plasmic-mcp-registry: withPlasmicRegistry package auto-detection returns empty (6 failing tests)

[field123]

withPlasmicRegistry's package auto-detection returns an empty list, so no Plasmic packages are detected and the webpack externals rule never fires. Six tests in packages/plasmic-mcp-registry/src/__tests__/next.test.ts fail.

Reproduce

yarn --cwd packages/plasmic-mcp-registry test

FAIL  next.test.ts > auto-detects @plasmicpkgs/* packages from dependencies
  AssertionError: expected [] to include '@plasmicpkgs/commerce'
FAIL  next.test.ts > auto-detects @elasticpath/plasmic-* packages
  AssertionError: expected [] to include '@elasticpath/plasmic-mcp-registry'
FAIL  next.test.ts > auto-detects @plasmicapp/host
  AssertionError: expected [] to include '@plasmicapp/host'
FAIL  next.test.ts > detects packages from devDependencies
  AssertionError: expected [] to include '@plasmicpkgs/graphql'
FAIL  next.test.ts > handles empty config input
  AssertionError: expected 0 to be greater than 0
FAIL  next.test.ts > webpack externals externalizes Plasmic packages on server
  AssertionError: expected "spy" to be called with arguments: [ null, …(1) ]

Test Files  1 failed | 5 passed (6)
Tests       6 failed | 77 passed (83)

Not a regression

Reproduced at d3b343f72 — the commit immediately before PR #393 merged — with the identical 6 failures. Pre-existing, and unrelated to the security batch.

Why it matters

The failures are consistent with the detection returning [] rather than with stale assertions, so the feature itself looks broken rather than the tests being wrong. Worth confirming which before fixing: if detection genuinely never matches, consumers relying on automatic externalization are silently getting none.

[field123]

Correcting my own framing: the empty result is intentional, not a broken feature. PLASMIC_PACKAGE_PATTERNS and WEBPACK_EXTERNAL_PATTERNS in src/next.ts are deliberately [], with a comment explaining why:

Empty by default — with the eval("require") handling in capture.ts for @plasmicapp/host, there's no remaining reason to externalise Plasmic-related packages at the Next config level. Externalisation forces Node to load modules with a separate React instance, which breaks SSR of client components whose hooks then hit a null dispatcher.

So the six failures are stale tests asserting the old externalising behaviour, not evidence of a regression. The fix is to update the tests to the current design, not to restore auto-detection.

That change is also load-bearing — see #397. The published 0.2.1 still externalises; master's 0.2.1 does not, and that difference is what makes the example render.