From Copilot's eighth pass of #1962. The no-op guard tested only
`files.length === 0`, which stopped meaning anything once
`SHARED_SOURCE_FILES` was added: `vitest.shared.mts` alone keeps the total
nonzero, so a moved or renamed `core/` would leave the guard deriving
candidates from a near-empty set and passing on skew it exists to catch.
`sourcesWithNoFiles` now requires every configured dir and every named file to
have contributed, and names the ones that didn't. Directory matching is on a
path separator, so a prefix sibling (`core-internal/`) can't vouch for a
renamed `core/`.
Also drops two test comments left stale by the move to `ts.preProcessFile` —
they still described the deleted TRIVIA regex.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
The guard resolves typescript from `clients/web`. The realistic way for that
to fail is a root install run with INSPECTOR_SKIP_CLIENT_INSTALL=1, which
leaves `clients/web/node_modules` empty — and a bare MODULE_NOT_FOUND stack
gives no hint that the fix is `npm install` at the root. Throw with that
guidance and the original error as `cause`.
Deliberately not a silent skip: an unrun guard guards nothing, which is the
failure mode the sibling-vouch ring exists to prevent.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
From Copilot's sixth pass of #1962.
Take the TypeScript-parser suggestion, which was raised across three rounds
and was right. The regex scan got both directions wrong and every widening
traded one failure for the other: it *missed* valid syntax (`import x =
require(…)`, an import-attributes argument, a comment between tokens — each a
silent miss, so the package never entered the candidate set and its skew
passed), and it *invented* names from prose, since `// adapted from "react"`
is indistinguishable from an import to a pattern that cannot tell code from a
comment. The earlier prose test only passed because `cwd omitted` isn't a
valid package name.
`ts.preProcessFile` is the cheap answer I'd missed while arguing against the
full AST: TypeScript's lightweight pre-parse scanner, no parse tree and no
type checking, purpose-built to return module specifiers. It handles every
import form, trivia, strings, and regex literals, and never reads a comment as
code. typescript resolves from `clients/web`, which already carries it, via
the `createRequire` base `smoke-web-browser.mjs` established — a bare import
would resolve relative to `scripts/`, not the cwd.
The derived set drops 18 → 17 real names: every genuine package is retained
and the one prose artifact is gone. Regression tests now use *real* package
names in comments and strings, the case the old test couldn't cover.
Also records the KNOWN BOUNDARY the review's other finding identified.
Candidates cover what the shared sources name directly, so a package reaching
the program only through another package's `.d.ts` is invisible —
`@modelcontextprotocol/sdk` is the live example, skewed 1.29.0 vs 1.30.0 and
present in web's program from both installs, never written in first-party
code. Closing it properly changes what the guard measures, so it is tracked
as #1965, with both candidate derivations measured there: a lockfile closure
is unusable (155 packages, 25 skewed, nearly all irrelevant tooling, and it
misses the SDK anyway), while `tsc --listFilesOnly` is correct and small
(15 for clients/web).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
From Copilot's fifth pass of #1962. `TRIVIA` covered block comments but not
`//`, despite the contract right above it saying a comment is legal wherever
whitespace is — so `import(// lazy\n"pkg")`, `require(// lazy\n"pkg")`, and
`from // reason\n"pkg"` were stepped over, and such a package would never
enter the candidate set. Same silent-miss direction as the block-comment gap.
Both comment syntaxes are now covered. The line-comment branch runs to
end-of-line only; the newline itself is matched by TRIVIA's `\s` branch.
Regression test added alongside the block-comment one.
The derived set is unchanged at 18 real names — widening trivia does not
admit prose, since a specifier must still follow immediately and
`packageNameOf` rejects anything not shaped like one.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
Both suppressed comments from Copilot's fourth pass of #1962.
TypeScript allows a comment anywhere whitespace is legal, so
`import(/* webpackIgnore: true */ "pkg")` and `from /* why */ "pkg"` are
valid imports the patterns stepped over. That is the dangerous direction: a
missed specifier never enters the candidate set, so the package's skew passes
the guard silently, against the over-approximation the module claims. A
`TRIVIA` fragment now stands in for `\s*` at every inter-token position, with
regression cases for the commented static, dynamic, side-effect, and
`require` forms.
I did not move to the TypeScript parser. This is a root `scripts/` `.mjs`
tool with no bundler and no TS dependency; pulling in a compiler API to read
import specifiers is a lot of machinery for a scan that only needs to
over-approximate, and each missed form is a one-line pattern with a test
beside it. The derived set is unchanged at 18 real names, so nothing here
widens what is checked today.
The README's command row also still described the candidate scan as `core/`
and `test-servers/src` only, omitting the `vitest.shared.mts` the guard now
includes; it also never mentioned that an allowlisted package is tolerated
only within a major. Both stated.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
All four suppressed comments from Copilot's third pass of #1962. Each was
correct.
