chore(scripts): detect a SMOKE_BROWSER assignment in any shell dialect (#2146)

Copilot, sixth review: the run-script rule matched POSIX `NAME=value` only.
PowerShell is the DEFAULT shell on a Windows runner, so
`$env:SMOKE_BROWSER = "firefox"; npm run smoke` redirected the suite with the
guard silent — on exactly the workflow least likely to be read closely.

Three patterns now, one per dialect: POSIX (which also covers cmd's
`set NAME=…` and the GitHub-native `>> $GITHUB_ENV` append, since both carry
the same substring), PowerShell's `$env:NAME =` and `${env:NAME} =`, and the
.NET SetEnvironmentVariable call reachable from PowerShell. Regression cases
for all five spellings, plus a negative for a PowerShell assignment of
chromium.

Signed-off-by: Cliff Hall <cliff@futurescale.com>
Signed-off-by: cliffhall <cliff@futurescale.com>
This commit is contained in:
cliffhall 2026-08-27 01:40:27 -04:00
commit 74aa94fb1f
4 changed files with 92 additions and 15 deletions

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@ -1003,7 +1003,7 @@ Everything about the selection lives in **`scripts/lib/headless-browser.mjs`**
- **An unrecognized `SMOKE_BROWSER` is an error, never a fallback.** Falling back to Chromium would report a green Chromium run under a job labelled `webkit` — coverage claimed but not run, which is worse than none.
- **A launch failure names the engine that failed** and a remedy that works **from where the caller actually is**: `npm run smoke:web:<engine>`, or `npx playwright install --with-deps <engine>` run *from `clients/web`*. Naming `chromium` while WebKit was missing would send the reader to install a browser they already have — and naming a bare root-level `npx playwright` would send them to a version that is not the pinned one, which can install a browser revision the pinned Playwright still cannot launch.
- **Firefox is gated locally, not in CI, and that asymmetry is deliberate.** A GitHub Actions job was trialled and removed. It was cheap — ~2 minutes, parallel with the 15-minute `build` job, so zero added wall-clock — but across a dozen runs Firefox never once disagreed with Chromium, so it spent runner minutes on every push, from every branch, carrying a real flake surface (`playwright install --with-deps` runs `apt-get update`, which fails whenever a third-party repo in the runner image breaks) to re-confirm a result already in hand. Moving it into `npm run local:gate` keeps the check where a human is about to push a change they can still reason about, and pays for it once rather than on every push. **Don't re-add the CI job on the argument that cross-engine coverage is good in principle** — that argument was accepted, and the pre-push gate is what serves it. Re-add it on evidence: a cross-engine regression that reached `v2/main` because someone skipped the gate.
- **A guard enforces the split, so it cannot be undone by accident (#2146).** `scripts/lib/workflow-gate.mjs` is run by `npm run test:scripts` over every file under `.github/workflows/`, and fails the suite on: an invocation of a `local:*` script (the prefix *means* local-only, so a future sibling is covered without editing the guard); an invocation of a non-Chromium engine pass, derived from `SUPPORTED_BROWSERS` so a fourth engine extends the guard rather than opening a hole in it; an invocation of `smoke:web:engine`, whose engine comes from the environment and so cannot be read off the workflow at all; or `SMOKE_BROWSER` set to anything but a literal `chromium` — the back door that would redirect an otherwise innocent `npm run smoke`, and one that includes setting it to *nothing*, since present-and-empty is rejected rather than defaulted, and `container.env` as much as a job's own `env`. That rule is kind-aware — an `env:` key, or a shell assignment in a `run:` — so a script printing the variable's name is not read as setting it. A name built from a workflow **expression** counts as forbidden too (`smoke:web:${{ matrix.browser }}`, `local:${{ matrix.task }}`): a matrix the guard cannot read may well contain `firefox`, so an unreadable name is not waved through. Its limit is worth knowing — a fully opaque `npm run ${{ matrix.script }}` names no family at all and is not detectable. It deliberately does **not** forbid `npm run smoke`, `smoke:web:chromium`, or `smoke:tui`: those belong in CI and are there today, and `smoke:tui` self-skips under `process.env.CI` on