feat(devx): a closure-wide declaration sweep after the workspace build names a package whose .d.ts vanished (#15042) (#15796)

* feat(devx): sweep the built closure for vanished declarations after the workspace build

`scripts/check-dts-emitted.mjs` runs per package, immediately after that
package's own `tsup`, and is the last thing that ever looks. On #15042's
observation it reported `3/3 declared declaration file(s) present` and the
files were gone later in the same tree, with no second build and no `rm`.

Adds `scripts/check-dts-closure.mjs`: a sibling that re-reads the whole built
workspace once, AFTER the closure build. The derivation is imported from the
per-package guard, not re-written, so the per-package contract is untouched
and there is still one answer to "which declarations does this manifest
promise". Exit 1 names the package and each missing file; exit 3
PREREQUISITE NOT MET when no package has a `dist/` at all, never a pass.

Wired as `check:dts-closure` and run directly after the closure build in
lint.yml's two full-closure lanes and ci.yml's `build-core`.

Does not touch any `tsup.config.ts` `clean` semantics and makes no claim
about what deleted the files.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012zGPuVVX3deAx9LdjK8jCk

* fix(devx): the closure sweep's self-test names its failure instead of crashing

Ablating the sweep predicate (`if (missing.length > 0)` -> `if (false)`) made
the self-test exit 1 through a TypeError on `findings[0].missing`, so the
named case that had already failed never reached the report. The optional
read keeps the exit code and restores the diagnostic.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012zGPuVVX3deAx9LdjK8jCk

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: claude[bot]

.github/workflows/ci.yml

@@ -1492,6 +1492,19 @@ jobs:
       - name: Build packages (excluding docs)
         run: pnpm build
 
+      # [#15042] The closure-wide declaration re-check. `check-dts-emitted` runs
+      # per package, immediately after that package's `tsup`, and is the LAST
+      # thing that ever looks: on the filing observation it reported
+      # `3/3 declared declaration file(s) present` and the files were gone later
+      # in the same tree, with no second build and no `rm`. Sits directly after
+      # the build so the tree the steps BELOW read is the tree this swept — a
+      # package whose declarations are absent makes an importing symbol `any`,
+      # and the direction that does NOT throw is a suite passing against a type
+      # nothing is checking (#7668, #12078). No `dist/` anywhere is exit 3
+      # PREREQUISITE NOT MET, never a pass.
+      - name: Sweep the built closure for vanished declarations
+        run: pnpm check:dts-closure
+
       # A package that builds with plain `tsc` and does not exclude tests emits
       # `dist/**/*.test.js`. Two costs, and the second is the dangerous one:
       #

.github/workflows/lint.yml

@@ -5014,6 +5014,19 @@ jobs:
       - name: Build the ledgered packages' dependencies
         run: pnpm exec turbo run build --filter='./packages/*' --filter='./packages/*/*'
 
+      # [#15042] The closure-wide declaration re-check. `check-dts-emitted` runs
+      # per package, immediately after that package's `tsup`, and is the LAST
+      # thing that ever looks: on the filing observation it reported
+      # `3/3 declared declaration file(s) present` and the files were gone later
+      # in the same tree, with no second build and no `rm`. Sits directly after
+      # the build so the tree the steps BELOW read is the tree this swept — a
+      # package whose declarations are absent makes an importing symbol `any`,
+      # and the direction that does NOT throw is a suite passing against a type
+      # nothing is checking (#7668, #12078). No `dist/` anywhere is exit 3
+      # PREREQUISITE NOT MET, never a pass.
+      - name: Sweep the built closure for vanished declarations
+        run: pnpm check:dts-closure
+
       # ⚠️ `NODE_OPTIONS` here is HALF of the heap ceiling this gate runs tsc
       # under, and the two halves ship together or not at all (#14569, ruled
       # 2026-09-03). The other half is `CI_TSC_HEAP_CEILING_MB` in
@@ -5189,6 +5202,19 @@ jobs:
       - name: Build the nested packages the consumer gates resolve through
         run: pnpm exec turbo run build --filter='./packages/*' --filter='./packages/*/*'
 
+      # [#15042] The closure-wide declaration re-check. `check-dts-emitted` runs
+      # per package, immediately after that package's `tsup`, and is the LAST
+      # thing that ever looks: on the filing observation it reported
+      # `3/3 declared declaration file(s) present` and the files were gone later
+      # in the same tree, with no second build and no `rm`. Sits directly after
+      # the build so the tree the steps BELOW read is the tree this swept — a
+      # package whose declarations are absent makes an importing symbol `any`,
+      # and the direction that does NOT throw is a suite passing against a type
+      # nothing is checking (#7668, #12078). No `dist/` anywhere is exit 3
+      # PREREQUISITE NOT MET, never a pass.
+      - name: Sweep the built closure for vanished declarations
+        run: pnpm check:dts-closure
+
       - name: Type check example apps
         run: pnpm --filter './examples/*' run typecheck
 

package.json

@@ -145,6 +145,7 @@
     "check:published-readme-exports": "node scripts/check-published-readme-exports.mjs --self-test && node scripts/check-published-readme-exports.mjs",
     "check:published-readme-links": "node scripts/check-published-readme-links.mjs --self-test && node scripts/check-published-readme-links.mjs",
     "check:dual-build-cjs-loads": "node scripts/check-dual-build-cjs-loads.mjs --self-test && node scripts/check-dual-build-cjs-loads.mjs",
+    "check:dts-closure": "node scripts/check-dts-closure.mjs --self-test && node scripts/check-dts-closure.mjs",
     "check:type-check-coverage": "node scripts/check-type-check-coverage.mjs --self-test && node scripts/check-type-check-coverage.mjs",
     "check:type-check-debt": "node scripts/check-type-check-coverage.mjs --self-test && node scripts/check-type-check-coverage.mjs --re-measure",
     "check:driver-conformance": "node scripts/check-driver-conformance.mjs --self-test && node scripts/check-driver-conformance.mjs",