FileService dies during execution

[BarryDrez]

I have a Theia extension that has been working perfectly fine with Theia 1.40.0. I recently upgraded to Theia 1.50.1, and the FileService.exists (@theia/filesystem/lib/browser/file-service) is causing my extension to crash without throwing any kind of exception. I went through all of the breaking changes since 1.40.0 and fixed a couple that were required.

Any ideas what this could be? Could there be a dependency I am missing or need to upgrade?

[dipliveweb]

Hello, Theia team,

I am following up on Barry's query. We are still having the same issue. We would appreciate any suggestions or pointers.

Thank you

[msujew]

What kind of crash are we talking about here? Does the error crash the whole tab/browser window?

Aside from that, I'm not aware of any breaking changes in that area of Theia. Do you have reproduction steps for the issue?

[BarryDrez]

@msujew I have an iframe for my JSE extension that I invoke from one of my parent pages outside of Theia. When the following line is executed:
if (await this.fileService.exists(URIofFileInMyWorkspace)) {

The iframe disappears, and throws me back to the parent page.

Nothing in my code has been changed in this area since I upgraded Theia. I did however upgrade to nodejs version 20 from 18.

[BarryDrez]

@msujew I have traced the problem to file-service.ts: FileService.doReadAsFileStream (line 955).
The error is: "Unable to resolve nonexistent file '/user/tasks.json'"

Any idea what this means?
It runs OK on Windows.

[msujew]

@BarryDrez I see, thanks. Looking into the code, we do something weird that might cause this error:

https://github.com/eclipse-theia/theia/blob/master/packages/filesystem/src/browser/file-service.ts#L972

Even though it shouldn't happen, there might be cases where a promise rejects before its await is hit and therefore results in an unhandled rejection error - however that should generally lead to an error in the console and not the whole frame crashing.

Nevertheless, vscode does something different there see this code which is a bit safer. A fix for this issue might attempt to do the same.

[BarryDrez]

@msujew Thank you! I tried removing @theia/task from my package.json since I don't need tasks, but that didn't help.

In the call stack, I can see that the problem stems from theia\packages\preferences\src\browser\abstract-resource-preference-provider.ts: AbstractResourcePreferenceProvider.readPreferencesFromFile Line 154.

const content = await this.fileService.read(this.toFileManager().getConfigUri())

[BarryDrez]

@msujew Are there any updates on this? Should I apply the fix that you suggest, or is someone else working on it?

[msujew]

@BarryDrez I don't think anyone else is working on this right now. Feel free to contribute a fix for this :)

[BarryDrez]

@msujew OK, thanks :) We will look into becoming contributors.

[BarryDrez]

Hi @msujew, we are still investigating this. It turns out that readFileUnbuffered is not being called in our scenario. The failure is happening in the Theia class:
theia\packages\filesystem\src\common\remote-file-system-provider.ts

In the stat function (line 216). When this.server.stat(resource.toString()); is called, the application just fails with no exception.

Is there anything we need to be aware of with RemoteFileSystemServer as far as upgrading from Theia 1.40 to 1.51 is concerned?

[BarryDrez]

@msujew - It turned out that the root of the problem was caused when upgrading from 1.40 - 1.52. We have some views that extend AbstractViewContribution. They were importing Widget from '@phosphor/widgets', and they have the withWidget functions. This is what was causing the error, but I do not understand why the problem manifested itself in remote-file-system-provider.ts.

We have changed the views to import Widget from '@theia/core/lib/browser'. This resolved the issue.

You may want to mention this in the relevant Breaking Changes.

[msujew]

@BarryDrez I'm confused on how a change in the frontend has the ability to literally crash the backend - this generally shouldn't be possible. However, it's good to hear that the issue has been resolved :)