Upstream #1965 moved the tsc --listFilesOnly machinery into
scripts/lib/tsc-program.mjs (shared with the new verify:dep-lockstep),
still spawning `npx` — which is ENOENT on Windows. Resolve the conflict
by taking upstream's factoring and porting the #1939 fix into the lib:
rawProjectListing and verify-typecheck-coverage's --showConfig pass now
spawn process.execPath with the cached, hard-failing tscEntry resolver
(exported from tsc-program.mjs). Fixture copies in both main tests pick
up the new lib import graph. verify:dep-lockstep now runs on Windows
too.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Two findings from the Copilot review of #1965, both real.
1. The candidates were flattened to package names before the version
comparison, so a third install holding a different copy failed the guard
even when no program loads that copy beside another — and the diagnostic
named an install that never took part. `crossInstallPackages` now returns
the co-occurrences themselves (name → program → install → entry paths) and
`findSkew` compares per program, across only the installs that met there.
2. Folding a nested copy onto its outermost install lost the path that
identifies which copy was loaded, and the version was then read from the
install's top-level entry — absent or differently versioned, either way
letting a real pair pass. `classifyModulePath` now also returns the
`entryPath` npm keys the lockfile by, `topLevelLockVersions` becomes
`lockVersionsByPath`, and each holder is priced from the entry the program
resolved. A resolved copy with no lockfile entry is now a hard failure
rather than a silently dropped holder.
The failure output prints `in <program>` with each holder's install path
beside its version, so a nested copy is distinguishable from a top-level one.
Signed-off-by: cliffhall <cliff@futurescale.com>
`verify:dep-lockstep` derived its candidate set from the packages the shared
first-party sources named *directly*, so a package whose declarations reach a
program only through another package's `.d.ts` was invisible to it — it could
skew across installs and recreate the two-copy blow-up #1896 was about while
the guard stayed green. `@modelcontextprotocol/sdk` was the live example: never
written in first-party code, yet 16 of its `.d.ts` files land in clients/web's
test program.
Replace the derivation with the measured one: list every client tsconfig
project with `tsc --listFilesOnly`, map each resolved `node_modules` file to
its owning install and package, and keep the packages that reach ONE program
from TWO installs. That is exactly the set that can put two structurally
distinct copies of a type in front of one checker. The rest of the guard is
unchanged — top-level lockfile comparison, deny-by-default, `TOLERATED_SKEW` as
a name allowlist scoped to within-a-major.
The listing machinery moves to `scripts/lib/tsc-program.mjs`, shared with
`verify:typecheck-coverage`, so the two guards can't disagree about what a
program contains. It is deliberately not cached to disk between the two
processes: a stale fingerprint would make a guard measure a program that no
longer exists and pass on a real miss. The second pass costs ~14s.
`TOLERATED_SKEW` is now empty. `jose` and `@modelcontextprotocol/ext-apps` are
root-only since #1970 and cannot skew; `react` (whose types are `@types/react`,
resolved from one install) and `hono` never reach one program from two
installs. Each would be a rationale for a skew that cannot occur.
Closes#1965
Signed-off-by: cliffhall <cliff@futurescale.com>
From Copilot's fifteenth pass of #1962. `installDirs` filtered on the presence
of a lockfile, so a missing one silently removed that install from the
comparison rather than failing. For the root — the install every shared source
resolves from — that meant the guard could report success from client locks
alone, which is the deny-by-default contract inverted.
Enrolment is now by `package.json` (an install we are meant to compare), with
the root always enrolled, and a missing lockfile is a named, loud failure. A
`clients/` directory with no `package.json` is not an install and is skipped,
so a stray scratch dir isn't asked for a lockfile it should never have.
Three regression cases: a missing client lockfile in a fixture that IS skewed
(so failing open would show as a pass), a missing ROOT lockfile, and a stray
`clients/` dir that must not be enrolled.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
From Copilot's eleventh pass of #1962, and the most consequential kind of bug
for a gate: it failed *open*.
`topLevelLockVersions` returns an empty map for anything without a v2+
`packages` table — a lockfileVersion 1 file, or a malformed one. `main()` fed
that straight into the comparison, so such an install contributed no holders
at all, and a genuine skew among the remaining installs was reported as
aligned. The guard would have said OK to exactly what it exists to catch.
`hasReadableLockShape` now gates every discovered lockfile before any
comparison, requiring a `packages` object carrying the `""` root entry npm
always writes — "has a packages key" is not enough. An unreadable one is named
and exits 1, telling you to regenerate it. A JSON parse failure likewise
reports the file rather than dying on a bare SyntaxError with no path in it.
The empty-map behavior of the pure helper is kept and its test now says why it
is safe: the shape check rejects those inputs before they can reach
`findSkew`.
Three regression cases: a v1 lockfile in a fixture that IS skewed (so failing
open would show as a pass), a `packages` table with no root entry, and the
unit table for the predicate. Fixtures now write the `""` root entry, matching
real npm output.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
From Copilot's tenth pass of #1962. The suite covered only pure helpers, so a
regression in source enumeration, install discovery, lockfile loading, the
sibling-guard vouch, or the nonzero exit on real skew would have left it
green — and the negative cases had only ever been run by hand, once per review
round.
Five end-to-end cases build a throwaway repo and run the guard as a
subprocess: aligned installs exit 0; a skewed one exits 1 naming the package
and every holder while leaving the agreeing package unreported; a package
imported only by `test-servers/src` still fails (so dropping the second shared
tree can't pass); a shared source matching no tracked file fails; and a
`validate` chain that stopped running `verify:format-coverage` fails the vouch
even when the versions are fine.
The fixture must be realpath'd. On macOS `tmpdir()` is `/var/…`, a symlink to
`/private/var/…`, and the guard runs `main()` only when `import.meta.url` (the
resolved path) matches `process.argv[1]` — so launching it via the unresolved
path loads the module and does nothing, exiting 0 silently. That is how all
five first "passed" as no-ops, and the comment records it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