its own. It **parses** the workflow (via the root-declared `yaml` package) and descends the schema's executable paths — workflow `env`, job `env`/`container.env`/`with`, step `run`/`env`/`with`, with YAML aliases resolved — rather than matching pairs by key name anywhere in the tree, which would scan a workflow input legitimately named `env` and fail the gate on documentation of the gate. So it reads only what executes — so ordinary metadata such as a step `name:` explaining the rule is not reported as an invocation of it (Copilot); comments are skipped for the same reason, and because a guard that made the workflow undocumentable would be traded for the wrong thing. That scoping is a stated limit rather than a hidden one: an execution vector outside those three positions is not seen.
- **A guard enforces the split, so it cannot be undone by accident (#2146).** `scripts/lib/workflow-gate.mjs` is run by `npm run test:scripts` over every file under `.github/workflows/`, and fails the suite on: an invocation of a `local:*` script (the prefix *means* local-only, so a future sibling is covered without editing the guard); an invocation of a non-Chromium engine pass, derived from `SUPPORTED_BROWSERS` so a fourth engine extends the guard rather than opening a hole in it; an invocation of `smoke:web:engine`, whose engine comes from the environment and so cannot be read off the workflow at all; or `SMOKE_BROWSER` set to anything but a literal `chromium` — the back door that would redirect an otherwise innocent `npm run smoke`, and one that includes setting it to *nothing*, since present-and-empty is rejected rather than defaulted, and `container.env` as much as a job's own `env`. That rule is kind-aware — an `env:` key, or an assignment in a `run:` — so a script printing the variable's name is not read as setting it; and the `run:` half covers POSIX, cmd, the `>> $GITHUB_ENV` append and PowerShell (the default shell on a Windows runner), not just `NAME=value`. A name built from a workflow **expression** counts as forbidden too (`smoke:web:${{ matrix.browser }}`, `local:${{ matrix.task }}`): a matrix the guard cannot read may well contain `firefox`, so an unreadable name is not waved through. Its limit is worth knowing — a fully opaque `npm run ${{ matrix.script }}` names no family at all and is not detectable. It deliberately does **not** forbid `npm run smoke`, `smoke:web:chromium`, or `smoke:tui`: those belong in CI and are there today, and `smoke:tui` self-skips under `process.env.CI` on its own. It **parses** the workflow (via the root-declared `yaml` package) and descends the schema's executable paths — workflow `env`, job `env`/`container.env`/`with`, step `run`/`env`/`with`, with YAML aliases resolved — rather than matching pairs by key name anywhere in the tree, which would scan a workflow input legitimately named `env` and fail the gate on documentation of the gate. So it reads only what executes — so ordinary metadata such as a step `name:` explaining the rule is not reported as an invocation of it (Copilot); comments are skipped for the same reason, and because a guard that made the workflow undocumentable would be traded for the wrong thing. That scoping is a stated limit rather than a hidden one: an execution vector outside those three positions is not seen.
- **This makes `npm run local:gate` a strict superset of GitHub CI rather than a mirror of it.** That was already the direction (`smoke:tui` self-skips on CI and runs only locally); Firefox is the second such step. The invariant that still holds, and the one that matters, is the useful direction: **passing `npm run local:gate` locally means CI's gates will pass.**
- **`pack:verify` stays pinned to Chromium**, passing it explicitly rather than reading `SMOKE_BROWSER`. It is a _packaging_ check; the engine question belongs where the sandbox is under test, and pinning it also means it can't be pointed at an engine its npm script never installed.
- **WebKit fails the two App smokes**, for reasons nobody has identified — the failure stage even varies between runs. The investigation was dropped as not worth the effort once it became clear it does not reproduce in real Safari, and that an isolated repro of the suspected mechanism did not reproduce it under Playwright's WebKit either. Treat a WebKit failure as unexplained rather than as a defect until someone has actually looked.

