DevContainers: Support THEIA_DEFAULT_PLUGINS

[jonah-iden]

What it does

Fixes #14137

Adds support for copying and using plugins defined by local-dir through THEIA_DEFAULT_PLUGINS env variable

How to test

remove the "--plugins=local-dir:../../plugins" fro your start target,
set THEIA_DEFAULT_PLUGINS environment variable to "--plugins=local-dir:../../plugins".
reopen in any dev container. See that the plugins should be correctly applied

Follow-ups

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[sgraband]

@jonah-iden thanks for looking into this. Could you maybe explain a little bit more in detail on why you went with this approach?
As far as i can tell (but i am not too familiar with the code), we missed the plugin directories provided via THEIA_DEFAULT_PLUGINS before this change, right? Then this addition definately makes sense.
However, when an adoptor only provides the plugins via the cli and not via the env it will still not work, right? Because that was the original issue described in #14137.

[jonah-iden]

@sgraband could i have misunderstood the issue?
I thought the issue was that TheiaIDE did not correctly copy the plugins. That was because TheiaIDE is not using the commandline argument but instead is using the environment variable.
Using the command line variable still works fine and copies the plugins correctly as far as i tested. At least using theia ide with --plugins=local-dir... worked fine as well before this fix

[sgraband]

I actually thought that the Theia IDE sets the plugins via the cli param, and that the cli param did not work in a bundled environment. However i quickly checked and you are right. I will create a local build of the Theia IDE with your fix and check if it works 👍 Sorry for the confusion!

[sgraband]

I just tested it and i am afraid it still does not work in a packaged environment (local Theia IDE build with your changes).
The built-ins still do not show up correctly in the dev-container.
The main issue is, is that this is not really debuggable in the packaged application (at least there is no way that i know of).

[jonah-iden]

Thanks for testing. Do you know if in you test installation everything is bundled together into an asar archive?

[sgraband]

That should not be the case: https://github.com/eclipse-theia/theia-ide/blob/d2daf785498829593c46940f86720bb44cc3a284/applications/electron/electron-builder.yml#L10

[jonah-iden]

ok, are you sure you build the theiaIDE correctly. I just copied my lib/backend? folder build from the branch into my theia-ide installation resources/app/lib (renamed the old one). And it works fine for me with the copy

[sgraband]

I made a full local build of the theia ide following this: https://github.com/eclipse-theia/theia-ide/blob/jf/local-theia-build/local-theia-build.md. I can try it out again later on, but i am pretty sure i did not make a mistake.

Also note, that i am on ubuntu, maybe this makes a difference somehow?

[jonah-iden]

thanks i'll try to do a local build as well

[jonah-iden]

Sadly i can not get the local build to work even in wsl. Probably becuase docker is still running on windows and the dockerfile is build for unix.

[sgraband]

I just retested it with packaging the example electron app and everything works as intended. I think this is good to go. Should any issues arise when updating the Theia IDE to the next version i would investigate again on why this happens. I will create a reminder for myself.

Thanks for the improvement 🎉