Error starting the debug session TypeError: is_electron_1.default is not a function

[planger]

Bug Description:

The following error occurs when a debug session is started involving a debug adapter contributed by a VSCode plugin:

root ERROR Error starting the debug session TypeError: is_electron_1.default is not a function
    at Object.startDebugAdapter (/home/philip/Git/OpenSource/Theia/theia/packages/plugin-ext/lib/plugin/node/debug/plugin-debug-adapter-starter.js:44:48)
    at DebugExtImpl.<anonymous> (/home/philip/Git/OpenSource/Theia/theia/packages/plugin-ext/lib/plugin/node/debug/debug.js:725:82)
    at step (/home/philip/Git/OpenSource/Theia/theia/packages/plugin-ext/lib/plugin/node/debug/debug.js:33:23)
    at Object.next (/home/philip/Git/OpenSource/Theia/theia/packages/plugin-ext/lib/plugin/node/debug/debug.js:14:53)
    at fulfilled (/home/philip/Git/OpenSource/Theia/theia/packages/plugin-ext/lib/plugin/node/debug/debug.js:5:58)
    at processTicksAndRejections (internal/process/task_queues.js:97:5)

Steps to Reproduce:

1. Add the VSCode plug-in webfreak.debug, e.g. by adding
   "vscode-native-debug": "https://open-vsx.org/api/webfreak/debug/0.25.1/file/webfreak.debug-0.25.1.vsix"
   to the root package.json.
2. Run yarn download:plugins and yarn start:browser
3. Open the Theia browser app in a browser and create a launch config in .vscode/launch.json, such as

{
  "version": "0.2.0",
  "configurations": [
      {
          "name": "Debug",
          "type": "gdb",
          "request": "launch",
          "target": "./hello",
          "cwd": "${workspaceRoot}",
          "valuesFormatting": "parseText",
          "printCalls": true
      }
  ]
}

4. Go to the debug view in the Theia app and Start Debugging the launch config created above
5. The Theia app shows an error notification and prints the error above into the console

Additional Information

• Operating System: Ubuntu 20.04.2
• Theia Version: 1.15.0

Change that introduces the invocation of isElectron():
ab27299#diff-4cbce14389ca5434c2b22540901b6e30978a267684ca1f6636cb54221559f38b

[planger]

The is-electron package seems to incorrectly export the function isElectron as default in its released version 2.2.0. Their master branch includes a change that likely fixes this issue (cheton/is-electron#5) and / or Theia may require to set the esModuleInterop flag to true in its tsconfig.json. The is-electron fix is not yet released anyway even though there is a bug about it (cheton/is-electron#7).

@paul-marechal What do you think?

In the meantime we could use import the isElectron using require:

const isElectron = require('is-electron');

I'll open a PR with that change.

[paul-marechal]

If TypeScript allows us we could do import isElectron = require('is-electron');.

[planger]

If TypeScript allows us we could do import isElectron = require('is-electron');.

Unfortunately, TypeScript complains if I do that:

packages/plugin-ext/src/plugin/node/debug/plugin-debug-adapter-starter.ts:48:27 - error TS2349: This expression is not callable.
  Type 'typeof import("/home/philip/Git/OpenSource/Theia/theia/node_modules/is-electron/index")' has no call signatures.

48                 execArgv: isElectron()
                             ~~~~~~~~~~


Found 1 error.