`scripts/pr-reviews-test.sh` passed 19/19 locally and 2/19 in CI on the same
commit, because a multi-assignment `local` is not left-to-right on bash 5
while macOS's bash 3.2 tolerates it. The obvious half of the fix is pinning
the shell. The half that decides the design is not.
.envrc DOES already put a nix bash 5.3.15 on PATH, which is CI's semantics --
and it is not enough. `pkgs.mkShell` exports `name`, `out`, `outputs`,
`system`, `shell`, `builder`, `stdenv`, `phases` and about twenty more
generically-named variables that CI does not have, so a script reading one by
accident under `set -u` is SILENT in the dev shell and fatal in CI. That is
exactly what happened: the broken clause read `$name`, and in the dev shell
`$name` was `nix-shell-env`. Measured at 051f541^ on one machine:
macOS /bin/bash 3.2 19 passed, 0 failed
direnv exec . ./scripts/pr-reviews-test.sh 19 passed, 0 failed
the same, with `name` unset 2 passed, 17 failed
Two reasons for green, one of them the correct interpreter. A dev shell is a
third environment, not a reproduction of CI.
A nix shebang was measured and declined, on availability rather than speed:
warm, `nix shell nixpkgs#bash --command true` is 61.8ms against an ambient
5.1ms, and `nix-shell -p bash --run true` -- the manpage form -- is 675.2ms,
132x, inside git's merge machinery for beads-merge-driver.sh. But only the
`kb` job installs nix; build, test, wasm, js, harness-lint and browser have
none, so a nix shebang needs an installer step on three more jobs to reach a
bash those runners already ship. zsh is not a shebang change and the runner
does not have it either. Both declined in context/code/tooling.md section 5.
What lands instead pins interpreter and environment together, in one place:
scripts/checkers.sh is the one entry point for every check_the_checker, used
verbatim by CI and by the local gate. It pins a bash >= 5 (ambient first, nix
only when the ambient one is older, exit 3 when neither), scrubs the
environment to an allowlist, and refuses any shell shebang in scripts/ that
is not `#!/usr/bin/env bash`. The pinned bash goes on the front of PATH so
inner invocations get it too -- which is where the fault actually lived.
The second undetected split is closed with it: the four `#!/bin/sh` and one
`#!/usr/bin/env sh` scripts are now bash, and the six places that ran a
script through an explicit `sh` -- overriding the callee's own shebang, which
is the same disease -- now invoke it directly.
Verification, injected against the real script: restoring pr-reviews'
multi-assignment `local` leaves `sh scripts/pr-reviews-test.sh` at 22/22 and
`direnv exec . ./scripts/pr-reviews-test.sh` at 22/22, while
`./scripts/checkers.sh pr-reviews` reports 2 passed, 20 failed, exit 1 --
matching the 2/19 CI actually reported. scripts/checkers-test.sh is twelve
cases, each injecting rather than asserting; the pair that carries it runs
one fixture both ways, so the `set -u` case is a test of the runner and not
of `set -u`.
The old local gate was `for t in scripts/*-test.sh; do sh "$t"; done`, which
overrides every shebang with /bin/sh -- so it ran every suite under bash 3.2
in sh-mode regardless of what the file said. It is replaced by
`./scripts/checkers.sh`.
Workspace suite unchanged at 1689 passing over 38 binaries.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FC2jVn8Au7E9JPkw6bwXXH
improvise-oujb. A tagged release carried four native tarballs and nothing for
the web; the site shipped only by ci.yml's pages-deploy, on a push to main.
Pages keeps tracking main (user, 2026-09-22: "I like Pages showing the latest
main for now"), so this is a CAPTURE, not a second deployment: the tarball is a
self-hostable copy of the site as of the tag and a rollback target, not what a
visitor to the published site is running. pages-deploy is untouched.
Mechanism is dist's own [[dist.extra-artifacts]], so it survives `dist init`:
`dist plan` under the pinned 0.30.4 lists improvise-web.tar.gz beside the four
platform tarballs and `dist generate` leaves release.yml byte-identical. The
build command is scripts/build-web-release.sh, which calls web/build.sh and
web/assemble.sh -- the same two scripts ci.yml and a developer run, so there is
no second way to build the bundle. Its toolchain pins come from
scripts/web-toolchain-versions.env, which ci.yml's build job now reads too.
`github-build-setup` was measured and does NOT help: it injects into
build-local-artifacts only, which is the wrong job for a global artifact.
The page now names the build it was assembled from in #build-version, stamped
by web/assemble.sh with the same token as the bundles and verified by the same
scripts/assemble-stamp.sh gate. An unassembled tree honestly reads "unstamped".
Verified by running `dist build --artifacts=global` locally: the script ran,
the site assembled, and dist placed improvise-web.tar.gz in target/distrib.
Not verified: a real tag push, which would require cutting a tag.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FC2jVn8Au7E9JPkw6bwXXH
Edward Langley