This follows the user's rulings: CI should not care which bash or which
standard utilities it runs, and jobs take what the ci dev shell provides.
- checkers.sh: remove find_modern_bash, the 5.1 floor (improvise-fd0j) and
exit 3. Suites run under $BASH with PATH unchanged.
- checkers-test.sh: remove sections 2, 5 and 5b (the fake bashes and utilbin).
They existed only to pin the floor.
- scripts/kb: drop the BSD `stat -f` fallback. kb needs the dev shell for tpl,
and that shell's stat is GNU.
- ci.yml: remove every `shell: bash` override, so every step runs in the dev
shell. Remove the web-toolchain version probe and the Playwright
version/browser probe. The shell's PLAYWRIGHT_BROWSERS_PATH pins the
browsers. npm ci stays because @playwright/test is not nix-provided.
- flake.nix: update the comments that promised those CI checks.
Reasoning: context/code/tooling.md section 5. Evidence:
context/test-evidence/tooling.md.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VdfEGXA7aJ6ftMsCc9PJze
Section 5b (the bash 5.1 floor, #237) was written on a branch cut before the
NixOS-runner change (af44653f). That change moved section 5 off /usr/bin:/bin,
because on NixOS that path holds only env and sh. The two merged with no
conflict. On NixOS the runner then dies on `dirname` with exit 1, which turned
the KB job red on every PR at 666de199.
5b now uses utilbin too, and utilbin gains head and env for the 5.1 control.
Evidence and rivals: context/test-evidence/tooling.md.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VdfEGXA7aJ6ftMsCc9PJze
find_modern_bash accepted any 5.x, so a bash 5.0 was pinned and
pr-reviews-test.sh then failed on an invalid option. The probe now
reads major and minor; a 5.0 case and a 5.1 control guard it.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VdfEGXA7aJ6ftMsCc9PJze
`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
Edward Langley