File based auto code splitting not working with vite on Windows

[kad5]

Which project does this relate to?

Router

Describe the bug

On vite + windows, the latest version of tanstack router doesn't split code component automatically when building.
This happens only on vite with windows. when testing on a linux machine, the splitting works correctly.

images for windows and linux builds for the same test repo

Your Example Website or App

https://stackblitz.com/~/github.com/kad5/test-ts-code-splitting

Steps to Reproduce the Bug or Issue

1. on Windows run "npx create-tsrouter-app@latest my-app --template file-router"
2. add some dummy routes
3. npm run build

Expected behavior

previous to the latest update, the chunks were correctly produced. Currently I have another repo that has:
"@tanstack/react-router": "^1.115.2",
"@tanstack/router-plugin": "^1.115.2",
"vite": "^6.2.0"

and it works on windows but the current version 1.121.2 doesn't split on windows with vite 6.

Screenshots or Videos

No response

Platform

• OS: Windows

Additional context

there was an old issue from 2024 that is similar to this
#2167

[schiller-manuel]

can you please provide full debug logs on windows ?
set the env var TSR_VITE_DEBUG=true

[kad5]

Yea. I'm not sure why the TSR_VITE_DEBUG is not working but I think the issue comes from this code block found in node_modules/@tanstack/router-plugin/dist/esm/core/router-code-splitter-plugin.js
not running correctly:

handler(code, id) {
          var _a;
          const generatorFileInfo = (_a = globalThis.TSR_ROUTES_BY_ID_MAP) == null ? void 0 : _a.get(id);
          if (generatorFileInfo && code.includes("createFileRoute(")) {
            for (const externalPlugin of bannedBeforeExternalPlugins) {
              if (!externalPlugin.frameworks.includes(framework)) {
                continue;
              }
              if (code.includes(externalPlugin.identifier)) {
                throw new FoundPluginInBeforeCode(externalPlugin, framework);
              }
            }
            return handleCompilingReferenceFile(code, id, generatorFileInfo);
          }
          return null;
        }
      },

the if statement is never accessed as the generatorFileInfo returns undefined. logging like this when adding:

handler(code, id) {
          var _a;
          const generatorFileInfo = (_a = globalThis.TSR_ROUTES_BY_ID_MAP) == null ? void 0 : _a.get(id);
          console.log("test1", "const:", generatorFileInfo, "id:", id )
          console.log(globalThis.TSR_ROUTES_BY_ID_MAP)
          for (const key of globalThis.TSR_ROUTES_BY_ID_MAP?.keys?.() || []) {
            console.log("ROUTE MAP KEY:", key);
          }
          if (generatorFileInfo && code.includes("createFileRoute(")) {
            console.log("test2")
            for (const externalPlugin of bannedBeforeExternalPlugins) {
              if (!externalPlugin.frameworks.includes(framework)) {
                continue;
              }
              if (code.includes(externalPlugin.identifier)) {
                throw new FoundPluginInBeforeCode(externalPlugin, framework);
              }
            }
            return handleCompilingReferenceFile(code, id, generatorFileInfo);
          }
          return null;
        }
      },

the logs (partly):

transforming (49) node_modules\@tanstack\router-core\dist\esm\link.jstest1 const: undefined id: C:/kad5/code repo/test/src/routes/index.tsx
Map(6) {
  'C:\\kad5\\code repo\\test\\src\\routes/__root.tsx' => { routePath: '/__root' },
  'C:\\kad5\\code repo\\test\\src\\routes/index.tsx' => { routePath: '/' },
  'C:\\kad5\\code repo\\test\\src\\routes\\r1/r11.tsx' => { routePath: '/r1/r11' },
  'C:\\kad5\\code repo\\test\\src\\routes\\r1/r12.tsx' => { routePath: '/r1/r12' },
  'C:\\kad5\\code repo\\test\\src\\routes\\r2/r21.tsx' => { routePath: '/r2/r21' },
  'C:\\kad5\\code repo\\test\\src\\routes\\r2/r22.tsx' => { routePath: '/r2/r22' }
}

the generatorFileInfo is undefined and whatever function is creating the map makes every slash doubled as shown on the map console log.

when adding this bit to overwrite the map, the splitting and the paths work correctly.

handler(code, id) {
          var _a;
          globalThis.TSR_ROUTES_BY_ID_MAP = new Map(
            Array.from(globalThis.TSR_ROUTES_BY_ID_MAP.entries()).map(([key, val]) => [
              key.replace(/\\/g, '/'), 
              val,
            ])
          )
// the rest of it 

the logs:

transforming (8) node_modules\react\cjs\react-jsx-runtime.production.jstest1 const: undefined id: C:/kad5/code repo/test/node_modules/@tanstack/react-router/dist/esm/fileRoute.js
Map(6) {
  'C:/kad5/code repo/test/src/routes/__root.tsx' => { routePath: '/__root' },
  'C:/kad5/code repo/test/src/routes/r1/r11.tsx' => { routePath: '/r1/r11' },
  'C:/kad5/code repo/test/src/routes/index.tsx' => { routePath: '/' },
  'C:/kad5/code repo/test/src/routes/r2/r21.tsx' => { routePath: '/r2/r21' },
  'C:/kad5/code repo/test/src/routes/r1/r12.tsx' => { routePath: '/r1/r12' },
  'C:/kad5/code repo/test/src/routes/r2/r22.tsx' => { routePath: '/r2/r22' }
}
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/__root.tsx
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/r1/r11.tsx
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/index.tsx
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/r2/r21.tsx
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/r1/r12.tsx
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/r2/r22.tsx
transforming (46) node_modules\react\index.jstest1 const: { routePath: '/r2/r22' } id: C:/kad5/code repo/test/src/routes/r2/r22.tsx
Map(6) {
  'C:/kad5/code repo/test/src/routes/__root.tsx' => { routePath: '/__root' },
  'C:/kad5/code repo/test/src/routes/r1/r11.tsx' => { routePath: '/r1/r11' },
  'C:/kad5/code repo/test/src/routes/index.tsx' => { routePath: '/' },
  'C:/kad5/code repo/test/src/routes/r2/r21.tsx' => { routePath: '/r2/r21' },
  'C:/kad5/code repo/test/src/routes/r1/r12.tsx' => { routePath: '/r1/r12' },
  'C:/kad5/code repo/test/src/routes/r2/r22.tsx' => { routePath: '/r2/r22' }
}
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/__root.tsx
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/r1/r11.tsx
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/index.tsx
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/r2/r21.tsx
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/r1/r12.tsx
ROUTE MAP KEY: C:/kad5/code repo/test/src/routes/r2/r22.tsx
test2

and the splitting works:

dist/index.html                   0.71 kB │ gzip:  0.39 kB
dist/assets/index-LgnS-FOG.css    0.78 kB │ gzip:  0.50 kB
dist/assets/r22-C4VElInc.js       0.37 kB │ gzip:  0.22 kB
dist/assets/r21-J63emIGh.js       0.37 kB │ gzip:  0.22 kB
dist/assets/r12-hCSPkXPB.js       0.37 kB │ gzip:  0.22 kB
dist/assets/r11-DiElQe_8.js       0.37 kB │ gzip:  0.22 kB
dist/assets/index-BYcz-SXK.js     0.55 kB │ gzip:  0.30 kB
dist/assets/index-BRHBb7H_.js   261.89 kB │ gzip: 83.69 kB

I think whatever function creating the map must be the culprit. hope that helps.

[schiller-manuel]

yep that helped a lot. we need to normalize the paths

[kad5]

no worries. sorry for all the code snippet edits 😄