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@ -502,7 +502,7 @@ So the direction that matters holds: **passing `npm run local:gate` means CI's g
**The gate is deliberately not named `ci`** ([#2146](https://github.com/modelcontextprotocol/inspector/issues/2146)). That name collided with `npm ci` — a built-in that clean-installs from the lockfile, does **not** run this script, and is one keystroke away — and it invited the cross-engine passes into GitHub CI by looking like the thing a workflow ought to call. There is **no back-compat alias**: `npm run ci` now fails with npm's missing-script error, which prints the available scripts.
That is the readable half, and prose rots. The enforced half is `scripts/lib/workflow-gate.mjs`, run by `npm run test:scripts` over every file under `.github/workflows/`. It fails the suite if a workflow invokes a `local:*` script, a non-Chromium engine pass (`smoke:web:firefox`, `smoke:web:webkit`), or `smoke:web:engine` (whose engine comes from the environment and so cannot be read off the workflow at all), or sets `SMOKE_BROWSER` to anything but a literal `chromium` (including setting it to *nothing*, which is present-and-empty rather than unset, and is rejected rather than defaulted). That last rule respects **where** it is written — an `env:` entry whose key is literally `SMOKE_BROWSER`, or a shell assignment in a `run:` script — so a script that merely *prints* the variable's name is not read as setting it. It treats a name built from a workflow **expression** the same way — `smoke:web:${{ matrix.browser }}`, `local:${{ matrix.task }}` — since a matrix the guard cannot read may well contain `firefox`. It deliberately does **not** forbid `npm run smoke`, `smoke:web:chromium`, or `smoke:tui` — those belong in CI and are there today. It **parses** the workflow and descends the schema's executable paths — workflow `env`, job `env`/`container.env`/`with`, step `run`/`env`/`with`, with aliases resolved — rather than matching text or key names, so it reads only what actually executes — so a step *name* explaining the rule is not mistaken for an invocation of it, and the workflow can still document itself.
That is the readable half, and prose rots. The enforced half is `scripts/lib/workflow-gate.mjs`, run by `npm run test:scripts` over every file under `.github/workflows/`. It fails the suite if a workflow invokes a `local:*` script, a non-Chromium engine pass (`smoke:web:firefox`, `smoke:web:webkit`), or `smoke:web:engine` (whose engine comes from the environment and so cannot be read off the workflow at all), or sets `SMOKE_BROWSER` to anything but a literal `chromium` (including setting it to *nothing*, which is present-and-empty rather than unset, and is rejected rather than defaulted). That last rule respects **where** it is written — an `env:` entry whose key is literally `SMOKE_BROWSER`, or an assignment in a `run:` script (POSIX, cmd, a `>> $GITHUB_ENV` append, or PowerShell — the default shell on a Windows runner) — so a script that merely *prints* the variable's name is not read as setting it. It treats a name built from a workflow **expression** the same way — `smoke:web:${{ matrix.browser }}`, `local:${{ matrix.task }}` — since a matrix the guard cannot read may well contain `firefox`. It deliberately does **not** forbid `npm run smoke`, `smoke:web:chromium`, or `smoke:tui` — those belong in CI and are there today. It **parses** the workflow and descends the schema's executable paths — workflow `env`, job `env`/`container.env`/`with`, step `run`/`env`/`with`, with aliases resolved — rather than matching text or key names, so it reads only what actually executes — so a step *name* explaining the rule is not mistaken for an invocation of it, and the workflow can still document itself.
| Script | What it does |
| ----------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |

