move preload bits under Electron only

[paul-marechal]

The preload.js generated script is included in browser builds, this will cause issues for anyone trying to build a browser app.

This commit makes sure the Electron bits aren't used when building a browser app.

Closes #12490

How to test

There should be no mention of preload.js in the generated files for the browser (src-gen/* and gen-webpack.config.js).

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

[vince-fugnitto]

I've noticed some errors when attempting to start the electron application, the app is stuck on the loading screen:

Unable to load preload script: /home/vince/workspaces/theia-work/examples/electron/lib/preload.js

Error: Cannot find module '/home/vince/workspaces/theia-work/examples/electron/lib/preload.js'
    at Module._resolveFilename (VM123 loader:1002:15)
    at o._resolveFilename (VM158 renderer_init:2:3879)
    at Module._load (VM123 loader:848:27)
    at f._load (VM155 asar_bundle:2:13330)
    at o._load (VM158 renderer_init:2:3109)
    at VM158 renderer_init:2:33208
    at VM158 renderer_init:2:33334
    at ___electron_webpack_init__ (VM158 renderer_init:2:33338)
    at VM158 renderer_init:2:33461
    at BuiltinModule.compileForInternalLoader (VM10 loaders:331:7)
(anonymous) @ VM158 renderer_init:2

TypeError: Cannot read properties of undefined (reading 'getSecurityToken')
    at ContainerModule.registry (electron-token-frontend-module.ts:21:74)
    at __webpack_modules__.../../node_modules/inversify/lib/container/container.js.Container.load (container.ts:110:27)
    at index.js:107:1

[paul-marechal]

Fixed, wasn't expecting this.pck.ifElectron to not default to an empty string, turns out this.ifElectron does it.

[vince-fugnitto]

LGTM 👍

• the example-browser app works as expected (CI also successfully passes)
• the example-electron app works as expected
• a browser-only app referenced by file: no longer fails on build

[danepowell]

I see the deadline for the 1.38.0 milestone is May 25, more than two weeks from now. Since this fixes a critical regression in 1.37.0, could we please get a 1.37.1 release prior to then?

[vince-fugnitto]

@danepowell the patch v1.37.1 release was performed which fixes the regression 👍

[danepowell]

Awesome, thank you!

[tsmaeder]

@vince-fugnitto is this a release off master or is it branched off the 1.37 release with a "community-release" branch we can backport other fixes to? I was under the impression we don't do fix releases off master.

[vince-fugnitto]

@tsmaeder it's just a standard patch release that we've done in the past since the regression was brought up multiple times in discussions and issues. The release was performed branched off of https://github.com/eclipse-theia/theia/tree/release/1.37.0 and https://github.com/eclipse-theia/theia/tree/release/1.37.x was created (which includes the cherry-pick of 9f4ac12 and the release).

[tsmaeder]

@vince-fugnitto so this is the normal process we're using to patch community releases, right? And any further patches for the community release like in #12479 should go to the branch https://github.com/eclipse-theia/theia/tree/release/1.37.x, right?

[vince-fugnitto]

@tsmaeder it's just the normal process when doing any patch release not necessarily community one.
I think branching off of https://github.com/eclipse-theia/theia/tree/release/1.37.x (1.37.1) for the community release (will ultimately be 1.37.2) is fine yea.

[tsmaeder]

A community release is just a release designated as "community". So no branch off the existing branch 1.37.x require, IMO. Just as long as we branched off the 1.37.0 tag and not master. I put a topic in the community call to get everyone on the same page.

[vince-fugnitto]

@tsmaeder right it's definitely not, I only mentioned it since it seems to be a convention we followed in the past https://github.com/eclipse-theia/theia/tree/1.34-community-2023-02 (we have branches with -community- in them).