router-plugin: object-form loader breaks the code splitter when loader is split #8753

Which project does this relate to?

Router

Describe the bug

When loader is in a split grouping, a route whose loader uses the object form breaks the code splitter:

export const Route = createFileRoute('/posts/$id')({
  loader: {
    staleReloadMode: 'blocking',
    handler: async ({ params }) => load(params.id),
  },
  component: () => null,
})

• The ?tsr-split=loader chunk throws Unexpected splitNode type ☝️: ObjectExpression, so the build fails, and in dev the chunk fails to load.
• The route file replaces the whole object with lazyFn($$splitLoaderImporter, 'loader'), so staleReloadMode is gone.

A handler() {} method and a handler imported from another file fail the same way.

Complete minimal reproducer

https://gist.github.com/shkumbinhasani/0d4a67a26c2137a6e1ba1501a72e6e10

Steps to Reproduce the Bug

1. Clone the gist, run npm install, then npm start.
2. The script runs compileCodeSplitReferenceRoute and compileCodeSplitVirtualRoute from @tanstack/router-plugin 1.168.47 on the route above, with groupings [['loader'], ['component']].
3. See loader: lazyFn($$splitLoaderImporter, 'loader') in the route file and Unexpected splitNode type ☝️: ObjectExpression from the loader chunk.

A Vite dev server with tanstackRouter({ target: 'react', autoCodeSplitting: true, codeSplittingOptions: { defaultBehavior: [['loader'], ['component']] } }) gives the same output and the same error from server.transformRequest('/src/routes/index.tsx?tsr-split=loader').

Expected behavior

Only handler moves to the loader chunk, and the route file keeps the other options:

loader: {
  staleReloadMode: 'blocking',
  handler: lazyFn($$splitLoaderImporter, 'loader'),
},

A module-level binding read by both handler and another loader option should go to the ?tsr-shared=1 module, like any binding a split option shares with one that stays.

Screenshots or Videos

No response

Platform

• Router / Start Version: @tanstack/router-plugin 1.168.47; also on main (b1b1117)
• OS: macOS
• Browser: n/a (build time)
• Browser Version: n/a
• Bundler: vite
• Bundler Version: 8.3.4

Additional context

#8630 pins this as a known failure, and #8504 fixes it as part of the Yuku migration. I'll open a small fix for the current compiler. A loader object passed by reference (loader: loaderObject, the second pin in #8630) is a different case and not covered here.

AI disclosure: Claude Code wrote this report and the reproducer, and ran the reproducer against 1.168.47.