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@ -35,8 +35,8 @@
* 4. Setting `SMOKE_BROWSER` to anything but a literal `chromium` — the back
* door that would redirect an otherwise innocent `npm run smoke`. This one
* is KIND-AWARE: an `env:` entry counts only when `SMOKE_BROWSER` is
* literally its key, and a `run:` script only on a shell assignment
* (`SMOKE_BROWSER=…`). A blanket text match rejected `echo
* literally its key, and a `run:` script only on an assignment — in any of
* the dialects a step can be written in, POSIX and PowerShell alike. A blanket text match rejected `echo
* "SMOKE_BROWSER: firefox"`, which sets nothing (Copilot). A shell
* assignment inside an `echo` is indistinguishable without parsing the
* shell, and inside a `run:` block erring toward the finding is the safe
@ -129,13 +129,42 @@ const DYNAMIC_ENGINE_RE = new RegExp(
String.raw`\bsmoke:web:${EXPRESSION}`,
"gi",
);
// A shell assignment inside a `run:` script. The YAML `env:` spelling is not
// matched by text at all — it is recognized structurally, by key, so that a
// script merely PRINTING `SMOKE_BROWSER: firefox` is not read as setting it
// (Copilot). `\S*` rather than `\S+` because `SMOKE_BROWSER=` sets the empty
// string, which `resolveBrowserName` rejects as present-but-empty rather than
// treating as unset.
const BROWSER_SHELL_RE = new RegExp(`\\b${BROWSER_ENV_VAR}=(\\S*)`, "g");
/**
* The ways a `run:` script can set the variable, one entry per shell dialect.
*
* The YAML `env:` spelling is deliberately absent — it is recognized
* structurally, by key, so that a script merely PRINTING `SMOKE_BROWSER:
* firefox` is not read as setting it (Copilot).
*
* More than one dialect is needed because `shell:` and the runner's OS decide
* which one a step is written in, and **PowerShell is the default on a Windows
* runner** — so a POSIX-only pattern is silent on exactly the workflow least
* likely to be reviewed closely (Copilot). `\S*` rather than `\S+` throughout,
* because assigning nothing sets the empty string, which `resolveBrowserName`
* rejects as present-but-empty rather than treating as unset.
*/
const BROWSER_ASSIGNMENTS = [
// POSIX `SMOKE_BROWSER=firefox`. Also covers cmd's `set SMOKE_BROWSER=…` and
// the GitHub-native `echo "SMOKE_BROWSER=…" >> $GITHUB_ENV`, since both carry
// the same `NAME=value` substring.
{ re: new RegExp(String.raw`\b${BROWSER_ENV_VAR}=(\S*)`, "g"), value: 1 },
// PowerShell `$env:SMOKE_BROWSER = "firefox"`, and its `${env:NAME}` form.
{
re: new RegExp(
String.raw`\$\{?env:${BROWSER_ENV_VAR}\}?\s*=\s*(\S*)`,
"gi",
),
value: 1,
},
// .NET, reachable from PowerShell: SetEnvironmentVariable("NAME", "value").
{
re: new RegExp(
String.raw`SetEnvironmentVariable\s*\(\s*["']${BROWSER_ENV_VAR}["']\s*,\s*["']([^"']*)["']`,
"gi",
),
value: 1,
},
];
// A shell assignment inside a `run:` script can still be quoted; a YAML value
// arrives already unquoted from the parser, so this is a no-op there.
@ -348,10 +377,12 @@ export function findWorkflowViolations(text, file = "<workflow>") {
? [{ value: region.value, match: region.text.trim() }]
: []
: kind === "run"
? [...line.matchAll(BROWSER_SHELL_RE)].map((m) => ({
value: m[1],
match: m[0].trim(),
}))
? BROWSER_ASSIGNMENTS.flatMap(({ re, value }) =>
[...line.matchAll(re)].map((m) => ({
value: m[value],
match: m[0].trim(),
})),
)
: // A `with:` value is an action input, not an environment. Whatever
// it names is covered by the script rules above.
[];

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@ -175,6 +175,52 @@ describe("findWorkflowViolations", () => {
text: workflow(" - run: SMOKE_BROWSER= npm run smoke"),
rules: [VIOLATION.BROWSER_ENV],
},
{
// Copilot, sixth review: PowerShell is the DEFAULT shell on a Windows
// runner, so a POSIX-only pattern is silent on exactly the workflow least
// likely to be read closely.
name: "flags a PowerShell assignment",
text: workflow(
' - run: |\n $env:SMOKE_BROWSER = "firefox"\n npm run smoke',
),
rules: [VIOLATION.BROWSER_ENV],
},
{
name: "flags the PowerShell ${env:NAME} spelling too",
text: workflow(
' - run: ${env:SMOKE_BROWSER}="webkit"; npm run smoke',
),
rules: [VIOLATION.BROWSER_ENV],
},
{
name: "flags a .NET SetEnvironmentVariable call",
text: workflow(
' - run: |\n [Environment]::SetEnvironmentVariable("SMOKE_BROWSER", "firefox")\n npm run smoke',
),
rules: [VIOLATION.BROWSER_ENV],
},
{
// cmd's `set NAME=value` and the GitHub-native `>> $GITHUB_ENV` append
// both carry the POSIX `NAME=value` substring, so one pattern covers all
// three — worth pinning, since that is not obvious from reading it.
name: "flags a cmd-style set",
text: workflow(" - run: set SMOKE_BROWSER=firefox && npm run smoke"),
rules: [VIOLATION.BROWSER_ENV],
},
{
name: "flags an append to $GITHUB_ENV",
text: workflow(
' - run: echo "SMOKE_BROWSER=firefox" >> $GITHUB_ENV',
),
rules: [VIOLATION.BROWSER_ENV],
},
{
name: "allows a PowerShell assignment of chromium",
text: workflow(
' - run: |\n $env:SMOKE_BROWSER = "chromium"\n npm run smoke',
),
rules: [],
},
{
name: "flags a workflow-level env override",
text: [