The candidate boundary omitted `vitest.shared.mts` — root-owned, imported by
every client's vitest config, and already treated as shared non-client source
by `verify:typecheck-coverage`. It imports only Node built-ins today, which
is exactly why the omission would have gone unnoticed until a third-party
import appeared there, resolved from the root, and skewed. Shared *files* are
now a first-class list beside the shared dirs.
The allowlist was a blanket exemption by name. Each entry's rationale
establishes that a patch/minor difference is benign, which is no evidence
that a React 18-vs-19 or Hono 4-vs-5 split would be — that is a different
type surface. Being listed now tolerates skew only *within a major version*;
a cross-major skew fails like anything else. Deriving the major from the
lockfile version keeps this automatic, with no per-package range to maintain
and bump. A version that can't be parsed is treated as "cannot prove same
major" and fails rather than passes.
`verify-format-coverage.mjs`'s comment overstated the vouching graph: the
three guards do not each check the others. This one checks both siblings;
each sibling checks only this one. Described as it actually works.
The AGENTS.md rule said to bump a shared dependency in "root + all four
clients", but launcher declares no zod and `findSkew` ignores installs where
a package is absent — so the rule as written asked for spurious dependencies.
Reworded to every install that *declares* it, and mirrored in
`.github/copilot-instructions.md`.
The failure output follows: it no longer advises adding a package that is
already allowlisted, saying "MAJOR skew" instead, and it names all three
shared sources rather than the two dirs.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
From the suppressed comment on Copilot's second pass of #1962. Under-
approximating is the dangerous direction here: a package the scan misses
never enters the candidate set, so its skew passes the guard silently.
Three forms went unmatched. `import x = require("pkg")` and a bare
`require("pkg")` are the ordinary import syntax in `.cts` — which the
previous commit just admitted to the scan, so leaving them out would have
been an inconsistency introduced by that widening. A dynamic import carrying
import attributes (`import("pkg", { with: … })`) was missed because the
pattern required the closing paren. A static template literal
(`import(\`pkg\`)`) was missed for want of a backtick in the quote class.
Backticks are accepted only in the *call* forms. A `from` clause requires a
string literal, so allowing them there would buy nothing while reopening the
prose hazard the anchored specifier pattern closes: inline code in comments
is written with backticks throughout this codebase, and admitting it inflated
the derived set from 18 names to 41 with prose fragments (`tools`,
`connect()`, `messages`). Inert today, since a name absent from every
lockfile contributes nothing — but a prose word colliding with a real package
name would silently widen the set. Pinned with a regression test.
The real set is unchanged at 18, so these forms add no package today; they
close the syntax against the one that arrives later.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
Both from Copilot's review of #1962.
The candidate-set enumeration matched only `.ts`/`.tsx`, while
`verify:format-coverage` and `verify:typecheck-coverage` both gate all four
TypeScript extensions. No `.mts`/`.cts` exists under `core/` or
`test-servers/src` today, which is exactly why the omission would have gone
unnoticed until a shared dependency arrived through one and skewed — the
failure this guard exists to prevent. Extract the rule as the exported
`isSharedSourceFile` predicate, cover all four extensions, and pin it with
regression tests (including path-boundary anchoring, so a `core-internal/`
sibling isn't swept in).
The README's `validate` row also omitted `test:scripts` and claimed typecheck
was cli/tui only; launcher runs one too, and web typechecks via `tsc -b`
inside its `build`. Restate the row to match the actual script chain.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
Closes#1896
`clients/web`'s `tsc -b` exhausted the 4GB default heap at zod 4.4.x. The
cause is not a zod regression nor a pathological inference site of ours: it
is two copies of zod at *mismatched versions* inside one tsc program.
`clients/web/tsconfig.test.json` compiles `test-servers/src`, whose files
resolve zod (and the SDK's zod) from the **root** install, alongside web's
own sources, which resolve from `clients/web/node_modules`. At 4.3.6 vs
4.4.3 TypeScript must relate two structurally-distinct declarations of every
`@modelcontextprotocol/*` schema type, which is exponential over a recursive
generic surface — `TS2589 Type instantiation is excessively deep`, then OOM.
Bumping root zod to 4.4.3 and changing nothing else returns the build to
baseline: 11.4s and 2,567,882 instantiations, against 11.2s / 2,567,503 at
4.3.6. Two copies at the same version are harmless; skew is what explodes.
So drop the `~4.3.6` hold on `clients/web` and move all four manifests and
lockfiles to zod 4.4.3 together, and add `verify:dep-lockstep` to `validate`
to keep them there. The guard derives its candidate set from what `core/`
and `test-servers/src` import, compares the committed lockfiles' top-level
entries, and fails deny-by-default on any skew not in the annotated
`TOLERATED_SKEW` allowlist. It joins the existing mutual-vouch ring so
dropping it from `validate` is caught by `verify:format-coverage`.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
