Problem with Vite and symlinks

[probert94]

Description of the bug

In my current setup, I use symlinks for a vaadin project located on another drive.
Examle:
C:\Dev\VaadinProject -> The real project
D:\Dev\VaadinProject -> The symlink

In IntelliJ, I am using the symlink project located under D:\Dev\VaadinProject.
This setup worked fine until we updated to Vaadin 23 and started using Vite but now I get the following error:
com.vaadin.flow.server.ServiceException: java.net.ConnectException: Connection refused: no further information

It seems like the vite server started but stopped after an error, which is printed to the console:

TypeError: Cannot read properties of undefined (reading 'imports')
at runOptimizeDeps (file:///C:/Dev/VaadinProject/node_modules/vite/dist/node/chunks/dep-665b0112.js:42330:89)
at processTicksAndRejections (node:internal/process/task_queues:96:5)

After some debugging, I found that a resource should be loaded from D:\Dev\VaadinProject\fakt\node_modules and that does not seem to be allowed (missing in server.fs.allow).
The allowed folders come from the vite.generated.ts and are the following:

'D:\\Dev\\VaadinProject\\frontend',
'C:\\Dev\\VaadinProject\\target\\flow-frontend',
'C:\\Dev\\VaadinProject\\target\\frontend',
'C:\\Dev\\VaadinProject\\node_modules'

As you see, only frontend is allowed to be loaded from D:\, all other folders need to be loaded using C:\.
The reason for this seems to be, that __dirname, which is used to calculate the paths, already resolves the symlink (see nodejs/node#22602).
The first allowed path (frontendFolder) comes from settings.frontendFolder and is an absolute path, using D:\,
The other 3 are relativ paths (addonFrontendFolder from vaadin-dev-server-settings.json is target/flow-frontend) and are resolved using __dirname and therefor use the wrong path.

Minimal reproducible example

• Download a new vaadin starter project
• Create a symlink for it (on windows 10 use powershell and following command: ni D:\Dev\VaadinProject-i SymbolicLink -ta C:\Dev\VaadinProject\
• Start the project and open the browser

After the front-end is build, you get an error page instead of the application page.

Expected behavior

The application should start normaly.

Actual behavior

An error is shown

Versions:

- Vaadin / Flow version: 23.2.7
- Java version: Java 17.0.4
- OS version: Windows 10
- IDE (if applicable): IntelliJ Idea
- Development or production mode: Development mode

[Artur-]

Does it work when you add the folder to server.fs.allow in your vite.config.ts ?

[probert94]

Yes that seems to work.
I had to add all folders with C:\ and D:\ and start the server. After that it seems to be enough to allow all folders for D:\.
Might have been some caching problem...
Unfortunately this is not a solution, as there are multiple people working on this project and others might use different folder structure.

[Artur-]

If you do this on a mac

npx @vaadin/cli init test-proj
ln -s test-proj test-link
cd test-link
mvn

then all the entries of server.fs.allow point to the real project directory (test-proj) and all resources are also loaded from there so everything works.