Dynamic Virtual File Support in TypeScript 5.9.2 Causes Debug Failure

[cold juniper]

Hi TypeScript team,

I’m developing a custom TypeScript plugin and encountering a persistent Debug Failure in 5.9.2 when trying to provide virtual files. My goal is to dynamically supply temporary modules that don’t exist on disk so they can be imported and have default exports during editing in VSCode. I’ve tried overriding readFile, fileExists, and getScriptSnapshot on serverLanguageHost, but every approach triggers the same failure in _ProjectService.setDocument and getOrCreateSourceFileByPath. It seems tsserver doesn’t fully support fully dynamic virtual files in this version. Could you clarify if this is expected, or suggest a safe way to implement virtual modules dynamically within a plugin without causing Debug Failure?

[pulsar slate]

Hi,
Could you provide a bit more context, maybe some code snippets?
I know TypeScript VFS exists, maybe that is a helpfull resource https://www.typescriptlang.org/dev/typescript-vfs/

[cold juniper]

hi

i create a basic plugin like this

[cold juniper]

whenever I resolve a virtual file with resolveModuleNameLiterals it gives me the same error

for example
if the containing file is a ts or z file, check it. If there is no file with the name ts file, resolve it anyway.

everything is going well but it keeps giving this error

no matter what I do, no matter what I override from the host, it always gives this error

if I can figure this out or decide for sure whether it will happen or not, it would be great for me.

and

i think the library you suggested will not work for me, I am aiming to make a real-time plugin

[frigid cloud]

yes, this is expected tsserver 5.9.2 doesn't support fully dynamic virtual files, so the only safe option is to back tem with in memory scriptsnapshots exposed through getscriptfilenames

[cold juniper]

so, would it make sense to store dynamicly the virtual file name in resolvemodulenameliterals and then wait for getscriptfilenames to detect it? Or should I find a new way..

[frigid cloud]

you will need a new approach getscriptfilenames must already list the virtual files up front adding them later via resolvemodulenameliterals won't work reliably

[cold juniper]

I see, then it is definitely not supported at the moment