
     ensure_nvm
     nvm_sh "nvm install $NODE_VERSION"
     link_bin "$HOME/.nvm/versions/node/v$NODE_VERSION/bin/node" node
+    hash -r
+    if ! node_ok; then
+        echo "bootstrap: after installing node $NODE_VERSION through nvm," >&2
+        echo "  the node on PATH, $(command -v node), is not it" >&2
+        exit 1
+    fi
+    echo "bootstrap: installed node $(node --version)"
 }
 
-# ensure_yarn: corepack writes its shims (pnpm and yarnpkg as well as
-# yarn) into $TOOLCHAIN rather than next to itself, and the npm fallback
-# installs there too; only yarn is linked.
+# yarn_ok: yarn --version on PATH prints exactly YARN_VERSION, compared
+# over the whole version. A yarn that fails or prints anything else does
+# not pass.
+yarn_ok() {
+    if missing yarn; then return 1; fi
+    version="$(yarn --version 2>/dev/null)" || return 1
+    [ "$version" = "$YARN_VERSION" ]
+}
+
+# ensure_yarn: unless yarn_ok, prepare YARN_VERSION and link its yarn.
+# corepack writes its shims (pnpm and yarnpkg as well as yarn) into
+# $TOOLCHAIN rather than next to itself, and the npm fallback installs
+# there too; only yarn is linked. Afterwards yarn is looked up through
+# PATH again and must pass yarn_ok, so another yarn that hides the link
+# stops bootstrap.
 ensure_yarn() {
-    if ! missing yarn; then return 0; fi
+    if yarn_ok; then
+        echo "bootstrap: using yarn $(yarn --version)"
+        return 0
+    fi
     shims="$TOOLCHAIN/corepack-shims"
     mkdir -p "$shims"
     if ! missing corepack; then
@@ -182,6 +217,13 @@ ensure_yarn() {
         shims="$TOOLCHAIN/npm-global/bin"
     fi
     link_bin "$shims/yarn" yarn
+    hash -r
+    if ! yarn_ok; then
+        echo "bootstrap: after installing yarn $YARN_VERSION in $shims," >&2
+        echo "  the yarn on PATH, $(command -v yarn), does not report it" >&2
+        exit 1
+    fi
+    echo "bootstrap: installed yarn $(yarn --version)"
 }
 
 # go_ok: the go on PATH has its gofmt beside it (a Go release ships the

script/fmt

@@ -8,12 +8,47 @@ set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
+# Must match the pins in script/bootstrap.
+NODE_VERSION="22.17.0"
+NODE_MIN_VERSION="22.13.0"
+
+# node_ok: the node on PATH has the major version of NODE_VERSION and is
+# at least NODE_MIN_VERSION. Only the major is compared with the pin:
+# the Dockerfile's node stages start from a node 22 alpine image whose
+# exact version is not the pin, and nvm cannot install a prebuilt node
+# on alpine. node itself compares the versions: major, then minor, then
+# patch. A node that fails does not pass. script/bootstrap, script/fmt
+# and script/fmt-check carry this function unchanged.
+node_ok() {
+    if ! command -v node >/dev/null 2>&1; then return 1; fi
+    node -e '
+        const have = process.versions.node.split(".").map(Number);
+        const want = process.argv[1].split(".").map(Number);
+        const pinned = process.argv[2].split(".").map(Number);
+        if (have[0] !== pinned[0]) process.exit(1);
+        for (let i = 0; i < 3; i++) {
+            if (have[i] !== want[i]) process.exit(have[i] > want[i] ? 0 : 1);
+        }
+    ' "$NODE_MIN_VERSION" "$NODE_VERSION"
+}
+
 main() {
     cd "$ROOT"
     # script/bootstrap links the node, yarn and gofmt it installs into
     # ~/.local/bin, which the shell that called it may not have on PATH.
     PATH="$HOME/.local/bin:$PATH"
-    "$ROOT/script/frontend-fmt"
+    # prettier runs under a node script/bootstrap would use: the node on
+    # PATH when it passes node_ok, and otherwise the pinned node in nvm.
+    # nvm is a bash script, hence the bash.
+    if node_ok; then
+        "$ROOT/script/frontend-fmt"
+    elif [ -s "$HOME/.nvm/nvm.sh" ]; then
+        bash -c '. "$HOME/.nvm/nvm.sh" && nvm use "$1" >/dev/null && "$2"' \
+            bash "$NODE_VERSION" "$ROOT/script/frontend-fmt"
+    else
+        echo "fmt: no node script/bootstrap would use; run it first" >&2
+        exit 1
+    fi
     gofmt -l -w cmd internal
 }
 

script/fmt-check

@@ -6,12 +6,47 @@ set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
+# Must match the pins in script/bootstrap.
+NODE_VERSION="22.17.0"
+NODE_MIN_VERSION="22.13.0"
+
+# node_ok: the node on PATH has the major version of NODE_VERSION and is
+# at least NODE_MIN_VERSION. Only the major is compared with the pin:
+# the Dockerfile's node stages start from a node 22 alpine image whose
+# exact version is not the pin, and nvm cannot install a prebuilt node
+# on alpine. node itself compares the versions: major, then minor, then
+# patch. A node that fails does not pass. script/bootstrap, script/fmt
+# and script/fmt-check carry this function unchanged.
+node_ok() {
+    if ! command -v node >/dev/null 2>&1; then return 1; fi
+    node -e '
+        const have = process.versions.node.split(".").map(Number);
+        const want = process.argv[1].split(".").map(Number);
+        const pinned = process.argv[2].split(".").map(Number);
+        if (have[0] !== pinned[0]) process.exit(1);
+        for (let i = 0; i < 3; i++) {
+            if (have[i] !== want[i]) process.exit(have[i] > want[i] ? 0 : 1);
+        }
+    ' "$NODE_MIN_VERSION" "$NODE_VERSION"
+}
+
 main() {
     cd "$ROOT"
     # script/bootstrap links the node, yarn and gofmt it installs into
     # ~/.local/bin, which the shell that called it may not have on PATH.
     PATH="$HOME/.local/bin:$PATH"
-    "$ROOT/script/frontend-fmt-check"
+    # prettier runs under a node script/bootstrap would use: the node on
+    # PATH when it passes node_ok, and otherwise the pinned node in nvm.
+    # nvm is a bash script, hence the bash.
+    if node_ok; then
+        "$ROOT/script/frontend-fmt-check"
+    elif [ -s "$HOME/.nvm/nvm.sh" ]; then
+        bash -c '. "$HOME/.nvm/nvm.sh" && nvm use "$1" >/dev/null && "$2"' \
+            bash "$NODE_VERSION" "$ROOT/script/frontend-fmt-check"
+    else
+        echo "fmt-check: no node script/bootstrap would use; run it first" >&2
+        exit 1
+    fi
     unformatted="$(gofmt -l cmd internal)"
     if [ -n "$unformatted" ]; then
         echo "Go files not formatted:" >&2