fix: do not reject unknown schemes in WindowStateExt.asExternalUri

[AlexandraBuzila]

What it does

Fixes #12821

After testing the same workflow of the Gitlens extension in VS Code, I think URLs with unknown schemes were rejected prematurely in Theia.
When the Connect to Github action is triggered, the extension invokes two methods of the WindowStateExtImpl: first asExternalUri and at a later point openUri.

The parameter passed to the asExternalUri method is an URI of the form theia://... and the existing code rejects it.
In VS Code, the URI has an application specific schema as well (not http or https), but the code does not reject it. This allows the Github authentication to process the request and later on call the openUri method with a valid URI.

I modified the code and it now handles URIs similar to VS Code. This fixes the initial problem, which was reported for the gitlens extension, but I would love some feedback as I can't tell if this is generally safe for all extensions.

How to test

1. Install gitlens. I had to remove the vscode.git and vscode.github extensions from the excluded plugins list and removed the '@theia/git' package to make this work with the Theia examples.
2. Open an editor on a file in a github repo, for example theia itself.
3. When you hover at the end of a line, you get a hover that shows you information about the commit that last changed this line.
4. Scroll to the bottom of the hover
5. Observe: there is a link that says "Connect to Github".
6. Click the link
7. There's a popup that says "You have not yet finished authorizing this extension ...". Click 'Yes'.
8. Another popup shows up - click "Copy & Continue to Github".
9. A Github link should open in the browser.

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

Contributed on behalf of STMicroelectronics

[JonasHelming]

@AlexandraBuzila Is this ready for a re-review?

[tsmaeder]

The "Connect to Github..." workflow still does not work for me: when I invoke it, nothing happens and I get a dialog saying

Sie haben die Autorisierung dieser Erweiterung für die Verwendung von GitHub noch nicht abgeschlossen. Möchten Sie eine andere Methode ausprobieren? (Gerätecode)

I would expect to be redirected to the github authentication page.

[AlexandraBuzila]

I would expect to be redirected to the github authentication page.

Does the link open in the browser if you confirm that dialog?

I see now that the workflow in vscode looks different: you are asked to log in, while in theia you are asked to use another login method. I can check to see where the difference is coming from.

[JonasHelming]

@tsmaeder Opne question above :-)

[tsmaeder]

Does the link open in the browser if you confirm that dialog?

No

[tsmaeder]

After retesting, the login seems to work now.

[planger]

I'm very much looking forward to having this up and running.

So I tried with today's master, removed the git and github related extensions from theiaPluginsExcludeIds and tried the Github view as well as exactly the steps from this PR with Gitlens. When trying to connect to Github, I just received this though:

No browser window was opened. Do you have any suggestion @AlexandraBuzila? Thank you!

[AndKe]

Joining in as I too am very interested in this feature and I stop at the same issue as the post above.

[planger]

@AlexandraBuzila @tsmaeder Do you have feedback on the issue mentioned above? Should we re-open this issue?

[tsmaeder]

@AndKe how exactly is this failing for you? What's your setup for running Theia?

[AndKe]

@tsmaeder - I recieved good help from @planger to get this far: (so our methods are most likely more or less the same)

I started with copying my working plugins from vscode:
cp ~/.vscode/extensions/github.co* ~/.arduinoIDE/plugins
downloaded the .vsix from https://open-vsx.org/extension/vscode/github-authentication and copied it into .vsix file to the ~/.arduinoIDE/plugins
Then I started the arduino-ide_2.3.3-snapshot-de5b91f_Linux_64bit.AppImage

What I got was :

then clicked yes and got:

It may be worth mentioning that my copilot for vscode authentication also failed to spawn a browser window, like Arduino IDE fell back to alternative method.
PyCharm plugin, however authenticated perfectly smooth.

[tsmaeder]

@AndKe arduinoIDE is still on Theia release 1.41.0. The fix is not in that version.

[AndKe]

@tsmaeder are you saying that is should work in >= 1.41 ? / and where can I get that version?

[per1234]

@AndKe you must have forgotten the details of the discussion we had about this over on Arduino Forum. The "arduino-ide_2.3.3-snapshot-de5b91f_Linux_64bit.AppImage" you are using is a beta tester build of Arduino IDE with Theia version 1.46.1 (arduino/arduino-ide@de5b91f):

https://github.com/arduino/arduino-ide/actions/runs/8596568336#artifacts

[tsmaeder]

@AndKe as the PR was merged in Dec., it should be in 1.46.1.

I started with copying my working plugins from vscode:

This is not a good idea: when we download plugins, we select a version of the built-ins that works with that particular Theia version.

As for the gitlens example from the testing instructions, I don't even get the "Connect to Github" link anymore. Reopening.