Theia launched from Theia hangs on Windows [Electron] #11081

[jfaltermeier]

What it does

• Check existing environment for variants of the ElectronSecurityToken key on windows

fixes #11081

How to test

• Launch the Theia Electron Example on windows
• Inside the running example, open a workspace with a second clone of the Theia sources, build examples, and launch the Theia Electron Example
• The second electron application should start

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

[paul-marechal]

It seems that setting the key to uppercase fixes the issue on Windows, according to your change.

Ultimately it would be nice if we could understand why using uppercase works and lowercase doesn't, but let's just use uppercase.

theia/packages/core/src/electron-common/electron-token.ts

Line 23 in c6ac473

export const ElectronSecurityToken = 'x-theia-electron-token';

To:

/**
 * This token is unique to the current running instance. It is used by the backend
 * to make sure it is an electron browser window that is connecting to its services.
 *
 * The identifier is a string, which makes it usable as a key for cookies, environments, etc.
 */
// Note that it needs to be uppercase for it to work properly in Windows environments.
export const ElectronSecurityToken: string = 'THEIA_ELECTRON_TOKEN';

(I put the note as an inline comment to not pollute the public jsdoc with details)

[jfaltermeier]

Thanks, I will change it to upper case and update the PR. The information I found was this: https://nodejs.org/api/child_process.html

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On Windows, environment variables are case-insensitive. Node.js lexicographically sorts the env keys and uses the first one that case-insensitively matches. Only first (in lexicographic order) entry will be passed to the subprocess. This might lead to issues on Windows when passing objects to the env option that have multiple variants of the same key, such as PATH and Path.

---

I am not sure if there is a guarantee that windows always upper cases the keys, however nodejs will chose the upper-cased one in case there are multiple ones. So this should work.